Claim: U.S. corn yields are increasingly vulnerable to hot, dry weather – Data: corn yield trend positive

While a recent report tells us current droughts in the western USA hardly make the top ten, we have this from Stanford University, a claim about drought related crop insurance claims that doesn’t seem to match data on national yields and trend. While the 2012 drought had an impact, 2013 saw the third highest corn yield on record.

USDA_corn_yield

Data: http://quickstats.nass.usda.gov/results/90C69DEC-38D6-31B4-9953-4C6EB5E82D79?pivot=short_desc

U.S. corn yields are growing more sensitive to heat and drought, according to research by environmental scientist David Lobell. Farmers are faced with difficult tradeoffs in adapting to a changing climate in which unfavorable weather will become more common.

By Laura Seaman (Stanford writer)

Research by David Lobell of Stanford’s Center on Food Security and the Environment indicates corn harvests will be affected by drought conditions, which are occurring more often. 

Corn yields in the central United States have become more sensitive to drought conditions in the past two decades, according to Stanford research. 

The study, which appears in the journal Science, was led by Stanford’s David Lobell, associate professor of environmental Earth system science and associate director of the Center on Food Security and the Environment. “The Corn Belt is phenomenally productive,” Lobell said, referring to the region of Midwestern states where much of the country’s corn is grown. “But in the past two decades we saw very small yield gains in non-irrigated corn under the hottest conditions. This suggests farmers may be pushing the limits of what’s possible under these conditions.”

He predicted that at current levels of temperature sensitivity, crops could lose 15 percent of their yield within 50 years, or as much as 30 percent if crops continue the trend of becoming more sensitive over time.

As Lobell explained, the quest to maximize crop yields has been a driving force behind agricultural research as the world’s population grows and climate change puts pressure on global food production. One big challenge for climate science is whether crops can adapt to climate change by becoming less sensitive to hotter and drier weather.

“The data clearly indicate that drought stress for corn and soy comes partly from low rain, but even more so from hot and dry air. Plants have to trade water to get carbon from the air to grow, and the terms of that trade become much less favorable when it’s hot,” said Lobell, also the lead author for a chapter in the U.N. Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, which details a consensus view on the current state and fate of the world’s climate.

Rain, temperature, humidity

The United States produces 40 percent of the world’s corn, mostly in Iowa, Illinois, and Indiana. As more than 80 percent of U.S. agricultural land relies on natural rainfall rather than irrigation, corn farmers in these regions depend on precipitation, air temperature and humidity for optimal plant growth.

According to the research, over the last few decades, corn in the United States has been modified with new traits, like more effective roots that better access water and built-in pest resistance to protect against soil insects. These traits allow farmers to plant seeds closer together in a field, and have helped farmers steadily raise yields in typical years.

But in drought conditions, densely planted corn can suffer higher stress and produce lower yields. In contrast, soybeans have not been planted more densely in recent decades and show no signs of increased sensitivity to drought, the report noted.

Drought conditions are expected to become even more challenging as temperatures continue to rise throughout the 21st century, the researchers said.

Lobell said, “Recent yield progress is overall a good news story. But because farm yields are improving fastest in favorable weather, the stakes for having such weather are rising. In other words, the negative impacts of hot and dry weather are rising at the same time that climate change is expected to bring more such weather.”

Extensive data

Lobell’s team examined an unprecedented amount of detailed field data from more than 1 million USDA crop insurance records between 1995 and 2012.

“The idea was pretty simple,” he said. “We determined which conditions really matter for corn and soy yields, and then tracked how farmers were doing at different levels of these conditions over time. But to do that well, you really need a lot of data, and this dataset was a beauty.”

Lobell said he hopes that the research can help inform researchers and policymakers so they can make better decisions.

“I think it’s exciting that data like this now exist to see what’s actually happening in fields. By taking advantage of this data, we can learn a lot fairly quickly,” he said. “Of course, our hope is to improve the situation. But these results challenge the idea that U.S. agriculture will just easily adapt to climate changes because we invest a lot and are really high-tech.”

Lobell and colleagues are also looking at ways crops may perform better under increasingly hot conditions. “But I wouldn’t expect any miracles,” he said. “It will take targeted efforts, and even then gains could be modest. There’s only so much a plant can do when it is hot and dry.”

Laura Seaman is the communications and external relations manager for Stanford’s Center on Food Security and the Environment, a joint program of Stanford’s Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment.

For more Stanford experts on climate change and other topics, visit Stanford Experts.

-30-

This graph suggests to me that U.S. corn is far more tolerant of drought now than it was in the dustbowl years:

CornYieldTrend_US[1]

 

84 thoughts on “Claim: U.S. corn yields are increasingly vulnerable to hot, dry weather – Data: corn yield trend positive

  1. Well duh.

    Hot weather does effect corn yields. And wheat, barley and milo….

    The million $ question is as the clilmate changes does where we grow corn change?

  2. Lobell’s team examined an unprecedented amount of detailed field data from more than 1 million USDA crop insurance records between 1995 and 2012.

    There’s that word again. Unprecedented.

  3. This isn’t garbage research but forget about AG “Climate Change”, Corn production is going to suffer in the US as the Ogallala Aquafer is pumped down and/or if we get hit by one of the severe droughts Anthony wrote about a couple of days ago.

  4. What nonsense! FRAUD! Anthony your graph at the bottom is eloquent refutation of Stanford’s Center on Food Security’s deceit. Lobell says, “there is only so much a plant can do when it is hot and dry.” Your graph say, “Corn plants can do quite a lot” Looks to me like corn yields have been doubling every thirty to forty years. Talk about miracles.

  5. I am a corn and soybean farmer from northern iowa. Technology in agriculture is expanding at a very rapid rate. The ability of the plant breeders to produce new and varied corn hybrids is remarkable. The goal is to DOUBLE the yields by 2050. I think there is an excellent chance that will happen if not before. The biggest threat we face is that government will get in our way!

