Guest Post by Willis Eschenbach
I keep reading these claims that we’re all going to starve because of global warming. People say it’s going to be the death of agriculture, that increasing temperatures will cause significant drops in crop yields. Here’s a typical bit of alarmism (emphasis mine):
A study by the International Food Policy Research Institute (IFPRI), indicates that climate change would hit developing countries the hardest, leading to massive decline in crop yields and production.
Whoa, a massive decline in crop yields due to increasing temperatures, sounds scary. So I thought I’d review the facts. Here is the global situation, showing the global yields of rice, corn, and wheat, along with the change in global temperature.
Figure 1. Changes in global grain yields and global temperatures 1961-2011. Data Sources: FAO, BEST, Photo
Now call me crazy, but what I see going on there is not a global crisis. Nor is it “massive declines”. Notice that (according to BEST) the global temperature has gone up one full degree centigrade … anyone remember any thermal crises that have resulted from that one degree of warming? Since two degrees is supposed to bring untold sorrows, where are the sorrows of one degree? Where is the lethal sea level rise? Where are the disasters? ¿Où sont les neiges d’antan? And most of all, where are the decreases in yield from that one degree of warming?
Of course, you could say that this is just because it’s a global average, and not all countries produce wheat, so we wouldn’t expect good agreement between global temperature and global grain production. And you might be right. So … here’s the same chart, only this time just for the US;
Figure 2. As in FIgure 1, except for the US rather than for the whole globe. BEST US temperature data.
Again, there is no thermal related decline in yields. According to BEST the US, like the globe, has gone up about a degree since 1960 … where are the climate refugees? Where are the corpses? Where are the thermal catastrophes? And more to the current point, where are the declines in food production? I don’t see them.
Finally, I thought “Well, maybe if I detrend all of the US data and then see how well related the change in annual temperature is to the change in annual crop yields” … no joy there either. Below are the measurements for those relationships. The strength of a relationship between two variables is measured by something called “R squared” (written “R2“), which varies from 0.0 for no relationship between the variables, up to 1.0 for perfectly related variables. Here’s the relationship of US temperature and US crop yields:
R2, US BEST Land Temperature and US Maize (corn) yield : 0.001
R2, US BEST Land Temperature and US Rice yield : 0.000
R2, US BEST Land Temperature and US Wheat yield : 0.022
In other words, no relationship at all. I gotta confess, I don’t see what folks are screaming about. If you believe the BEST data, we’ve seen a full degree of temperature rise in the last half century, and it hasn’t done us any harm—no atolls gone underwater, no millions of climate refugees, no increases in extreme weather. And through all of that temperature rise, the crop yields have kept going up. Will they reach a maximum? Assuredly they will … but it doesn’t seem like that maximum yield is going to be much affected by the temperature.
So I fear that once again we’ll have to postpone Paul Ehrlich’s celebration. He’s been predicting the global Malthusian food crisis for decades now, to no avail. Near as I can tell, according to the Malthusian philosophers like Ehrlich, the problem is that this continued increase in crop yields works in practice, but it doesn’t work in theory …
w.
Further Reading: I put up a post a while ago called “Border Transgressions“, about wheat production and temperature in Mexico. I also discussed how much food people actually have to eat in “I am so tired of Malthus“.
[UPDATE] Some people seem to have understood me as saying that because temperatures were rising and crop yields were rising as well, that the rising temperatures were causing the rising yields. I am not saying that. It may indeed be true that in a warmer world, the general yield would be better, and I see no reason it would not be better … but that’s not what I’m saying.
Some people seem to have understood me as saying that crops are not affected by temperatures above their optimum range. I am not saying that. All crops have preferred temperatures, above or below which they do not produce as well.
People are over-thinking this. What I am saying is simple. It is the answer to the question in the subject of the post—do increasing temperatures lower crop yields? I say no.
Note that I am not saying that increasing temperatures increase crop yields, although they may do so. Instead, I am falsifying the alarmists forecasting things like “massive drops” in crop yields. I’m not saying yields will or won’t go up if it gets warmer … I’m saying they won’t go down.
Here’s what lowers crop yields. Bad weather forecasts lower crop yields. If the farmer knows it will be colder next year, don’t worry, she’ll make money, she’ll plant later, use a different variety, plant beans instead of corn, get a bumper crop, be the envy of her neighbors. Same thing in reverse if she knows it will be hotter, she’ll plant early and have her crop in while the neighbors’ crops are wilting in the field.
But a bad forecast, she puts in hot weather seed and it turns out to be a cold year, the yield will go down.
So increasing temperatures, particularly predicted increasing temperatures, particularly predicted gradual increases over a century, will be lost in the noise of the thousands of changes that farmers do each and every year to account for the much larger interannual variations and interdecadal variations. Every year, the farmers successfully deal with the fact that not next century but next year may be two or three degrees warmer or cooler than this year … do you really think a degree’s rise spread over decades will affect those farmers’ crops? It’s lost in the noise, they’ve got three degrees to think about. Here’s the part that I think many folks don’t understand.
At the end of the day, crop yield is a measure of the farmers, not of the temperature.
In evidence of this, I offer the fact that the above analysis of the detrended US temperature data and detrended US crop yield data showed only an insignificant relationship between the two.
w.
[UPDATE 2] Someone downthread asked about the yields in the poorest countries. Here is that data.
As you can see, progress has been much slower in the developing world. However, even in the worst off countries on the planet, even with the warming of the last 50 years, the yields are still rising. And it is worth noting that the worst countries are all at or above the global average yield rates in 1961. In my lifetime, the poor of the world have moved to where the global average was when I was a kid …
And obviously, of course, at this end of the spectrum even the simplest of improved methods and seeds would double the yield … which is why temperature is not the issue, and never was.
But you’re using empirical data, Willis. We mustn’t forget that the models tell a different story (after all, they were made to) and that is why we must continue to be alarmed and wet our beds.
Well done Willis. I spotted another alarmist piece about heat effects on maize production by MET Office scientist Ed Hawkins and Leeds Earth Sciences Prof. Andy Challinor recently which had some obvious flaws:
It was written up in a Guardian piece entitled:
Global food crisis will worsen as heatwaves damage crops, research finds.
So I spoofed the title and wrote a quick review here:
http://tallbloke.wordpress.com/2013/01/14/global-scaremongering-will-worsen-as-revelations-damage-research-funds/
🙂
Willis: I love your posts. Here’s a question in the form of some thoughts, but please bear with me, maybe you can help answer or correct where I’m going.
I too do not believe an increase in temperature would lead to an overall reduction of plant growth. That’s too broad sweeping a statement from the left. However, I do believe temperature has an affect on the life cycle of plants and may shift growing climates around (more growth in upper latitudes etc. But I digress: My question: Is there a way to separate the causes for increased “production” of crops as related to: advances in agricultural science, demand for more food leads to more supply, subsidies to grow certain crops etc etc. In other words, isn’t some of the increase in crop production due to more farming?
But one more piece here is that has a significant affect on plant growth is available CO2. There seems to be good evidence that extra CO2 increases efficiency of plant growth, Given that CO2 (and H20) are the molecules that plants need for their energy storage –and that their mass (protein, carbs and fats) is made up primarily of these molecules that are essentially rearranged using the energy of the sun.
So, how can we separate temperature from the rest of this puzzle? Your answer would be especially interesting to me.
Around 1975 when AGW was just getting started, Australia’s CSIRO successfully persuaded the Western Australian government that they shouldn’t open up the lands to east of the Vermin Fence (called the Rabbit Proof Fence in the Eastern States) to agriculture, because declining rainfall due to climate change would make wheat growing not viable and would make wheat growing across the whole the Western Australian Wheatbelt less viable.
A couple of years ago I got into a debate on this forum from someone from CSIRO who claimed this was a successful prediction.
Since 1975 the value of WA wheat production has increase more than 5-fold, with no increase in area.
http://members.iinet.net.au/~rgcason/cropsv/wheatvxstait/wawheatvgraf.gif
Couldn’t find a graph for volume, but from memory it’s more than doubled.
I have another crazy idea: If temperatures become too high for a crop, farmers will change to a different one that’s better suited to higher temperatures. It won’t happen overnight, there will be time to adapt.
massive decline in crop yields due to increasing temperatures?
Obviously the fool that wrote that does not have a lawn,
Mow once in 3 months in winter, mow once every 3 days in spring.
Have to agree. It is so obvious that increasing temps lower crop yeild.
Just look at the proliferation of vegation at the poles compared to the equator.
Poles win every time
/sarc
Our plant geneticists have demonstrated a great capacity to adapt plants to areas they are not native to, and now they also have the added and speedier tool of GM technology at their disposal… So warming is the best case scenario, if there must be a change, as I am pretty sure they cannot possibly breed plants to thrive in frozen ground.
Some (really simple!) geography …
The ends of the planet are currently permanently frozen and completely unproductive.
The ‘middle’ of the planet is currently warm, and mostly highly productive.
At the worst a shift towards a warmer world may (possibly, but not certainly) make some warm lands unproductive, but must make some frozen lands productive. (ie, we are buffered).
But, a shift to a colder world would only make the frozen ends bigger, with no possible compensatory buffering effect ….
Stupid they are not more not less.
In Holland there are lots of glass boxes were they grow plants, in those boxes its hot and often there is a lot of CO2 up and over 1000 ppm and there is plenty of light.
They do that for an better grow d of the crop and you now that they call it greenhouses? You bet scientist who call CO2 a pollutant greenhouse gas don’t even now what a greenhouse is.
And then they don’t even now what happened in the years long gone when there was a climate optimum.
Sometimes I even wonder how they came to the 2 degrees to be the maximum the temperature may rice.
Higher temperature more CO2 and more water vapor make it only better.
tallbloke says:
January 31, 2013 at 12:35 am
That’s great stuff, Rog. I find their claim that warm temps in France are a huge danger to French maize production to be trez bizarre, particularly given the following:
France
isn’t evenhas warmed about a degree, according to BEST, yields continue to rise, and your author is all atwitter … you were right to skewer him.I just don’t see how there’s anything to support any “global food crises” in there, but hey, what do I know? I was born yesterday …
All the best,
w.
So called green house gasses make a hugh difference.
CO2 – Plant food – bring it on
H2O – Add this – the rest is insignificant
The two primary considerations when growing plants and things are: frosts and water. I don’t recall temperature being one. Whenever it gets hot that would indicate plants need more water and if you don’t get the water right the plants die. I don’t suppose those who wish to draw the conclusion that higher temps lower yield have done any gardening or farming, in other words, get their hands dirty?
I wonder whether Wills, it is important measuring yields versus temperature, because it has been shown in a number of papers that temperatures in the Californian and Australian small country towns have not risen as much as in the large cities, if at all.
As I revealed in a previous blog, the temperatures in our tomato growing area of Echuca have actually gone down slightly. Since 1984, our tomato yields have increased three fold, mainly due to better hybrid varieties, better irrigation using underground drip, better fertigation using this drip technology, and better management techniques.
Willis believes that these increases must reduce at some time in the future, but work on soil microbes will continue to produce enormous yield increases.
It might be worthwhile looking at yield versus CO2, but CO2 has not increased threefold since 1984.
Regards, Ian
Here’s an even crazier idea. Scientists will continue breeding crop varieties that have better yields in warmer/colder/unchanging climatic conditions.
Agriculture has adapted for thousands of years to meet the needs of changing climates since neolithic times. We currently grow crops across many climates, from cold wet Wales to hot and dry California. I cannot for the life of me see how we cannot adapt to a changing climate as we have done for millennia. We may lose the potential for crops in one area, but gain in another. The change in numbers of bird species in the UK is good example of nature adapting, I’m sure we will do the same. I must admit though, going back to growing traditional Welsh crops like Cabbages, Leeks and root crops on our land works fine, but I do miss growing our own Sweetcorn, French beans and crops more suited to warmer climes. The Met office promised us a warmer and drier climate, we looked forward to being able to grow wonderful crops. In the event it got colder and wetter. We are deeply disappointed.
