From Dr. Roy Spencer’s Global Warming Blog
by Roy W. Spencer, Ph. D.
For the last decade I’ve been providing long-range U.S. Corn Belt forecasts to a company that monitors and forecasts global grain production and market forces. My continuing theme has been, “don’t believe gloom and doom forecasts for the future of the U.S. Corn Belt”.
The climate models relied upon by the United Nations Intergovernmental Panel on Climate Change (IPCC) are known to overestimate warming compared to observations. Depending upon the region (global? U.S.?), temperature metric (surface? deep ocean? lower atmosphere?) and time period (last 150 years? last 50 years?) the average model over-estimate of warming can be either large or small.
But nowhere is it more dramatic than in the U.S. Corn Belt during the growing season (June, July, August).
The following plot shows the 50-year area-averaged temperature trend during 1973-2022 for the 12-state corn belt as observed with the official NOAA homogenized surface temperature product (blue bar) versus the same metric from 36 CMIP6 climate models (red bars, SSP245 emissions scenario, output here).
This kind of sanity check is needed because efforts to change U.S. energy policy are based upon climate model predictions, which are often wildly out of line with observed history. This is why environmentalists emphasize models (which can show dramatic change) over actual observations (which are usually unremarkable).
Here is but only a small sample of the recent available literature relevant to the topic.
Mueller et al. 2016 DOI 10.1038/nclimate2825 – Cooling of US Midwest summer temperature extremes from cropland intensification
Lin et al. 2017 DOI 10.1038/s41467-017-01040-2 – Causes of model dry and warm bias over central U.S. and impact on climate projections
Alter et al. 2018 DOI 10.1002/2017GL075604 – Twentieth Century Regional Climate Change During the Summer in the Central United States Attributed to Agricultural Intensification
Zhang et al. 2018 DOI 10.1002/2017JD027200 – Diagnosis of the Summertime Warm Bias in CMIP5 Climate Models at the ARM Southern Great Plains Site
Qian et al. 2020 DOI 10.1038/s41612-020-00135-w – Neglecting irrigation contributes to the simulated summertime warm-and-dry bias in the central United States
Coffel et al. 2022 DOI 10.1029/2021GL097135 – Earth System Model Overestimation of Cropland Temperatures Scales With Agricultural Intensity
One thing I’ve not be able to find easily is research regarding how much this form of land use biases the global average temperature (GAT) datasets. As most are well aware urban land use can have a biasing effect on the GAT when urban observations are used as a proxy for rural areas and vice versa. There is a similar effect for agricultural land use where crop observations are used as a proxy for non-crop areas and vice versa. Is the cooling effect of crops more or less than the warming effect of UHI?
I believe the cooling effect is for IRRIGATED crops.
Presumably even this effect is being diminished. The center-pivot irrigation systems in the 1970s were designed to throw water up into the air to get it to travel a long distance.
The more recent models have outlets that now hang just above the top of the subject crop. Presumably the evaporative water losses (and atmospheric cooling) are reduced by the more efficient modern systems.
Regardless corn appears to be doing very well with warming since 1940
And is steadily increasing yields at about 1.9 bushels per acre per year
This graph should be posted to every person and quasi organization like Greenpeace and green parties around the world .
This shows a massive increases in yield because of three reasons.
The first reason is chemical weed control .The second is that plant breeders are continually improving maize varieties and the third reason and the most important is the use of nitrogen and phosphate fertilizer .
Yields have increased from 40 bushels per acre in 1950 to 180 bushels in 2018. A 450 percent increase in 68 years .
BUT if Greenpeace persuade governments to limit or ban nitrogen fertilizer because of the ill informed notion that emissions from this fertilizer will warm the world ,food production would fall so quickly that the world would be in famine within a year .
Just think about that as bans and limits on nitrogen fertilizer will lead to an immediate crisis far greater than the supposed threat of climate change .
Don’t forget that more efficient farming practices and the growth in agriculture in the third world also contributes to the total harvest. Something the CAGW crowd would like to stop in the third world – let’em starve is the CAGW mantra.
Something else to consider is planting-density practices have changed through the years. I can remember as a small child in the ’40s, that corn was planted in rows wide enough to allow a horse-drawn wagon to collect the corn husked by manual field laborers. This allowed plenty of opportunity for weeds to grow and compete with the corn for water and nutrients.
Today, the corn is harvested with machines and the corn is planted so densely that it is difficult to walk through a field. Thus, weeds, which usually don’t grow as fast as corn, are shaded out and find it difficult to compete. It is basic technology advances that have allowed the available soil to be used more efficiently. However, there probably isn’t much potential improvement left along that path.
