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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117 thoughts on “Carnage Cornage in Africa from Global Warming

  1. 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.

  2. 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”.

  3. 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.

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

  5. 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.

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

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

    Perhaps she assumed wrong.

  8. 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.

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

    IanM

  10. 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?

  11. 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.

  12. 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.

  13. 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

  14. 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 …

  15. 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.

  16. 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.”

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

    sarc off.

  18. 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.

  19. 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.

  20. 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.

  21. 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.

  22. 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.

  23. 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.

  24. 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.

  25. “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.

  26. 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…

  27. 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.

  28. 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.

  29. 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.

  30. 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.

  31. 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”?

  32. 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.

  33. 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.

  34. Gee, let me guess….

    They put all of their “data” into a corn computer model to get the result.

  35. 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.

  36. 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.

  37. 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.

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

  39. 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.

  40. 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.

  41. 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?

  42. 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.

  43. 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.

  44. This is desperately eking out a paper from failed science. Years of crop testing at over a large area with no weather monitoring at the sites!! What the f!

  45. Maize is a C4 crop and does not respond to higher CO2 levels like the other corn crops that are C3 photosynthesis (wheat, barley etc). C4 has an advantage over C3 in low CO2 atmosphere.

    Maize is a relatively drought resistant crop, but has a particularly sensitive period at silking (when pollination occurs). No kernels = no human food yield, but could still be used as a whole crop for animal feed.

    As others have expressed, it is extraordinary that these experiments were not conducted with a mini weather station on site.

  46. This article makes me sick. I know the Economist takes some knocks on this website, but they can have really good information at times on articles like this. They recently had an extensive article on yields for crops (wheat specifically).

    Practices make the biggest differences. There is a reason this test was done in Africa where practices are poor at best. If they did this in the US the results would be different. It would be easy to correlate temperature to yield in the US, but they want it to look bad.

    http://www.economist.com/node/18200618?story_id=18200618

  47. If the photo in the article is representative, the corn field shown is suffering from drought. Powder dry soil, stunted corn plants with dry bottom leaves – drought. If these are genuinely corn test plots, they will have accompanying data on LOCAL rainfall. Where is the data?

  48. There is nothing wrong with research on how crops grow and how crops have high and low yield or none. What is wrong here is their research is to find how to grow crops when conditions are brought about by an unproven theory, and in view of that and the actual conditions on earth to be studied it seems like a waste of money and time until the theory is proven.

    However if you intend to have government take over the world food supply and manage its production and distribution rather than through the productive free enterprise system then there has to be a reason to justify the change so why not tie it to the one big cause for world socialism and redistribution of wealth, that being global warming, climate change with mans misuse of CO2 as the culprit.

    Testing of hybrid seed corn by is done on a voluntary basis on productive farms usually privately owned and are marked with signs saying so, at least in the US. The entire growing season is monitored and tests are made on the conditions at the site and recorded. Besides testing, the results if good are an advertisement to buy. Farmers are provided with incentives to grow strips of the test crop and to buy, and that is the free enterprise system where the money flows primarily through the private sector where the incentive is to produce rather than through government where the incentive seem to be to promote a theory.

    This free enterprise system has done well for improving crop production, distribution and sales and well for the tax payer. No airplane could be sold, for commercial use, before man could build one and before it was proven to fly as advertised. A theory should not be sold as truth before proven, nor should research in other areas be justified by a not proven theory and government should not promote the sale of a theory. Especially one justified with deception, biased against argument, and wanted by politicians for legislation and regulation.

  49. It would seem important for the study to control for water (too little or too much, timing of application), fertilizer (if any), insecticides and a whole host of co-correlated variables. The statement that a “hidden trove of historical crop yield data… shows that corn….is a likely victim of global warming” is a bold one.

  50. While “jive” is much more amusing, I believe that “jibe” is the more correct word. ;-)

    [Fixed, thanks. ~dbs]

  51. From TerryS on March 14, 2011 at 10:21 am

    So an increase of 1c would drop yields by 65%.