They say the Sahara was Savannah 6,000 years ago, was that because the rain patterns changed?
I also heard some statistic that Africa has something like 60% of the Worlds arable land, which really surprised me.
Willis Eschenbach says:
January 31, 2013 at 1:13 am
[…]
Thanks Willis.
Their premise seems to be that ‘hot days’ damage the crop, and AGW means there will be more of them. They don’t stop to consider than less frosty days might help even more than hot days hinder though…
But the main flaw is their naive belief in the claims of the fertiliser, pesticide, tractor and seed companies that the increased yields are all down to their products.
Sure, modern methods make for bigger yields, but longer sunshine hours have a lot to do with it too…
Here’s another amusing one for you to check out, Willis. The migratory birds are arriving 4 days earlier, so a wildlife corridor must be set up to save them from climate change or something. 20 years of research too. West Australian Science once again/sarc: http://pindanpost.com/2013/01/31/tell-that-to-the-birds/
Wouldn’t a rise in temperature improve food production further North and South of the Equater? And do recent years’ food production figures take account of the huge areas of land taken out of food production for bio fuel purposes?
Willis, This is 2009 stuff.
They say the areas to be hit the hardest are in the developing world.
Can you bring data from Sahara, Africa, India and such?
To Ian: I think Willis’ point is this: Just looking at the evidence, shows that the claim that higher temperatures will reduce crop yields is unsubstantiated. It’s to me no different than saying living naturally will lead to a longer healthier life… when in fact the life expectancy of people living in civilization live longer than people living in the wild. Willis’ point is right on, I think.
Excellent work Willis … simple common sense tells us warmer temps and increased CO2 are generally beneficial to plant growth – and you show that in the simplest terms.
True as tallbloke notes – some of the gains are an increase in productivity through science, but it seems pretty clear that all things factored crop production is benefited by warmth and CO2.
When we dip back into the inevitable, and looming, descent into the next glacial cold cycle we will want and need all the crop production we can get.
.
In answer to the title question, wouldn’t that depend on the starting point?
I mean, the Prairie Provinces in Canada could easily benefit from a 5-10C rise in temperature for production of almost everything we grow. Can’t say the same would benefit wheat or corn producers in Texas.
Good job again Willis! You might check out AgPHD.com
Those Hefty boys are kind of smart!
Alfred
Another piece of common sense, thanks.
Anyone with half a brain can see that warmer is better as far as food crops are concerned. I do not care about biofuel crops they can die in the fields and let the food prices revert to the level that is affordable to the developing world.
This is a situation where averages tell us nothing. Critical events at specific stages of crop development can have a major impact on crop yield. e.g. heat wave during flowering, frost during grainfill, high temperatures during grainfill leading to premature senescence of leaves that provide carbohydrates for grainfill. For winter cereals, high temperatures during stem elongation can accelerate crop development and restrict amount of tillering leading to a constraint on grain production even when more favourable conditions return.
Bottom line is that average temperatures do not necessarily tell us whether the frequency of these “adverse” events is increased or indeed whether these are coincident with critical stages of crop development.
Therefore a more useful metric would be to plot frequency and severity of frost days during flowering, incidence of “heatwave” conditions at stem elongation, flowering (taselling in maize), and grain fill in cereals. Even then, this does not take into account the impact of management practices which allow for a spread of flowering dates (reducing exposure to single extreme events), varietal selection, nutrient management.
The tendency to look at a headline number for temperature is pretty useless as many commenters have pointed out the upward trend in crop yields.
Good post, as always.
You might have noticed that this issue featured in the Stern report which cited a study showing how yields of typical temperate crops declined at higher temps. That was debunked when it was revealed that the study had subjected the crops to constant high temps – as if it stayed at or above 30 degC 24/7.
On the related topic of keeping people alive, I was disappointed but not surprised to note the lack of media clamour over a statement by Bill Gates in a BBC address. He stated that, in his lifetime, the number of children dying before reaching 5 years old has dropped from around 20m per year to 5m. (I would add that is against a background of population growth). While there is a long way to go, that is huge progress which deserves banner headlines.
Nice article.
3 simple points:
1) Plants mature according to ‘degree days’. How many days ABOVE a certain minimum and how many degrees above. For most plants, more degree days is better up to a very high temperature.
2) Phoenix Arizona. How high that ‘very high point’ is can be found by looking at ‘grow season dates’ in the Sunset Garden Book. Only one place has a ‘poor growth’ band in summer. That is Phoenix Arizona. Even then, in exchange, you get growth in all THREE other seasons, so a total longer growing season. So until everywhere is as hot as Phoenix, no worries. (Oh, and in summer they still grow things, just more heat tolerant plants like tomatoes).
3) What you grow matters. Barley grows in Alaska. Oats sprout at 34 F just a hair above freezing. On the other end, Millet grows in the Sahara just on the edge of the sandy bits and tepary beans grow in the Mojave (about as hot as Phoenix, but not irrigated…). So it’s as much what you choose to grow as any given heat level.
Oh, and water maters a whole lot more than heat….
More details here:
http://chiefio.wordpress.com/2013/01/11/grains-and-why-food-will-stay-plentiful/
“Where are the snows of yesteryear?”
They’ll be back.
As an old and now retired farmer, one who was very interested in and mixed up in agricultural research for many years, we have a much, much greater danger from whack job city politicians and bureaucrats reducing their support and funding for agricultural research because they are out ,of money due to it all being spent on non visible climate warming research and the massive subsidies for hot air mitigation and going to the wealthy city scammers with their completely useless and inefficient so called renewable wind and solar power generators.
And no doubt they will take the attitude that there is plenty of food so we can cut back on agricultural research
And I don’t mean agricultural subsidies which to all intents and purposes don’t exist in Australia at all.
Australian farmers depending on the type of crop, put in 1% of their gross income each year towards research which is matched by the federal government.
This is distributed in grants to Ag researchers.
State governments generally support the various Agricultural research institute’s basic infrastructure and salaried researchers and support staff.
Through the Gene mapping and now the very rapid ability to access the various genetic specifications of plant material via the internet and genetic sources of plant material in the seed banks of a surprising number of countries around the world, the world’s plant and crop breeders can rapidly sort through their needs in genetic material, locate as to where some of this material might be stored in the 40C below zero vaults of the various international seed banks and get usually only 2 or 3 seeds posted to them within days so that the new material can be incorporated into the new season’s plant crosses.
From those crosses will come in perhaps ten years time after selecting from perhaps as many as 15,000 initial plant crosses, a new variety might emerge for farm commercial production to finish up somewhere on the plate of the consumer in a form they will never recognise as coming from a plant, let alone from a seed used to grow a single plant some ten or more years ago, a single seed that came from somewhere half a world away.
The curators of these global seed banks all know one another very well and the interchange of plant genetic material goes on by devious channels even through low level conflicts between nations. Like all agricultural researchers, there is a deep knowledge that if they let their international system of swapping genetic material and information and technology fall apart then all nations will eventually suffer as genetically controllable diseases become uncontrollable due to the lack of access to genetic material which would have natural resistant genes to those plant diseases and which a transfer of perhaps 2 or 3 seeds with natural resistance to that disease / insect / fungal pathogen and etc from a national seed bank of one country to the plant breeders of another country where the problem has arisen, would lead to resistance being incorporated into new crop plant material within perhaps some 5 to 7 years.
And the devastating crop losses would be almost halted from that disease or even the ability to again grow the crop would be re-established .
Exactly the situation here in Australia in the mid 1990’s with our chick pea industry when a highly virulent fungal pathogen developed through a genetic shift of the fungal pathogen and the growing of chick peas almost ceased until the plant breeders using overseas plant genetic material, bred full resistance to that pathogen back into the new generation of chick pea plant material.
We have far, far more fear of stupid politicians and bureaucrats interfering and stopping funding for that quiet, absolutely essential to future world food supply, international plant and genetic material swapping system than we will ever have from a degree or so change or shift in the temperature of the local climate.
A shift that occurs in any case with every individual and different in climate season and usually by much more than a degree.
Well, Willis, as you are surely aware, the alarmist claim is about the catastrophes that they reckon will occur in the future, just as soon as the temperatures get stoked up a bit. So while I share your view that it is all nonsense, your logic will have no effect on such a mindset.
@markx:
Generally, yes, the ‘first frost date’ determines the end of the growing season. However… for only minor cold / frost there are a few plants folks can grow. Spanish Winter radishes, turnips, kale (that can be harvested from under snow!) all come to mind. The rate of growth is still temperature proportionate, so faster when warmer….
Don’t really need to GMO or develop any more heat tolerant plants. They are fine up to about 110 F for most things. Since most of the planet will get nowhere near that temperature, simply shifting plant types a bit north will cover most anything possible.
Since most ‘warming’ is not higher highs, but higher lows, warming is pretty much universally a benefit.
@Julian in Wales:
It was Savanna because at higher temperatures, the rising air pulled water laden winds inland, and rained more.
http://chiefio.wordpress.com/2010/08/10/cold-dry-sahara-hot-wet-savanna/
IFF the world really warms (which I sorely doubt) the Sahara becomes one giant garden…
Look on a Globe. Look at the size of the USA, and Brazil. Look at the part of Africa not a desert… I think that 60% is way off… I think you are echoing this quote, but without the modifiers and caveats:
http://blogs.worldwatch.org/nourishingtheplanet/the-fertile-continent-agriculture%E2%80%99s-final-frontier/
@george Lawson:
Yes. Effectively, everything cooler than Phoenix Arizona ( I was there one day when the shut down the airport as the tarmac was melting in the sun… 128 F or so in the shade… and there’s no shade…) will gain growing days until they have a full 4 season growing window. Then the summers start to be limited to ‘hot temperature crops’ as they warm to match Phoenix.
That means the 45 and 60 day growing periods of the “Frozen North” have about 300 growing days to add (and about 2 or 3 more crops per year…) before it’s an issue. Now look at how big the land is in Russia, China, Mongolia, Canada, Alaska, …
@Code Tech:
Look at south slightly west Texas. More sorghum, less corn. As Texas gets hotter, (and dryer) they shift to sorghum (or millet) at similar yields. (Though AGW theory says we ought to be warmer and wetter… for that, look at Brazil with spectacular growth of corn and soybeans…)
isn’t this testable? Setup 2 greenhouses, one with higher CO2 and higher temps and no fertilizer, the other with lower CO2 levels and lower temps and all the fertilizer they want. Keep H2O the same.
Wouldn’t this be an appropriate test?
@ Eyal Porat
Data is a little older, but interesting.
http://www.nationmaster.com/graph/agr_cro_pro_ind-agriculture-crop-production-index
“Crop production index shows agricultural production for each year relative to the base period 1999-2001. It includes all crops except fodder crops. Regional and income group aggregates for the FAO’s production indexes are calculated from the underlying values in international dollars, normalized to the base period 1999-2001. “
Plucking a few:
# 2 Morocco: 148.6 % 2004
# 13 Algeria: 128.4 % 2004
# 25 Ghana: 121.2 % 2004
# 30 Angola: 119.2 % 2004
# 38 Chad: 115.7 % 2004
# 41 Maldives: 115 % 2004
[must be a lot of underwater agriculture]
# 50 Rwanda: 113.1 % 2004
# 50 Botswana: 113.1 % 2004
# 58 United States: 111.3 % 2004
# 182 United Arab Emirates: 57.4 % 2004
Developing countries??? I thought most of the warming would be felt as you moved towards the poles??? Anyway, I digress.
What is the result after the recent global temperature rise, hottest decade on the record with highest levels of atmospheric co2 in 800,000 years?
The biosphere has been greening as well as the Sahel & Sahara I wonder why?
