You may remember seeing scare stories like these in the media.
Claim: Climate Change will Cause a Global Corn Crop Failure
Global Warming Will Cut Crop Yields – Assuming No Adaption
Reality bites in two ways; 1. Actual data shows yield increases, and 2. New study says warming has actually helped corn yields.
Research links warming temperatures and localized cooling to increased maize production
The past 70 years have been good for corn production in the midwestern United States, with yields increasing fivefold since the 1940s. Much of this improvement has been credited to advances in farming technology but researchers at Harvard University are asking if changes in climate and local temperature may be playing a bigger role than previously thought.
In a new paper, researchers found that a prolonged growing season due to increased temperatures, combined with the natural cooling effects of large fields of plants, have had a major contribution to improved corn production in the U.S.
“Our research shows that improvements in crop yield depend, in part, on improvements in climate,” said Peter Huybers, Professor of Earth and Planetary Sciences in the Department of Earth and Planetary Sciences (EPS) and of Environmental Science and Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).
“In this case, changing temperatures have had a beneficial impact on agricultural production, but there is no guarantee that benefit will last as the climate continues to change. Understanding the detailed relationships between climate and crop yield is important as we move towards feeding a growing population on a changing planet.”
The research is published in the Proceedings of the National Academy of Sciences (PNAS).
“Understanding the detailed relationships between climate and crop yield is important as we move towards feeding a growing population on a changing planet.”
The researchers modeled the relationship between temperature and crop yield from 1981 to 2017 across the so-called Corn Belt: Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, Ohio, South Dakota, and Wisconsin. They found that as temperatures increased due to global climate change, planting days got earlier and earlier, shifting by about three days per decade.
“One of farmers’ biggest decisions is what they plant and when they plant it,” said Ethan Butler, first author of the paper and former graduate student in EPS. “We are seeing that farmers are planting earlier – not only because they have hardier seeds and better planting equipment — but also because it’s getting warmer sooner.”
Butler is currently a Postdoctoral Research Associate in the Department of Forest Resources at the University of Minnesota.
Early planting means the corn has more time mature before the end of the growing season.
There is also a second, more surprising trend that has benefited corn yields. Whereas the vast majority of temperatures have warmed over the last century, the hottest days during the Midwestern growing season have actually cooled.
“Increasingly productive and densely-planted crops can evaporate more water from leaves and soils during hot days,” said Nathaniel Mueller, a former postdoctoral research fellow at the Harvard University Center for the Environment and co-author of the paper. “Widespread increases in rates of evaporation apparently helps shield maize from extreme heat, cooling the surrounding area and helping to boost yields.”
Mueller is currently an Assistant Professor of Earth System Science at the University of California, Irvine.
The researchers estimate that more than one-quarter of the increase in crop yield since 1981 can be attributed to the twin effects of a longer growing season and less exposure to high temperatures, suggesting that crop yield is more vulnerable to climate change than previously thought.
The researchers also show that the planting and harvest dates farmers currently use is significantly better adapted to the present climate than it would be to climates in earlier decades.
“Farmers are incredibly proactive and we’re seeing them take advantage of changes in temperature to improve their yield. The question is, how well can they continue to adapt in response to future changes in climate,” said Huybers.
This research was supported in part by the Packard Foundation and the National Science Foundation.
The paper (open access) http://www.pnas.org/content/early/2018/10/31/1808035115
Peculiarly pleasant weather for US maize
Significance
Over the course of the 20th century, US maize yields have improved by more than a factor of five. Whereas this trend is often attributed exclusively to technological improvements, here, we also identify contributions from improved temperatures during the growing season. More than one-quarter of the increase in crop yield since 1981 is estimated to result from trends toward overall warmer conditions, but with cooling of the hottest growing-season temperatures, and from adjustments in crop timing toward earlier planting and longer maturation varieties.