“It is basic technology advances that have allowed the available soil to be used more efficiently. However, there probably isn’t much potential improvement left along that path.”
A rather heroic prediction.
Not so heroic if you were paying attention. I suggested the increase in planting density as being a major contribution, which from Bryan A’s graph, probably transitioned about 1955. There is simply so little space between plants today that I don’t think that approach has much potential.
I think that the opportunities lie along the lines of genetic manipulation, if people don’t get paranoid about messing with genes. Considering what has happened in the past with GM crops, and the recent reactions to COVID vaccines, I think that there is a good chance that the public will reject that path.
One almost always finds that production curves have a point of diminishing returns, so I think it would be prudent not to expect or depend on an indefinite increase in production such as we have seen between 1955 and today.
I don’t think all the advances to increase crop yields have encountered yet. Satellites and GPS have helped tremendously, but have limited use down to the small grids. Drones are now being developed to help manage the planting, fertilizer, weed/insect control chemicals, etc. because they allow much finer attention due to their closeness to the field.
What amazes me now is that semi’s and large grain trailers are used right along side the combines which are also humongous pieces of equipment. It has progressed from old two-ton trucks at the end of the field being filled from a stopped combine to multiple semi’s being needed to handle the grain being harvested.
I would characterize what you remarked about as ‘fiddling’ to squeeze out a little more. My feeling is that the major gains have already been made. When one is concerned about correcting problems in small patches of the field, it suggests to me that we are already transitioning to the portion of the production curve with diminishing returns.
I wouldn’t argue that we are on a curve where the marginal difference is reduced. However, If an extra 100 bushels can be squeezed from a field, that is not small change at today’s prices.
That’s consistent with the literature. We have significantly altered the land especially in the cornbelt. One thing to note though…corn is only part of the picture. Several other crops like soybean, sorghum, etc. participate in the evapotranspiration cycle.
The list is actually endless. The underlying basis is the introduction of new farming practices, fertilizers, insecticides, and seeds have allowed a large increase in productive crop lands globally, not just in the central US. Yet somehow this always seems to get short shrift in the climate models.
Irrigation might be some of it. But evapotranspiration is also a major factor.
Irrigation is part of it. Evapotranspiration still occurs regardless though.
And yet you wonder why some of us are so adamant about the uncertainties associated with the GAT. You simply can’t wish away uncertainty through averaging. If the data itself is uncertain then no amount of independent, single measurements of different things can decrease that uncertainty by averaging. All you can do is calculate how close you are to the population average. Whether that population average is accurate or not is determined by the uncertainty in the underlying data and it simply doesn’t matter how many significant digits you include in the calculation of the average.
Not exactly what you asked for. It does show how the use of degree days is a more useful metric than temperature for determining the heat accumulation (growing degree days) on crops.
https://www.nature.com/articles/s41598-018-25212-2
“But nowhere is it more dramatic than in the U.S. Corn Belt during the growing season (June, July, August).”
Indeed. The triumph of successful cherry picking!
Here is a map of annual trends, 1970-2019. There is a lot of natural variation. And yes, if you look around, you can find places with little trend.
The GAT exists nowhere in the real world.
This is not GAT.
Explain how looking at corn belt temperatures by themselves is “cherry picking”.
Roy explained it
“But nowhere is it more dramatic than in the U.S. Corn Belt during the growing season (June, July, August).”
Hey Nick!
YAWN!
Agriculture intensification has grown all over the globe, not just the central US. If that has led to the climate models being wrong for the central US then why shouldn’t we expect them to be wrong for many other regions such as in Africa, South American, Asia, etc?
I doubt that neither you Nick or Bdgwx have ever grown a sweet corn cob in your life.
I can tell you from 55 years experience growing maize (corn) that it is a frost tender plant and that the cumulative heat units that the climate delivers in the first four months after planting will determine the yield as long as there are no severe drought conditions, weeds or lack of nutrients.
Maize roots can grow very deep into the soil to seek water and deep chisel ploughing will help with this.
We now grow exclusively for silage employing local contractors to chop and ensile our crop to feed our 500 cow herd over winter and early spring .
If the climate became marginally warmer farmers would start planting earlier,but there is always the risk of a late frost as the plants are emerging.
There is obviously no change in the climate in the Corn Belt states.
A small warming around the world is nothing to fear .
I agree with you Graham. I love having farming explained to me by people that couldn’t manage to grow a lima bean in a styrofoam cup.
In the clip, Bloomberg can be heard saying: “I could teach anybody — even people in this room, no offense intended — to be a farmer. It’s a [process]: you dig a hole, you put a seed in, you put dirt on top, add water, up comes the corn.”
You are correct. I have never grown corn in my life.
This statement is not consistent with the evidence.
“This statement is not consistent with the evidence.”
Neither are the claims of the CAGW advocates. The earth is *NOT* burning up or suffering from massive crop failures, massive coastal flooding, or massive species extinctions.
Not true: The evidence is that extreme weather has not become more frequent, intense nor of longer duration over the past 120+ years. There were more and longer heatwaves in the area in the 1930s, even with the governmental liars changing the definition heat waves.
If you want to claim that the beneficial warming of about 1℃ since the end of the Little Ice Age meets the current definition of climate change (CAGW) then go right ahead. Urban Heat Island (UHI) effects in the 20th and 21st Centuries doesn’t count.
I think you may have me confused with someone else. I’ve not discussed extreme weather, heat waves, or whether 1 C of warming meets the definition of CAGW in this blog post. BTW…I don’t even know what CAGW is and every time I ask I get a different answer.
Where is the evidence that the climate has changed in the corn belt that would effect corn yields ? you ask.
There is no change that you or I could notice over 90 years ,even Stokes knows that as he posted a colored graph above.
There is the evidence for all to see that there has been little warming and records from the 1930s show much hotter times than now .
I didn’t ask how climate change effects crop yields. Above I asked how much crop intensification effects regional temperature biases.
This is lame, even for you, Stokes; YOU accused Roy of cherry picking:
That doesn’t answer at all. I hate to call people out, but you make it very difficult. But I suppose when the facts don’t back you up, you have to cherry pick as only you can.
I thought CO2 was well mixed throughout the troposphere and the world. How on earth can large temperature excursions exist in this environment when CO2 is obviously part of the devil’s work? Funny how all the CO2 radiation accumulates in the northern polar region and none in the southern polar region! Maybe the GAT metric is a waste of time?
Yeah, Nick, but your global representation means I’m going to move to Alaska and start mosquito farming in the northern part.
Interesting how the colour choices makes the minimal amount of warming in the Arctic (0.4 degrees) look so scary. In fact, since it is always well below freezing, any warming there is highly desirable. As well as that, the same colour is used for 0.0 – 0.1 degrees as for 0.0 to -0.1 is designed to hide any cooling that exists in the tropics, where it would be a significant issue.
This is clearly designed to advocate, not to inform. In other words, propaganda.
The colour scale is standard rainbow, symmetric about zero trend. The Arctic warming is not 0.4°C, but 0.4°C/decade – ie 2°C over this period.
even better- praise the Lord! 🙂
The horror, of a slightly less frigidly frozen Arctic wasteland!
So what decade will the corn belt have expanded to the Arctic ?
Minus 20C to minus 18 C still far colder than you will ever experience in Australia Nick.
One of the problems with using anomalies or temperature trends is that it emphasizes changes that may have little practical impact. Because ice melts at 0 deg C, if it starts out well below the melting point, even these ‘huge’ changes of tenths of a degree over a decade may result in negligible a difference in the ice coverage.
Interestingly, the southern half of South America shows zero trend.
As is typical, there is nothing said about the variance in the temperature trends or uncertainties. Stoke’s map makes it look like these are precisely known measurements. A casual examination shows that apparently the map is the result of Loess smoothing.
Yes there are areas without much trend, regardless the global average of the real world also does not match the output of the models.
Nick.
To me, it is not cherry-picking but corn-picking.
Spencer was [likely] paid to give expert opinion on a particular region for
which the models have shown little skill [regional forecasts] as Spencer’s graphic demonstrates..
Companies, and farmers, have clear interests in accurate forecasts.
Climate modelers on the other hand have a vested interest in scary projections
so as to keep grant funds flowing. Modelers’ clients are the governments who dole out
billions of research dollars each year, regardless of the accuracy. It is a form of rent-seeking.
The last time he critiqued models he mixed up the ‘tas’ and ‘tos’ fields and overweighted the CanESM5 model in his results. I don’t think either were intentional though. And I’m not saying his critique isn’t valid this time. But past experience tells us we need to be skeptical of his “expert” opinion.
Have you read ANY of the agricultural studies done on the region? They all agree with Dr. Spencer. First frost and last frost have been extended providing a longer growing season primarily due to raised minimum temperatures. Too bad you and Stokes are inculcated into promoting the propaganda that it is maximum temperatures that are increasing and will kill us all. Never a look at Tmax and Tmin separately by regions or localities. Do so, you might learn something.
Once again Mr Stokes tries to derail the conversation and only serves to diminish his reputation.
I see the most warming in the areas with the least data.
Hmmmm .
We’ve been hearing these climate-induced agricultural meltdown stories for years now, but none of the alarmists are willing to explain the reasons for the global increase in overall food production. Besides if agriculture is facing such a threat from a changing climate, shouldn’t it be affecting population growth and life expectancy? Yet during the past half-century the former has doubled globally while the latter has increased by 16 years.
Oh but they are going to take away fertilizers now, so then crop yields will go down and PRESTO! then they will blame it on CC and feel vindicated! Just like the models predicted, they will say. They will force the outcome they wrongly predicted.
My very first post here in 2011 (late to the party) involved deliberate NRDC mis
information presented to Congress about future corn yields. And the paper they misrepresented was itself very bad science, omitting from the yield/temp by county regression a cross term KNOWN since decades to be important. Corn (maise) yields suffer when it is hot and dry, but NOT when hot and wet. The researchers omitted the temp/precipitation cross term from their analysis, explicitly, and via a completely spurious statistical rationale. It was way back in 2011 a clear case of climate related academic misconduct.
Lying, once started, is difficult to stop. (Human inertia.)
Of course! One has to keep inventing new lies to support the original lies.
Im not in the “corn belt”, but I grow sweet corn on a home plot on the west coast. This year, I’ve had to plant 3 times because the ground wasn’t warm enough to germinate properly and the seed rotted. Everything is at least a month late. Never had this happen before.
“This is why environmentalists emphasize models (which can show dramatic change) over actual observations (which are usually unremarkable).”
Heck, who wants boring reality when you can have exciting models! /sarc
Personally I find most of them too skinny and anorexic. (A sexist would say h/t Greg Gutfeld)
Of course the models are too skinny.
The alarmists run the models hundreds of times until they get the results they want! 😉
Where I am about 35 miles NNE of Indianapolis among the soya bean and corn fields, and black angus pastures we have not hit 100 deg. F since 2012. We got close but no cigar out here at my place. Highest temp so far this year is 89.
And the crops are looking great!
This is common in the central US. According to my weather station we had exactly one day where the temp hit 100F last year. That’s about what it has been over the past decade.
The CAGW advocates don’t want people to know that max temps are *not* going up in at least part of the globe, if not in major parts of the globe. Only minimum temps are going up – AND THAT’S A GOOD THING! They can’t admit to “good” things, it would ruin their ability to scare people in order to generate funds from the government. If the “average” temp is going up well it must mean THE EARTH IS GOING TO BURN UP! Leading to mass human migration, crop failures, flooding of the global coastal areas, mass extinctions of many species including humans, wars, and pestilence. The truth is that human migration today is driven by economic/political forces and not climate change, crop failures are *not* occurring on a mass scale, New York/Miami are not underwater, species extinction is not being driven by climate change but by human intervention, wars are not being driven by climate change but by economic/political considerations, and we are not seeing any more mass die-offs of humans than we have historically.
Having sloged my way through Alan Longhurst book “Doubt and Certainty in Climate Science” I have concluded that rather than the divide being Skeptics vs. Alarmist it is more about Observationalist vs. Modellers.
Modeling uncertain data, i.e. curve fitting, only leads to models with uncertain outputs. And that is all the climate models really are – curve fitting exercises. All in the belief that if you can fit the recent curve close enough you can predict the future. It’s a fool’s errand. I
think it was E.E. “Doc” Smith that wrote a series of novels about the Lensmen. The advanced race named the Arisians knew that in order to predict the future you had to have complete knowledge of the past – not just an uncertain set of observations but an intimate knowledge of what caused the past. The climate modelers all need to read at least the first and last novel in that series. The modelers think if they can write enough equations to get a close enough fit to the the data that they then “understand” the underlying causes of the observations. That’s simply a pipedream.
The “Realists” (as opposed to “observationists”) understand that we really don’t have a good understanding of the thermodynamic system we call the Earth and any “model” of it has huge uncertainties that just can’t be eliminated by using statistical descriptors. If we had the Arisian’s “perfect knowledge” we could forecast the weather accurately for weeks, months, and years ahead. But we can’t. The future climate is not an “average” of the recent past weather.
And, they ignore that there is no ‘Deep Thought’ computer that can handle the energy exchanges that take place in clouds, at the scale of all the other processes, and they resort to parameterizations obtained from the subjective opinions of experts, scaled to the spatial resolution of the other processes. That is, they are not calculating everything from ‘First Principles,’ as claimed, and have introduced subjectivity — even before they tune the models to get an acceptable match to history.
We’re going to need advanced AI to compile and track all the failed predictions of the climate crusades and framing efforts of biased media.