It’s always the bad things they promote and avert their eyes at the good things about global warming such as an expansion of food growing areas northwards and the introduction of crops which used to grow further south.
Now let’s look at the effect of far higher temperatures and levels of Co2 than we have today in a poor, third world country.
Just my 2 cents.
An attempt at humor here (I, retired, have quit my day job). Is there any chance this whole kerfuffle is due ab initio to misreading greenhouse glasses as greenhouse gasses, a simple typographic error?
Yes, our local greenthumbs use coldframes and de facto greenhouses. Mine, a legacy of my greenthumb builder/owner is about 50 sq. feet, head-high, and made of plastic scrap. We have also a triangular room, that squares up an odd angle, with a window, and a 500 Watt strip heater where he started tomato seedlings. He also transplanted native Cypripedioideae, Lady’s slipper orchids!
Back to climate change; our builder/owner sailed the Great Lakes when he was sixteen years old – evidenced by his AB Seaman’s Card that I found while cleaning. Now Lake Michigan is at a historical low level. Our ferry company has put an alternative deeper water dock in service.
There are two measuring devices that I believe could provide meaningful drought/climate change data were they formally distributed and operated; (non-weighing) lysimeters and pan evaporators.
The general reduction in pan evaporation rates may be evidence of solar and/or global dimming.
ROM says: January 31, 2013 at 3:24 am
“……. we have a much, much greater danger from whack job city politicians and bureaucrats reducing their support and funding for agricultural research because they are out ,of money due to it all being spent on non visible climate warming research and the massive subsidies for hot air mitigation and going to the wealthy city scammers with their completely useless and inefficient so called renewable wind and solar power generators. And no doubt they will take the attitude that there is plenty of food so we can cut back on agricultural research…”
Truly well said ROM …. Agricultural research funding seems to get cut back every year, but the success stories are everywhere … these are the people who are the saviours of humanity!
(Sorry to disappoint Michael Mann and James Hansen, that title is not reserved for you, though you will be held up to students in the future as a laughable example of how policy and noble cause corruption can hijack science).
A study by the International Food Policy Research Institute (IFPRI), indicates that climate change would hit developing countries the hardest, leading to massive decline in crop yields and production.
Whoa, a massive decline in crop yields due to increasing temperatures, sounds scary
In this note they do the crafty “climate change” meme. So no temperature increase there then ?
Also, the big problem in recent years in france has been the droughts. Rainfall has been below average for maybe 10 years BUT that is now changing. I have found that if I can get enough water for my legumes they grow very well indeed with average temps 5°C higher than the southern UK.. The comparison is with the UK where, with temperatures lower and rainfall higher the crops still don’t grow as well as here in france with less water.
We grow corn in Canada…and corn in Florida
…tomatoes in Alaska….and tomatoes in Mexico
beans in Siberia…and beans in Cuba
…where are these delicate crops these scientists keep finding
cRR Kampen says:
“climate change just dropped your economy into contraction”
1:
http://www.ft.com/cms/s/0/32ca94f2-6ae1-11e2-9670-00144feab49a.html#axzz2JYYaCnTZ
2:
Sandy wasn’t caused by climate change.
http://wattsupwiththat.com/2012/11/05/an-inconvenient-truth-sea-surface-temperature-anomalies-along-sandys-track-havent-warmed-in-70-years/
cRR Kampen says: January 31, 2013 at 3:57 am
“..the disaster? Check it out: http://www.barchart.com/commodityfutures/Grains .
Learn what a factor of three means, start with corn and remember last year’s cattle slaughter worldwide….”
Sorry, you will have to be a little more specific regarding your meaning …. are you trying to point out that putting 40% of the US crop into biofuels is affecting prices? Or that futures fluctuate on every report, weather and financial? Forgive me if I am a little slow, I last traded agricultural commodity futures about 12 years ago…
“…O and climate change just dropped your economy into contraction….” ….
…and here you point to an article on the effects of the storm ‘Sandy’…??!!
Hang on, do you hold the position that storm was purely the result of climate change? Even Trenberth noted that even he could attribute only a few percent of the effect to warming to date, being more of the opinion that this was just an indicator of things to come… (but, lets give him the benefit of the doubt and say the storm WAS 5% worse due to climate change…lets see, if the economy slowed down 0.4% and the climate change contribution was 5% of that, then I guess we MAY have seen a climate induced effect of 0.02% on the economy).
As our paper on French maize has been mentioned, I thought I had better comment briefly:
1) For those in doubt about whether hot daily maximum temperatures reduce yields, then have a look at 2003 in Europe. The hottest (and presumably sunniest) summer ever in France, and maize yields went down 20% on the year before.
2) It is not average temperature that matters. Studies in laboratory environments have shown there are temperature thresholds beyond which crops start suffering. Also, an increase in average temperature = a change in the number of extremes.
3) Maize yields have increased (by a factor of ~4) over the past 50 years because we have become better at growing crops, better irrigation (as discussed in our analysis) etc – technology has played a a large part in this, and long may it continue. But, that yield trend has slowed.
4) CO2 is plant food, but not so much for crops which use the C4 photosynthesis pathway, like maize – laboratory experiments demonstrate this. These details matter.
5) Our projection of a 0-12% drop in maize yields by 2016-2035 assuming no technology development is not exactly alarmist! It gives the crop breeders information they need.
6) I am not a ‘Met Office’ scientists as Rog has suggested – I am at the University of Reading.
The paper is available here for anyone that wants to read the whole study:
http://www.met.reading.ac.uk/~ed/home/hawkins_etal_2012_GCB.pdf
Ed.
The words are French, but the punctuation is Spanish!
The simple correlation of yields and temperature would not prove Willis’ point, because other factors also intervene, chiefly technological change (new crop varieties, new farming practices, geographical dispersion of crops, etc. More sophisticated methods are needed, but the general conclusion roughly coincides with Willis.
Crops (like maize) are not a homogeneous set of identical plants, from maize in the Highlands of Peru to maize in Iowa. There are a large number of varieties, and each variety has a large number of “cultivars” (lineages of plants). There are also some genetically modified varieties, besides ordinary selection by breeding. Each cultivar of a variety of a crop, in turn, may be cultivated in different manners (e.g. no tilling, limited tilling, traditional tilling; with or without fertilizer; with different amounts of fertilizer; with or without pesticides; on soils having a varied composition; etc.
Each cultivar, cultivated in a certain manner at a specific site, has an average yield that is a function of temperatures and precipitation. Not just annual temps or annual rainfall, but their distribution at key phases of the crop cycle. There is variation around that average yield, not only from year to year but from field to field, etc.
Each cultivar/variety/crop has thus a RANGE of climatic conditions (say, combinations of temp and rain at different stages of crop cycle) in which the average or expected yield is economically convenient at a certain market price for the output and for inputs. The same yield that makes maize unsuitable in Iowa would be perfectly acceptable in Oaxaca (Mexico), or for that matter, on either side of the US-Mexican border where vastly different yields of maize prevail.
Agriculture is unlike natural vegetation, because agriculture is itself an adaptation of human activities to natural conditions. Farmers plant crops suitable for their fields, and do so in a manner that is, to the best of their knowledge, the most adequate. Perhaps not the optimum, but the best they can do at the moment. And they adapt when conditions change, even in the short term (e.g. rain-fed farmers advance or delay the date of planting in relatively dry areas, depending on the rainfall they get in a particular year). In a longer term, other adaptive changes are introduced (new cultivars/varieties/crops, different farming practices, etc.).
Just as one cannot conceive of a plant not ‘responding’ physiologically to a changed climate, one cannot conceive of a farmer not ‘responding’ behaviorally to changes in environmental conditions. Her job as a farmer is precisely that: responding to changes in the environment.
Suppose that normal climate at a certain place gradually changes along 50 or 100 years. This would change the mean and distribution of expected yields of all cultivars in that area.
The most common way to ascertain the expected change in yields for a certain change in climate is to compute an agronomic ‘crop model’, making yield a function of all relevant variables. Once the “maize production function” is statistically obtained (for one or more cultivars at one or more sites), the analyst SIMULATES a change in climate by forcing the crop (on paper) to undergo a higher temperature or, say, a reduction in rainfall. The usual result, of course, is a reduction in yields, because the original cultivar or variety is perhaps no longer as suitable as it was before, especially because no change has been introduced (‘forced’) in farming practices, let alone the cultivar itself. Now, a few hundred miles South (or North, depending on your hemisphere) the crop has been planted for years in a warmer climate, only the cultivar or variety was different (slightly more adapted to warmer or drier or wetter or colder conditions). Once soil composition is considered, changing the cultivar or variety would ordinarily do the job (keep or increase the yield under the new climate, compared with the situation before). There is ample time to do that by trial and error along 50 or 100 years, involving three or four generations of farmers.
Besides the effect of changed temperature and rainfall, AGW is supposed to occur due to increased atmospheric concentrations of CO2. Now, as plants synthesize their tissue taking carbon from the atmosphere through photosynthesis, more CO2 means more photosynthesis, and ordinarily produces a rise in yield. In some crops (the A4 variety, including maize) the effect on yields is less important, but more CO2 has the curious effect of greatly reducing the plant’s water requirement (by reducing water loss in leaf stomata). According to various experiments, this factor alone may cause an increase of 20-40% in yields (in C3 plants like wheat) and/or a 20-50% reduction in water needs (in C4 plants like maize).
Warming in very hot areas (say the Sahel) and especially if at the same time they become drier, may suffer indeed a reduction in yields, not considering CO2 fertilization, and not considering farmer’s response, a reduction variously estimated from 0% to -40% in various studies. But at the same time, enormous amounts of land in temperate zones (say, in North America or Eurasia) would have an expansion of the no-frost period, and a general improvement of plant suitability. There would also be a large expansion of arable land as more land becomes suitable that previously wasn’t. The net effect is not easily ascertained. The best studies considering these factors (even if including them in an extremely conservative manner) do not foresee a very large net effect. The best evaluations come from so-called “integrated assessment” models (IAM) combining agronomic crop models, agro-ecological zones, soil maps, climatic models, and socio-economic models predicting behavior of people and economic/technological development (including displacement of crops to new areas, changes in crop mix and crop schedule, introduction of double cropping with short-cycle crops where the no-frost period expands, and so on). IAM studies have been mainly carried out at IIASA, the International Institute for Applied Systems Analysis, Laxenburg (Austria), by a team led by Dr Gunther Fischer. The global effects they have calculated are ordinarily based on the ‘worst’ climate scenarios, and often do not take account of all the factors (e.g. may not include new cultivated areas, or may assume a very small or no CO2 effect on plants), but in all cases, under a variety of models and scenarios, the effects are relatively small (say from +5 to -5% effect, to be observed on a FUTURE agricultural production that will be four or five times as large as it is today, due to modest improvements in agricultural practices, as farmers in developing countries catch up with existing technology, or allowing for some extent of technological progress in the meantime). The net effect on hunger is that by 2080 the percentage of humankind suffering hunger (now 12.5% according to FAO) will be reduced to about 1-6% depending on scenarios (figures below 5% as regarded by FAO as not significantly different from zero, due to the method used). The most recent IIASA study (Fischer 2011) can be found at:
FAO, 2011. Looking ahead in World Food and Agriculture: Perspectives to 2050. Edited by Piero Conforti. FAO, Rome. http://www.fao.org/docrep/014/i2280e/i2280e00.htm.
(Fischer’s study looks farther ahead to 2080, and is based on FAO very prudent projections of farm output, plus effects of climate, and also considering the effect of crop-based biofuels that are likely to be introduced according to current targets).
Sure; up to a point warmth can increase plant growth. But speaking practically?
The USA had its hottest year on record in 2012 (1). So following Willis’s logic, perhaps we should expect crop yields to be the best on record? Well in fact yields in almost all sectors—including livestock—saw significant reductions, with a consequent rise in prices (2).
