Remember when climate alarmists told us global warming was going to kill the U.S. corn crop? Never mind.

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.

Components of the yield trend. Observed yields averaged over the US Midwest between 1981 and 2017 (black dots) along with our temperature-driven model estimate (gray line). The yield trend is broken into components attributable to an improvement in climate [red, 0.2 (0–0.5) t/ha, best estimate and 95% CIs, timing adjustments [blue, 0.2 (0–0.3) t/ha per decade], and other factors improving yields [green, 0.9 (0.9–1.0) t/ha per decade]. Also shown is the baseline yield referenced to 1981 (6.2 t/ha). The stacked bar on the far right side shows the total contribution, as of 2017, from each of these components and the associated 95% CIs.

“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)

Peculiarly pleasant weather for US maize


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.


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 (929°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.

0 0 votes
Article Rating
Newest Most Voted
Inline Feedbacks
View all comments
Paul Penrose
November 5, 2018 3:30 pm

They say that the changing climate as helped increase yields, but then they add the obligatory disclaimer that the benefit may not last. So it’s OK to show some doubt in this case, but we can’t doubt the climate forecasts (models)? You have to wonder if they would have made that kind of disclaimer before the whole CAGW movement took over this area of science.

Bryan A
Reply to  Paul Penrose
November 5, 2018 7:33 pm

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.

In other words the cooling effect corn has on it’s localized environment helps it to grow better especially in warmer climates. This would seem to indicate a LESSENED VULNERABILITY to climate change rather than a increased vulnerability.

Richard Patton
Reply to  Bryan A
November 5, 2018 9:01 pm

“more vulnerable to climate change than previously thought.”

is required boilerplate in almost every scientific paper now days.

Richard G.
Reply to  Bryan A
November 6, 2018 7:17 am

The longer growing season is due to increases in T-min while T-max has been stable. Also ignored is the fact that photosynthesis actively converts photons into high energy chemical bonds and the process is thus a heat sink.

Samuel C Cogar
Reply to  Bryan A
November 6, 2018 8:18 am

Bryan A – November 5, 2018 at 7:33 pm

In other words the cooling effect corn has on it’s localized environment ….. yada, yada …

Bryan, ….. ya gotta quit assuming what you read is literal fact. To wit:

Quoting co-author Nathaniel Mueller:

Widespread increases in rates of evaporation apparently helps shield maize from extreme heat, cooling the surrounding area and helping to boost yields.

How can the above possibly be true given the following science fact, to wit:

Since water is used as the electron donor in oxygenic photosynthesis, the equation for this process is:

CO2 + 2H2O + photons → CH2O + O2 + H2O
……………. or …..
carbon dioxide + water + sunlight = carbohydrate + oxygen + water vapor

There is NO per se, “rates of (H2O) evaporation” associated with photosynthesis that produces “cooling of the surrounding area” …… simply because the water (H2O) being emitted from the stomata is already in vapor form. A vapor cannot be evaporated.

On the contrary, during extreme photosynthesis activity, such as in a cornfield, the outgassing of large quantities of water (H2O) vapor [a greenhouse gas] from the leaf stomata will surely cause an INCREASE in the near-surface air temperatures ……. rather than a DECREASE (cooling).


Reply to  Samuel C Cogar
November 6, 2018 2:20 pm

Odd.. the H2O is still evaporated, and yet your post says other wise. Sunlight is absorbed, and that energy is used in part for evaporation.

Samuel C Cogar
Reply to  EdB
November 7, 2018 4:12 am

EdB says: “Odd.. the H2O is still evaporated

“NO”, ….. EdB, ……. the water vapor (humidity) IS NOT the result of evaporation, …… its the byproduct of a chemical reaction instigated by the chlorophyll in the corn leaf.

CO2 + 2H2O + photons → CH2O + O2 + H2O vapor

November 5, 2018 3:31 pm

Why no mention of the “Greening””effect of more CO2 ?


