Via Eurekalert. This doesn’t jibe with what I know about corn crops in America, but maybe they aren’t taking advantage of the enhanced seeds like what is produced by DeKalb and other USA seed companies. 40C and higher I might agree with, but we have massive corn crops that do well at 30-40C in the USA. Based on the “blind date” comment, it seems the researchers are really pleased with the “perilous” result indicated in the headline. Maybe one of our farming friends can shed some light on the subject. This essay is going to be in the new fandangled free Nature journal, Nature Climate Change, for which I applied for a free subscription, and since I’ve heard nothing, I assume that my application was not successful. -Anthony
Untapped crop data from Africa predicts corn peril if temperatures rise
A hidden trove of historical crop yield data from Africa shows that corn – long believed to tolerate hot temperatures – is a likely victim of global warming.
Stanford agricultural scientist David Lobell and researchers at the International Maize and Wheat Improvement Center (CIMMYT) report in the inaugural issue of Nature Climate Change next week that a clear negative effect of warming on maize – or corn – production was evident in experimental crop trial data conducted in Africa by the organization and its partners from 1999 to 2007.
Led by Lobell, the researchers combined data from 20,000 trials in sub-Saharan Africa with weather data recorded at stations scattered across the region. They found that a temperature rise of a single degree Celsius would cause yield losses for 65 percent of the present maize-growing region in Africa – provided the crops received the optimal amount of rainfall. Under drought conditions, the entire maize-growing region would suffer yield losses, with more than 75 percent of areas predicted to decline by at least 20 percent for 1 degree Celsius of warming.
“The pronounced effect of heat on maize was surprising because we assumed maize to be among the more heat-tolerant crops,” said Marianne Banziger, co-author of the study and deputy director general for research at CIMMYT.
“Essentially, the longer a maize crop is exposed to temperatures above 30 C, or 86 F, the more the yield declines,” she said. “The effect is even larger if drought and heat come together, which is expected to happen more frequently with climate change in Africa, Asia or Central America, and will pose an added challenge to meeting the increasing demand for staple crops on our planet.”
Similar sources of information elsewhere in the developing world could improve crop forecasting for other vast regions where data has been lacking, according to Lobell, who is lead author of the paper describing the study.
“Projections of climate change impacts on food production have been hampered by not knowing exactly how crops fair when it gets hot,” Lobell said. “This study helps to clear that issue up, at least for one important crop.”
While the crop trials have been run for many years throughout Africa, to identify promising varieties for release to farmers, nobody had previously examined the weather at the trial sites and studied the effect of weather on the yields, said Lobell, who is an assistant professor of environmental Earth system science.
“These trials were organized for completely different purposes than studying the effect of climate change on the crops,” he said. “They had a much shorter term goal, which was to get the overall best-performing strains into the hands of farmers growing maize under a broad range of conditions.”
The data recorded at the yield testing sites did not include weather information. Instead, the researchers used data gathered from weather stations all over sub-Saharan Africa. Although the stations were operated by different organizations, all data collection was organized by the World Meteorological Organization, so the methods used were consistent.
Lobell then took the available weather data and interpolated between recording stations to infer what the weather would have been like at the test sites. By merging the weather and crop data, the researchers could examine climate impacts.
“It was like sending two friends on a blind date – we weren’t sure how it would go, but they really hit it off,” Lobell said.
Previously, most research on climate change impacts on agriculture has had to rely on crop data from studies in the temperate regions of North America and Europe, which has been a problem.
“When you take a model that has been developed with data from one kind of environment, such as a temperate climate, and apply it to the rest of the world, there are lots of things that can go wrong” Lobell said, noting that much of the developing world lies in tropical or subtropical climates.
But he said many of the larger countries in the developing world, such as India, China and Brazil, which encompass a wide range of climates, are running yield testing programs that could be a source of comparable data. Private agribusiness companies are also increasingly doing crop testing in the tropics.
“We’re hoping that with this clear demonstration of the value of this kind of data for assessing climate impacts on crops that others will either share or take a closer look themselves at their data for various crops,” Lobell said.
“I think we may just be scratching the surface of what can be achieved by combining existing knowledge and data from the climate and agriculture communities. Hopefully this will help catalyze some more effort in this area.”
Lobell is a Center Fellow at the Program on Food Security and the Environment, a joint program of Stanford’s Woods Institute for the Environment and Freeman Spogli Institute for International Studies.
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I think its true that sustained high temperatures can reduce corn yields but what can reduce them much more is sustained low temperatures. I don´t see a lot of food crops growing above the arctic circle but I do see a lot growing on the equator. This is another nonsence report, where do these people get their funding from?
