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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Funny how that works.
I lived in South Africa for twenty years and 40C in summer was not uncommon.
Drought is the problem. Any checks made on ENSO? Friends say they are in
drought conditions on the east coast south of Durban. I understand La Nina
still prevails.
Here in Central Illinois, the absolute heart of America’s corn country, we on average experience 30 days at or above 90 Degrees F with no ill effect. Their statement “The data recorded at the yield testing sites did not include weather information” is extremely problematic. Corn has a 10 to 12 day critical window during the silking stage wherein the plant is trying to “decide” how large an ear to shoot and how many kernals to pollinate. Optimum soil moisture and moderate (90 degree or less) temperatures are needed to maximize the yeild. Without weather data at the test plots this study is pretty much worthless.
The new super hybrids that are out there make the crop much less sensitive to these types of issues. The last outright crop failure I can remember occurred in 1988 during an extreme drought. The new hybrids were developed starting in the late 1990s and since then we’ve seen our crops do quite well in what would formerly have been very worrysome conditions. It seems very likely that further advances corn GMO technology will all but eliminate the potential for widespread crop failures.
“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.”
Why don’t they look at the real world?
Maize (what we call corn) crops in my region this year failed or grew poorly if they were not planted early. I planted 6 hectares early (mid October) and will have the best yeild ever but I planted early. We grow two varieties, an early and a late maturing variety. This reduces risk but reduces risk,
Planting early is risky as a late frost will kill the crop. Planting late is risky because it can get too dry too early. I was lucky The hot dry weather that caused other crops to fail was after my crop was well established and so the result was excellent growth.
Trying to make predictions based on just weather and yeild data is just silly as it ignores too many other variables that farmers can control. Farmers adjust to variable weather with changes to things like crop type, variety and planting times.
oops, that should have been “This reduces yeild but reduces risk, “
What happens when corn is subjected to periods of 0°C or lower for even short periods of time?
Seems this is more likely to happen. Remember the soccer games in S. Africa last year? Brrrr…
Being a layman sceptic I read the story as any member of the public would and take it on board as the truth. However as an avid reader of WUWT I must say it never ceases to amaze me as to how quickly the people with expert knowledge on any given subject shoot down the stupidity in flames…usually with a degree or so of humour.
Thanks lads…can’t wait till later when many more people will have their say.
Smokey: “Go sell your debunked snake oil elsewhere, Mike. This is a science site, not Elmer Gantry’s portal.”
Smokey is as charming and informed as always. /sarc off
Meanwhile, ferd berple has posted a link to an interesting science based article that does indeed present evidence for the ‘AGW is not so bad’ point of view. Good for him! It should certainly be taken into account along with other more pessimistic research. Let’s not cherry pick in either direction.
These people are “scientists” and are therefore to be trusted as far as you can toss a live bull up a silo.
They failed to adjust for enhanced CO2, they estimated the temperatures, and (I stronly suspect) they failed to accurately control moisture addition rates and soil properties.
I’d want to know more about the soil and fertilizer used before I’d suspect heat. A sulfur and/or nitrogen deficiency would be a more likely culprit, imho.
These studies never take into consideration the developments in plant varieties and farming technology:
http://apps.cimmyt.org/english/wps/news/2010/apr/study-dtma.htm
Study says drought tolerant maize will greatly profit African farmers
So an increase of 1c would drop yields by 65%.
Does this mean that a temperature decrease of 1c would increase yields by 285%?
Or is the report claiming that, like baby bears porridge in Goldilocks, the temperature at their test sites is “just right”?
And what other influences did they neglect? I know from personal experience that a flock of pigeons can ruin a recently sown field by eating all of the kernels. Also a few cold nigths just after the seeds started germinating will have a devastating effect, much more than warm weather. I know that during the sixties, we had to sow our fields repeatedly due to cold nights, reducing the number of successfully germinasting seeds. The same for sugar beet. Costed a fortune in seed. And what about rain? Plenty of rain during the first weeks exposes the kernels in the soil, to be eaten by mouses, pigeons. Water saturated soil does not support maize germination, every kernel will start to rot or be attacked by funghi. The same holds true for the time the maize starts flowering: you need dry weather, with some moisture in the air to expose the silks (the female organ) and heating afterward with relatively dry air to release the pollen. When it rains constantly, you will get surprisingly low yield of kernels per acre.