Reply to  Michael
November 5, 2018 4:02 pm

Exactly. They purposely ignore the elephant in the room and the fact that higher CO2 probably makes corn able to germinate and grow at lower temperatures, meaning that the farmers can plant earlier, even without any detectable warming.

Reply to  Michael
November 5, 2018 5:47 pm

Corn is a C4 plant – it spends some energy in concentrating CO2, giving it a considerable advantage over C3 plants when CO2 is scarce. The “greening” effect of an increased concentration of CO2 benefits primarily C3 plants.

Reply to  Curious George
November 6, 2018 2:18 am

Coincidentally, in a private email exchange yesterday I wrote that:

“C4 crops benefit little from higher CO2 levels, except when under drought stress. However, since most corn and sorghum are grown where drought is a significant risk, higher CO2 levels significantly benefit even corn and sorghum production.”

At least w/r/t corn, I was wrong. Dr. Craig Idso corrected me, replying:

“I concur with nearly all that you said, with the exception of C4 crops benefitting little from CO2 except under drought stress. That is an exaggerated and incorrect narrative. Multiple studies have shown (and I have reviewed dozens, if not hundreds, of them on the CO2 Science website) that examine the effects of CO2 on C4 crops under normal watering conditions. These studies consistently show yield/biomass increases on the order of 15 to 40% depending on crop, cultivar and other growing conditions. As one example, here is a link to a study I posted on maize just last week,, which showed grain yield increases of 21 and 29 percent at 550 and 700 ppm CO2, respectively. These values fall in line with the average of 54 CO2 enrichment studies for maize posted in our plant growth database, that yield a 27.3% increase in biomass for a standardized 300 ppm increase in CO2. Similar positive responses to elevated CO2 have been noted for other C4 crops posted in our database.”

The paper he cited is: Xie, X., Li, R., Zhang, Y., Shen, S. and Bao, Y. 2018. Effect of elevated [CO2] on assimilation, allocation of nitrogen and phosphorus by maize (Zea Mays L.). Communications in Soil Science and Plant Analysis 49: 1032-1044. (Reviewed here)

Review excerpt:

“Results of their study revealed that elevated CO2 increased the aboveground biomass in the 550 and 750 ppm treatments by 5 and 12 percent, respectively, whereas it increased the grain yield by a much larger 21 and 29 percent, again respectively. Additionally, elevated CO2 increased spike number, kernels per spike and 100-grain weight. Total nitrogen accumulation within the maize grains at harvest were also enhanced by CO2 enrichment, by 7 percent in the 500 ppm CO2 treatment and 70 percent in the 750 ppm CO2 treatment, helped in part by CO2-induced improvements in nitrogen translocation efficiencies.

In light of the above findings, it would appear that maize is carbon-limited at the present-day atmospheric CO2 concentration and that it will experience larger than anticipated grain enhancements similar to those observed for C3 crops as the air’s CO2 concentration continues to rise in the future.”

Note that “nitrogen accumulation in grains” basically means protein content. Proteins contain nitrogen; carbohydrates, fats & oils don’t. So higher CO2 levels apparently increase protein content in corn, when it is grown with adequate fertilization.

Here’s the rest my email (slightly refactored), i.e., the part I didn’t get wrong:

The benefits of rising CO2 levels are well-measured for major crops, and in most cases the benefits are so large that even climate realists have a hard time believing it, and the natural inclination is to understate them.

The vast majority of economically important crops are C3 plants. (The main exceptions are corn [maize], sorghum & sugarcane, which are C4 grasses.) In general, C3 (and CAM) plants benefit dramatically from rising CO2 levels, and C4 plants benefit less.

However, there is quite a bit of variation. E.g., legumes (beans, alfalfa, etc.) benefit more than most other C3 crops, and they have the advantage that their symbiotic bacteria fix nitrogen for them, so that their increased productivity does not require correspondingly increased nitrogen fertilization.

Even C4 crops benefit from higher CO2 levels when under drought stress. Since most corn and sorghum are grown where drought is a significant risk, higher CO2 levels are beneficial for corn and sorghum production.