In 2012 the UK had average temperatures which, using the same rationale, would suggest—if temperature were the-be-all-and-end-all—that we should have seen average crop yields. In fact, most likely because of increasing rainfall (3), year-on-year the UK’s agricultural yields are slowly falling (4).
So overall what does this tell us? Could it be that—speaking practically—while both are important, the optimum amount of water has a greater impact than the optimum temperature when it comes to agricultural production? The evidence suggests that due to climate change the unreliability of rainfall—with, at the extremes, an increase in both drought and flooding events—will be the greatest headache for farmers. (5)
So note the specific question Willis uses as the title for this post and beware any extrapolation to the suggestion, “climate change is good for us”. If in doubt, why not actually ask the question of a farmer?
References
1: http://www.climatewatch.noaa.gov/video/2012/the-making-of-the-hottest-year-on-record-usa-temperature-update
2: http://www.ers.usda.gov/topics/in-the-news/us-drought-2012-farm-and-food-impacts.aspx
3: http://www.metoffice.gov.uk/news/releases/archive/2013/2012-weather-statistics
4: http://www.thecropsite.com/reports/?category=87&id=1385
5: http://www.metoffice.gov.uk/climate-change/guide/impacts/food
Willis, in order to see what Alarmists see, you just need to have the reality-suppressing, fear-inducing Warm-O-Vision © goggles they wear. Not sure if they’re still available, but perhaps on ebay.
E.M.Smith, you replied to my admittedly brief comment with the obvious statement that in higher temperature areas it’s trivial to switch crops.
I guess the part I skipped out was that we could continue to grow the same crops as we do now if the temperatures were higher, since the Canadian Prairies aren’t exactly known for overall warmth. However, in areas that are already nearing the upper limits for a type of plant then sure, increasing temps could be a problem. And no, I don’t know the average temps in Texas or the exact tolerance of the kinds of wheat and corn we grow here, so maybe Texas wasn’t a great example.
Apparently the obvious thing missing in the original article is that people don’t just continue to blindly do the same things when conditions change, and making that assumption when attempting to project the results of “climate change”, whatever that means, is just stupid. It’s like saying that a monotonous, slow rise in sea level would be catastrophic when we KNOW that people won’t just sit and chew their nails watching it happen. Sea walls would be built, existing structures might be altered, future designs in the area would be adjusted.
Again, lower crop yields might be the result if people plant the same crops in the same place where climate is “changing”, and make no other changes to account for this alleged “change”. However, people are just not that stupid (with the possible exception of “climate scientists”…)
For God’s sake everyone. Plants hate additional CO2 and warmer climates, they told me so and I published it in a paper. Arctic ice! Radiative properties of CO2! Peer review!
P.S: Ultra-thunder-mega-super-hurricane Sandy!
P.P.S: Anyone can see that the tropics are all desert. Vegetation cannot exist in a warm, humid environment. Show me the peer-reviewed evidence that suggests otherwise! You can’t be bothered to find it? Then I’ve won the argument. You didn’t respond? Then I’ve won the argument. You did respond with the peer-reviewed evidence that suggests otherwise? Then I’ve won the argument. Why? Because of peer review, arctic ice, the radiative properties of CO2, and Ultra Thundercane Sandy. That’s all I ever need to say.
What’s that officer!? I was speeding!? Perhaps you can point to where in the peer-reviewed literature it says I was speeding!? I wasn’t speeding, so just tear that ticket up. I can prove I wasn’t speeding because of peer review, arctic ice…well, you get the point.
–
markx says:
January 31, 2013 at 4:47 am
“Hang on, do you hold the position that storm was purely the result of climate change?”
–
Of course. Track with abrubt left turn by way of highly anomolous blocking high during and because of the Arctic sea ice minimum.
Tremendous intensification into the most energetic system the planet ever saw to measure, by crossing the axis of a record warm Gulf Stream.
It’s not hard to understand, but then I have something that is even easier to see: one swallow does not make summer, so a trillion swallows must mean Ice Age 🙂 Same logic gives Queensland, AUS, a flood of the century every year.
So well, Sandy just rinsed four thousand billion $ into the Atlantic. If you just kept up your dykes according to sea level rise for a tiny fraction of that cost, you know, you could still afford the luxury of climate revisionism. Now you guys are not just on borrowed money, you are operating on ruins.
As for the droughts hitting crops all over the world, biofuels won’t grow in droughts, like corn won’t. So maybe you really should start investing in biofuels 😉
/cRR
Most farmers are smart enough to grow crops suited to the prevailing conditions. As climate changes, in whichever direction, they will make the choices which make them the best returns.
I appreciated Mr. Hawkins’ adhockery, but the Procrustean narrative fallacy holds on public forums as well as in academia. Make your case and reserve argument (means defense) for peers’ reviewed literature (read the final clause closely).
“No adhockery. Bruno de Finetti coined the term “adhockery” to describe the profusion of frequentist methods.(http://www.johndcook.com/blog/2009/04/07/four-pillars-of-bayesian-statistics/)”
John Russell
seasonal weather variability would affect crops, normally causing a reduction in yields if the crops are already adapted to the historical average climate of the area and the year is beyond the ordinary range of fluctuation. Thus, if in a certain year you have extreme heat or a drought, the yields will be lower. In other years, with better weather, you’d get a bumper crop.
But this is not an effect of ‘climate change’. Climate change is a gradual change in the average climatic conditions, occurring over a number of decades and several generations. This involves also a gradual adjustment of plants, animals and farmers to the new conditions. Just as farmers in the past have adopted the most suitable crops, varieties, cultivars (or livestock breeds) and farming techniques for their particular farms, so would do their children and grandchildren (or the buyers of their farms if they decide to sell at some point) as the climate gradually changes amidst the endless year-yo-year weather fluctuations.
The main point here, I think, is to reckon that (as regards impact of climate change) agriculture is itself an adaptive activity of humans, not a natural system (as are, for instance, rainforests or ice caps). One cannot define or analyze future agriculture based only on the physiological response of plants: one should necessarily include the spontaneous response of farmers, and the exogenous progress and diffusion or agricultural technology. And one should also distinguish between a sudden jump in temperature or rainfall, either occurring in reality or simulated into a model, and a gradual change of average climate over 50-100 years.
Apols to Ed Hawkins for getting his affiliation wrong. I thought he was Reading Uni and MET Office.I know they work closely together anyway.
cRR Kampen says:
January 31, 2013 at 3:57 am
“O and climate change just dropped your economy into contraction…”
You are partially correct – O (aka Obama) DID cause our economy to contract (big time). Climate change…not so much. 🙂
Graham W says:
January 31, 2013 at 5:21 am
“P.S: Ultra-thunder-mega-super-hurricane Sandy!”
Remember those halcyon days back in the 60s when the climate was “normal” and our climate science geniuses were “turning on, tuning in and dropping out” at their liberal colleges? They NEVER had any bad storms back then, NEVER…
http://en.wikipedia.org/wiki/Hurricane_Camille
Willis,
This is the very first time I think you have overlooked something significant in your audits. In keeping with your excellent track record we must be careful to remain true to accuracy or else we risk opening ourselves up to questions of integrity. I’m not going to make a counter claim here but I would ask you to consider that U.S. agriculture is “Industrial Agriculture” which has benefited the most in the time frame you represented from advances in sustainable agriculture. On the flip side developing nations are primarily “Traditional Agriculture” which is well behind countries like the U.S. in areas such as soil conservation, pest control, etc. In short, our production has increased through knowledge and technology at a rate that climate variabilty either way cannot keep up with. It is true that climate warming or cooling could potentially and negatively affect crop yields worldwide. This would be more visible in developing countries. Still, the claims you respond to are alarmist in nature because temperature variability is only one aspect of cause. Shifting rain and wind patterns are due to ocean heat content (solar activity) are more likely to affect crop yields as they might limit irrigation and thus accelerate soil errosion issues in some areas while offering a net gain to others.
To Ed Hawkins:
Thanks for coming to defend your paper. One of your points have been raised by
others, e.g., there are temperature thresholds beyond which crops begin suffering.
Beyond that, you mention that 2003 was the hottest year in France and maize yields
went down by circa 20%. What was the rain situation that year?
Again, thank you for coming.
Did the study perhaps use Zimbabwe as the agricultural proxy for the rest of the world? Boy have they been hit hard by climate change (/sarc).
So much garbage in those claims; it’s hard to know where to start.
In addition to many available adaptive strategies (develop/use better adapted graine varieties), keep in mind that yield in the field does not feed people in the cities; bulk transportation infrastructure is required. Crop disruption due to floods, draughts, storms., etc. are regional events. In pre-industrial times they would also be regional disasters. Now we can transport sufficient food from unaffected areas to make up the regional shortfall. That is of course assuming we can continue to burn fuel to power the trucks, trains and ships.
To Chris R:
Good question – 2003 had lower than average rainfall, but not extremely low – 1962, 1964, 1986 & 2005 were all lower in rainfall for the maize growing regions. See Figure 2 in the PDF I linked to. Also, as irrigation has increased since the 1960s the sensitivity of yields to rainfall has reduced (Figure 4). In summary, both temperature and precipitation are important, but for 2003 it was predominantly the heat.
Ed.
Ed Hawkins says:
January 31, 2013 at 4:58 am
5) Our projection of a 0-12% drop in maize yields by 2016-2035 assuming no technology development is not exactly alarmist!
Props to Ed for commenting here at WUWT.
In the Guardian article linked on my blog, Ed says this:
“Our research rings alarm bells for future food security”
And his co-author Andy Challinor says this:
Supplies of the major food crops could be at risk unless we plan for future climates.
So if the paper only worries to a 0-12% extent, why make statements like these through major newspapers and scare the public?
1) For those in doubt about whether hot daily maximum temperatures reduce yields, then have a look at 2003 in Europe. The hottest (and presumably sunniest) summer ever in France, and maize yields went down 20% on the year before
Wrong on most counts. 2003 was no the hottest ever ever ever in france but it was very dry as most years have been since 2002. Watering of crops was banned in many important areas because rivers ran dry. Rivers like the Charente, Dordogne, l’isle etc. You need to do more research on science instead of funding.
My crops here have been very good not because it’s been cold but because it has been hot and I have been able to irrigate.
So gardeners and veg producers have been wasting their time and money all these years building green houses. Someone should tell them the new science “consensus” has dispelled this centuries old myth.
ROM has hit the nail on the head for a vast array of modern problems
“much greater danger from whack job city politicians and bureaucrats”
An interesting counterpoint to Ed Hawkins paper:
The paper states that maize has a temperature threshold point at 32 degrees C.
Above that threshold, yields drop. This is from the abstract:
“A significant reduction in maize yield is found for each
day with a maximum temperature above 32◦C, in broad agreement with previous estimates.”
Hmmm. That would be news in Hallam County, Texas. The daily high goes above
that threshold on 23 June and stays there for 52 days, on average. This is a very
far cry from the ~22 days above that critical temperature in France in 2003. Yet,
Hallam County’s corn harvest exceeded 20 million bushels in 2010 and yields this
year are still between 180-200 bushels per acre! The key is that Hallam County
corn growers, like all of the Texan panhandle corn growers, use irrigation.
Hawkins et al. attempt to correct for precipitation, and he correctly notes
that precipitation is negatively correlated with hot weather. I have not read his paper
in full detail, but it looks like an impressive piece of work.
I would say, to the title, it depends. Obviously higher temperatures will have different effects in different areas of the globe. Of course there is no such thing as a global mean temperature so a raise in one hemisphere could just as easily be a drop in an area of another. If higher temperatures lead to greater drought conditions on certain areas where irrigation is difficult then crop yields may indeed drop. However it could be just the opposite in areas where the temperature rises and annual rainfall rises with it, which seems to be the current conditions appearing in temperate climates ( here in the UK, despite the claims of record temperatures the annual rainfall is rising ).