Abstract
Continuation of historical trends in crop yield are critical to meeting the demands of a growing and more affluent world population. Climate change may compromise our ability to meet these demands, but estimates vary widely, highlighting the importance of understanding historical interactions between yield and climate trends. The relationship between temperature and yield is nuanced, involving differential yield outcomes to warm (9−29 °9−29 °C) and hot (>29 °>29 °C) temperatures and differing sensitivity across growth phases. Here, we use a crop model that resolves temperature responses according to magnitude and growth phase to show that US maize has benefited from weather shifts since 1981. Improvements are related to lengthening of the growing season and cooling of the hottest temperatures. Furthermore, current farmer cropping schedules are more beneficial in the climate of the last decade than they would have been in earlier decades, indicating statistically significant adaptation to a changing climate of 13 kg·ha−1· decade−1. All together, the better weather experienced by US maize accounts for 28% of the yield trends since 1981. Sustaining positive trends in yield depends on whether improvements in agricultural climate continue and the degree to which farmers adapt to future climates.
Sorry peeps, but you really do not get any greater degree of cherry picked confirmatoryily biased & confused bunkum than this.
Skeptic says” Climate Change is happening but gonna have no significant effect.
Yet we learn here that it is happening and is having a significant effect.
So which is it, how many times can you eat one piece of cake without choking?
Then we are blinded and confused by the CO2 issue.
Recently, the Wunderkids told me about ‘Corn Sweat’, whereupon 90 million+ acres of corn were raising the humidity and making life unbearable if you lived among the stuff.
Of course, people were gonna die.
As if everyone lives forever. (Guilt ridden people want to. *Then* they won’t ever have to answer probing questions from my namesake up at The Pearly Gates)
But hang on, is that not a change of weather? (Climate if you have a Big Willy)
Is it not that the corn in that sort of acreage is making its own weather?
Just like a big power station near here did during the recent UK ‘Heatwave’
How a large ‘thing’ pumping huge amounts of water (vapour) into the air managed to reverse a quite extreme and long-lived High Pressure Weather anomaly to create, clouds, shade and actual rain.
I know that, I went there and did that.
Then, just as the Beer Lorry arrives at a drunken party that’s going along nicely, everyone cheers and proceeds to drink ever more beer. That can only end happily.
Because, it does raise the question of what you’re doing with all that corn.
I get 180 bushels to be about 4.5 tonnes per acre. Assume one bushel = 25 kilograms, keeps the maths simple.
Increasing due to (undisclosed) agricultural technology. What’s the Big Secret?
Just roughly, = a US per capita daily consumption of 3.4 kilograms
(The Truly Wicked amongst us might suggest that that explains a few things)
Feeding The Poor are we?
But no, you’re burning it.
You are growing stuff and setting fire to it, albeit in a clever technological way inside the engines or motor cars and Ford Fat Fifty Pickup Trucks
It is, all said and done, a slight variation on slash and burn agriculture.
A technique used by humans across the recent millennia to create such climate friendly places as Australia, The Sahara, Southern California(= work-in-progress) and to wipe out other place like the Garden of Eden (aka The Fertile Crescent – not so fertile now is it)
Today’ Fact Check comes out of something I saw where upon a middle aged and sensible sort of girl told me that ‘plants’ require, in total, 52 different nutrients from the soil.
Some more than most etc etc etc Is that right?
How many of those 52 nutrients does A Corn Plant need?
Where do they all come from?
When the corn is harvested, by what mechanism do they return to the farm/field, if at all?
2nd Fact Check might be to read a Seed Catalogue such a A Farmer might see/ read/use
Because the only significant feature of *most* New Plants and varieties are that they are ‘Deeper Rooting’ than their predecessors.
What’s *that* all about. Why is *that* such an advantage?
Is *that* the Big Secret?
Enquiring minds……….