A conservative estimate is that at least 15% (probably closer to 20%) of current agricultural production is the direct result of the fact that atmospheric CO2 levels have increased by about 45% (from ~280 ppmv to ~407 ppmv) since the LIA. That’s one of the reasons that famines are becoming rare.

I calculate that if we lacked that additional productivity, we could almost (but not quite) make up the difference by putting all the world’s rainforests under the plow (optimistically assuming that they would be as productive as existing cropland).

The Idsos’ indispensable CO2 Science web site has an huge catalog of studies of the measured effects of varying CO2 levels on various crops.

Here’s the German Wikipedia page on photosynthesis:
(Or Google-translated to English.)

Here’s a graph from that article (except that I added the brown and blue “280” and “408 ppmv” lines). It depicts the approximate dependence of the rate of photosynthesis on the amount of CO2 in the air, for C3 and C4 plants:

comment image

(The source reference for that graph is a German-language botany textbook.)

In the graph, that’s CO2 concentration on the horizontal axis, and rate of photosynthesis (i.e., plant growth rate), on the vertical axis. Compare the rate of photosynthesis at “0,028” (280 ppmv) to the rate of photosynthesis at “0,0407” (407 ppmv). You can see that, for C3 plants, the benefits of additional CO2 do not begin to taper off until well above 1000 ppmv, which is far above the highest level that fossil fuel use could ever drive CO2, outdoors. Most commercial greenhouse operators maintain daytime CO2 levels between 1200 and 1500 ppmv.

The tremendous benefits of higher CO2 levels for agriculture have been known to science for a century. Here’s a 1920 Scientific American article about it:

Here’s a photo from that article, showing the benefit of CO2 supplementation (from blast furnace exhaust) for potatoes:

That’s the difference between about 303 ppmv CO2 (1919 ambient) on the right, and heavily supplemented (probably at least 1500 ppmv) CO2 on the left.

Reply to  Curious George
November 7, 2018 6:13 am

Most crop plants are bred to optimize for carbs as well, thats part of why nutrition content decreases slightly with higher CO2. They are also not N and P constrained and so don’t share resources with soil.

Richard M
Reply to  Michael
November 6, 2018 8:07 am

I suspect a large part of the “other factors” is CO2 fertilization.

Tom S.
Reply to  Michael
November 7, 2018 11:33 am

I was told increasing yields were because American farmers are out standing in the field.

steve case
November 5, 2018 3:31 pm

Of course corn productivity is up.
We are putting in our gas tanks.
A crime against humanity if you
ask me.

Reply to  steve case
November 5, 2018 4:10 pm

I’ve often said that the fear of CAGW is crop failure leading to starvation. Their answer is to burn the food.

Can’t make this stuff up.

Duncan Smith
Reply to  steve case
November 5, 2018 5:14 pm

It would make the Green’s heads explode if they found out the Ethanol Subsidy (45 cents per gallon) was paid (tax credit) to the gasoline refinery owners to mix petrol with ethanol (some of which makes it to the farmers). Even more so, if they found out Trump is keeping the Ethanol subsidy to hold onto political backing in the corn belt.

“Faced with the potential loss of influence over some of his strongest congressional backers, Trump quickly told Pruitt to back off any future talk of cutting the ethanol subsidy.”

Reply to  Duncan Smith
November 5, 2018 6:35 pm

The ethanol blender’s credit expired at the end of 2011. There is currently no Ethanol Subsidy.

Note also that the ethanol producers did not get the subsidy: the oil companies did.

Duncan Smith
Reply to  Chris4692
November 5, 2018 6:51 pm

Agreed, there is no subsidy but there is a tax credit. On your second point, my post above say the credit goes to the oil refineries (BP et al.)

Chris Wright
Reply to  steve case
November 7, 2018 3:23 am

Yes, they are almost literally taking food from empty stomachs in order to feed empty gas tanks.
I agree, it may well be a crime against humanity – as is much of CAGW.