The fact is that plants, on the whole, love warmer climes with wetter summers and higher available CO2. And given that’s what the alarmists are telling us is happening ( unless there is a convenient drought bandwagon for them to jump their hypocrisy to ) then I think crop yields, in general are in for favourable times.
Physiologically, crops are sensitive to temperature usually only during germination and flowering. A cold (or warm) spell at the wrong time can massively affect yield – 100% if you have, say, a frost during flowering in wheat and pretty high reduction for high temperatures during flowering in lupins (two crops which which I am familiar). Lack of moisture is also important, but here it is very difficult to separate overall rainfall vs a dry period in an otherwise wet year, which brings me to my main point regarding the study referred to by Tallbloke.
My first take on the french study is that the authors picked maize – a crop which is unusually sensitive to relatively short periods without adequate moisture. [In the US, the research into “drought tolerant” maize is focussed on withstanding a 4-week period without rain – not what you would call a drought for most people, but critical to maize yields.] I would like to know if the authors (I see Ed Hawkins has commented here) had considered rainfall as opposed to temperature in their paper, as well as periods between rainfall events. I would also like to see wheat yields for the year in question to see whether the high temperature affected a crop which is far less affected by dry periods (a far deeper root system).
As a researcher in plant genetics, I know that breeders can pretty much give you anything you ask for in terms of adaptation to growing temperatures. Temperate climates have massive within season temperature changes, far in excess of any postulated climate change, and there is no inherent reason why crop varieties cannot be bred to handle these small changes in average temperatures. If the outcome of the CAGW scare is to increase funding to crop breeding to increase the capacity to adapt to changes in the climate (in whatever direction), then this would be a benign, even beneficial, outcome. However, articles claiming the end of the world is nigh merely play into the hands of those who would hinder our capacity to adapt by forcing massive reductions in energy use to no useful purpose.
At the equator the world is covered in jungles. Plants like it warm. Thus we build greenhouses to grow them, and add CO2 to the greenhouses.
Why would plants object to turning the earth into a greenhouse?
And as a jab at those alarmists who enjoy talk of tipping points, if the Earth continues to warm as predicted by their silliness, there is a truly wonderful agricultural “tipping point.” That is, when farmers can begin to plant multiple crops on the same land, because the expanded growing season.
Don’t get me wrong. I don’t believe for a second that we’ll warm enough to have multiple planting seasons in most locations where only 1 planting season currently exists. I only mention this to note that not all tipping points are bad ones, and not all temperature increases, even massive ones, can be judged as all bad.
To Ed Hawkins:
Thanks for your gracious response. I see you state that irrigation has increased in
France.
I just posted, before I saw your response, a note about corn production in Hallam
County, Texas, where the high temperatures exceed your stated threshold for a very
long time, yet yields are quite high, due to irrigation.
Perhaps the corn (maize) cultivars used in France might be a little different from those
used in extremely hot Texas? Or perhaps increased irrigation could offset the heat
somewhat? That could obviate the concern you and your co-authors stated in section 4:
“Improved technology will need to increase base level yields by 12%
above current levels to be confident about maintaining current maize yields. The current
rate of yield increase due to technology is not sufficient to meet this target.”
Again, thanks for coming here to defend and discuss your paper, and I re-iterate my
appreciation for an impressive piece of work
Willis!
I made some calculations on world production of cereals (as production per hectar) in 1950-2010 and compared various parameters in relation to them. Actually I was interested in the difference in normal production and “organic” (“ecological” etc) production. For that purpose I tried to exclude the effect of some parameters to be able to extract the organic production. The increase in global production was more than twice in that period. The increase in cultivated area was about 10 %. So it was effectively about 100 % increase in the yield per hectar. Then I used data from Idsos on the effect of doubled CO2 levels on cereals (it was based on several hundred experimental studies). That gave about 7 % increase in the yield in 1950-2010 because of increased CO2. I never tried to estimate the effect of temperature because I thought it was too interconnected with humidity and varies a lot with latitude. I tried to estimate the relative importance of fertilizers, GMO and organic production. I could not do that because I simply did not find global statistics for organic production. I think most of the increase is actually attributed to fertilizers and partly to GMO combined with more efficient irrigation methods which prevent erosion. I estimated insecticides to have been a static parameter through times, that is they are continually developed in case of resistance.
Generally organic production gives something between 30-80 % of the normal production depending on latitude (it decreases towards high latitudes). I don’t know if there has been any progress in the yield.
I would really appreciate it if someone could clarify the following:
Is “CLIMATE CHANGE” intended to be a term describing
(1) a cause or:
(2) an effect
If it is meant to describe a CAUSE, then I would like to know
what it is that actually constitutes this ’cause’
and if it is an effect, then I would like to know what it is that is
the cause of this effect … and you are not allowed to cite
“global warming” !
Nice, Willis, but you left out the most important graph. What would the yield look like over time without global warming. For that you need imagination and a model, but it would be the only graph given credence by the nutters in charge.
Another chart, to be more serious for a moment, would be one that indicates demand for food grains. Regardless of weather (climate is stuck on 0) and increased yields, are we keeping up and warehousing the excess, keeping up and feeding the excess to our cars, or just staying even and starving the hungry while feeding our cars?
Philip Bradley says:
January 31, 2013 at 12:54 am
… the Vermin Fence (called the Rabbit Proof Fence in the Eastern States) …
###
Stupid question I could probably answer myself if I had time to wiki-wiki wiki. Is this the same as the Dingo Fence? Also is the name Dingo Fence real or just something cooked up by an American Activist?
cRR Kampen says: January 31, 2013 at 5:47 am
Same logic gives Queensland, AUS, a flood of the century every year.
I have heard that it has happened before…. and that we may not have yet, in our 200 odd years of history there, have seen the worst of it…
http://www.bom.gov.au/cgi-bin/silo/cyclones.cgi?region=aus&syear=1906&eyear=1949&loc=0
Nature 413, 508-512 (4 October 2001)
High frequency of ‘super-cyclones’ along the Great Barrier Reef over the past 5,000 years
Jonathan Nott & Matthew Hayne
http://www.nature.com/nature/journal/v413/n6855/full/413508a0.html
Fundamentally, the article is flawed.
Plant growth is described Liebig’s Law and it is limited by pestilence. Growing degree days and C02 are two of the limits and are far more significant limits prior to the summer solstice. C4 plants are limited by growing degree days early in the growing season and c3 plants are limited primarily by C02. An increase in growing degree days prior to the summer solstice will greatly increase C4 yields. In increase in C02 will see an increase in C3 yields.
To Chris R:
It may well be that the corn grown in Texas is a different cultivar – I don’t know. Maybe some crop experts do. And, I imagine that the strain of maize grown in France has changed in the past 50 years as well – all part of the trend due to improving ‘technology’.
To Stephen R:
As for 2003 – I should have said the summer as an average was 1.5K hotter than any summer since records began in 1750 (according to the BEST timeseries). And, yes, it was dry in 2003, but not extremely dry as I’ve said elsewhere.
Ed.
At this moment, in what the US Weather Services terms the Upper Mississippi Valley, the outside air temperature is 8 degrees F. There is no sign of a green leaf or a green blade of anything related to grass. On the other hand, there is about 3 inches of snow on the ground.
Last summer, when the temperatures were above 100 degrees F, I was mowing grass and harvesting tomatoes and apples. The big problem during the last growing season was not heat; it was drought.
A question of much greater importance is: How much will agricultural output decline when the inevitable cooling begins, when gains due to warmer temperatures and atmospheric moisture are taken back. Why is civilization so blinded to their food sources and what makes them thrive? How many civilizations must fall due to cooling climate, before we learn to buffer with increased granary storage and stockpile management. We must use warmer times of plenty, to offset cooler times of scarcity. GK
I’m not certain I’m looking at the exact same study Willis is talking about. I’ve taken a cursory look at an IFPRI Food Policy Report titled ‘Climate Change, Impact on Agriculture and Costs of Adaptation’ (www.ifpri.org/sites/default/files/publications/pr21.pdf).
The paper appears to rely on temperature projections for 2050 using the CSIRO and NCAR models, predicting (projecting, whatever) +2C and +4 to +5C respectively from a base temperature in 2000, eyeballing the color graphs provided (They claim AR4 A2 scenario, I haven’t verified this, just taking their word). They provide a chart which breaks out differences assuming CO2 fertilization (with CF) and no CO2 fertilization (no CF), with no CO2 fertilization meaning 369 ppm atmospheric CO2 and CO2 fertilization meaning 532 ppm atmospheric CO2.
To digress for a moment, it’s interesting that they break out the columns into ‘with CF’ and ‘without CF’. In the notes (note 7) the authors attempt to justify this by saying ‘because the effects of higher CO2 concentrations on farmers fields are uncertain, we report the results both with … 369 ppm and 532 ppm CO2’. Apparently, the authors feel the certainty afssociated with the temperature projections require no such disclaimer, possibly because they are already in such ridiculous disagreement with observed trends that any bureaucrat reading the report would feel he is on comfortable and familiar ground, but the benefits of CO2 fertilization are … uncertain, models and observations to the contrary notwithstanding.
To digress for a moment more, let’s unplug from the models and return to the real world from the Matrix to check some numbers. I see we were at 394 PPM in Dec 2012. It looks to me as if Atmospheric CO2 goes up by about 2 PPM per year, so we’re already looking a little light on the CO2 count for 2050; looks like we should be just a bit shy of 500, not at 532. If we’re going to make it +2C by 2050 we’ve got a ways to go, since it’s already 2013 and we’ve seen no statistically significant warming for the past 16 years. This is the CSIRO scenario, if you’re worried about the NCAR scenario you might as well stop reading now and go seek professional help. We’ve got 37 years left to warm at least 2C, which means we’ll need to see a trend of about +.11 C every couple of years (yes you read that right, +.1C every two (2) years) for here on out. For those who hold that we’ll see warming in El Nino spurts like the big one in ’98 instead of a steady trend, I estimate we need to see about six of those ’98 Nino events over the next 37 years to reach +2C. Hold your breath if you wish, I’m not holding mine.
To finally get to the point though, looking at the CSIRO with CF case, which appears to be the closest thing this venture into fantasy land provides anyway, I see a picture that doesn’t appear particularly bleak. Percent change in yield between 2000 and 2050 are given for maize, wheat, and rice, broken out into irrigated and rainfed, further broken out into developed and developing countries. Eight of these twelve categories show percentage increases. Three more categories show very minor (approx 1.3%) decrease. The only big loser in this scenario is irrigated wheat in developing countries, which is projected to decrease by 21%. But the point remains that even under this unrealistic and unlikely CSIRO scenario, most cereals / region / method combinations show improved yields. Developing countries might have to tough it out with less irrigated wheat, but if it’s possible for them to shift towards other crops, mass starvation doesn’t appear to be in the cards.
I’ve run out of time, and although I’ve scanned some articles which seemed to imply that wheat in developing countries may be to a large extent a matter of convenience and changing tastes in urban areas, I haven’t found a solid source for this. I’m not an agricultural expert, but still I’m somewhat suspicious of findings that show +9% increases for rainfed wheat across the board in 2050 under these projections and yet shows a 21% decrease for irrigated wheat; I’d like to see the mechanics of that.
The increase per acreage in agricultural production was due to the improved strains of crops and better agricultural practices. Temperature increase was a minor player if any at all.
The effect of higher temperature generally increasing plant growth is well-and-long established.
I’d just like to point out that in this case, the graph lends itself very easily to an argument of correlation vs. causation, especially since gains in fertilization and irrigation technology, among other technologies, certainly have had an effect on yield over the last 50 years beyond a minute average temperature increase.
In plain English, a 1 degree C increase will not produce a 150-200% increase in yield (which is what this graph shows…).
Nice article and link to the 2010 article. Is it my imagination or have the “everything is shit Malthusians” eased off on their cliff metaphors and overshoot scenarios since oil prices have declined from their highs of a few years ago?