Sad looking corn in the picture. Looks like stress from temperature and lack of water. Yields are supposedly reduced during silking from temperature/low water stress. Corn is also high nitrogen consumer. The picture looks like a field that has been drowned and then ignored as it dried. Hard to day if the authors thought this was representative of all African corn.
My expertise is plant physiology. Maize/Corn is what is called a C4 plant. Its photosynthesis is specifically adapted to high light/temperature conditions and it has a broad temperature optimum centred around 35 degrees C (over 95F).
It is also water use efficient.
Whatever these guys have found it is not temperature that is causing the yield reduction.
Oh, but it fits the grant application!
Just to illustrate how dramatic rainfall can be in terms of timing, consider what every dry land farmer knows about “optimal rainfall” early in the growing season for cereal crops. It is potentially very very very BAD.
The learned climatologistwithanagenda rushes out and measures stem growth in height and thickness and imagines this can be correlated with the “optimal rainfall” for that early portion of the growing season. WRONG! WRONG! WRONG!
All that tells you is what the optimal amount of rain is to maximize growth during THAT period. The optimal amount of rain early in the growth season is dependant upon THE AMOUNT OF RAIN IN THE REST OF THE GROWING SEASON.
If cereal crops get enough moisture to maximize growth early in the growing season, they do. Since moisture appears plentiful, the roots don’t need much development to sustain the plant, and the bulk of the growing occurs above ground and our brilliant scientists magicaly calculate “optimal rainfall”. If later in the season there is a dry spell, the shallow plant roots dry out quickly, and the plant is already at the point where it needs to put growth resources into seed growth, there is no longer any value in growing the rest of the plant, it already has more resources than it needs to produce seeds….just no water. Tall, thick, luscious crops and crappy yield. If there is NO dry spell of course, then it doesn’t matter nearly as much. Dry land farmers remember with fond clarity the years which that happened…OK, year. If they’re old enough to remember it.
Turn it around and now and watch what happens with a “less than optimal” rainfall early in the growth period. Note that I said “less than optimal” not none. The plants don’t grow nearly as agressively, they tend to be shorter though about the same thickness (unless we’re taking near drought and then they will be spindly too). But they are growing more than the dopey scientists who only measure what they can see. The roots are developing, and they are going DEEP in search of water. That’s the limiting resource at that point in the plant’s development, and so that’s where the bulk of the growing effort goes. Now we have a short, unimpressive crop with deep roots.
Then we get some mid season rain. With a deep root system that can take advantage of what little water there is because the water can be absorbed from the soil for so much longer, the “optimal rainfall” is now LESS. Even though there is less rain, the larger deeper root system captures so much more of it that the limiting factor becomes hours of sunshine, so what would have been the optimal rainfall for the plants that got lots of moisture early, is TOO MUCH for the plants that got less early, they need more sunshine instead. And if there is a dry spell, the deep root system crop will survive it quite nicely while the crop that got “optimal moisture” early wilts.
I have no more idea what “optimal moisture” means in this context than I do what “average temperature” means. Or what military intelligence means. Or what Post Normal Science means. No, wait, I got that one.
PNS is where scientists who don’t know what they are doing, are paid to not know what they are doing on the proviso that they produce reports supporting the political position of the people who are paying them. I think this is a business opportunity. I can produce reports of similar quality just sitting at my desk top and writing them. The politicians are paying for field work that clearly isn’t necessary since the outcome of the report is predetermined. Just give me the end result and I’m certain I can come up with something more credible at a fraction of the cost. Save the politicians some money, and I will make a bundle.
I have personally witnessed corn growing very well in a desert in Ethiopia where the cool season has highs of 40 C, and the hot season has temps >50 C (OK, I didn’t witness them in the hot season). Given a water source, there are obviously varieties quite resistent to heat. Photo of corn with farmer taken by me: http://chipotle.phanfare.com/1835917#imageID=23003052
Oh, really? Then they should immediately import and grow the type of corn that’s grown in Ohio:
Bulletin 472-05
Chapter 4: Corn Production
By Dr. Peter Thomison, Dr. Pat Lipps, Dr. Ron Hammond, Dr. Robert Mullen, and Bruce Eisley
Successful corn production requires an understanding of the various management practices and environmental conditions affecting crop performance. Planting date, seeding rates, hybrid selection, tillage, fertilization, and pest control all influence corn yield. A crop’s response to a given cultural practice is often influenced by one or more other practices. The keys to developing a successful production system are to recognize and understand the types of interactions that occur among production factors, as well as various yield limiting factors, and to develop management systems that maximize the beneficial aspect of each interaction. Knowledge of corn growth and development is also essential to use cultural practices more efficiently to obtain higher yields and profits.