    Not exactly. They’re saying of the “present maize-growing region in Africa” that an increase of 1°C (or 1K) will drop yields in 65% of that area “provided the crops received the optimal amount of rainfall.” If drought conditions then all of the area will have reduced yields, with more than 75% of the area having yield losses of at least 20%. For some reason they want to add that “1°C” note for drought conditions as well. So what are the yield losses for what percentage of the area for drought conditions without the temperature increase?

  52. For those who don’t know, CIMMYT is one of the biggest of the CGIAR centers (along with IRRI) and they have just had their commission for climate change meeting (http://wattsupwiththat.com/2011/03/11/new-commission-confronts-threats-to-food-security-from-climate-change/), so this is a quick plug to make sure they don’t get left out of the research funding.

    The problem is still that Africa’s yields have not increased in the last 20 years, despite yields increasing everywhere else in the world. For all CIMMYT, IRRI, CIP etc. have done, there has been no improvement in African agriculture and to use field trial results from this period (20,000 trials is a long time) suggests to me that they have run a big data dredge to try and shift the focus away from their lack of impact.

    For those questioning the poor data, these trials would have been run before global warming was the issue and so before there temperature records were deemed critical. And remember, these are in Africa where the infrastructure for such trials is hardly ideal – on the whole, I would take this study with a very large pinch of salt , but let’s not let that spoil a good global warming scare story eh?

  53. Isn’t this data available for many countries around the world?
    For example, in the U.S.
    Step 1. Gather weather data by U.S. county for the past 50 years.
    Step 2. Gather crop yield data by U.S. county for the past 50 years.
    Step 3. Regress yield on weather data.

    This test must have been done a thousand times. Why is Africa different?

    What’s the natural variation in growing season temperature from year to year? It must be greater than 1 or 2 degrees and we don’t see 50% variation in crop yield. I grew up on the midwest and yields don’t vary that much unless there is drought.

    As Billy Joel said when he left the stage at Shea Stadium for the last time, ‘Don’t take any Sh!t from anybody!” (By the way, his new release is incredible on blu ray.)

  54. Des Moines, Iowa average temperature is 86 F in July and 84 F in Aug (TWC). Corn must be “knee high by the 4th of July” for a good crop so I think we grow corn at or above what he says destruction starts.

  55. This is total and complete CRAP. I have raised corn all my life. We require an active temperature in excess of 60 degrees F. When the summer is not warm enough (like last summer) it impacts how the corn develops. Heat is not a problem. We grew a 200 bushel/per acre crop a few years ago and had many days that were 100+. The biggest factor in corn growth is water and humidity. Without those two factors, your sunk. Here in western Colorado we have low humidity, but with enough water the corn generates its own humidity. These “scientists” need to come actually work with farmers. Anyone who grows corn here in the USA would tell them that farmers pray for heat. Rain if you are a dryland farmer. But without heat, nothing grows. Took forever for our tomatoes to ripen last year too. Warming isn’t a problem…cooling is.

  56. This has got to be one of the silliest studies I’ve ever read about. If you want to know how corn reacts to hot temperatures, just ask a farmer. He’ll know. You don’t need to do no stinking study or extrapolate any temperatures. The guy that’s been out in his field every day for the last 40 years can give you a better answer than any study.

    And, I’m sure that if corn is “long believed to tolerate hot temperatures”, then it’s probably true. It’s not like humanity has little experience with growing corn.

  57. For starters, you can’t just look at “optimal rainfall” for ANY crop. You have to look at how much of the optimal rainfall occured at critical points in plant development and what weather immediately followed. An inch of rain at just the right time followed by a week of dense cloud produces a very different result that an inch of rain followed by clear skies and bright sunshine. I’ve seen bumper crops from a variety of crop types produced in years when rainfall was near to drought conditions. What little fell did so at just the right time and was followed by just the right sunshine conditions. “Optimal rainfall” is meaningless unless it is correlated over the growing season with seeding time and scores of other factors.

    But I suspect that the big one they missed is wind. Corn grows fast, and it sucks up an enormous amount of CO2. Take an air sample in the middle of a corn field on a windless day and you’ll get a reading of zero, the corn sucked it all up and until the wind blows some more in, it stops growing. Just a smidge of a breeze to keep the local air turbulent and cycling CO2 laiden air back into proximity of the corn can make a huge difference to yields.