Ed Hawkins,
Have you done a study on the grape harvest of the English wine industry and how that depends on temperature?
Ed Hawkins says:
”an increase in average temperature = a change in the number of extremes”
Are you sure about that?
”The clear evidence is that extreme high temperatures are not increasing in frequency, but actually appear to be decreasing.” — John Christy
http://epw.senate.gov/public/index.cfm?FuseAction=Files.View&FileStore_id=66585975-a507-4d81-b750-def3ec74913d
G. Karst says:
” We must use warmer times of plenty, to offset cooler times of scarcity.”
I agree with the sentiment but I doubt there’s many food stuffs capable of century scale storage, best to be well positioned (plenty of electricity generation capacity) to remove as much agricultural production away from the whims of Mother Nature as necessary if the need arises.
Frank K: How right you are. There were no storms of any significance back then. Modern storms, or ultra thundercanes as is the new scientifically-corrected term, are identical in size and power to some old-fashioned storms, but worse. The approximate worseness is of exactly 97.6 % worsitude as is confirmed by peer review. All thundercanes that pass the peer review process are considered absolute proof of climate. We dropped the “change” and decided to go straight for the jugular and just call the problem “climate”. I was outside earlier and the weather was terrifyingly normal for this time of year = 83.7% proof of climate.
Anyone can disagree if they want, so long as their brain has been peer-reviewed. If not, then you’re not the sort of person we want to be arguing with; hence we won’t, with 95.7% confidence.
Global warming does not mean a gradual, universal increase in temperature, but rather a disturbance of established weather patterns. One of the key factors in the northern hemisphere is arctic sea ice loss, which links with the southward displacement of the jet stream that is behind the extreme heat in the US and extreme wet in the UK in 2012.
Another factor is the increased atmospheric moisture content that happens in warm air. This produces more cumulus cloud, which in turn accounts for the changes in precipitation that we are beginning to observe – not least, in the pattern of the Indian monsoon – which has been changing to episodes of more intense rainfall than was the norm.
So it seems that we are indeed beginning to experience periods of extreme weather. True, there are a few workers who challenge the view that droughts and floods are increasing. If however it emerges that we are in fact getting extreme associated with a mere 0.7-1C change – and at a time when land temperatures (although not the ocean heat content) has been pretty static for 16 years, we need to take the news seriously. If we are getting changes at 1C, then 2C, which all lukewarmers accept is likely, is going to be challenging, to say the least.
Sorry boys and girls but Plants Rule this world.Yeah,yesterday I put 24 pepper seeds
in a flat of potting soil. Next week I will plant those tomato seeds I saved from last years
garden.Plants have me trained well. I weed ,I water I feed ,they never give a man a break.
Not just men,but all animals. I saw a blue jay fly into one of my flower beds (yeah like I own
it.flowers have me trained also). This bluejay poked his beak into the soil,then he covered
it up.He did this eight times.I just had to see what he was up to.I dug up where he was and
discovered he planted eight acorns.Oak trees have birds working for them.A fox will plant
blackberries.So I ask who is running this world? Icould go on on……
Alfred
Ed Hawkins says:
January 31, 2013 at 4:58 am
Thanks, Ed, for coming here to defend your work. I took a look at the relationship you discuss, between hot summer days and maize yields. These are not average temperatures, but (as you recommend below) maximum temperatures.
Yield and temperature values have been detrended.
You’ll have to point out to me how the maize yields are so affected. Yes, I see your year 2003, it’s the top blue dot with the reduced yield … but other than that and a few outliers, there is not much relationship with temperature. If you pull out the top three records (the three hottest summers) there is no statistically significant trend in the remainder of the data. Your entire trend depends on 6% of the data, three summers only, and 94% of the data shows no statistically significant relationship … not encouraging.
This indicates that extremely hot summers cut the yields, but that most summers are not in that category and the temperature makes little difference to the yield. For the majority of the summers, there is no statistically significant relationship between maximum temperatures and yields.
Seems to me like all that you have shown is that unexpectedly hot days are bad for whatever variety of corn the French farmers grow, just like is true in both warmer and colder locations … but given that corn is grown in places much warmer than France, this seems like a problem with the variety, not the temperature.
Ummm … well, to start with your projection is alarmist because you don’t have a clue what the temperature will be in 2016-2035, but you are acting like you are very sure it will be hotter … and that, my friend, is alarmism—claiming you know about future possible catastrophes when your model is nothing but guesses.
Next, it’s alarmist because you haven’t done simple data checks. For example, if your claim is that hot weather cuts the maize yield, you’d expect that the more northern countries than France, say Germany, would have greater maize yields than France does, while Spain would have poorer maize yields … in fact, here’s the countries with the biggest yields:
Since Israel, Jordan, and Kuwait have the highest yield, and those countries are MUCH hotter than France, I fear the idea that a slight temperature rise is going to cut France’s yield by 12% is … well, let me call it “flying in the face of the evidence”.
In any case, are you saying that the French crop breeders were unaware that extreme heat stress causes a drop in maize yield until you came along? People have been screaming about the gradual temperature increases for some decades now. Farmers know all about the effects of hot weather. Why would French crop breeders need you to bring that to their attention? What makes your fantasies about a future Thermageddon™ “information they need”.
Finally, you say in your paper:
In the event, the 2011 yield per FAOSTAT was 1.02 kg m-2, a greater yield than your model expected, 10% better than what you call the “mean present day yield” … and this despite the fact that the summer was not “close to the long term mean” for maximum temperatures, it was hot, in the upper quartile of the hottest summers. It was a hot summer, and despite that, the yield in hot conditions was greater than your whiz bang model predicted for normal conditions and 10% above the present day mean … do you really think farmers are going to pay the slightest bit of attention to those kinds of results?
I’m sorry, Ed. I know that you think you’re doing the crop breeders in France a favor with your research, but your model has already failed its first test fairly spectacularly … not a good start.
The bigger problem is, I doubt greatly whether French crop breeders are unaware that extremely hot days cut maize yields. And I find it equally doubtful that French farmers don’t know enough to switch to a warmer-weather variety of corn if the weather warms … farmers the world over have plenty of smarts, the French are no exception.
So while your work has academic interest, and I’m sure you can tease out more of the nature of the relationship, all you’re proving is what the farmers already know—if you plant the wrong maize variety for hot weather, you’ll lose your chemise … unless the weather isn’t hot.
And since in reality you have no clue about what the weather in France will be like from 2016 to 2035, I fear that all your warnings are useless to the farmers and the crop breeders.
w.
Richard Lawson says:
“Global warming does not mean a gradual, universal increase in temperature…”
I see you are moving the goal posts by inventing your own definition of global warming. In reality, global warming means that the globe is warming. Everything else is simply a justification for your “what ifs”.
In fact, extreme weather events have been declining for decades. To translate your post: ‘Although global warming has stopped for a decade and a half… watch out! Things are gonna get really bad!’
But the reality is that the past 150 years or so have been unusually benign. The extremely mild 0.7ºC rise in global temperature for a century and a half is not typical of the Holocene and before. We are currently living in a truly “goldilocks” climate, and there is no indication that the rise in CO2 has made the slightest difference.
You are the victim of the alarmist propaganda that rains down on us 24/7/365 from all directions. If you start to think for yourself, you will begin to see that the “carbon” scare is being promoted by folks with a vested, self-serving interest in alarming the public.
Don’t be their dupe. Look out your window. Nothing unusual is happening. The weather is the same as always. There has been no global harm from the rise in CO2. We are very fortunate to be living in such a wonderful climate. Be thankful, not scared. The alarmists want you to be scared. It means more loot for them. And they want you to be the chump that pays the loot.
Richard Lawson says:
January 31, 2013 at 10:56 am
Global warming does not mean a gradual, universal increase in temperature, but rather a disturbance of established weather patterns.
———————————————————————–
Stop right there. Why refer to the phenomenon as ‘Global warming’ then?
———————————————————————–
One of the key factors in the northern hemisphere is arctic sea ice loss, which links with the southward displacement of the jet stream that is behind the extreme heat in the US and extreme wet in the UK in 2012.
Another factor is the increased atmospheric moisture content that happens in warm air. This produces more cumulus cloud, which in turn accounts for the changes in precipitation that we are beginning to observe – not least, in the pattern of the Indian monsoon – which has been changing to episodes of more intense rainfall than was the norm.
So it seems that we are indeed beginning to experience periods of extreme weather. True, there are a few workers who challenge the view that droughts and floods are increasing. If however it emerges that we are in fact getting extreme associated with a mere 0.7-1C change – and at a time when land temperatures (although not the ocean heat content) has been pretty static for 16 years, we need to take the news seriously. If we are getting changes at 1C, then 2C, which all lukewarmers accept is likely, is going to be challenging, to say the least.
—————————————————————————
Hi Richard,
I’m sorry if I’m misunderstanding your position. The way I’m reading it is that you acknowledge that land temperatures have been pretty static for 16 years, but the effects predicted for increased temperatures are proceeding on regardless; that global warming is driving arctic sea ice loss and increasing atmospheric moisture content. If this is indeed what you’re saying, the mechanism is missing if the atmospheric temperature has shown no change for 16 years.
Weather averages and associations with crop yield are less than USELESS.
Only using highly structured, randomized field tests with multiple input factors can humans determine to a high degree of certainty the relative contribution of each competing factor. In these tests, subtracting all imputs other than temperature (or substantiating that these factors were not limiting in the management of the test plot) has determined that the impact of high temperatures on the major field crops is:
1. Greatest during pollination and initial seed growth. The impact at these stages of plant growth (specie dependent) is highly sentitive and the plant responds in an “all or nothing” fashion. High temperatures decrease or eliminate stamen survival.
2. Subsequently, yield response to increasing temperatures is subject almost exclusively to the temperature sensitivity of the initial enzyme catalyzing the incorporation of CO2 into a stable molecule. This molecule is then translocated into a specific cellular structure, where it is converted into a soluble sugar. The enzymes fall into general classes for particular related plants, and the end products are different within each specie, but in general:
a. Enzyme pKa’s are relatively stable between 50F and 85F-(C3), or 95F-(C4), but fall off
exponentially on either side.
b. Enzymes have an absolute temperature above which they become decarboxylases rather
than carboxylases. (i.e. in the case of most crop C3 plants, ribulose bisphosphate
carboxylase becomes ribulose bisphosphate decarboxylase).
The combination of a.) and b.) suggests temperatures
above that temperature threshold cause the plant to reduce net photoassimilate, resulting in
a net loss of stored energy. Therefore, ignoring the temperature effect on pollination, a plant
subjected to temperatures close to and above the threshold enzyme pKa is incrementally
losing potential yield every hour it is above that threshold. These data imply that averaging
temperature for a given day, week or month, tells us very little about the specific effect of
temperature on yield. To elaborate, if the temperature for a given day was above the
threshold for six hours, the effect on yield would be greater than if the temperature was
above the threshold for three hours. (Night time temperatures have some effect also
attribitable to dark respiration, but much less so.)
Understanding this information in regards to this thread, I interpret this experimental evidence as suggesting with a high degree of confidence that a 1F averged anomaly increase tells us next to nothing about the potential consequence on crop yield.
Disclaimers:
I am a crop physiologist.
Extraordinary that until Austin, Chad Jessup and Big D in TX no-one has really pointed at the true reasons for yield increases. And there hasn’t been a mention of leaf/cell temperature (where the action is) with/without irrigation, as opposed to some vague land temperature.
@richard Lawson: You wrote: “Global warming does not mean a gradual, universal increase in temperature, but rather a disturbance of established weather patterns.”
+++++++++++++++++++
Please spare us the ever changing code words your people use to keep you confused. You are a self proclaimed Green Party Activist. That is YOUR filter, which makes it impossible for you to discern truth from feelings. You have given up your brains and own thoughts and have become a parrot of your party.
1) Global Warming means the globe is warming.