How Climate Affects Corn Production
Temperature
Corn can survive brief exposures to adverse temperatures—low-end adverse temperatures being around 32 F and high-end temperatures being around 112 F. Growth decreases once temperatures dip to 41 F or exceed 95 F. Optimal temperatures for growth vary between day and night, as well as over the entire growing season. For example, optimal daytime temperatures range between 77 F and 91 F, and optimal nighttime temperatures range between 62 F and 74 F. The optimal average temperatures for the entire crop growing season, however, range between 68 F and 73 F.
http://ohioline.osu.edu/b472/0005.html
Note that 95 F indicated above exceeds Lobell’s yield threshold of 86 F by 9 degrees! I doubt the 1 degree temperature increase attributable to global warming is going to have any impact whatsoever on corn yield in Africa!
Let’s get this straight – these ‘scientists’ conducted a trial in order to ‘get the overall best-performing strains into the hands of farmers growing maize under a broad range of conditions.’ And yet they didn’t bother actually recording those conditions at the growing sites???!!! Words fail me! I know schoolkids who would do a better job!
we grow maize here on our farm in Somerset, UK. We get the best yields when the weather is lovely and warm, a bit of moisture, plenty of manure and well fertilised. I would like to know the variety of maize, the condition of the soil, rainfall levels etc. Personally we have had had better crops in hotter summers, the last few cooler summers have seen a slight drop in yield and the size of the plants.
Some crops, vegetables, fruit etc cannot be grown in certain places in the world if the condions are not suitable for growing healthy crops. I would love to grow mangoes and bananas here but unfortunately its not going to happen!
It seems like Eurekalerts distorted the findings.
Compare this quote from the Eurekalert article:
“They found that a temperature rise of a single degree Celsius would cause yield losses for 65 percent of the present maize-growing region in Africa – provided the crops received the optimal amount of rainfall.”
To this quote from the published article:
“Each degree day spent above 30 °C reduced the final yield by 1% under optimal rain-fed conditions, and by 1.7% under drought conditions.”
Here is a link to the original article:
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1043.html
This is discussing growing corn in sub-Saharan, tropical, equatorial Africa. Can’t really compare that to temperate North America.
The temperatures being discussed aren’t maximum daily temperature but are degree days.
Norman Borlaug was associated with CIMMYT for many years and they are one of the premier green revolution organizations in the world. They are trying to ensure that plants grow where they haven’t been able to grow before and trying to constantly increase production. As the plants are already at their limits in equatorial Africa it doesn’t take much to stress them passed the limits. If anyone can find a way to ensure that the plants can thrive it will be CIMMYT.
The data recorded at the yield testing sites did not include weather information. Instead, the researchers used data gathered from weather stations all over sub-Saharan Africa. Although the stations were operated by different organizations, all data collection was organized by the World Meteorological Organization, so the methods used were consistent.
Unless they have data AT THE FIELD they don’t have anything, nothing at all.
The data recorded at the yield testing sites did not include weather information. Instead, the researchers used data gathered from weather stations all over sub-Saharan Africa. Although the stations were operated by different organizations, all data collection was organized by the World Meteorological Organization, so the methods used were consistent.
Lobell then took the available weather data and interpolated between recording stations to infer what the weather would have been like at the test sites.
They wanted to find some correlation between weather conditions and crop yields but didn’t record the weather at the test sites? Instead they chose to rely on interpolation to infer what the weather would have been like? They had 8 years to conduct the trials and it never occurred to them to record the actual weather conditions at the test sites? This was set up to FAIL.
Yields are predicted to decline by at least 20 percent—compared to what control group, grown where and under what conditions? Where did they get the baseline for the optimal yield? What variety of corn did they grow? There are so many holes in that study that it might as well be mosquito mesh.
These grant trollers say that “a temperature rise of a single degree Celsius would cause yield losses for 65 percent…” As if.
It’s widely accepted that the global temperature has risen 0.7°C over the past century and a half. Along with that rise corn yields have risen dramatically. This paper reminds me of Orwell’s “War is peace, freedom is slavery, ignorance is strength.”
On balance, a 1° warmer world would be better for the biosphere, not worse.
Heat and water are primary drivers for maize production. Extremes of heat at critical times can have considerable impact with loss of plant stand during establishment and pollination failure. These may not correlate with average seasonal temperatures (interpolated or not).