Mark Lee
November 5, 2018 3:37 pm

I think the article is in error as to the cause of the growth, at least in this century. Since temperatures haven’t gone up to any appreciable degree for the last 20 years, shouldn’t the continuing, if not the prior decades of increased yield be attributed to rising CO2 and not temperature?

Reply to  Mark Lee
November 5, 2018 4:33 pm

Bingo. Same thought occurred to me. Unfortunately, that doesn’t make you or me right, but it is still a good question, Mark.

Duncan Smith
Reply to  KaliforniaKook
November 5, 2018 5:28 pm

From what I can tell, everything to do with industrialization after WWII (my two cents). Note the ‘drought’ yields in 1901 and 2012, still miles ahead.

comment image

Reply to  Mark Lee
November 5, 2018 8:25 pm

On the other hand, I notice some significant dips in production. Are these in La Nina years?

Samuel C Cogar
Reply to  Mark Lee
November 6, 2018 8:35 am

shouldn’t the continuing, if not the prior decades of increased yield be attributed to rising CO2 and not temperature?

Mark Lee, ….. actually, ….. prior decades of increased yields are directly attributed to “increased use of high-nitrogen fertilizers”.

Tom Halla
November 5, 2018 3:41 pm

As maize originated in southern Mexico or Central America, the crop should favor warm weather.
My understanding from archaeology is that it took at several thousand years for corn to be developed for more northern conditions.

Rich Davis
Reply to  Tom Halla
November 6, 2018 3:03 am

Exactly! Corn that grows just fine in Florida or Mexico will suddenly stop growing in Iowa if the average temperature rises by 1 to 2 degrees (which without looking it up, I would guess would mean that Iowa would still be considerably cooler than Tennessee or North Carolina is today)

Do these people care at all about being logically consistent? The question answers itself.

November 5, 2018 3:44 pm

Anthony, you misunderstood that scary headline by the greens – they actually meant that only the part of the corn crop used for food (~60% in the US?) would fail due to CAGW – the corn used to create fuel Ethanol would not be affected because…climate change. / sarc off

michael hart
November 5, 2018 3:47 pm

So when it comes to understanding crop yields, farmers are 1/2 a century ahead of failed climate ‘scientists’ at Harvard 1/2 a continent away?
Color me gobsmacked, Bruce.

November 5, 2018 3:58 pm

now they are saying that climate change will reduce the nutritional quality of the corn

Reply to  chaamjamal
November 5, 2018 4:49 pm

Researchers have the nasty habit of finding the results that they want to find. link

Somebody, Jones, Trenberth, I can’t remember, said that the MWP was a problem. Up pops Mann’s hockey stick.

Folks notice that CO2 increases crop yields … that’s a problem for CAGW. Up pop studies that say that the nutritional value of those crops decreases. I’m skeptical.

Reply to  chaamjamal
November 6, 2018 5:39 am

Hmm I understand that for humans ,corn is not all that good ,nutritionally speaking ,being poorly digested &absorbed from the gut .Animals may be different I guess .I believe it’s good for fibre for constipated people .

Tom Halla
Reply to  kendo2016
November 6, 2018 5:49 am

Maize lacks certain amino acids, so trying to survive on a pure corn diet will result in pellagra. Add in beans, and one will avoid that deficiency disease.
Better yet, feed some of the corn to chickens, and eat the chickens.

S C Cogar
Reply to  Tom Halla
November 6, 2018 8:53 am

Or better yet, plant beans with your corn.

The beans will vine up the cornstalk, which makes them easy “picking”, ……. plus the fact beans are legumes, which mean they put (fix) nitrogen in the soil …… which the corn loves with a passion.

An example of symbiosis that benefits the corn, the beans and the gardener.

Reply to  chaamjamal
November 6, 2018 11:39 am

Crop bred to optimize for carbohydrate production.