I really wonder whether some of these factors were incorporated in the study.
Correlation is not causation.
The last time I saw a map of Africa that showed weather station coverage, there were lots of gray areas in central Africa. Just how far are they interpolating? This seems to be a shaky way of estimating temperature. How much error is there in the interpolations? Are they also interpolating rainfall? I’m skeptical.
Gee, let me guess….
They put all of their “data” into a corn computer model to get the result.
So they’ve been running ‘experimental maize fields’in Kenya – but didn’t record the temperatures at those fields?
What sort of experiment is that?
Or perhaps they did check the temperatures then – only nothing showed up as cAGW.
Without this newfangled interpolation, they wouldn’t have been able to show that AGW is bad, so no paper to be published … that makes sense.
dallas says:
March 14, 2011 at 9:48 am
“Night time temperature during silking is a big factor…That limits the growing season in the hot humid south.”
I take it that you have not actually owned a commercial farm and grown corn over a period of years for profit, right? Also, please keep in mind that the hot, humid south extends from at least Little Rock, Arkansas to Miami, Florida.
I wonder how much it cost for CIMMYT to work out that drought causes crop yields to decline. Keeps ’em out of trouble I suppose.
Perhaps David Lobell and the boys and girls at the International Maize and Wheat Improvement Center should go on “a blind date” with Brenda B. Lin of the Australian Commonwealth Scientific and Industrial Research Organization. Her solution is for farmers to grow a broader range of species or varieties, either at the same time or in rotation, or introduce structural variety into uniform fields. In other words, diversification.
I seem to remember that corn was developed in central Mexico. Surely one of the cooler areas of the world. (/sarc)
Jeff Carlson says:
March 14, 2011 at 9:36 am
lets see if we can grow corn in one of the worst places on earth for crops … notice those stunted trees in the background and the color of the soil … can you say claylike …
The soil doesn’t look particularly clayey, but the red color is indicative of a highly oxidized horizon that is probably really low in nutrients to begin with.
I they use Monsanto–genetically modified seeds, they have a problem, the plants are not strong enough in dry or wet or warm or cold climates.
The local not–modified seeds are stronger.
Are they interpolating between the nearest airports?
Here’s something with David Lobell’s insights from just a few months ago:
http://www.climatecentral.org/blog/climate-change-and-global-food-production-qa-with-david-lobell/
Climate Change and Global Food Production: Q&A with David Lobell
Published: January 25th, 2011
It doesn’t sound too alarming, and starts off criticizing another AGW-based alarming agricultural report, albeit one that even Gavin Schmidt felt the need to criticize (perhaps because it says soybeans would do better?).
It has a highlighted quote similar to what’s above:
Right above that is the proposed mechanism:
So one can guess what’s going on here. Even though it says in the Eurekalert notice copied above (bold added):
Apparently they start off with the optimal amount of rainfall for a given temperature, then figure that with the temperature rise there’ll be additional evaporation that reduces the amount of available water from the previously-optimal amount. So at the higher temperature there is effectively a less-than-optimal amount of rainfall, which also somehow yields a shorter growing season, and a drop in yield. Amazing discovery by these researchers, eh?
That’s my guess, from what I read in the Q&A with Lobell and the Eurekalert notice above. Anyone else want to look at that Q&A and see what they can make of it?
Having been a backyard gardener for about 30 years I would want a LOT more data than just interpolated temperature. Exactly what type of corn was grown? What about site-specific temperature and humidity data? How about fertilizer use, soil nutrients, soil moisture, soil pH, soil temperature, etc.?
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.
More than temperature, drought might the deciding factor here. So they should read Meteorology and Climate of Tropical Africa by Leroux because drought result in quaternary record from cold periods not warm periods.