However, water supply is more likely to be a limiting factor in Africa – many soils used for crop production have limited water holding capacity and may not be managed optimally to conserve incident rainfall (research plots are more likely to be frequently cultivated leading to compaction and loss of surface moisture and plant residues that retard evaporation of soil moisture). Thus the effects of short term “drought” (days rather than weeks) are amplified on soils that store limited water and lack soil nutrition that promotes optimal root development.
Sorghum is a more drought tolerant crop but is not generally a human food staple except in parts of Africa.
This article could of used a PEER Review by a farmer – my brother would be willing to do that for you – he farms 600 acres in South Dakota – Sioux Falls area. If you want a decent corn crop you NEED a bunch of 90 to 95 (33 – 35 C)degree days – now admitted if there is no mositure in the ground – 90 and above can be rough on the corn – but insufficient moisture will always cause a low yield.
I think it is safe to say that it is a good thing for AGW advocates that their primary audience is not farmers. My guess is that the same holds for everyone who works outdoors, including ranchers of all kinds, people in the timber business, fishermen, and all the others.
Now, one other thing about corn. It can withstand extreme temperatures, but it needs some cool nights to respire and recover. Then this
To this quote from the published article:
“Each degree day spent above 30 °C reduced the final yield by 1% under optimal rain-fed conditions, and by 1.7% under drought conditions.”
makes sense. However, there is still an awful lot that needs to be known about the study. Varieties, planting dates, etc, etc. And I still maintain, without actual records at the sight, the whole thing was a gigantic waste of time.
I’m just back from Ecuador, which is on the equator. Maize thrives on the coastal lowlands where it is hotter than 30 degC in the daytime, and in the highlands 7000 ft up where it is cooler.
If the increase in heat is due to the supposed greenhouse effect, i.e. increasing CO2, then the temperature of optimum growth increases, as does resistance to heat stress. See the third figure in my post:
http://buythetruth.wordpress.com/2009/06/13/photosynthesis-and-co2-enrichment
Crops are vastly more tolerant of heat, cold, drought, salinity etc when CO2 levels are higher.
FTA “Stanford agricultural scientist David Lobell …
“Lobell, who is an assistant professor of environmental Earth system science.”
So which is it, I know what a agricultural scientist is basically but a “environmental Earth system science” sounds like witchdoctor’s shaking beads and rattles; if its beads and rattles the 30 C, probably means 15 C at the coolest of night and 45 C at the hottest point of the day ( 59- 113 F)! So yeah corn probably wouldn’t do too good.
Of course the other thing they fail to mention is corn is basically a bad crop for Africa anyways it needs too much water and too much fertilizer for Africa.
Theo Goodwin says:
Mike says:
March 14, 2011 at 9:20 am
“Yields of three of the most important crops produced in the United States – corn, soybeans and cotton – are predicted to fall off a cliff if temperatures rise due to climate change.”
Corn, soybeans, and cotton do really well in North Florida. So, are you suggesting that Nebraska is going to be warmer than North Florida? I suspect that you have no experience whatsoever with corn, soybeans, or cotton.
I’m beginning to think Mike doesn’t even know what a growing crop looks like.
I’ve been gardening for many years now. A couple years ago I moved from Southern California (Zone 9) to North Carolina (Zone 7). As I result, for the same plants grown in similar conditions (I keep my growing conditions pretty well controlled), I have experienced a noticeably shorter growing period and substantially lower yields. Anecdotal, perhaps, but all the reading I’ve done suggests that my experience is pretty common.
Zone 9 is significantly warmer than Zone 7. The warmer climate in Zone 9 was much more conducive to a good vegetable garden. I’m seriously thinking about building a greenhouse.
Mike has also informed me that we’re going to lose crops if it gets any cooler, too. Apparently, we need to stabilize our climate EXACTLY WHERE IT IS, or we’re going to run out of food. It seems that our modern crops and modern techniques are nowhere near as robust as they were during the medieval and Roman eras. We’ve engineered extreme fragility into our food crops, it would seem, since either colder OR warmer will cause problems.
I would suggest that Mike spend a little time outside getting his hands dirty and getting familiar with these ‘crops’ he’s so worried about. He might gain a little respect for them.
I think most farmers would agree with me that this hardly seems like groundbreaking or important research. Are crop yields affected by temperature and rainfall? To most farmers this question is akin to “does the sun rise in the east”? We thought that was established thousands of years ago.
The real problem here from an agricultural perspective is that warmer temperatures are much easier to deal with than colder temperatures. The potential for large areas of crop failures due to frost in important growing areas of North America, Russia, Argentina, South Africa, and Australia far out weighs any threat from warmer temperatures. We already have much skill and many ways of dealing with extreme heat and still producing crops, especially in areas of Africa where water is available.