November 5, 2018 4:01 pm

… but there is no guarantee that benefit will last as the climate continues to change. “

Oh, come on ! There is no guarantee that lightening won’t strike me before I finish typing this … {rumble, rumble, crash, bright light, explosion}

[Note: The mods claim no responsibility, implied or stated, for remote operation of their “bright light, explosion” device. .mod]

November 5, 2018 4:08 pm

As a wheat grower for 12 years on the family farm, my dry land (non-irrigated) white winter wheat 2018 yield averaged 93 bushels/acre (5580 lbs/acre); in 2016 yield averaged 98 bu/acre (5880 lbs/acre) in eastern WA (USA). This compares to average for my father at 44-49 bu/acre on the same land. Fertilizer is 80 lbs N/acre, the same rate as father in past decades but he always battled serious weed infestation. This is a two year rotation: crop-fallow-crop-fallow to build nitrogen load with wheat straw mulch contributing approx. 35-40 lbs/ac N, so with larger crops, more N from mulch accumulates. The major factors to high yields are (1) new non-GMO cultivars originated from agricultural research universities in the region (Washington, Idaho, Oregon), (2) much improved pesticides which almost eliminate weed infestation (99.9%+) (3) carbon dioxide plant food, and (4) top-notch advice from highly educated crop advisors employed by local chemical supplier. I would include a picture but don’t know how that’s done.

John Tillman
Reply to  DAVID
November 5, 2018 6:58 pm

Same here in NE Oregon.

Improved genetic strains (big heads, small stalks), herbicides, pesticides, fossil fuel for tillage, field work and harvest, without irrigation, mean that my great grandfather’s yields of ~15 bu/A (if lucky) are now ~120 bu/A, with summer fallow in both cases. Same land. Same rainfall. Same growing season, more or less. Roughly:

GGF: 15 bu/A (after sheep had eaten down the native bunchgrass, so that the soil could be plowed)
GF: 30 (Federation wheat with long stalks)
F: 60 (Stephens wheat with shorter stalks)
Now: 120 (cutting edge of wheat tech, plus more plant food in the air).

Would be less in a dry year, of course, but that’s what’s possible now.

John Tillman
Reply to  John Tillman
November 5, 2018 7:19 pm

Dry year, maybe 80 bu/A rather than 120 on the same land.

Reply to  John Tillman
November 5, 2018 11:59 pm

John Tillman

Herbicides and pesticides are also reliant on fossil fuels for their production. Irrigation too, probably.

I suspect that with enough horses/oxen and manpower one could harvest as efficiently as you can with mechanisation, but without fossil fuel produced herbicides, pesticides and electric pumps you just wouldn’t have the same crop to harvest.

James Francisco
Reply to  HotScot
November 6, 2018 6:07 am

HotScot. Don’t forget that about 1/3 of your crop would have to be fed to those horses and oxen. A very important point that I think is missed by those who wish to go back to the good old days.

Samuel C Cogar
Reply to  James Francisco
November 6, 2018 9:08 am

“Yup”, fueling a 40 horsepower farm tractor with fossil fuel ….. is a lot simpler, less time consuming and less costly …….. than feeding harvested biomass to 40 horses. 😊 😊

November 5, 2018 4:24 pm

You missed the later article explaining how CO2
was going to boost corn production so much first,
no one would know what to do with all the corn,
so the price would collapse to 5 cents each,
and the corn farmers would go broke,
have their farms foreclosed,
and then their bankers would have to be farmers,
but they wouldn’t want to gets their suits dirty,
so the farms would remain unsold and unused.

Then, with all that fallow land,
and foreclosed farms looking for buyers,
there would be a corn shortage the NEXT year.

This here climate science is complicated stuff.

Reply to  Richard Greene
November 5, 2018 5:57 pm

The Lotka–Volterra equations, also known as the predator–prey equations, are a pair of first-order nonlinear differential equations, frequently used to describe the dynamics of biological systems in which two species interact, one as a predator and the other as prey. The populations change through time according to the pair of equations. [Wikipedia]

Reply to  Curious George
November 5, 2018 8:29 pm

I’ve also seen this done with Markov Chains.

Javert Chip
November 5, 2018 4:36 pm

I think our “climate science” dudes have been drinking the corn, if you know what I mean, and I think you do.