  6. We, I, see the 2012 drop in yield and stipulate the drought correlation. Did I miss the drought as exclusive and sufficient cause for the drop in yield? Farmers do not farm on a level economic ground that may also cause the 2012 drop in yield.

  7. The next step is for the EPA to restrict irrigation claiming some invented reason related to CO2 and climate change. Then the claim will be stated with authority that agricultural yield is being restricted by Catastrophic Anthropogenic Global Warming.

  8. This certainly has a lot of Spin added. Another way to look at this data is that corn yields have increased on average for the last 60 years by about 2 bu/ac every single year – thanks to genetics and crop technology. One must also assume this progress has to “max out” one day. I can cherry pick from the graph and conclude that since the mid 90’s, the average yield has in fact “peaked”and held steady at 140 bu/ac +/- 15% . That’s pretty reliable production over the last 20 years. Weather will always play a role in that 15% variation.

  9. “The United States produces 40 percent of the world’s corn, mostly in Iowa, Illinois, and Indiana. As more than 80 percent of U.S. agricultural land relies on natural rainfall rather than irrigation, corn farmers in these regions depend on precipitation, air temperature and humidity for optimal plant growth”

    That could be a problem, as the drought seasons come nearer.

    As the temperature differential between the poles and equator grows larger due to the cooling from the top,

    http://www.woodfortrees.org/graph/hadcrut4gl/from:1987/to:2015/plot/hadcrut4gl/from:2002/to:2015/trend/plot/hadcrut3gl/from:1987/to:2015/plot/hadcrut3gl/from:2002/to:2015/trend/plot/rss/from:1987/to:2015/plot/rss/from:2002/to:2015/trend/plot/hadsst2gl/from:1987/to:2015/plot/hadsst2gl/from:2002/to:2015/trend/plot/hadcrut4gl/from:1987/to:2002/trend/plot/hadcrut3gl/from:1987/to:2002/trend/plot/hadsst2gl/from:1987/to:2002/trend/plot/rss/from:1987/to:2002/trend

    very likely something will also change on earth. Predictably, there would be a small (?) shift of cloud formation and precipitation, more towards the equator, on average. At the equator insolation is 684 W/m2 whereas on average it is 342 W/m2. So, if there are more clouds in and around the equator, this will amplify the cooling effect due to less direct natural insolation of earth (clouds deflect a lot of radiation). Furthermore, in a cooling world there is more likely less moisture in the air, but even assuming equal amounts of water vapour available in the air, a lesser amount of clouds and precipitation will be available for spreading to higher latitudes. So, a natural consequence of global cooling is that at the higher latitudes it will become cooler and/or drier.

    Better to move south when the droughts start kicking in.

  10. Corn is a C4 plant. As such, it economizes water under higher CO2 concentrations in the atmosphere. If the crop was already grown in relatively dry environments such as Mexico or the US Southwest, this also leads to increased photosynthesis. Under the more humid environment of the corn belt, increased CO2 would lead to small increases in photosynthesis, but large reduction in water requirement. Besides, of course, if the normal climate (as opposed to transient droughts) turns to be warmer (say, 2°C hotter), there are plenty of corn varieties currently grown in warmer climates (e.g. Argentina or Brazil) that could be adopted instead. That is only counting on existing varieties, not considering future plant breeding in the US, or development of new genetically modified varieties that are more resistant to heat and drought. The above is a delicate way of saying that the Lobell study is little more than BS.

  11. Old Huemul says:
    May 3, 2014 at 6:16 am
    Corn is a C4 plant
    ====
    That should have been the first post……

  12. Hot and dry? I thought the meme was hot and humid under anthropogenic climate warming. If the growing season air is getting hotter and dryer we likely are having an oceanic issue, IE oscillation, not an anthropogenic driven increased water vapor issue. Hot and dry summers usually mean cold winters caused by the double whammy of oceanic and atmospheric weather pattern oscillations. Let’s see now…did we have a cold winter in the corn belt area?

    To these trough slopping, money trolling researchers I say lier lier pants on fire.

  13. In this article, the author suggests that a big factor in increasing yields is that new varieties of corn can be planted closer together, so there are more plants per acre. It is not a stretch to see that more plants per acre require more water per acre for the same productivity per plant. If so, even normal rainfall could be inadequate for the new crop density. Perhaps this is less a drought problem and more a crop management problem.

    That said, in my work on western water law and irrigation, it became obvious to me that farmers were planting corn in marginally suitable areas, and depending on irrigation to tide them through the hot, dry days. When there were more hot, dry days than planned for, and available or allowable water use limited, crops failed. Farmers’ decisions are driven by lots of considerations, and one of those is the price of the product. As the corn prices have gone up, use of marginal areas for planting corn has also gone up. For the farmers, crop insurance lessens the risk that a bad crop management decision will have catastrophic financial impacts.

    It seems to me the issues are more related to crop management practices (and its cousin, financial management) and the risks assumed (or not) by individual farmers. Reintroducing the financial risks might encourage farmers to go back to crops suitable for dry land farming in places not suitable for a water intensive crop such as corn.

  14. Uploading daily weather forecast maps out to 2019, upload run is up to around end of November 2014 at this time. Free access to temperature and rainfall contour maps, ad free site, just the maps, and an explanation of how it works. Currently loading about three months of new maps per day, I have viewers that have made upwards of $750,000.00 playing in the futures markets. Not what I intended, it was for the use by the original producers that was my original intent.

  15. Assumption #1 – the public are as lazy/stupid as I, the ‘journalist’, am and will do no research to verify this hit-piece.

    Assumption #2 – see assumption #1

  16. “Some of the increasing yields are due to the increase in CO2 levels, making photosynthesis more efficient. Did they take that into account?”

    C02 is a trace gas. It cant warm the earth or make plants grow.