    One degree? That’s probably a measure of the number of degrees they research team had between them?

  58. Stanford is famous as an Ag school. /sarc alert.
    The sillycon valley mostly grows silicon wafers. Great with milk and cookies.

  59. The IPCC also came out with a similar statement in 2001 pointing out that poorer countries would be impacted most and that common crops were close to their temperature limit which would reduce yields but this appears to be an economic issue not an unusual climate issue. The ultimate solution would be to develop a perennial for common crops.

    Oddly, common crops found in regions like Africa are likely to already be drought and temperature resistant so you really have to question this study.

    Scientists Sow Ancient Seeds to Survive Global Warming

    Pioneer
    Optimum® AQUAmax™ hybrids for water-limited environments

    http://www.pioneer.com/home/site/us/products/corn/seed-traits-technologies-corn/optimum-aquamax-hybrids/

    “Drought stress has been an ongoing challenge to high corn yields in many corn-producing areas of North America, and Pioneer has been a leader in conducting drought corn research for more than 50 years.”

    “Currently using dedicated drought research sites – located in Nebraska, Kansas, Colorado, Texas, California and North Carolina, – Pioneer research has more than doubled the number of bushels/inch of water over the past three decades.”

  60. I can only speak from what I saw in Nigeria over many years but obviously Lobell never tried his stuff there. Well over 30 and it grows like a weed! Check any street vendor BBQ-ing the stuff!

  61. Rob Potter says:
    March 14, 2011 at 11:30 am
    “The problem is still that Africa’s yields have not increased in the last 20 years, despite yields increasing everywhere else in the world.”

    Interesting comment Rob. I would hazard a guess that the yields were larger before Mugabe changed “Land Management”!

  62. Supposedly, temperatures in the tropics will be less affected by global warming than other regions. Isn’t the rise supposed to mostly affect the poles?

  63. Why all the fuss about maize which is a “New World” species? Millet crops better all over Africa as do many of the “Old World” species, they just don’t get the limelight and the research money.These reports are written more for the benefit of the writers than for the health and well-being of the hungry instead of looking at what does grow and yield well under local conditions.As one person commented a while back,maize is not a favorite crop in Scotland !
    Mention of the potato in Ireland reminds me of the number of deaths caused by the issue of dried maize to the starving who had never seen the stuff before,had no means of grinding it and fed it to their children with disastrous results. If food crops are needed ,send out some farmers to access the situation,not a bunch of hippies in white coats.

  64. Kiboko Kenya Agricultural Research Institute, elevation 1,000 mts. at 2*3′S & 37*8′E is off the Nairobi road heading to the Mombasa coast. The Masai tribe’s pastoral territory is to the west , Kyulu Hills conservation area to the south and agro/pastoral Kamba’s tribes homeland are to the north & east of the Institute’s land.
    This is red sandy loam territory and the Kibuko River plain waterlogs during the rainy season. There is a limited amount of volcanic soil and likewise some volcanic rock pans. Marginal agricultural land , like this semi-arid region of Acacia trees, is constrained by many problems .
    The Institutes land used to be relegated for wild game hunting. The Tse Tse fly prevalence in that zone of Kenya merited a TseTse study habitat site be established ( at 2*15′S & 27*45′E ). My Swahili is pretty rusty after more than 40 years, but I remember vehicle stops on the main road (going from Mombasa toward Nairobi) by mosquito net helmeted inspectors trying to keep TseTse flys from hitching out of the area.

  65. Ecofraud is the expenditure more resources to save less resources. Ethanol is a prime example. We worry about corn only to burn it in the bonfire of ethanol’s perverse energy exchange: $1.45 of energy to produce $1 of ethanol energy.

  66. 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?

  67. 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.

  68. 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!

  69. 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.

  70. 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

  71. “Essentially, the longer a maize crop is exposed to temperatures above 30 C, or 86 F, the more the yield declines,” she said.

    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!

  72. 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!

  73. 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!

  74. 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.

  75. 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.

  76. 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.

  77. 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.

  78. 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.

  79. 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.

  80. 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.