What temperature increase? NOAA’s Climate Reference Network clearly shows that there has been no increase in the average, max or min temperature of CONUS since the system first started in 2005. Any gains in corn production over the period would seem to be the result of CO2 fertilization better farming or something else,
but not temperature. Perhaps the CRN shows a temperature increase in corn States balanced by declines elsewhere? Perhaps if these “researchers” looked for actual data, their results would have some value. As it is, it’s just babble.
I think they looked more specifically at the corn belt. Since I live there I can say the nights have warmed a bit while the days have stayed close to the same (maybe cooled slightly). Growing season has also increased due to fewer late frosts and early freezes.
Certainly, these changes are not major. The biggest factor in recent years is most likely the increase in CO2.
I live in the corn belt, jogging distance from corn and soybean fields, and have noticed that for the last 30 years nights have become warmer, and rain has increased in the summer. The old adage “knee high by the 4th of July” is way out of date. On this 4th of July, some of the corn in our area was over eight feet high. In most years the determining factor for yield is if the fields are dry enough in May for the machinery to get in the fields without compacting the soil.
Don’t underestimate the impact of the technologies embodied in the seed itself as no crop has benefited more than corn in that arena. Not only genetic modification for resistance to diseases, pests & herbicides which are themselves incredibly important but also in basic plant breeding and the ability to target specific hybrids to specific regions or even specific soil types within a single field. The difference between a regionally well-adapted hybrid and a poorly-adapted one can easily run 25% of total yield.
“Never Mind” sounds like it could be the title of a book with many chapters.
Look again at the crop yields of the past NH growing season. Significant crop losses and poor quality harvests all over the planet. Drought, cold, floods, hail storms you name it. Ice Age Farmer maintains a crop loss map. Interesting information.
“Significant crop losses and poor quality harvests all over the planet”
I do wish the markets would take heed of those words and run with them. Unfortunately the markets are well aware that production problems in one area of the planet ( Australia & parts of Europe this year) are taken care of with extra production elsewhere (from the US this year).
It always pays dividends for the prudent marketer of grains to watch the larger picture of world wide grain production.
Bear in mind C4 uses 2 steps: 1st in mesophyll involving bicarbonate HCO3- & a form of pyruvate enzymatically made into acids of 4 carbon atoms, then 2nd in bundle-sheath chloroplasts those 4-carbon acids get de-carboxylated freeing CO2 for Rubisco to become assimilated carbon.
The conductance of CO2 from leaf stomata to where 1st step occurs is known to be different
depending on what is the leaf age & the temperature. Recent (2018) maize genetic profiling has demonstrated that among just 5 tested maize lines there are different responses occurring related to bicarbonate &CO2; involving as well variablity of key enzymes (ex: carbonic anhydrase as controller of conductance & phosphoenolpyruvate carboxylase as key processor of 4-carbon).
O.P. specifies cooler season temperature was significant key to boosting corn/maize yields. We know more leaf evaporation cools plants &, as explained, conductance to the mesophyll is partly a function of temperature
(& maize genetics). I am skipping how earlier in season planting gets better leaf canopy is synergistic with favorable temperature.
C4 plants reduce leaf stomata transpiration in response to elevated CO2 more so than do C3 plants & thus, for C4 plants particulars of their mesophyll conductance in response t temperature are crucial (ex: why a farmer gets better yields planting certain varieties). The point is that the corn/maize yield boost reported over O.P.’s frame of time line is not related to the slight rise of CO2 during the period of time.
Corn/soybean/grains/hay, etc yields in my local area are pushing records every yr now (west MD and south-central PA). Combination of increasing CO2, improving practices and good weather. Knee-high by the 4th of July for corn is so last century — more like chest high now, or more.
Now that’s some disaster, ain’t it? /sarc
I been saying this for years. Anyone who understands agronomy doesn’t need a frickin Harvard study to tell him that global warming is good for crops.
One day, it might get warm enough for Illinois and Iowa farmers to plant and harvest TWO CROPS a year. You think that will finally shut up the “global warming cause crop failure” idiot?