Almost no researchers are working on more frost tolerant varieties, because our acedemic institutions have bought into the warming scam lock stock and barrel.
RE:
Dr. Dave says:
March 14, 2011 at 11:01 am
“…When I lived in Michigan we grew wonderful sweetcorn almost effortlessly. I now live in northern NM and I’ve not been able to grow a decent corn crop in 16 years. I have always attributed this to our overnight low temps. We get daytime highs > 95 deg F at the height of summer, but the temp drops 30-40 deg F overnight.”
I once wandered about along I-40 in your area, and up tp Farmington and over into Arizona. If you can, ask a Native American farmer how the heck they grow corn in what seems to us to be hostile environments. I recall driving to the north of I-40 and seeing, in the distance, a Hopi farmer tending widely-spaced corn plants on what seemed to be the steep side of a sand dune.
I myself tried growing corn in New Mexico one spring, and a Navajo fellow I knew laughed at me, because I was planting the kernals and inch or two down, like I did back in New England. He said they had to be planted a foot deep. If you tried that in New England you’d never see a shoot emerge, but in New Mexico the water vanished into the sand so quickly the sand hardly seemed to get damp. (I was so restless in those days I moved on before my crop was knee high, so I can offer no results for my experiment.)
Local farmers have local tricks.
Like many climate scare stories this article falls in the category of: “If global warming, then a catastrophe.” The authors can relax because there is no so-called “anthropogenic” or any other kind of global warming now and there never was any except for a short spurt of step warming. How do I know this? Because satellites have been measuring global temperature for thirty one years and they simply don’t see this alleged warming that so-called “climate” scientist are pushing, not even the one that Hansen warned us about. There was a step change, yes, that raised global temperature by a third of a degree in four years and then stopped in the year 2002. That was it for global warming. Its cause was oceanic, a super El Nino and its aftermath, and not anthropogenic. There was no warming before it and there has been none since. There is non-global warming in the Arctic but it is caused by warm Atlantic waters melting the ice and not by any imaginary greenhouse effect. It started suddenly at the turn of the twentieth century and laws of physics do not permit carbon dioxide to be its cause simply because its absorbancy in the infrared is a physical property that cannot be changed. The only other way to start CO2 greenhouse warming is to put more gas in the air and we know this did not happen in the year 1900. So relax and enjoy your popcorn.
I grew up on an Eastern Oregon Cattle/Wheat ranch. Here we do mostly Wheat, Potatos,Mint, and sugar beets. Too cold for good corn. Lately tooo cold for good tomato
groth either-with proper protection.Hmmm…
This paper is quite frankly,Bravo Sierra. ..
The reason they were doing test plots in these places south of the Sahara is precisely because its dry savanah country and they wanted to see if strains that can take the climate. They get a rainy season for a couple of months (depending on latitude – more or less) bracketed by a month of high humidity. When it ends there is virtually cloudless days for the rest of the year. The crop has to make it on soil moisture and irrigation where that is possible. Using these trials as if they were uniformly the same for statistically is not correct. Some trials would be better than others depending on a number of factors: strain of corn, quality of the soil, treatments of the soil, mini-topograhic variations, timing of first rains and planting…. How am I doing for confounding stat analysis. Later trials may also be less successful than earlier trials – how do you decide that temp is the main parameter?
I mapped the geology of 30,000sqmi of this kind of country in Northern ,igeria in the 60s. They couldn’t grow corn there then but they grew so many 1000s tons of peanuts that the railway couldn’t move this short-season crop out in 12 months thereby creating the famous “Kano Pyramids – long rows of piles of sacks of peanuts 20 feet (guess(imate) high. This crop grew like crazy and is a way higher in protien than corn. These technical aid professors are putting Sub-Saharans at risk.
The best technical aid agriculture I ever saw was a wheat plantation in Tanzania az far as the eye could see – put in by Saskatchewa wheat farmers, not environment doctors. Send over a dozen Iowa corn farmers and then let’s repeat the experiment. BTW at night after a 40C day, you want to pull on a cardigan as it dips down to the low to mid 20s.
“…When I lived in Michigan we grew wonderful sweetcorn almost effortlessly. I now live in northern NM and I’ve not been able to grow a decent corn crop in 16 years. I have always attributed this to our overnight low temps. We get daytime highs > 95 deg F at the height of summer, but the temp drops 30-40 deg F overnight.”
Low, low, low humidity isn’t helping you any. However, in Colorado, just to the Northeast, they can grow some tremendous irrigated corn, and I do mean tremendous. Dryland corn is a crapshoot, at best.