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.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
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.