  81. 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.

  82. 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.

  83. 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.

  84. 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.

  85. 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.

  86. 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.

  87. 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.

  88. 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. ..

  89. 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.

  90. …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.

  91. The story is rather corny, if you ask me.
    This guy can’t grow corn in his interpolated paper greenhouse.
    Send him a box of Crayola Crayons and a label from a can of Green Giant Corn.

  92. Did they really plant that corn in the soil shown in the photo?
    Wow – what optimists!
    No wonder that they were disappointed with the yield.

  93. Funny I never noticed any problem with Ohio corn in the 35years I lived there– getsw up to nearly 95-100F during July-August when the corn is taller than a pro basketballer….

  94. Someone just needs to find the data used and one would find it tells a completely different story than the abstract and the pro-AGW spin put on it.

    This is the inaugural issue of “Nature – Climate Change”. Of course it is going to show we are all going to starve to death/burn to death from increased CO2 level (which benefits both C3 broad-leaf plants and C4 grasses and corn especially in drought conditions). It is “Nature” which drank the kool-aid long ago and refuses to go back to real science pursuits again.

    I can guarantee you the actual data supports the supposition that higher temperatures results in more corn yield (including the actual data provided by Prof. Lobell in this study).

  95. My experiances with growing corn are it likes the heat (its often up to 37 degrees here) so long as theres adequate moisture – the key to getting a good harvest is to ensure good and even germination – was that a factor accounted for in their study? Wind pollination and plant spacing is important, if there not pollinated by hand (which typically gives better results).

  96. From NOAA Climate Prediction Center:

    A corn growing degree day (GDD) is an index used to express crop maturity. The index is computed by subtracting a base temperature of 50°F from the average of the maximum and minimum temperatures for the day. Minimum temperatures less than 50°F are set to 50, and maximum temperatures greater than 86°F are set to 86. These substitutions indicate that no appreciable growth is detected with temperatures lower than 50 or greater than 86.

    This is the commonly accepted calculation in the ag industry used to calculate maturity. This is the ideal temperature range. Prolonged high temps cause plant wilting and stress the plant without enough moisture in the air or soil. Plant transpiration reduced if night time temps not cooling below low 80s affecting yield, maybe as high as 20% yield reduction from maximun yield potenial this year in missouri and ohio river valleys.

    Hybrids do exist that are drought and heat tolerant but are not preferred for planting because there yield potential is marginally less. Bottom line, this is a non issue since it is easily adaptable.

  97. what about reading the letter. it’s linked up there and much more even-handed than the ridiculing comments indicate.

  98. Corn, like all other species, has selectable traits.

    We can make a high temp corn or a low temp corn (within limits) if it becomes an issue. But it just isn’t an issue.

    So, to me, the basic problem is when they say “We assumed it was a high temperature crop” (or something close). You can stop Right There.

    WHICH cultivar? WHAT temperature range? Exactly? Under which water regimin?

    It’s all just trash talk. There is a Hope (IIRC) strain of corn that makes a Tap Root suited for droughts. I’ve got corns with harvest times from 45 days to 120 days. Some grow 3 feet tall, some 16 feet. Exactly WHICH corn are they talking about? Don’t know? They you know nothing.

    http://www.ag.ndsu.edu/pubs/plantsci/rowcrops/a834w.htm

    points out:

    Corn is currently grown in every county in the state, though the productivity and risk of production varies considerably from region to region. Temperature, rainfall and radiation are the major environmental factors that influence the growth and yield of corn.

    Got that? you need water and radiation to know what yields to expect. Were all these controlled for in their tests?

    Temperature and moisture are of particular concern in North Dakota. Temperature affects the rate of corn growth and the length of the growing season. Although corn is classified as a warm season crop, it still yields best when temperatures are moderate.

    Oh, so corn is a temperate crop really… So anyone with heat and drought stress might do better with tepary beans or with soya or with a dozen other crops. Yes, corn grows well in heat, but there are other crops that grow even better….

    The potential productivity of corn is also directly related to the length of the growing season. The longer the growing season, the longer the corn plant has to photosynthesize and accumulate dry matter for grain yield.

    So, did they control for length of season? Was the length of season of the seed chosen matched to the place? Did they try simply swapping from a 120 day corn to a 90 day corn?

    Growing degree day (GDD) accumulations, also referred to as heat units, are the most common way of characterizing the length of the growing season. Unlike the number of days between killing frosts, GGD provides quantitative information about temperature during the growing season. In calculating GDD for corn, temperatures from a lower limit of 50 degrees and an upper limit of 86 degrees are accumulated for the growing season by applying the formula below to each day’s maximum and minimum temperatures.

    Maximum temperatures higher than 86 degrees are entered as 86 and temperatures below 50 degrees are entered as 50 in the formula. GDDs are accumulated from seedling emergence until physiological maturity. Historical as well as current season GGD accumulations can be obtained from the North Dakota State University NDAWN weather site at http://ndawn.ndsu.nodak.edu/application/corn degreedaysform.html.

    Another “got that?” moment. Corn is optimal between 50 and 86 F. We are using a measuring stick with specific well known preferences. Yeah, it will grow hotter, but it loves 86 F. So any real surprise that above that it’s less happy? (even if only a little). Nope. BUT also note that Degree Days thing. When it’s hotter, you get more degree days and more yield.

    At this point I like to point out that Phoenix has a GREAT crop yield. You need to allow for heat depression of growth over about 120 F, BUT that comes with longer warm ‘ends’ in spring and fall. In exchange for a small reduction of cool crops in summer (so plant tomatoes already ;-) you gain growing season on 2 ends as both spring and fall add time and degree days. The limit case is that you lose summer growth but gain Fall, Spring, and Winter growing seasons. The whole “hot summer so not farming” argument is just so broken….

    Look at Phoenix and then tell me what you loose.

    They grow many ‘table vegetables’ for all of the USA. Their major “issue” is that Mexico where it is hotter grow even more in winter and it’s hard to compete with them…

    GDD accumulations vary considerably in the state, from up to 2,400 GDD in the southeast to less than 1,700 GDD in some seasons in the north. Matching the maturity length of a corn hybrid with the likely GDD accumulations at a given location is one of the basic management practices for successfully producing corn. Minimum soil temperatures of 46-50 degrees are required for corn germination and seedling growth.

    OK, so you MUST be over 50 F to have any hope at all. And you get more GDDays in the south than in the north. So if we DID heat up such that ALL OF THE SOUTH was hotter than PHOENIX, we would gain more growth up north than we lost down south…. Hmmm…. why am I not feeling particularly worried…. Oh, yeah, there is nore DIRT up north than down south as the continents get wider as you go north….

    Think about it…

  99. As we are finding in Florida, cold is far more deadly … CO2 just makes crops grow, why do you think there are greenhouses.

  100. Did these “climate scientists” have a control to study how temperatures effect corn growth under controlled conditions? How about how soil conditions and water effect corn growth with varying soil and water conditions?

    I know its a rhetorical question and that the answer is, “no”, and that is really all you need to know about this study.

    Also, why did they choose to study a region with a history of people being unable to feed themselves? Could it be the best place to get a predetermined conclusion?

  101. The corn farmers are correct in the above comments. Some 40 years ago our company had farms ranging from the Rio Grande to Idaho. The crops were corn and alfalfa used in cattle feeding. One other important variable, in my opinion, has not been mentioned.

    Animals increase in size as they increase their distance from the Equator. Full grown horses transported from the Panhandle of Texas put on another 200 pounds in Montana. Steers were driven from Texas to Montana in the old days to fatten before going to market. I suspect they preformed similarly. Cattle full grown in South Texas gained weight in the Panhandle, and cattle raised in Wyoming did not do as well there.

    Grain production was similar. The yields increased as one went from Southern Texas to the northern tier of States. I believe it was due to longer periods of daylight which enabled the grain to produce more.

    W. A. McQuiddy

  102. Okay, a couple of issues here.

    1. “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.”

    So what they are revealing here, is that the study is a comparison between apples and oranges. Different strains that perform well in some conditions, but poorly in others? Let’s just add an infinite amount of complexity and uncertainty to the problem, but still reach the conclusion that climate change will starve the world!

    2. “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.”

    You might be able to do this with Temp and humidity across the domain of study, but precipitation is on a much smaller scale.

  103. In southern Africa the most critical adverse factor for maize production is el Nino. This generally brings drought conditions to this part of the world and high maize yields and drought do not go together. The second major factor is the need for good rains in early January when the main crop is tasseling. I have listened to farmers complaints all of my life (they are just a tad prone to it) but I don’t recall ever hearing one say that it is too hot. What might be interpreted as a yield drop caused by a one degree rise in temperature, might be more certainly attributed to poor January rainfall.

  104. It seems like a lot of people want to either: a) question the legitimacy of the study because Americans can grow corn at this temperature, b) suggest Africans should grow something besides corn , or c) begin using more resilient U.S. seeds.

    Instead of questioning why the Africans aren’t able to farm the way Americans can or suggest they do something else – why don’t we ask why they should have to do anything different than what they were doing in the first place? They are not the ones that created the temperature change in the first place so isn’t it both unjust and patronizing to tell them how they should have to adapt to a problem they didn’t create?

    Our carbon-intensive lifestyles are having a negative effect on theirs. Swallow that simple truth.

  105. JD,

    I agree that Africans are not the ones that created temperature change. But you think too small: there is no evidence that anyone on earth created temperature change. The planet is still emerging from the LIA. Natural variability is sufficient to explain the entire rise, without invoking an extraneous variable such as the minor trace gas CO2.

    And when you say “our carbon-intensive lifestyles,” you exhibit scientific illiteracy. CO2 has one carbon atom and two oxygen atoms. Saying “our oxygen-intensive lifestyles” would be twice as accurate, no?

    …No. We’re talking about carbon dioxide, a tiny trace gas. All the wild-eyed arm waving over the demonization of a harmless and beneficial trace gas is based on the covetous greed of politicians, and their useful idiots, to tax the air we breathe. Science has nothing to do with it.

    Any time you see someone babbling about “carbon” when referring to CO2 you are seeing a scientific illiterate. The really scary thing is that these know-nothings can vote.

  106. Smokey,

    Thanks – Not only did you expose my scientific illiteracy but you exemplified your scientific expertise by describing CO2 as a “tiny” gas, to be sure I didn’t confuse it with all of the “large” gases.

    If you’re right about recent changes being a result solely of natural variabilities – then why did the Republicans in the House Energy and Commerce Committee reject all three amendments to the “Energy Tax Prevention Act of 2011″ that would have publicly rejected the scientific basis of climate change?

    It’s because even Republicans know that the evidence supports anthropogenic climate change – they just don’t support regulating greenhouse gases.

    You know what natural variations are for CO2 concentration in the atmosphere? Between 180 and 300ppm. You know what they are now? We both know it’s a very unnatural 390 ppm.

    You speak with such cockiness – show some humility. I agree that NOBODY should be saying the evidence is conclusive – only that the evidence strongly suggests our CO2-intensive lifestyles is altering the climate for us and future generations. As a democratic society, we have chosen to use public money to fund scientists who conduct research to safeguard us from future harm. I trust them, not you or this site.

  107. JD,

    Sorry about the lack of humility, but I get very irritated when someone has their hand in my pocket, feeling around for my wallet. The demonization of “carbon” is being promoted for money and political power, not on the basis of the scientific method.

    And IANAR, nor do I speak for or apologize for Republicans. I also don’t dispute the fact that the rise in CO2 is due to human emissions. But I draw the line at the follow-up assumption, that the rise in CO2 will lead to runaway global warming and climate catastrophe. There is no scientific evidence for that assumption, none at all.

    I will change my mind if you can provide any testable, real world evidence showing any global harm due to the rise in CO2. As a matter of fact, there is no such empirical evidence.

    Therefore, since there is no evidence of global damage due to the rise in a tiny trace gas that has demonstrably increased agricultural profuction, the only reasonable conclusion is that CO2 is both harmless and beneficial. More CO2 is better.

    If you agree, then there is nothing to worry about. If you disagree, you need to convincingly show the global damage that CO2 has caused. It’s as simple as that.

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