Carnage Cornage in Africa from Global Warming

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

This is an experimental maize field managed by CIMMYT in Kiboko, Kenya, Photo by David Lobell, Stanford University

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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James Sexton

Anthony, I’m with you. Being a long time resident of rural SE Kansas, I know corn is grown in the hottest time of the year. 86 deg F is nothing. I’d be hard pressed to find a continuous period that temps don’t get to 86 deg during July and Aug. And, last I checked, there were several places on the globe much warmer than Kansas that grows corn.
I’m not sure what dynamic they’re witnessing, but it isn’t heat that causes corn not to grow. I’ve a buddy that’s a corn farmer here, I’ll try to see if he’s any particular insights to this, but I’m guessing this is just another jigged study to get results they were looking for.
It would be nice to see the study itself.

noaaprogrammer

The higher the level of CO2, the better a plant can withstand drought.

Pull My Finger

Oh brother, the following leads me to call B.S.

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.

As usual, lot of “coulds”, “woulds”, and “interpolations”.

Mike

U.S. Crop Yields Could Wilt in Heat
http://news.ncsu.edu/releases/crop-yields-could-wilt-heat/
Release Date: 08.24.2009
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.
In a paper published online this week in Proceedings of the National Academy of Sciences, North Carolina State University agricultural and resource economist Dr. Michael Roberts and Dr. Wolfram Schlenker, an assistant professor of economics at Columbia University, predict that U.S. crop yields could decrease by 30 to 46 percent over the next century under slow global warming scenarios, and by a devastating 63 to 82 percent under the most rapid global warming scenarios.

Ceri Phipps

I live in Scotland. We don’t grow maize here, it’s too cold. So guess what! We grow things that do grow here!

J. Knight

This is BS. I live in the southern United States, and corn crops are grown from south Texas to northern Florida, and every place in between, including central and southern Louisiana, where temperatures in the summer growing season are routinely in the high 90s F, and occasionally low 100s F. Only extremely dry weather will cause the crop to wilt.

L Nettles

Wouldn’t maize be considered an invasive species in Africa? Kinda like those potatoes in Ireland?

Speed

” … we assumed maize to be among the more heat-tolerant crops,” said Marianne Banziger, co-author of the study …
Perhaps she assumed wrong.

Our corn crop in the garden sets in June, when daily high temps average 96 F. We plant ‘ultimate’ which is a sweet corn. In fact, hotter seasons usually yield a larger crop, but that’s likely because hotter seasons usually correspond to more sunny days.

Ian L. McQueen

Funny, I was under the impression that it gets hot in the corn-growing parts of the USA.
IanM

Theo Goodwin

There must be more to the story. A temperature rise of 1.7 degrees Fahrenheit had this effect? I grew up on a working farm and am happy to testify that a rise of 1.7 degrees Fahrenheit cannot possibly have this effect.
Then there is this:
“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.”
Darn nice of these folks to explain that they are the most absent-minded scientists to survive an experiment. They took no temperature data at the experimental sites? Or did they prefer interpolated data? How does this stuff get published?

David Miller

Corn responds to high night time temperatures (above 80F) by not opening the stomata on the plant leaf to conserve moisture causing inefficient sugar production resulting in lower yield.
Last summer in the midwest, above average night time lows (probably a result of above average rainfall and humidty) was blamed for lower yields. However the abundant moisture also made 2010 a near record crop.

Ben of Houston

You wonder how Texans have been able to grow corn for the past few centuries. 86F is considered a cool day in the summer, and drought is relatively common.

Speed

There is a chance that we might be able to stem the effects on plant yield from this climate change,” said L. Curtis Hannah, a plant molecular biology researcher at the University of Florida. “But a betting man knows that our best chance is to learn to adapt — to develop crops that will feed people in a hotter climate.

Hannah developed two heat-stable variants of AGPase genes Sh2 and Bt2. Under hot environmental conditions, the Sh2 variant increased the yield of wheat by 38 percent and increased the yield for rice by 23 percent. The combination of the two variants provided a 68 percent increase in yield for maize.

There’s lots we still don’t know.
Man has been growing these crops for thousands of years, but we’ve only had the tools to try to understand what really makes them grow for a relatively short amount of time,” Hannah said. “There’s a long way to go before we have a truly comprehensive picture of why they do what they do.”
http://www.livescience.com/3527-heat-tolerant-corn-prevent-future-starvation.html

Jeff Carlson

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 …

Vince Causey

Do we know if these high temperatures coincided with drought?
That is one of the problems with field studies – so many variables, so much noise to signal. A more sensible and useful experiment would be to carry out maize growing under controlled conditions, varying temperature but keeping water and other factors constant.
But I suppose that would go against the consensus that the future will bring only droughts and heat waves.

wrcornell

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.
http://southwestfarmpress.com/texas-corn-yield-winner-cautions-growers
341 bushels per acre out of west Texas (Hart, Texas).
Average high temperatures during growing season :
May 80.6 F, June 88.1F, July 89.9F, August 88.3F.
Seems like there may be a problem with the farming practices in the study. The gentleman that won this contest, claims there is even more potential to increase yields on his land.
“My next goal is to break the world record corn yield,” he said. That’s 442.14 bushels per acre, according to the National Corn Growers Association. The record was set back in 2002 in Iowa. Albracht thinks that’s within reach, even in Texas.
“Then I want to make 500 bushels per acre. I think it’s possible, but everything has to be perfect.”

ferdberple

That isn’t what National Geographic has to say. They are predicting that the Sahara will return to a green state, as it was thousands of years ago, before the temples of Egypt were buried in sand. Of course disaster stories are always goood press.
http://news.nationalgeographic.com/news/2009/07/090731-green-sahara.html

John in NZ

When corn was subjected to temperatures above 99degC for 5 minutes, researchers found it was ready to eat.
sarc off.

James Sexton

Pull My Finger says:
March 14, 2011 at 9:18 am
Oh brother, the following leads me to call B.S.

Lobell then took the available weather data and interpolated between recording stations…..
====================================================
Yeh, I’m wondering if they’re using NASA’s “interpolating” methods. God forbid that they’d actually do something like real observation in a science study. Thermometers being soooo cost prohibitive.

Theo Goodwin

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.

Mike says:
Down is up, evil is good, white is black, war is peace, and ‘U.S. crop yields could decrease by a devastating 63 to 82 percent.’ Always the pessimist.
Go sell your debunked snake oil elsewhere, Mike. This is a science site, not Elmer Gantry’s portal.

Night time temperature during silking is a big factor. “Warm night-time temperature even when day-time heat is not excessive tends to reduce yield by shortening the filling period. Cool night-time temperatures after silking are associated with the higher yielding years in Iowa.” That limits the growing season in the hot humid south.

TXRed

OK, a few questions. 1) exactly how much did the yield decline, and did the quality (protein and sugars) in the maize decline with the yield? 2) Were pests more active during the warmer periods? 3) What hybrid were they using and was it one developed for warmer climates (there are rapid-growing “90 day” maize-varieties for growing in places like northern Iowa and Minnesota)? 4) What was considered sufficient rainfall? Maize is a somewhat thirsty crop compared to some grains (wheat, sorghums).
If those questions are answered in the article and show that temperature was the only variable that could have affected the outcome of the experiments, then I’ll come out of the “sceptic” side of the camp. If there is a difference, I’d wonder about temperature and the soil – encouraging certain pests or processes that affect the plants.

Sorry, here is a link, http://www.extension.iastate.edu/CropNews/2010/1008elmore.htm It also limits tomatoes which I enjoy filching from my neighbor’s garden right now.

…she said. “The effect is even larger if drought and heat come together”

Funny how that works.

Richard111

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.

erik sloneker

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.

John in NZ

“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.

John in NZ

oops, that should have been “This reduces yeild but reduces risk, “

bubbagyro

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…

Holbrook

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.

Mike

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.

jorgekafkazar

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.

Curiousgeorge

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.

Jarmo

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

TerryS

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”?

Iskandar

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.

starzmom

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.

Derrick

Gee, let me guess….
They put all of their “data” into a corn computer model to get the result.

Viv Evans

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.

Theo Goodwin

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.

stupidboy

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.

Rhoda R

I seem to remember that corn was developed in central Mexico. Surely one of the cooler areas of the world. (/sarc)

Duster

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.

Carlo

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.

Hu McCulloch

Are they interpolating between the nearest airports?

kadaka (KD Knoebel)

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:

When you look at most regions of the world, one degree of warming will translate to a general loss of five to ten percent crop yield. So, if the global average temperatures change by a couple of degrees, a 15 percent loss in crop yield is feasible, but it just doesn’t look like we will be anywhere near this in the next 10 years, or even the next 20 or 30 years.

Right above that is the proposed mechanism:

Higher temperatures around the world are going to be somewhat damaging for plants. They will lower crop yields and shorten the growing season in the tropics because water will evaporate from the ground faster.

So one can guess what’s going on here. Even though it says in the Eurekalert notice copied above (bold added):

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.

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?

Dr. Dave

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.

TomRude

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.