2) Climate Change means means the climate changes.
The second has always been true based on historical records. The first is true while the globe is warming, and is false when the globe is not warming. But your people have changed the words to mean different things –yet you stick to the ever changing script.
3) Green: Your people have also changed what Green means. Green, when used in ecology, refers to the color of chlorophyll which gives plants their “green” color. Your people have distorted that CO2 (which is required and tends towards more greening) is the opposite of what it is. By definition CO2 is the ultimate green molecule.
4) Subsidy: Used to mean something which has been subsidized, or something which is given to someone to help them along. But now, when oil companies get to write of some expenses (like all corporations) to keep a larger percentage of THEIR OWN earnings, that’s called a subsidy by your people. AND when “Green” companies are given other people’s money, that is equated to oil companies paying their own taxes.
Your people are unreasonable.
Good of Ed to offer some guiding comments here – helps that everyone is free to comment here unlike certain other blogs. The work he has done – correctly or incorrectly according to some posts and not having the time for an in-depth read – is exactly where funding should be going as food production is important, However – you could tell one was coming – if he is required or has chosen to go the warming route, his work is not of much use now that the decent into a little ice age has started. Would he get any funding if he asks for it to research the effects on crop production of a world of cooler temperatures and more wild weather swings as we are seeing now? It has been said before that anecdotal evidence provided by records of grain harvests that go back much farther than temperature records can give some rough idea of weather conditions. What happened during the warm spells and what happened during the Dalton & Maunder minimums?
And I can’t believe that Mann has said something that makes sense regarding crop ranges. If the crop range is larger – further north & higher up – then there must be more produced? Surely in warm Roman England when vines were grown around Newcastle, they must have also been grown where English wine is produced in the south – net result more wine.
It is grains that are stored in granaries. Properly silo ‘ed or binned grain will keep indefinitely. Even the ancient Egyptians knew this. In any event, it is not necessary to store the grain indefinitely. Each year, a portion is sold and replaced by new harvest, maintaining a world bread pantry. It would also be a seed supply, should crops ever fail globally. Maintaining a “just in time” delivery of foodstocks… is risky IMO. GK
These graphs all look very convincing to me. After successive doom-laden predictions failing one after the other, and the failure of peak-oil to eventuate, it is time for Ehrlich and the prophets of doom to fade away like Malthus.
@Mark Bofill: The IFPRI Food Policy Report relies on “NCAR model” without providing any details. I assume that it is a CAM 5 (Community Atmosphere Model 5). This model has a 2.5% error in heat transfer by water evaporation at 25 degrees C (3% at 30 C). They don’t know the impact of this error – excuse me, an unannounced approximation – and they apparently don’t care.
Willis Eschenbach says:
January 31, 2013 at 11:40 am
Ed Hawkins says:
January 31, 2013 at 4:58 am
Said as a farmer; We, the tax payers pay and pay for this academic crap!
Those real and completely unrecognised and unsung heros of all of global mankind, the plant breeders. the men and women on whom ultimately the whole of mankind depends on to feed our numbers far into the future, just get on with their work of breeding new varieties of crops that give higher yields, better tolerance to changing seasonal conditions, better tolerance to drought or heat or cold, better nutrition, better storage longetivity, better disease and insect resistance, easier processing and better baking and cooking characteristics.
All this with a genetic complexity of life that makes analysing the global climate look like a kindergarten exercise.
For that they are rewarded with only a fraction of the income that the climate warming scientists who have contributed nothing to mankind except the promotion of deep fears about the future and the destruction of immense amounts of wealth and the increase in societal conflict.
And for what ?.
Why the hell is our society and civilisation so screwed up and twisted up that the most important people for mankind’s future, the plant breeders are the most neglected group of scientists and regarded by our society as the being at the bottom of the pile in science whilst the most useless and most destructive group of scientists, the global warmers are getting all the big rake off’s and all the gloss?
To Stephen R:
As for 2003 – I should have said the summer as an average was 1.5K hotter than any summer since records began in 1750 (according to the BEST timeseries). And, yes, it was dry in 2003, but not extremely dry as I’ve said elsewhere.
Ed.
I call no rain for 5 mths extremely dry and in the following years we had periods of no rain for 4 mth, 3mths, and 2 x 2 mth periods in one year. The spring and the autumn. The hottest day recorded in SW France was below the highest recorded temperature of 42°C. In 2003 we had June, July and August with every day over 32°C and everyday of july over 37°C. We saw no rain here during the spring and summer and in february of that year I was on the terrasse in my shorts painting the shutters. Sun temperature (open land T) was 26°C.
That year the maïs was good and the wine better.
Curious George says:
January 31, 2013 at 1:20 pm
@Mark Bofill: The IFPRI Food Policy Report relies on “NCAR model” without providing any details. I assume that it is a CAM 5 (Community Atmosphere Model 5). This model has a 2.5% error in heat transfer by water evaporation at 25 degrees C (3% at 30 C). They don’t know the impact of this error – excuse me, an unannounced approximation – and they apparently don’t care.
———————–
Yup. The paper I read presented NCAR and CSIRO, and just couldn’t make myself talk seriously about the NCAR case, which looked to be a 4 to 5C increase by 2050 in the document. If I’m going to sit around dreaming, I’d prefer to dream happy dreams; that supermodels are going to start throwing themselves at me in 2030 and the I.R.S. is going to give me back every dime I’ve ever paid them with interest by 2043. ~shrug~
For papers with technical details see:
Interactive Effects of CO2 and Temperature on Plant Growth at CO2Science.org
and Terrestrial Plants and Soils at the NIPCC
By contrast, note that Finland lost a third of its population due to famine during a prolonged “cold snap”:
Neumann, J.; Lindgrén, S. (1979). “Great Historical Events That Were Significantly Affected by the Weather: 4, The Great Famines in Finland and Estonia”. Bulletin of the American Meteorological Society 60 (7): pp775–787. doi:10.1175/1520-0477(1979)0602.0.CO;2. ISSN 1520-0477.
Our critically important challenge as a civilization is not global warming, but how to prevent the next glaciation in about 1500 years. i.e. can we generate enough warming to prevent glaciation!
I’ll vote with Minnesotans for Global Warming on the vital importance of warmer weather and catastrophic consequences of colder weather.
Ed Hawkins says:
January 31, 2013 at 4:58 am
“As our paper on French maize has been mentioned, I thought I had better comment briefly”
“1) For those in doubt about whether hot daily maximum temperatures reduce yields, then have a look at 2003 in Europe. The hottest (and presumably sunniest) summer ever in France, and maize yields went down 20% on the year before.
2) It is not average temperature that matters. Studies in laboratory environments have shown there are temperature thresholds beyond which crops start suffering. Also, an increase in average temperature = a change in the number of extremes.”
A 1 – 2 degree World average increase is not a ‘hot’ daily maximum, it’s only 1 – 2 degrees!
You can hardly compare an unusual heatwave and resultatnt drought in France with a 1 – 2 degree average increase in World temperature. Presumably the heatwave conditions to which you refer had local temperatures much higher than 1 – 2 degrees over an unusually long period. Droughts with or without increased temperature are fortunately an unusual occurance and will ruin crops whenever and wherever they occur, but thankfully these are not the norm, otherwise farmers would not grow the crops that suffer in drought conditions. It is a strong bet that even corn growing in France let alone all other crops would benefit from a degree or two of average warmer weather. It would most certainly have benefits here in Britain and across all latitudes of Northern Europe, but occasional heatwaves and droughts will ruin crops in Northern latitudes just as much as they do in any part of the World, but that doesn’t mean that a very slight average warming would not be generally beneficial.
John Russell says:
January 31, 2013 at 5:15 am
STRAW MAN ALERT! Ladies and gentlemen, there is high fire danger, please extinguish all smoking materials, no open flames permitted. STRAW MAN ALERT!!
John, I neither said nor intimated that extreme weather events didn’t affect crops. I grew up on a cattle ranch, I know about weather and crops. What I said was that global warming, the centuries-long increase in the global surface average temperature, would not lower the crop yields.
Instead, farmers will simply plant different crops. But if heat caused low maize yields, how come Yemen and Jordan and Israel have the highest yields in the world?
That’s what I’m talking about, not your fatuous claim that somehow I indicated that extreme hot weather should lead to a bumper crop. I said nothing of the sort. That’s a straw man.
In this regard, folks, please QUOTE MY WORDS if you disagree with what I said. John didn’t, and paid the price.
w.
Sean C says:
January 31, 2013 at 6:26 am
Thanks, Sean. I looked at the global yields as well as the US yields. Since the global yields includes all of the developing nations, they are included in the graph … so how is it that I am overlooking them exactly?
Perhaps it would be valuable for you to point to the nation you are talking about. What nations are you saying make a difference in the corn/wheat/rice yield equation, and what kind of change do they make? Hang on …
OK, here’s the grain yields of the Least Developed Countries (LDCs) and the Landlocked Developing Countries:
As you can see, even in the worst off countries on the planet, even with the warming of the last 50 years, the yields are still rising.
So now that you’ve busted me, remind me again … what was I not being “true to accuracy” about? Where am I risking “questions of integrity”?
Folks, making claims is easy. I put the links to the data to encourage you to not just spout off with your brilliant claim, but to go and see if it actually is true before bothering us all with it … how come I gotta do the work on your theory, Sean?
w.
PS—In passing, let me point out that the grain yields of the worst off countries, the LDC and the landlocked developing, are now at or above the global average yields of just a half century ago …
Austin says:
January 31, 2013 at 8:59 am
Fundamentally, this comment is useless. If I have said something you disagree with, QUOTE MY WORDS and tell my why you disagree. Claiming it is “flawed” and then rambling about C3 and C4 plants does nothing.
w.
@CodeTech:
I was mostly just using your statement as a jumping off point…
FWIW, in most places what would happen (IFF warming were real…) is that the “last frost” date would be earlier, so folks would plant earlier, and follow the same temperature / time profile as now, just a day or two earlier. At the end of the growing season, they might have some added growing days, so get more crop, or just harvest early. Some places would get enough added time to add a second crop per year (as is presently done in warmer areas).
Yeah well, alarmists were stampeding governments into initiating force against people in the 1970s – over the disastrous impact global cooling would have on agriculture.
People who can’t adapt quickly will have trouble, but aren’t there a range of plant variations today and much ability to grow more? Within the past year wasn’t there a discusion about wheat in WUWT, which noted it grows from mid-Canada cool to Africa hot?
REf: Ed Hawkins’ paper:
Any crop, whatever the weather the rest of the summer has been, is subject to catastrophic localised events such as flood or hailstorms, so the correlation of an especially hot summer in France with a poor crop cannot be assumed as cause and effect. Very hot summers are often followed by more violent than usual storms at summers’ end, which can devastate a crop. The wide variation of quality and size in wine vintages is testament to that!
As for the overall attempt to relate crop yields to climate, I fear it is meaningless. The vast majority of many staple crops (esp maize /corn, soy and ‘canola’ or rapeseed) in North America is now GM: genetically modified. Records therefore cannot be compared to those of previous years, since strains change in nature over a short period, and in just ten let alone twenty years the crops grown have mutated so far that records are no longer comparable. These foodstuffs are engineered to crop heavily, but are different in kind to those grown in the past.
Monsanto, Dow and their ilk are getting a stranglehold on the food supply with their pesticide-laden and sterile frankenfoods; I’ve been studying this in detail for a few years now and this imo is an even greater problem for our collective future than the AGW scare. Most people don’t seem to understand how far advanced this process has been advanced, least of all consumers in the US and Canada where the advance of GM foods is almost beyond reversal.
If you wish to compare crop yields over the last ten or twenty years, it would be best to limit yourself to Europe or other places where GM crops are not yet the norm. The picture in N America is too distorted by them now for meaningful comparisons.
Charles Dickens made it all up?
Thirty years ago, Marseilles lay burning in the sun, one day.
A blazing sun upon a fierce August day was no greater rarity in southern France then, than at any other time, before or since. Everything in Marseilles, and about Marseilles, had stared at the fervid sky, and been stared at in return, until a staring habit had become universal there. Strangers were stared out of countenance by staring white houses, staring white walls, staring white streets, staring tracts of arid road, staring hills from which verdure was burnt away. The only things to be seen not fixedly staring and glaring were the vines drooping under their load of grapes. These did occasionally wink a little, as the hot air barely moved their faint leaves.
There was no wind to make a ripple on the foul water within the harbour, or on the beautiful sea without. The line of demarcation between the two colours, black and blue, showed the point which the pure sea would not pass; but it lay as quiet as the abominable pool, with which it never mixed. Boats without awnings were too hot to touch; ships blistered at their moorings; the stones of the quays had not cooled, night or day, for months. Hindoos, Russians, Chinese, Spaniards, Portuguese, Englishmen, Frenchmen, Genoese, Neapolitans, Venetians, Greeks, Turks, descendants from all the builders of Babel, come to trade at Marseilles, sought the shade alike—taking refuge in any hiding-place from a sea too intensely blue to be looked at, and a sky of purple, set with one great flaming jewel of fire.
The universal stare made the eyes ache. Towards the distant line of Italian coast, indeed, it was a little relieved by light clouds of mist, slowly rising from the evaporation of the sea, but it softened nowhere else. Far away the staring roads, deep in dust, stared from the hill-side, stared from the hollow, stared from the interminable plain. Far away the dusty vines overhanging wayside cottages, and the monotonous wayside avenues of parched trees without shade, drooped beneath the stare of earth and sky. So did the horses with drowsy bells, in long files of carts, creeping slowly towards the interior; so did their recumbent drivers, when they were awake, which rarely happened; so did the exhausted labourers in the fields. Everything that lived or grew, was oppressed by the glare; except the lizard, passing swiftly over rough stone walls, and the cicala, chirping his dry hot chirp, like a rattle. The very dust was scorched brown, and something quivered in the atmosphere as if the air itself were panting.
Blinds, shutters, curtains, awnings, were all closed and drawn to keep out the stare. Grant it but a chink or keyhole, and it shot in like a white-hot arrow. The churches were the freest from it. To come out of the twilight of pillars and arches—dreamily dotted with winking lamps, dreamily peopled with ugly old shadows piously dozing, spitting, and begging—was to plunge into a fiery river, and swim for life to the nearest strip of shade. So, with people lounging and lying wherever shade was, with but little hum of tongues or barking of dogs, with occasional jangling of discordant church bells and rattling of vicious drums, Marseilles, a fact to be strongly smelt and tasted, lay broiling in the sun one day.
http://www.gutenberg.org/files/963/963-h/963-h.htm#link2HCH0001
PS To the basic premise of Willis’s article – that warmer weather / climate will increase crop yields: I fully agree with this. Indeed all our our collective observation and experience confirms this to be true. In my reference to the preponderance of GM foods in intensively cultivated developed countries, I was merely pointing out the problem of proving this using yields, since we are no longer able to compare like with like
DesertYote says:
January 31, 2013 at 8:13 am
… the Vermin Fence (called the Rabbit Proof Fence in the Eastern States) …
###
Stupid question I could probably answer myself if I had time to wiki-wiki wiki. Is this the same as the Dingo Fence? Also is the name Dingo Fence real or just something cooked up by an American Activist?
The Dingo Fence is another fence in the East.
The Western Australian Vermin Fence primarily keeps emus out of the wheat areas. There are very large numbers of emus in the forested area on the other side of the fence. A fire burned through in the mid-1990s and an estimated 60,000 emus died.
There was an movie made called The Rabbit Proof Fence, which is why people outside WA call it that.
In the south of WA the land on the other side is quite heavily forested and not hospitable to rabbits. Further north where the country is more open, the fence, which at one time went pretty much the whole length of WA, may have been built to keep rabbits out.
Remember the Medieval English vineyards followed by Frost Fairs on the Thames
The warming since the Little Ice Age is just beginning to return us to the much more productive agricultural conditions in the Medieval Warm Period and the earlier Roman warm period.
Sam the First says:
January 31, 2013 at 5:53 pm
Thanks, Sam. Actually, my basic premise was the other way around—that a warmer climate will not lower crop yields. It may increase them, but that’s not what I have showed.
w.
I’ve added an update at the end of the post to try to clarify some misconceptions that I find floating in the ethernet … plus a graph I posted above of the LDCs.
w.
The threats to crops are five-fold:
1. Lack of sunlight.
2. Torrential rain over long periods, rendering the soil anaerobic.
3. Denuding the soil of essential trace elements.
4. Denuding the soil of essential microorganisms and earthworms.
5. Direct damage to crops through weather events, be that harsh frosts, extreme hailstorms or prolonged drought.
Of course, different crops have different optimum temperatures and some are indeed heat sensitive. You have the option, if it gets warmer, to plant such crops either earlier in the year, in a more shaded environment, outside rather than in glasshouses etc. You have the option of harvesting sooner if the heat comes earlier in the year. You presumably have a longer growing season between the last dangerous frosts of the early spring and the first dangerous frosts of early autumn.
My view is the greatest dangers come by destroying soil fertility rather than changing temperature.
Philip Bradley
January 31, 2013 at 6:59 pm
DesertYote says:
January 31, 2013 at 8:13 am
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WOW, thanks for the information! I found it fascinating. On a side note, when I first heard of the Dingo Fence, I actually owned a Dingo and thought the idea of someone trying to building a fence to control her movements was kind of funny. She was scary smart and more agile then a cat. Owning her was very instructive.
And thanks again. This is why I come here to read, one of the few places where the comments are usually more interesting then the article being commented on.
Slightly off thread. Our activist friends the Greens last year broke into a Canberra CSIRO trial plot of GE modified wheat and shredded the lot.Thanks to all the Ag scientists who have contributed here. It helps explain why MSM arts/humanities educated journos (i.e. most) do not understand or care about agriculture (or science). Dingos (wild dogs) are native to Australia. The dingo or dog fences were constructed to keep sheep country free of dogs. They are still maintained for this purpose. PS It’s obvious more should be spent proportionately on ag.science research than on climate change stuff. Cheers from soggy (again) Sydney.
@John Russell says:
January 31, 2013 at 5:15 am
“Sure; up to a point warmth can increase plant growth. But speaking practically?
The USA had its hottest year on record in 2012 (1). So following Willis’s logic, perhaps we should expect crop yields to be the best on record? ”
++++++++++
Actually, the US had a drought, caused by colder than average temperatures of the Pacific West Coast. Note colder. Colder air holds less moisture. The normal Easterly winds naturally blew this dry air over the middle of the country where the cloudless skies made it hot. Dry air holds much less latent heat and so warms up faster. The drought was the problem –not global average temperature.
If you are trying to lead people to believe Willis suggested that drought-caused higher temperatures should lead to increased crop growth, then you are just looking for an argument.
“So I thought I’d review the facts.”
Willis, really, this is climate science, there’s no need to get carried away……..
Global warming is supposed to manifest itself gradually over this century. Farmers have plenty of options such as planting drought / heat resistant strains or planting new crops. Cold and wet can also cut yields in ONE summer. What does that tell me about man-made global warming?
Mark Bofill says:
January 31, 2013 at 9:38 am
[bunch o’ stuff, and ‘still I’m somewhat suspicious of findings that show +9% increases for rainfed wheat across the board in 2050 under these projections and yet shows a 21% decrease for irrigated wheat; I’d like to see the mechanics of that.’]
———————–
Okay, I feel justifiably stupid. The explanation for this is right there in the paper clear as day, it says ‘the Middle East and North Africa and Sub-Saharan Africa regions both experience (average IRW) reductions of about 4 percent’. Basically the argument is that irrigated crops suffer because the water available from precipitation goes down in these places.
I don’t know if this is TRUE, but that’s the explanation at any rate. Kudos to Paul_K’s comment on Lucia’s the Blackboard (Lower Crop Yield for AGW?) for prompting me to re-read the darn thing and pay better attention. 🙂
Mario Lento
January 31, 2013 at 11:48 pm
Actually, the US had a drought, caused by colder than average temperatures of the Pacific West Coast. Note colder. Colder air holds less moisture. The normal Easterly winds naturally blew this dry air over the middle of the country where the cloudless skies made it hot. Dry air holds much less latent heat and so warms up faster. The drought was the problem –not global average temperature.
###
I wish I could have said this as well as you, and I hope, even though this thread is a bit old, others read and remember it. In the past, I have tried, unsuccessfully to make this point. I had even thought to do so in this thread, yesterday. But, I was so crazy busy that I did not want to withstand the frustrations of trying to communicate even moderately complex concepts.
I grew up in the shadow of the Hohokam along the Salt River, had a few O’odham (the Hohokam’s descendents) friends, and learned a little bit about their history. Almost all the periods of drought (and high land temps) happened during times of globally cool climate. Not only that, but the Hohokam culture had its golden age, with cool temps and plenty of rain ( and sometimes too much) during the MWP!
Food fight at the Blackboard.
http://rankexploits.com/musings/2013/lower-crop-yield-twitter-storm/
Jimbo says:
February 1, 2013 at 5:53 am
Global warming is supposed to manifest itself gradually over this century. Farmers have plenty of options such as planting drought / heat resistant strains or planting new crops. Cold and wet can
also cut yields in ONE summer.
Yes. And there are large annual swings in precipitation. Two years ago there was extensive flooding along the Mississippi and Misouri River Basins. Crops were flooded out. Last year the reverse happened with high temperatures and drought. Crops died or were stunted for lack of water.
There was a similar pattern for the years 1952 and 1953. My dairy farmer cousins in Missouri had a hard time both years.
Keith Sketchley says:
January 31, 2013 at 4:47 pm
I suspect you are talking about several posts discussing an article by Mark Hertsgaard claiming global warming meant we would have to give up pasta. See here .
Further to my point about the recently greening biosphere and Sahel we now have a new paper predicting more greening in the future.
“New paper predicts CO2 fertilization will greatly improve plant productivity by 40-60% ”
http://hockeyschtick.blogspot.com/2013/01/new-paper-predicts-co2-fertilization.html
God bless Norman Borlaug (RIP).
One of the themes that some people keep raising is whether the pace of technological advancements will continue. Yes, they say, Norman Borlaug did stunning work, but what evidence do we have that that progress will continue?
For me, the answer is simple. I look at the size and diversity of the effort. The effort to feed more people off of the same land is going on all over the world. Hundreds of thousands of people on farms and in schools and universities do nothing all day long but work on that challenge. Not only that, but they have done so for years. In many cases, they were trained in the struggle by their predecessors and will train the next generation in turn.
In short, the question of feeding more people off the same dirt is one that we are crowdsourcing. And because of the worldwide size, diversity, determination, and motivation of the crowd in question, I have no doubt that we have the capacity to solve the problem … as we have done for decades after decade, as I show in the graphs above.
I was inspired to this comment by noting a post with the subtitle:
Corn is one of the main plants keeping us fed, and as a result, it has been intensely studied for years … and here is some group of people that you and I have never heard of, who do nothing but study and investigate corn, who have come up with a major breakthrough. They have achieved a 10% increase in yield … ten percent! That’s huge, and that’s just one unknown group, perhaps one of several at the laboratory, one laboratory among many labs and schools in the city, one city among many in the US with people studying the same question, and the same in every country of the world …
So yes, I have great faith in the ability of a dedicated, world-wide, financially motivated crowd of folks to be able to crowdsource answers to further our unending struggle to feed more people off of the same area of land, whether the temperatures go up or down.
w.
Willis there seems to be another news flash hiding in the charts: The US Best temp shows 2010-2011 temps lower than 1980 and 1990!! and this with all the championship fiddling going on..
Er this chart is for the USA