Sadly, we are now far enough into this CAGW-timeline crap that young PhDs (say, 30-ish) will outlive all this nonsense and have to look back on their participation in this fraud. I wonder how the intellectually honest ones will deal with that.

James Francisco
Reply to  Javert Chip
November 6, 2018 6:18 am

I have pondered that thought also. My fear is that they will just shrug their shoulders and not suffer in any way. No job loss not a thing. They will miss out on a better life they could have had if they hadn’t been part of a scheme that is holding back progress and prosperity that could be passed onto them.

John F. Hultquist
November 5, 2018 4:51 pm

About 1950, I helped husk corn using a deer antler, and then fed the corn into a one-hole hand-cranked sheller. There are several videos and many photos of this in the web. This was on a neighbors small family farm. Uncles grew wheat and oats. That was slightly more mechanized and the kids did help there, too.
Things changed rapidly.

I smiled at this phrase in the post: “. . . Farmers are incredibly proactive . . .
I never heard the term “proactive” used by the neighbors or our family farm relatives, but they sure were active.

November 5, 2018 5:20 pm

“Whereas this trend is often attributed exclusively to technological improvements, here, we also identify contributions from improved temperatures during the growing season. ”
Technological improvements i.e. planters, harvesters, trucks, tractors etc. are ironically powered by fossil fuels.

John Tillman
Reply to  Ron
November 5, 2018 6:47 pm

More importantly, herbicides, pesticides and chemical fertilizers, which have so boosted yield, are also all based upon fossil hydrocarbons.

Even in the late 20th century, US grain was about 40% oil. Now it’s even more.

Timo Soren
November 5, 2018 5:24 pm

Every positive comment HAS to be chaperoned by a “but it might not last” or “How long will it last” etc…. the PC correct climate of climate science publications makes me ill.

Crispin in Waterloo
Reply to  Timo Soren
November 5, 2018 7:58 pm


Then we can subscript, “On the other hand, it may last indefinitely.”

November 5, 2018 5:44 pm

Read a paper several years ago that showed corn fields on calm days ran out of CO2 by 10:00 am and shut down photosynthesis. CO2 monitors in the field actually read 0.0 on CO2 until the wind picked up in the afternoon. Seems to me that higher CO2 concentrations could push that shut down time back by several hours and maybe increase calm day production.

Luckily, corn is mostly grown in the part of the country that is rarely windless, negating a large part of the problem.

Reply to  OweninGA
November 5, 2018 5:57 pm

It’s called photorespiration when plants run out of CO2 but still have sunlight, water, and O2.
Take a clear pane of glass, lay it on green growing grass in the sunlight. Within a 1 hour, those grass leaves will yellow and will die and take weeks to recover if the roots haven’t been killed..

Peta of Newark
Reply to  Joel O'Bryan
November 6, 2018 4:31 am

Joel, you’ve created a fantastically powerful and localised greenhouse with the pane of glass.
The grass has actually been burnt, nothing at all to do with CO2

Repeat with human skin, *if* you wanna risk being badly burned or contracting cancer……

Mike Wryley
Reply to  OweninGA
November 5, 2018 7:59 pm

Still ,,, pretty remarkable to take a gas concentration from 400 ppm to 0.0 ppm without using a machine and a lot of energy, in a volume of over a quarter million cubic feet per acre. I wonder if a plant has a sense of suffocation?

Peta of Newark
Reply to  OweninGA
November 6, 2018 4:37 am

Owen, I’m glad you said ” I read”
Demonstrates scepticism because I call Total BS on the 0.0 CO2 reading

Don’t we hear even round here that photosynthesis shuts down at 150ppm and less, some folks venture an even higher figure, 180ppm or anything less than 200 even.

Is it inconceivable that the corn itself, by being of a low albedo and effectively a ‘heat sink’ in reverse is causing the wind to blow.
Hot air rises etc etc..
IOW, The corn creates its own weather, especially if there is enough of it.
Just like Rainforests do.