  17. My goodness, Stanford has just demonstrated that corn crops prove that the Earth is getting less and hot and dry.

  18. Lowell’s whole academic reputation is centered in this false thesis, developed by dubious data mining techniques. All his research grants are to support this spurious alarmism. Wrote about it in Gaias Limits.
    As noted above, maize is a C4 which economies water with increased CO2. Second, corn does fine up to about 40C provided there is sufficient water for transpiration. Only the combination of hot and dry reduces yields, but over 80 percent of the effect (based on CYMMT field trials in Africa) is during anthesis (tasseling), a period that lasts 2-3 weeks. Not even the IPCC can find a connection between regional drought and CAGW, let alone on such brief time scales.For the US, there is a regional drought connection to various phases of the PDO and AMO and ENSO, reseach published a decade ago by USGS. That is the 2014 Kansas winter wheat problem. Finally, CYMMT for Africa and Monsanto for the US (in part because of the depleting Ogallalla) have been developing drought tolerant strains. The newest US hybrid in field tests 2012 did about 6% better yield under moderate drought conditions ( simulated by controlling center pivot irrigation) than the previous best. Due for market release this planting season. CYMMT strain improvements for Africa have already succeeded in improving yields about 40 percent in a region (centered on Kenya) where the ‘long rain’ (MAM) is too short to ever be optimal since maise takes 4-5 months to mature.

  19. non-irrigated corn under the hottest conditions.

    So if you don’t water your crops they will not grow well. Who’d a think it.

  20. You just can’t win…..
    =====
    2013 saw the third highest corn yield on record.
    =====
    May 07, 2013 11:30
    Rain is too much of a good thing for region’s farmers after last year’s drought

    But now, after weeks of above-average rain, much of the nation’s corn belt is a muddy mess, leaving farmers frustrated and planting weeks behind schedule, potentially cutting into this year’s expected record crop.

    http://www.stltoday.com/business/local/rain-is-too-much-of-a-good-thing-for-region/article_0ea4d64a-16bb-56a8-8686-746f5acc6eac.html

  21. lenbilen says on May 3, 2014 at 5:51 am

    “Now that yield curve was a hockey stick if i ever saw one!”

    Great point!

    I think this is a perfect Mannian proxy for global temperature. Even though it samples less than 0.5% of the globe’s surface area, it *must* be tele-connected with global temperatures. Throw in a dash of stationarity (absent global warming, assume that corn production would have been flat), a smidgen of hockey stick data processing that extracts this proxy from the swamp of traditional Mannian proxies (aka ‘noise’), and voila! The next SPM cover photo for AR6 emerges. Why, even the inflection point coincides with the IPCC’s canonical 1950’s decade when mankind took control of the climate.

    What’s not to like?

  22. Almost all of the corn and bean farmers in my neck of the woods (Northern Indiana) irrigate – or at the very least having irrigation pumps and lines in place. This allows the farmers to water their fields when it counts the most. Yes, in drought conditions like we saw a few years ago, these systems were working overtime. However, they were not built for drought, but normal conditions. If Mother Nature fails to come through at the right time, the farmers can do it themselves.

    The larger industrial farms in my area possess huge grain silos. One farm built 3 250,000 bushel silos and a fourth is being built. These silos are full. The warmer weather of the last 35 years have in no way detracted from yields – quite the opposite. As a matter of fact, the demand for corn products has created a real estate bubble in farm lands. You wouldn’t believe what an acre of farm land sells for. Outside of Energy, Big Ag and its attendant industries are going through a Golden Age of sorts (new tractors, combines, infrastructure upgrades, and very, very good incomes).

  23. “Claim: U.S. corn yields are increasingly vulnerable to hot, dry weather”

    There is some truth to this despite the growth in corn yields, although climate change doesn’t have much to do with it.

    Corn is one of the most water intensive agricultural crops, yet it is increasingly being grown in dry areas where it’s cultivation is entirely dependent on artificial irrigation.

  24. Mosher:

    “C02 is a trace gas. It cant warm the earth or make plants grow.”

    Maybe you’re right, and if anyone were to believe .04% is too small a percentage of the atmosphere to do one thing, they should also believe it’s too small a percentage to do ANY thing.

    But I know YOU don’t believe the first thing, so what are you saying about the second thing? Are you agreeing with the comment you replied to, that extra CO2 should help crop yields, or are you disagreeing with it? I have to assume you’re completely agreeing with it…if not then there might be something wrong with your assumption that the 2 things (ability to warm atmosphere/ability to make plants grow) are necessarily equivalent and their truth or falsehood can’t be evaluated independently, but instead must be fully accepted or fully rejected as a package.

    Regardless, I think very few people here believe the first thing, so I think whatever “point” you were trying to make will largely fall on deaf ears.

  25. How much of that 40% is grown for ethanol? And what % of the ethanol crop is not artificially irrigated?

    Shut down the ethanol production and what % of that crop acreage could be feasibly shifted to food production to reduce the number of people dying from malnutrition every year?

  26. Steven Mosher says:
    May 3, 2014 at 6:38 am
    —————————————-
    Really? Have you ever tried to grow a plant without CO2 in the air?

  27. Steven Mosher says:
    May 3, 2014 at 6:38 am
    —————————————-
    My dear Mr. Mosher, please excuse my flippancy. Carbon ditaxable is essential for the growth of plants and bureaucracies, but seems to have no effect on the warmth of the earth.

  28. Increasing CO2 increases plant growth and decreases water use dramatically. Rarely mentioned is that it also increases the ideal growth temperature which even further increases growth. Indoor gardeners that use CO2 supplementation and high intensity lights know this. We are always battling with excess heat from the lights. For my favorite plants (a C3), with CO2 at 1,400 ppm, ideal growth temperature moves from about 85F to about 90F.

  29. If global warming is really happening and a threat to corn growing in the south it will also be a boon to corn growing in the north. The corn belt will move north and judging by the land configuration probably increase the amount of land in it. It won’t take a government program to fix, farmers will plant corn in the corn belt because that’s where they can make a profit at it, that is, unless the government gets involved and pays them to continue growing corn where it won’t grow anymore. If the government doesn’t intervene GW will most likely increase the harvest. There is no problem except the possibility of government solutions.

  30. Stephen Mosher – I thought you should know someone has hijacked your account and is posting bozo comments on WUWT.

    Your pal,

  31. Just wondering how they control for factors unique to the non-irrigated land. To what extent has this been marginal or intermittent land, that is now in production because corn price increases are making the economics favorable? To what extent is the land not irrigated because of individual farm economics?

  32. Steven Mosher says:
    May 3, 2014 at 6:38 am

    “Some of the increasing yields are due to the increase in CO2 levels, making photosynthesis more efficient. Did they take that into account?”

    C02 is a trace gas. It cant warm the earth or make plants grow.

    You maybe right since Warmists call co2 a toxin. By the way co2 can warm the Earth just like water vapour and CFCs.

  33. Mike Borch says:
    May 3, 2014 at 5:51 am

    “I am a corn and soybean farmer from northern iowa. Technology in agriculture is expanding at a very rapid rate. The ability of the plant breeders to produce new and varied corn hybrids is remarkable. The goal is to DOUBLE the yields by 2050. I think there is an excellent chance that will happen if not before. The biggest threat we face is that government will get in our way!”

    Yes and if we look at the current World record held by a farmer from Iowa that is achievable:
    Childs (Iowa) sets new world record for 394 bushel of corn per acre

    http://www.hpj.com/archives/2000/0224tocorntxtHTM.cfm

    In any case does the optimum growth latitude for grains not move 170 degrees North for every 1 C increase in temperature. That being so, if we accept the alarmist predictions there will be plenty of land and water from melting glaciers in Greenland to compensate any reduced yield as well as a major potential to improve yields in Africa to the current US level – provided the Greens do not succeed in denying those farmers the fuel, hybrid seeds and agricultural chemicals to do.

  34. I live in Northern Illinois. We get changes in the weather here all the time! Now, as I listened to the farm reports a couple of years ago they were in trouble because we weren’t getting the rains we needed. Last year was good, though, just like you said. This year we’ve had snow cover and rain, so if anything the farmers have had to delay planting because the ground wouldn’t support the equipment. If the trend for this year keeps up as it has, I think we might have another good year.
    If anything, the ongoing chatter about “Frankenfood” may hurt farmers. Most corn and soybean seems to be a Monsanto product, and the do-gooders are telling us every chance they get that genetically-engineered foods are no good for you and that you should go to the organic stores and buy food at three times the price of what you get in the supermarket.

  35. Research by David Lobell of Stanford’s Center on Food Security and the Environment indicates corn harvests will be affected by drought conditions, which are occurring more often.

    And why is that?

    IPCC
    6.6.5.5 The Record of Hydrologic Variability and Change in the Americas
    Multiple proxies, including tree rings, sediments, historical documents and lake sediment records make it clear that the past 2 kyr included periods with more frequent, longer and/or geographically more extensive droughts in North America than during the 20th century (Stahle and Cleaveland, 1992; Stahle et al., 1998; Woodhouse and Overpeck, 1998; Forman et al., 2001; Cook et al., 2004b; Hodell et al., 2005; MacDonald and Case, 2005). Past droughts, including decadal-length ‘megadroughts

    Thus, the palaeoclimatic record suggests that multi-year, decadal and even centennial-scale drier periods are likely to remain a feature of future North American climate, particularly in the area west of the Mississippi River.

    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-6-5-5.html

  36. Steven Mosher says:
    May 3, 2014 at 6:38 am

    C02 is a trace gas. It cant warm the earth or make plants grow.
    ___________________
    Did you forget your sarc tag?

  37. Brad says: May 3, 2014 at 7:48 am How much of that 40% is grown for ethanol? And what % of the ethanol crop is not artificially irrigated? Shut down the ethanol production and what % of that crop acreage could be feasibly shifted to food production to reduce the number of people dying from malnutrition every year?

    In 2013 87.2 million acres were planted in corn, with 13.99 billion bushels produced – for an average 160/bu per acre yield. There were 4.9 billion bushels dedicated to ethanol production, or 35%.

    However, each of those bushels, weighing 56 pounds, used for ethanol produced 2.8 gals of ethanol AND 17.5 pounds of distillers dried grain animal feed. DDG are a high quality animal feed that replaces a large share of the corn used to produce ethanol. Because of the superior feed value each pound of DDG replaces appx 1.3 pounds of feed corn.

    The 17.5 pounds of DDG replace appx 23 pounds of corn. Appx 41% of each bushel of corn used for ethanol is returned as DDG feed – meaning that instead of 4.9 billion bushels, the ACTUAL NET corn after the DDG feed replacement is appx 2.9 billion bushels. Instead of 35% of the corn crop being used to produce ethanol – the NET actual corn used after return of DDG feed is only appx 20.7%

    The claim that corn dedicated to ethanol is taking land away from food production is false. The US is the worlds largest corn supplier – producing over 40% of the world corn crop. It is also the worlds corn supplier – providing more than 60% of world corn imports for many years. Even in the drought year of 2012 the US still exported more corn than every other major corn supplier combined.

    The US meets 100% of the domestic demand, for feed, fuel, and food. They also provided 100% of the export demand, including for feed corn AND for white corn – which is what Mexico, Guatemala and all those other places eat. These countries import US white corn because it costs LESS, not more as claimed – and it helps LOWER food costs for these importing countries. It also allow s their farmers to grow more valuable crops for export.

  38. It seems to me that many of these ‘studies’ don’t show alarming things that have happened, only what might happen. Yahoo news runs an article every day about the terrible things that might happen if the alarmist computer models come true.
    Every indication I see is that the models are hopelessly wrong.
    That said, I certainly think we should have a long term energy plan to lessen CO2 output over the next hundred years and that plan should be mostly nuclear. There is risk to adding CO2 to the atmosphere indefinitely. Problem is that no one knows so we should have a rational discussion and then a plan. Nuclear power seems to be a great compromise, but many of the most vocal proponents of AGW seem quite unwilling to compromise, even if it hurts those they say they want to protect.
    We are unfortunately dealing with many zealots who seem unable to rationally discuss solutions.

  39. Plenty of corn is grown in Arizona – where temps are regularly 110+ … and where they see yields above 200 bushels per acre. Corn in AZ is irrigated, but shows these claims that heat affects corn yield are outright ridiculous. IF temps increase enough in the Midwest the same seed as used in AZ could be used there – and get similar yields. IF that occurred we would also see a major expansion into Canada In such event production would increase.

  40. Corn being the topic, I have to go off-topic to mention a May 1 WSJ article titled “Sizing Up Wheat in Parched Midwest Fields” by Tony C. Dreibus.
    File it under weather is not climate.
    _________________
    R Taylor says:
    May 3, 2014 at 7:50 am
    Steven Mosher says:
    May 3, 2014 at 6:38 am

    Steven Mosher reminds me of Rodney Dangerfield – the I don’t get no respect comedian. The one liners, such as today’s CO2 comment, are the on-stage meant to be laughed at spurts of silliness. It is reported that off-stage Dangerfield was gentlemanly and intelligent and resented being seen as obnoxious. When Mr. Mosher provides a thoughtful data-driven comment he, also, is worth listening to and deserving of respect.

  41. Nancy C says:
    May 3, 2014 at 7:47 am

    Mosher:

    “C02 is a trace gas. It cant warm the earth or make plants grow.”

    Maybe you’re right, and if anyone were to believe .04% is too small a percentage of the atmosphere to do one thing, they should also believe it’s too small a percentage to do ANY thing.

    While 0.04% is less than one part per thousand in the atmosphere, it cant have much of an effect on the total atmosphere. However, compared to the baseline of 275 ppm it represents a 45% increase in fertilizer delivered to the plants. This surely has some effect.

  42. Then why are we burning coal in our gas tank. Especially when we have 500 – 1000 years of Coal, oil, NatGas?

  43. The final graph looks quite like the rise in global atmospheric CO2 above a base line requirement of about 200ppmv.

    Since anything that increases in a way roughly similar to CO2 is deemed to be caused by CO2, why go any further. It’s “robustly” proven that current corn production is “unprecedented”.

    If this trend continues the whole of surface of the lower 48 will be infested with corn by 2100.

    We must act now. to reduce atm CO2 before it’s too late.

  44. Let me read the article and make comments when I get a chance later today.
    I forecast the effect of weather on corn, soybeans and wheat for a living.

    http://www.marketforum.com/?id=1251466&ss=met

    http://www.marketforum.com/?id=1251467&ss=met

    Couldn’t resist making some quick comments:
    1. Before the drought of 2012, the US Cornbelt had gone a record 24 growing seasons without a widespread major drought. Interesting how that one severe drought get’s so much weighting but 24 years with some of the best weather/growing conditions ever(1993 flooding was one of the big exceptions) gets put lower down.

    2,. They state: “The United States produces 40 percent of the world’s corn, mostly in Iowa, Illinois, and Indiana”
    In order of production ranking:
    1. Iowa
    2. Illinois
    3. Nebraska
    4. Minnesota
    5. Indiana
    This incorrect statement probably doesn’t effect the results of their study but as soon as I read that statement, I thought “this person can’t possibly know much about growing corn in the Midwest!”

    http://www.bing.com/images/search?q=State+Rankings+in+Corn+Production+2013&qs=n&form=QBIR&pq=state+rankings+in+corn+production+2013&sc=0-34&sp=-1&sk=#view=detail&id=98F2F77CAE2C9CBF0A648CA2E67644261BA02F3E&selectedIndex=15

  45. “Lobell’s team examined an unprecedented amount of detailed field data from more than 1 million USDA crop insurance records between 1995 and 2012.

    “The idea was pretty simple,” he said. “We determined which conditions really matter for corn and soy yields, and then tracked how farmers were doing at different levels of these conditions over time. But to do that well, you really need a lot of data, and this dataset was a beauty.””

    Crop insurance coverage and laws have changed a great deal. The criteria to measure has also changed and amount covered has increased greatly, so that claims have soared. Many farmers in the Midwest drought of 2012 actually made more money from the insurance pay out, then they would have growing a decent crop.
    This happened as the average price of corn was so high, that even with insurance that paid on 70% of their crop on that price, it was better than 100% of what they would have made on a good crop in an average year(without all the work).
    Farmers work hard and take tremendous risk. I have great respect for them. However, the government insurance plan providing protection for them(the government now pays for a large portion of crop insurance), provides more incentives to NOT grow a crop and especially, take advantage of the benefits that didn’t used to be there.

    The other thing, weather too cool and wet in the Spring has been a much bigger issue in recent years with regards to farmer decisions on using crop insurance.

    http://www.extension.iastate.edu/agdm/crops/html/a1-57.html

    I would really like to see these unprecedented detailed field data reports. Insurance payouts have skyrocketed and the biggest reason is the changes in the insurance(including the fact that tax payers now fund a big portion of the premiums)

  46. “‘ Steven Mosher says:
    May 3, 2014 at 6:38 am

    C02 is a trace gas. It cant warm the earth or make plants grow.””

    Pedantic snark.
    Someone please change the baby’s diaper.

  47. Interesting that the start and end of the study was 1995 and 2012. 1995.

    What a coincidence, those were the 2 years with the lowest corn yields. 1992 and 1994 had record yields from perfect weather. 1993 had low yields in Iowa and insurance pay outs from too much rain(can’t have that in your study that is assigning damage to hot/dry).
    If I wanted to maximize hot and dry by cherry picking, it would be to start at 1995 and end at 2012.

    http://blogs.desmoinesregister.com/dmr/index.php/2013/01/11/iowas-2012-corn-yield-lowes-since-1995/article

    If I was a reviewer of this paper………..I’ve forecast the effects of weather on corn, soybeans and wheat for a living since 1992, I would have rejected it before I was done reading it.

    My comments so far, have not even mentioned CO2.

  48. The link they provided for their data, also confirms that 1995 and 2012, the start and end points were cherry picked.

    http://quickstats.nass.usda.gov/results/90C69DEC-38D6-31B4-9953-4C6EB5E82D79?pivot=short_desc

    If, for instance, I was allowed to cherry pick and used data from 1996 to 2011, the results would have much different……..or any other 2 start/end points.
    Other than picking a starting date of 1988, the previous widespread major Cornbelt drought(which would have made the cherry picking blatantly obvious), the years they chose maximized what they were trying to prove.

  49. Maybe I’m crazy, but it occured to me if these so called Climatologists quit obsessing over predicting the temperature a century from now and started to figure out how to accurately predict the rainfall durring the growing season, then the Farmers would know how close to plant their seeds for optimum yeilds. Also if they learn to accurately predict the rainfall over a 3 month period, I’d be more inclined to consider their climate models were more than unicorn farts.

  50. Well, if doesn’t seem that whatever happened between 1950 and now or 1980 and now was bad for corn Unless you don’t like corn. Looks like like drought tolerance nearly doubled if they still use the same amount of water per acre. I blame fossil fuel driven tractors for the increase in yield.

  51. Lobell said, “Recent yield progress is overall a good news story. But because farm yields are improving fastest in favorable weather, the stakes for having such weather are rising. In other words, the negative impacts of hot and dry weather are rising at the same time that climate change is expected to bring more such weather.””

    Clearly, some of the information they supply is not accurate, some is cherry picked/biased. Some shows the opposite of what they conclude.

    “He predicted that at current levels of temperature sensitivity, crops could lose 15 percent of their yield within 50 years, or as much as 30 percent if crops continue the trend of becoming more sensitive over time.

    The evidence shows the exact opposite. However, if you assume CAGW is going to happen, then you can “speculate” that the last 2 decades in the Cornbelt, which represent the best growing conditions since corn has been grown in that region, “might” change to less favorable……….this is all they are doing.

    A 15% to 30% reduction in corn yields within 50 years, based on a non existent trend in the real world is very silly and a quintessential example of extreme alarmism with no empirical data or evidence to support it.

  52. Stephen Mosher wrote, “C02 is a trace gas. It cant warm the earth or make plants grow.”

    … techniques of Free-Air Carbon dioxide Enrichment (FACE) have been developed that allow natural or agricultural ecosystems to be fumigated with elevated concentrations of CO2 in the field without use of chambers (Figure 1). As these experiments are the most naturalistic, they should provide the best indication of the responses of plants to increased CO2 under the real-world conditions of the future.
    [ … ]
    Since photosynthesis and stomatal behavior are central to plant carbon and water metabolism, growth of plants under elevated CO2 leads to a large variety of secondary effects on plant physiology. The availability of additional photosynthate enables most plants to grow faster under elevated CO2, with dry matter production in FACE experiments being increased on average by 17% for the aboveground, and more than 30% for the belowground, portions of plants (Ainsworth & Long 2005; de Graaff et al. 2006). This increased growth is also reflected in the harvestable yield of crops, with wheat, rice and soybean all showing increases in yield of 12–14% under elevated CO2 in FACE experiments (Ainsworth 2008; Long et al. 2006).

    http://www.nature.com/scitable/knowledge/library/effects-of-rising-atmospheric-concentrations-of-carbon-13254108

  53. With respect to recent slowing of the growth of corn yields …

    FRINGE STATE YIELD DRAG

    While total U.S. corn production climbed by more than 25 percent since 2005 off a 16.6 percent increase in planted area, the national corn yield increased by less than 7.5 percent over the same period.

    But lower grade soils are also to blame for much of the persistent underperformance of corn yields at a national level.

    Corn yields in the “Top 5″ states have averaged 10 bushels per acre above the national average for the past five years, while the mean yield for the largest corn growers on the fringes of the Midwest, Kansas, South Dakota and North Dakota, is more than 25 bushels an acre below the national average.

    This significant underperformance of “Fringe state” yields relative to core Corn State yields has dragged heavily on the national average, especially in recent years when those non-core states have contributed a historically high proportion of corn planted area.

    But the likelihood for a reduction in corn plantings on those fringe acres in 2014 is also a major reason why this year’s average corn yield has the potential to pop well above the recent average should growing conditions prove broadly friendly.

    http://www.producer.com/daily/analysts-grumble-at-usda-corn-yield-forecast-column/

  54. My suggestion for corn yield growth is trickle irrigation with soda water.
    /sorta kidding

  55. Quoting article:

    This graph suggests to me that U.S. corn is far more tolerant of drought now than it was in the dustbowl years:
    ———————–

    Really now, is that what it suggests?

    I don’t think so …… because I think it suggests this, to wit:

    Following World War II, fertilizer use expanded rapidly in the United States, but leveled off in the early 1980s after reaching a peak of 23.7 million nutrient tons in 1981.
    Source: http://www.tfi.org/statistics/statistics-faqs

  56. Mike Borch says:
    May 3, 2014 at 5:51 am
    I am a corn and soybean farmer from northern iowa. Technology in agriculture is expanding at a very rapid rate. The ability of the plant breeders to produce new and varied corn hybrids is remarkable. The goal is to DOUBLE the yields by 2050. I think there is an excellent chance that will happen if not before. The biggest threat we face is that government will get in our way!

    Just so I am clear, are you referring to the government that approved the $956B farm bill in February of this year? That government? The one that established land grant colleges, provides extension agents, and lobbies nations around the world to open their markets to our agricultural products? Is that the government you are complaining about?

  57. Chris says: May 3, 2014 at 12:56 pm
    . Mike Borch says:May 3, 2014 at 5:51 am … The biggest threat we face is that government will get in our way!

    Just so I am clear, are you referring to the government that approved the $956B farm bill in February of this year? That government? The one that established land grant colleges, provides extension agents, and lobbies nations around the world to open their markets to our agricultural products? Is that the government you are complaining about?

    The one subsidizing ADM and unsustainable ethanol and wants to put catalytic converters on cows? Aside from the land-grant colleges, yep.

  58. “..One big challenge for climate science (!) is whether crops can adapt to climate change by becoming less sensitive to hotter and drier weather.”

    Isn’t the challenge for farmers and agriculture? Also I look at a graph like that above and I see that only a CAGW cultist could come to such an adverse conclusion. The English of the writer is a little ambiguous, too. Does she really mean the corn is getting more and more sensitive to drought (of the usual intensity) or that it will become affected by drier conditions to come? Maybe they should also put up a graph of drought intensity over the past century which shows less intense droughts than previously. One is left with the erroneous idea that droughts are on the rise. This gets an F.

  59. Mike McMillan says:
    I believe Chris says: is referring to the same government that wiped out many farmers in 1980 with the grain embargo.

  60. ….”I am a corn and soybean farmer from northern iowa. Technology in agriculture is expanding at a very rapid rate. The ability of the plant breeders to produce new and varied corn hybrids is remarkable. The goal is to DOUBLE the yields by 2050. I think there is an excellent chance that will happen if not before….
    The biggest threat we face is that government will get in our way!”….

    Bravo!!

  61. Apparently, the good professor understands that “Plants have to trade water to get carbon from the air to grow”. This is the gigantic unacknowledged fact in the Global Warming debate.

    Since no one disputes that CO2 is increasing, and that is after all the fundamental reason for the whole alarmist shriek, doesn’t that mean that corn is going to become LESS sensitive to drought?

    In short, increasing CO2 is a really GOOD thing. It is making the earth more vibrant and ecosystems more alive and more resistant to problems. Want to literally Go Green? Burn some coal.

  62. The IPCC admitted in AR5 that there has been absolutely no global increasing trend in droughts over the past 50 years.

    What the AR5 failed to mention is that increasing CO2 levels will greatly increase crop yields by around 40% once they hit 560ppm and already and that the higher CO2 levels to date have already increased crop yields/global greening by about 16~18%.

    The AR5 report also failed to mention that the higher CO2 levels shrink leaf stoma (breathing holes), which decreases moisture loss from plants and allows them to thrive with LESS water requirements.

    It’s a well known fact that global precipitation of both snow and rain have increased since the end of the Little Ice Age 163 years ago, due to the 0.75C increase of global temperatures, which have increased ocean evaporation.

    During the global warming trend from 1980~1998, there were FIVE El Nino events which greatly increased rainfall patterns in the West and Mid-West during those 18 years. Since 1998, there has only been TWO El Nino events, which has slightly decreased US rainfall in the West and Mid-West over the past 16 years.

    We’re about to enter another El Nino event later this year, which will mean the West and Mid-West will be getting more rain/show than they’ll know what to do with….

    Rather than storing this surplus rain, the EPA has prevented states from building new and much needed reservoirs. Moreover, the EPA also forces states to dump huge amounts of water from existing reservoirs into rivers to help “save the snail darter and salmon”….

    The world has gone insane.

  63. Chris says:
    May 3, 2014 at 12:56 pm
    Mike Borch says:

    “Just so I am clear, are you referring to the government that approved the $956B farm bill in February of this year? That government? The one that established land grant colleges, provides extension agents, and lobbies nations around the world to open their markets to our agricultural products? Is that the government you are complaining about?”
    —————————————-

    Yes, Chris, that’s precisely, the government that completely distorts price discovery for goods, misallocates land/labor/capital and greatly increases the costs of food throughout the world and kills millions of poor each year from all their subsidies and mindless meddling.

    The US government should close down the Department of Agriculture as it is an unconstitutional and unneeded entity. The market and farmers are perfectly capable efficiently running their businesses without any “help” from the US government. About the ONLY thing the US government can and should do is encourage other countries to allow free trade.

    The US Farm Bill is just a collection of bribes and extortion to secure the farmers’ votes and to extort campaign contributions from Big Ag corporations. The Food Stamp portion of the Farm Bill is simply to buy votes from poor and to keep them poor and dependent on the government.

  64. Mike Borch says:
    May 3, 2014 at 5:51 am
    I am a corn and soybean farmer from northern iowa.

    Mike,
    What are your average yields (bushels/acre) on your farm?
    Do you use traditional tillage, low till, or no till methods?
    What is your soil type(s)? Sand/silt, black prairie, clay, ???
    In your experience, how much have local yields increased in the last 10/20/30 years?

    Just curious…. I grew up on a central Wisconsin farm, when traditional plowing, planting, and tillage techniques were just starting to succumb to low till/no till, ‘air’ planters, applications of more herbicides and anhydrous ammonia, etc.
    Mac

  65. Around 1940 is when applications of man made/synthetic nitrogen caused the start of a strong trend up in corn yields. Here’s an interesting history/time line of the technology and facts going back 200+ years.

    https://www.agclassroom.org/gan/timeline/farm_tech.htm

    Site specific management of nitrogen for corn using rapidly improving technology is improving efficiency.

    http://ianrpubs.unl.edu/live/ec163/build/ec163.pdf

    Agree on fringe state yield drag. When the ethanol industry demand for corn put huge upward pressure on prices, those higher prices made it profitable to plant on ground that was unprofitable at $2 corn but profitable at $4. Corn prices at $6 caused millions of additional acres on crummy ground to be brought into production. The lower yields on these additional acres brought down the national average.

    Farmers are in the business to make money and they will plant whatever makes them money. They will also pay more money to nurture/manage a $6 corn crop, than a $2 corn crop.

    So $6 corn brings out less yielding/marginal ground but at the same time, will result in justification to spend more money to spend more money to maximize those yields.

  66. So it’s going to be hotter and dryer, is it?

    Good job the CO2 is going up then, right?

  67. Richard, your link is strong on junk science; somewhat short on fact. Did you notice that anyone on that site who expresses an opinion contrary to the accepted point of view is automatically labeled a shill for Monsnto?

  68. Most forms on nitrogen fertilizer use anhydrous ammonia.

    ” Natural gas is used both as a raw material to react with air and supply hydrogen and as a fuel to create the necessary heat and pressure. Manufacturing 1 ton of anhydrous ammonia fertilizer requires approximately 33.5 MCF or 34.4 MMBtu of natural gas”

    https://rbnenergy.com/fertile-prospects-for-natural-gas%E2%80%93can-ammonia-soak-up-bakken-gas-surplus

    Without the fossil fuel, natural gas, corn yields would be ??? lower.

    Here’s a study that showed a10% yield increase when nitrogen rates were increased from 120 lb/acre to 240 lb/acre.

    http://msue.anr.msu.edu/news/corn_yield_enhancement_through_planting_densities_and_nitrogen_managem

    Another little appreciated benefit from a fossil fuel.

  69. Cherry picked dates, two years of drought, 31 years data combine with inaccurate regional climate models to be confident yields will drop by 30%. As others have stated did not take into account land use or CO2. This is as bad as medical claim that malaria cases wil rise due to GW. Yields more dependent on seed lines, crop inputs, farming practices and subsidies.

  70. Little could be more propitious an omen than to have the IPCC predict a calamity (or climatity) is about to strike your area.

  71. “Lobell and colleagues are also looking at ways crops may perform better under increasingly hot conditions. ‘But I wouldn’t expect any miracles,’ he said. ‘It will take targeted efforts, and even then gains could be modest. There’s only so much a plant can do when it is hot and dry.'”

    Lobell and his colleagues are morons. All you have to do is plant the corn EARLIER. If the “pause” ends, and temperatures begin increasing again, then spring temperatures will increase more than summer temperatures and winter temperatures more than spring temperatures. That means you can plant corn earlier, and it will be done with any development the heat could adversely affect long before the heat became a problem. After the ears and kernels are filled, drought and excessive heat is actually GOOD for corn. At that point, the entire plant could DIE, and it would not affect yield; in fact, it would be great for farmers if their corn plants died at that point, because at that point the crop is “made”, and the only thing left is for it to dry down enough to harvest mechanically. Death of the plant would speed the dry-down process by disabling uptake of water, and the heat and drought would speed evaporation of the water already in the kernels. Of course, speeding the dry-down would not really increase yield either. However, in cold years, some corn in more northerly growing areas (i.e., Minnesota) is lost because it never does dry down enough for harvest, but rots in the field. That would be a much less common occurence if global warming were to resume.

    As someone well-educated in agricultural sciences, I have never understood why anyone would think that global warming is a danger to the world’s food supply. There are three things crops need more than anything else: heat, CO2, and water. All three of these things will increase under anthropogenic global warming. The relationship between CO2 and yields has no diminishing returns, at least not at any level ever used in experiments (and some experimenters using enclosed greenhouses have increased CO2 to several times anything seen in the open). Heat can be said to have a diminishing return, in the respect that, above 92F, the corn does not develop any faster than it does at exactly 92F, but it doesn’t die at 92F, nor even slow down development, but maintains the same development rate as at the optimal 92F. More heat means more evaporation, means more precipitation. And while the evaporation part might decrease moisture avaialable to the plants, the precipitation part will more than make up for it. You see, most of the evaporation will take place over the oceans, where the vast majority of the water is, while precipitation will be more uniformly spread across the earth’s surface, for a net increase in moisture over land areas.

    So if all three of the most important factors in crop yields are increasing, how can yields do anything but increase? But not only will yields increase in more traditional farming areas, but new areas, presently too cold for farming, will become suitable. Vast areas of Canada and Siberia will be warm enough to grow corn, wheat, soybeans, and other crops. If I thought the global warming “pause” was going to end any time soon, I’d invest every penny I had in real estate in the Canadian tundra.

    But think about this. Right now, and for the last 30+ years, rice growers in Texas and South Louisiana have been harvesting their crops TWICE each year. They discovered that, if you harvest early enough (which you can if temperatures are warm enough), then the seed head will REGROW, and you can harvest it again a couple months later. The yield on the second cutting isn’t nearly as high as on the first cutting, but it’s all lagniappe, as they say in South Louisiana, because it’s pretty much a free bonus. Now, imagine that temperatures in Arkansas (where about half of the US rice crop is grown) increased to the same level as current temperatures in South Texas and South Louisiana (it would only take 2-3 degrees F). Then Arkansas rice growers could do that too. And not just that, but since Arkansas is about the northern limit of rice production, it could be done pretty much everywhere rice is grown in the US. And Texas and Louisiana farmers, whose temperatures would also increase, would get more yield on that second cutting. I don’t have any way of knowing exactly how much the total rice production in the US would go up, but I suspect that the “second harvest” effect alone would increase overall yields by between 20 and 30%. That’s not including the primary effect of the heat on per-cutting yields, nor the yield-increasing effect of more CO2 (more rainfall would not affect yields, since rice is 100% irrigated).

    Now imagine that Chinese rice farmers could do that.

    Regards,
    Trevor

  72. Mike Maguire: “if you assume CAGW is going to happen, then you can “speculate” that the last 2 decades in the Cornbelt, which represent the best growing conditions since corn has been grown in that region, “might” change to less favorable……….this is all they are doing.”

    Excellent point … and if you assume CAGW is going to happen they must acknowledge the trend already underway … that IF warm temps do affect yields in current farm belts – there are huge amounts of land farther North … and in to Canada … where temps would become highly favorable.

    There is also the inconvenient fact that there is plenty of high yielding corn grown in AZ – where summer temps are often in the 110+ deg F range. It should be easy for farmers to simply use seed developed for these higher temp areas.

    The whole paper is pretty much worthless.

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