Samuel C Cogar
Reply to  Peta of Newark
November 6, 2018 9:24 am

Owen, I’m glad you said ” I read”
Demonstrates scepticism because I call Total BS on the 0.0 CO2 reading

Ha, 0.0 CO2 is phony bologna. The corn plant’s own metabolism produces CO2. That’s why elevated CO2 ppm can be measured at nighttime.

Steven (back in KY)
November 5, 2018 5:50 pm

How well did corn grow during the last ice age? Just saying, maybe they want that instead?

November 5, 2018 5:52 pm

Climate change alarmism has been and always been a future problem. The “tomorrow” that never gets here.

The Climate Change priesthood concocted their CMIP5 RCP8.5 forcing scenario specifically so all the other rent-seekers could jump on the Climate Change gravy train and ride it to grant success with their publish-or=perish scaremongering fairy tales in peer-review journals. But when they have to model the past few decades, which was the “tomorrow” forecast in TAR or or AR4, the projections of crop demise collapse in utter failure.

The cultit’s Cargo Planes refuse to land.
But they’ll keep tweeking thier runways and bamboo control towers until they do or they run out of money. I’m guessing on the latter.

November 5, 2018 6:01 pm

Life’s majesty grows grander and grander the closer you are to the equator.
More species, higher net primary productivity.
And these are the warmest areas on earth.
We have nothing to fear from warming, in fact it will be a net benefit.

Reply to  Jeff
November 6, 2018 12:04 am


Imagine all those billions of acres across Canada and Russia released from perma frost to agriculture. What a boon to mankind.

November 5, 2018 6:41 pm

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 do not base their planting or harvesting decisions on the Climate. They base their decisions on the weather.

November 5, 2018 10:43 pm

The Cold is here:
comment image

November 6, 2018 12:05 am

This article left me with a feeling of sadness for how out of touch acadamics are with the lowly hicks who actually produce things. They find it *incredible* that farmers can actually adapt to take advantage of changes.
We see this over and over again in scare stories – they assume that people will blindly continue with whatever is current practice, rather than adapt to changes as they occur.

James Schrumpf
Reply to  auralay
November 6, 2018 10:35 am

Years ago I read a science fiction short story where space-dwelling alien “animals” sniffed Earth’s radio output and followed it back to earth, where they happily gorged themselves on our electromagnetic output. Civilization immediately lost radio communication, electrical power, internal combustion engines — anything more sophisticated than steam engines.

But don’t worry, the gub’mint was on the job, and Washington bureaucrats showed farmers how to use draft animals in place of the motorized tractors and combines they’d been using.

I always laughed at that part.

November 6, 2018 12:26 am

The prctical experience of farmers David and John Tillman’s forebears is worth more than all the opinions of climate scientists put together.

Peter Plail
November 6, 2018 1:08 am

Bear in mind two things.
The major increase in yield (green part of the graph) was achieved through “other factors”.
The proportions shown are a result of modelling.
Contributors above have noted that increases in CO2 do not seem to have been included. If the “researcher” who set up the model did not think to include it then it wouldn’t show up in the results.

November 6, 2018 2:22 am

Re: ““One of farmers’ biggest decisions is what they plant and when they plant it,” said Ethan Butler, first author…”

That sounds like two decisions, not one. 😀

David Chappell
Reply to  Dave Burton
November 6, 2018 5:39 am

Post-normal decision?

Peta of Newark
November 6, 2018 5:12 am

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……….

November 6, 2018 5:22 am

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.

Richard M
Reply to  DHR
November 6, 2018 8:27 am

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.

Thomas Stone
November 6, 2018 5:36 am

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.

November 6, 2018 6:42 am

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.

Steve O
November 6, 2018 7:21 am

“Never Mind” sounds like it could be the title of a book with many chapters.

R. de Haan
November 6, 2018 7:36 am

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.

Reply to  R. de Haan
November 6, 2018 8:56 am

“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.

November 6, 2018 9:14 am

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.

November 6, 2018 10:22 am

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

November 7, 2018 1:58 pm

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?

%d bloggers like this: