Claim: Future heat waves pose threat to global food supply

But there seems to be no signs of a major slowdown despite heat waves of the past 60 years.

indicator3_2013_ProductionGrain[1]

From the Institute of Physics

Heat waves could significantly reduce crop yields and threaten global food supply if climate change is not tackled and reversed.

This is according to a new study led by researchers at the University of East Anglia and published today, 20 March, in IOP Publishing’s journal Environmental Research Letters, which has, for the first time, estimated the global effects of extreme temperatures and elevated levels of carbon dioxide (CO2) on the production of maize, wheat and soybean.

Earlier studies have found that climate change is projected to reduce maize yields globally by the end of the century under a “business as usual” scenario for future emissions of greenhouse gases; however, this new study shows that the inclusion of the effects of heat waves, which have not been accounted for in previous modelling calculations, could double the losses of the crop.

Lead author of the study Delphine Deryng, from the Tyndall Centre for Climate Change Research at the University of East Anglia, said: “Instances of extreme temperatures, brought about by a large increase in global mean temperature, can be detrimental to crops at any stage of their development, but in particular around anthesis—the flowering period of the plant.

“At this stage, extreme temperatures can lead to reduced pollen sterility and reduced seed set, greatly reducing the crop yield.”

The impacts on wheat and soybean are likely to be less profound, primarily because of the fertilisation effects that elevated levels of CO2 can have on these crops.

In plants, CO2 is central to the process of photosynthesis—the mechanism by which they create food from sunlight, CO2 and water. When there is more CO2 in the atmosphere, the leaves of plants can capture more of it, resulting in an overall increase in the biomass of the plant.

In addition, plants are able to manage their water use much more efficiently in these conditions, resulting in better tolerance to drought episodes. However, it is not clear whether these CO2 fertilisation effects will actually occur in the field owing to interactions with other factors.

If the CO2 fertilisation effects do occur, the researchers found that the yields of wheat and soybean are expected to increase throughout the 21st century under a “business-as-usual” scenario; however, the increases are projected to be significantly offset by the effects of heat waves, as these plants are still vulnerable to the effects of extreme temperatures.

The positive impacts on soybean yield will be offset by 25 per cent and the positive impacts on wheat will be offset by 52 per cent.

The researchers, from the Tyndall Centre for Climate Change Research (University of East Anglia, Norwich), Grantham Research Institute on Climate Change and the Environment (London School of Economics and Political Science, London), and Global Environmental and Climate Change Centre (McGill University, Montreal), arrived at their results using the global crop model PEGASUS to simulate crop yield responses to 72 climate change scenarios spanning the 21st century.

The study also identified particular areas where heat waves are expected to have the largest negative effects on crop yields. Some of the largest affected areas are key for crop production, for example the North American corn belt for maize. When the CO2 fertilisation effects are not taken into account, the researchers found a net decrease in yields in all three crops, intensified by extreme heat stress, for the top-five producing countries of each crop.

“Our results show that maize yields are expected to be negatively affected by climate change, while the impacts on wheat and soybean are generally positive, unless CO2 fertilisation effects have been overestimated,” continued Deryng.

“However, extreme heat stress reinforced by ‘business-as-usual’ reduces the beneficial effects considerably in these two crops. Climate mitigation policy would help reduce risks of serious negative impacts on maize worldwide and reduce risks of extreme heat stress that threaten global crop production.”

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From Thursday 20 March, this paper can be downloaded from http://iopscience.iop.org/1748-9326/9/3/034011/article

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hunter

Even if this was not a transparent bit bs, the answer the AGW hypesters offer is ridiculous:
Curb CO2, tax carbon and raise taxes.

Bob Diaz

I think this one should be filed next to, “The children in Endland won’t know what snow is” …

u.k.(us)

Zero sum thinking.

Gunga Din

That’s funny. I don’t recall ever having to cut my grass in winter.

Brian hatch

Dr hubert lamb of east anglia uni said in the 1970s that the global cooling then happening would cause crop failure and famine. are both right?

a jones

Och aye, the usual suspects then: but I sis like the oxymoron about reduced sterility.
Kindest Regards

Patrick

“The researchers, from the Tyndall Centre for Climate Change Research (University of East Anglia, Norwich), Grantham Research Institute on Climate Change and the Environment (London School of Economics and Political Science, London), and Global Environmental and Climate Change Centre (McGill University, Montreal), arrived at their results using the global crop model PEGASUS to simulate crop yield responses to 72 climate change scenarios spanning the 21st century.”
Meaning it’s more GIGO. I would rather trust the real world opinions of farmers than computer simulations. But this is what we have come to expect from the UEA.

Alan

so they have modelled the “large increase in global mean temperature” then modelled the “Instances of extreme temperatures” created by this, then modelled the effects on crops. Then called the output findings “Our results show” Did they explain what “large” and “extreme” represent? Is there any reference to actual effects of these in the past.
More from the university of sod all better to think about

David L. Hagen

CO2 is plantfood
See: The response of global net primary productivity (NPP) to CO2 increasing and climate change: Evaluation of coupled model simulations Shanshan Hou et al.

During 140 year long simulations, global NPP increasing steadily when CO2 concentration quadrupled and climate changed together or CO2 increasing alone, the growth rates can reach up to 0.31%/yr (MPI-ESM-LR simulated). However, there is a down trend of global NPP when climate changed alone.

u.k.(us)

“Our results show that maize yields are expected to be negatively affected by climate change, while the impacts on wheat and soybean are generally positive, unless CO2 fertilisation effects have been overestimated,” continued Deryng.
===============
So, climate change might affect the fact that 40% of the current U.S. maize production, is being converted into ethanol, at a net loss to taxpayers.
Did taxpayers also pay for this study ?
You might want to find a new field of study, cus this line of investigation is just about to play-out.

Pamela Gray

This area of Central and NE Oregon has ended up damaged due to cold, not heat. And heat, in the winter, usually comes with rain, something that dryland farmers love in the wintertime. But alas, cold comes with drought. These idiots are telling us the exact opposite of reality. Fear cold and dry, not warm and wet.

Eve

So we have increased coffe prices because coffee growers in Brazil were hit by cold, increased prices os citrus because of the Florida freeze and increased vegetable prices because California was hit by a freeze and we should be afraid of warm because?

TomRude

Another paleoclimatically ignorant study that forgets drought and heatwaves mostly occur during cooler periods…

New paper predicts wheat & soybean yields will continue to improve through the 2080s from CO2 fertilization, even with IPCC exaggerated warming
http://iopscience.iop.org/1748-9326/9/3/034011

SAMURAI

These CAGW grant grubbers should change the name of their climate model from the mythical horse Pegasus to the mythical turtle, Chelone, because it’s “turtles-all-the-way-down” for these clowns….
According the World Bank’s global crop yield data, US crop yields have increased almost 80% since 1980 with a considerable portion of that increase due to: CO2 fertilization, plants requiring less water due to leaf stoma shrinkage from higher CO2 levels, a slight increased global precipitation, slightly longer growing seasons due to the slight increase in global temperatures, increased arable land area in Northern latitudes due to slightly warming temperatures, etc…
http://data.worldbank.org/indicator/AG.YLD.CREL.KG
Where is the warming trend for the past 18 years? Where is the catastrophe? Why is CAGW still taken seriously? Why is the world still throwing $trillions down the toilet on this CAGW scam?
Man’s CO2 emissions have been a boon to the Earth’s ecology and economy and have helped save billions of humans from starvation over the years. In the process of burning fossil fuels, we’ve also created the energy necessary to drive the fastest economic expansion in human history and have managed to lift billions of people from abject poverty… Try doing that with wind turbines and solar panels… Give me a break.
In the process of burning all this fossil fuel, the US has actually managed to substantially DECREASE real air pollution by up to 90%:
http://www.epa.gov/airtrends/aqtrends.html
If you asked the average Joe on the street what’s happened to air quality in the US since 1980, I bet 80% of the people surveyed would say air quality has worsened…
I wonder why that is… (sarc off)..

Anything is possible

Extreme heat stress is bad for crops concluded researchers, from the Tyndall Centre for Climate Change Research (University of East Anglia, Norwich), Grantham Research Institute on Climate Change and the Environment (London School of Economics and Political Science, London), and Global Environmental and Climate Change Centre (McGill University, Montreal), who arrived at their results using the global crop model PEGASUS to simulate crop yield responses to 72 climate change scenarios spanning the 21st century.
Extreme heat stress is bad for crops concluded “Anything is possible” after reading a copy of the Grapes of Wrath borrowed free of charge from the local library.

Crispin in Waterloo

>”Earlier studies have found that climate change is projected to reduce maize yields globally by the end of the century under a “business as usual” scenario for future emissions of greenhouse gases; however, this new study shows that the inclusion of the effects of heat waves, which have not been accounted for in previous modelling calculations, could double the losses of the crop.”
If there were such a sustained increase in temperatures, the land base on which we could grow crops in Canada would greatly increase by several million square km, especially for long season crops like maize.
I cannot see a downside to this. With an increase in temperatures, rainfall is not expected to decline. It increases, as cold causes dryness = droughts. A frozen world is a relatively dry world. As to date the models have invariably been wrong, there seems to be nothing to worry about except a reduction in available acreage from a cooling climate which my all measures, seems to be upon us.

norah4you

Claim has same value as shown in the Liar problem after:
Propositional Logic and a Liar Problem
The letters p and q, below, stand for statements which are true (T) or false (F), e.g, “1+1=2”, “the moon is made of green cheese”, etc.).
From these two elementary statements, compound statements can be constructed using five truth functions: not, and, or, ifthen, and iff. The latter is read “if and only if”.
Here are the English translations of expressions using these functions and propositions.
ifthen(p, q): ” p implies q”, or “if p then q”;
iff(p, q): “p if and only if q”, or “p is logically equivalent to q”;
or(p, q): “p or q”;
and(p, q): “p and q”;
not(p): “it is not the case that p”.
Rather than saying “It is not the case that the moon is made of green cheese” we usually say “The moon is not made of green cheese”. With the exception of not, which takes a single statement’s truth value as input, the four other truth functions require two statements’ truth values as inputs. In every case the output is either T or F. Truth tables are the “graphs” of these functions, i.e., a complete display of the output values associated with all possible input values. The truth tables for not and and are shown, below. Follow the instructions to see the truth tables of the other truth functions. Then scroll down and solve a Liar Problem. Propositional Logic and a Liar Problem, uri.edu/artsci/math/ page logic
The article
Claim: Future heat wave pose threat to global food supply lack credibility due to the fallacies that’s been used as well as that the claim’s proposer forgotten that one need to prove that A ->B always leads to B -> C and that this can be used i all cases where C is involved. It’s not only bad usage of Theories of Science. Statements and models using such methods aren’t using any logic science method at all. As we said back in 1970th: Computers work from logic some programmers don’t. Bad input – bad output

Proud Skeptic

In order to make this argument you must first prove your underlying assumption…that climate change as characterized within the article is real and will be as projected. This has not been proven, therefore the rest of the argument is built on shifting sand.

Truthseeker

Maybe someone should tell these geniuses that rising CO2 is causing an 11% greening of the Earth due to increased vegitation. They should also be told that most mass crops prefer warm to cold.
Obviously they do not get out much.

John F. Hultquist

I wonder if this crew of researchers have ever grown anything other than head lice?
. . . arrived at their results using the global crop model PEGASUS . . .
I went out today and pulled some of the straw covering my strawberries and asked them when they thought I should uncover the lot of them. I told them global warming was at hand and they should start earning their keep. The word “global” caused them to laugh uncontrollably. In unison they said we don’t give a crap about global and locally it is cold. One said, we’ve heard farmer’s across the Nation are even now deciding on the crops they will plant this spring based on forecast of coming growing conditions. Now, cover us back up and get your foot off of little Timmy.

Dale Muncie

It seems that maize (corn) and soy beans grow rather well up to about 85F.

Timothy Sorenson

At least at our college the biologist are still using growth chambers and actually seeing what happens and not what some model says.

Greg

Which part of no warming for 17 years are they suggesting we reverse?
This is getting like some Hollywood disaster movie. Never mind the facts as long as it makes a good scenario.
Is that why IPCC refers to it’s projections as “scenarios”.

Alcheson

So, did I read this right? Because the excessive heat waves that their non-working models project might cut the possible 50% increase in production to only a 25% increase, we need to reduce CO2 to make sure this doesn’t happen. Instead they actually recommend we should go for an actual 50% reduction in current yield so we can avoid the possible 50% reduction of a possible 50% increase. I would be laughing hysterically if these guys were only affecting their own future and not mine and the people I love.

Them researchers got to be dumber then a wooden fence post. I guess they grow their crops in a computer funny farm. Any real farmer would tell them that warmer is better! longer growing seasons better! Bull Scat belongs in the field. pg

juan slayton

It’s an uphill climb, but I do try to get my students to take time to read what they just wrote, just to see if they said what they think they said. Somebodies in UEA should have paid more attention to their grade school teachers:
…extreme temperatures can lead to reduced pollen sterility…

dp

These claims leave one with the impression that those making them have never picked up a history book, or worse, they’re in the embrace of some delusional madness that makes them believe that modern society is immune to weather.
Anasazi – all you’ll ever need to know about people, weather, and the consequences of choosing badly where to hang your hat.

Dr. Strangelove

“Heat waves could significantly reduce crop yields and threaten global food supply if climate change is not tackled and reversed.”
This is just fear mongering. The negative effect is on corn. US produces 40% of the world’s corn supply and 70% of US corn goes to animal feeds, biofuel, beer and whiskey. Truthfully these scientists should say climate change threatens animal feeds, biofuel, beer and whiskey supply. But that wouldn’t be too scary. BTW the staple foods in most countries are rice and wheat.

another useless prediction to go from printer to bin.

Dr. Strangelove

China produces 30% of world’s corn supply and 70% of China corn is for animal feeds too. Maybe if the animals die because of climate change the vegans will rejoice.

Brian H

All based on the baseless assertion that extreme heat waves will become the norm. Drivel.

bertief

UEA – enough said.

Old England

How meaningless is this study? I’ve just tried checking the parameters used for Pegasus to see if it uses increasing / changing growth areas coupled with any temperature increases. No luck on that one but going through the PNAS.org study covering ‘Global gridded crop model intercomparison’ the variations between models are quite astounding.
Maize – varies from +38% to -38%
Wheat – varies from +38% to -27%
Rice runs off the scale looking at 100%++ increase to a -19%
Soy – varies from +80%++ to -30%.
(These tables are found on page 15 of the supplementary appendix)
Spreads of output between the models are so vast as to render them meaningless.
I guess that UEA (University for Environmental Activists) which created the Pegasus model is doing its bit to keep the climate change scare alive as part of what appears to be the current and well-orchestrated release of scare stories .

Pause for thought.
Yes they are right.
But the temperature has to go up first.
Over how long?
Then how fast can crops adapt or be adapted?
Work for the Wunderkinds.

Bert Walker

There has been no global warming for over 17 years. However since Earth is continuing to recover from an ice age it seems likely global temperatures will continue to eventually rise. Fortunately increased CO2 fertilization will help to mitigate heat sensitivity various plant species may face.
Drought stress in temperate maize germplasm during flowering season is well known.
Both temperate, and sub/tropical maize germplasms are sensitive to drought stress, less so to heat stress during it’s flowering season reducing yield.
If there is increased rainfall associated with globally increased temperatures, much of the heat and drought stress of maize will be mitigated as this is in a large part due to concomitant drought conditions during periods of elevated temperature.
Current research to identify and optimize maize germplasms for use in Sub Saharan Africa, and Asia are under way. In these areas both drought and heat stress are factors. Fortunately there has been some early success in identifying tropical and subtropical maize germplasms (Asian) that are more resistant to heat and drought stress as part of the Heat Tolerant Maize for Asia (HTMA) project. It is likely these strains can be optimized through further breeding programs to produce viable strains of maize useful in a warmer world.
Overall the likelihood of success of mitigation efforts to lower global CO2 for global climate control seem to be essentially nonexistent despite the billions of dollars and undying faith of many. On the other hand, it will be very likely heat stress tolerant, drought tolerant maize germplasms will be available to feed the world, when needed.
Reference: “Breeding for Heat Stress Tolerance in Tropical and Subtropical Maize.” at
https://scisoc.confex.com/crops/2013am/webprogram/Paper78761.html

Phil's Dad

I would have thought “reduced pollen sterility” would increase crop yields but I shall put that one down to a misquote by the interviewer.
The three real problems with this report are 1) the lack of any definition of “extreme” or a statement of the likelihood of the “extremes” being reached, 2) the fact that their projected climate scenarios still improve crop yields overall and 3) the assumption that, even if the climate does become untenable for these crops where they are now, the farming can not re-locate.

Alan the Brit

“however, this new study shows that the inclusion of the effects of heat waves, which have not been accounted for in previous modelling calculations, could double the losses of the crop.”
I just cannot get past the obtuseness of these OCD intellectuals, why do they believe everything that comes out of the backside of a computer model? The end of Humanity is truly nigh!

lee

‘extreme temperatures can lead to reduced pollen sterility ‘
Does that make it more fecund?

Jimbo

Heat waves could significantly reduce crop yields and threaten global food supply if climate change is not tackled and reversed.

Can I say speculation? Europeans of the Little Ice Age must have been positively obese with all that famine and failed crops.
Now let’s see the results after the ‘HOTTEST DECADE ON THE RECORD’ and the rapid, alarming rise in temperature since the late 1970s. It’s worse than we thought, it’s all our fault and we must act now!
Since we are allowed speculation here is some more.

Abstract – 2013
P. B. Holden et. al.
A model-based constraint on CO2 fertilisation
Using output from a 671-member ensemble of transient GENIE simulations, we build an emulator of the change in atmospheric CO2 concentration change since the preindustrial period. We use this emulator to sample the 28-dimensional input parameter space. A Bayesian calibration of the emulator output suggests that the increase in gross primary productivity (GPP) in response to a doubling of CO2 from preindustrial values is very likely (90% confidence) to exceed 20%, with a most likely value of 40–60%. It is important to note that we do not represent all of the possible contributing mechanisms to the terrestrial sink. The missing processes are subsumed into our calibration of CO2 fertilisation, which therefore represents the combined effect of CO2 fertilisation and additional missing processes.
doi:10.5194/bg-10-339-2013

And here are some recent observations after all this terrible heat.

Abstract – 31 May, 2013
CO2 fertilisation has increased maximum foliage cover across the globe’s warm, arid environments
[1] Satellite observations reveal a greening of the globe over recent decades. …….Using gas exchange theory, we predict that the 14% increase in atmospheric CO2 (1982–2010) led to a 5 to 10% increase in green foliage cover in warm, arid environments. Satellite observations, analysed to remove the effect of variations in rainfall, show that cover across these environments has increased by 11%.…..
http://onlinelibrary.wiley.com/doi/10.1002/grl.50563/abstract
_____________________________
Abstract – May 2013
A Global Assessment of Long-Term Greening and Browning Trends in Pasture Lands Using the GIMMS LAI3g Dataset
Our results suggest that degradation of pasture lands is not a globally widespread phenomenon and, consistent with much of the terrestrial biosphere, there have been widespread increases in pasture productivity over the last 30 years.
http://www.mdpi.com/2072-4292/5/5/2492
_____________________________
Abstract – 10 April 2013
Analysis of trends in fused AVHRR and MODIS NDVI data for 1982–2006: Indication for a CO2 fertilization effect in global vegetation
…..The effect of climate variations and CO2 fertilization on the land CO2 sink, as manifested in the RVI, is explored with the Carnegie Ames Stanford Assimilation (CASA) model. Climate (temperature and precipitation) and CO2 fertilization each explain approximately 40% of the observed global trend in NDVI for 1982–2006……
http://onlinelibrary.wiley.com/doi/10.1002/gbc.20027/abstract
_____________________________
Abstract – May 2013
The causes, effects and challenges of Sahelian droughts: a critical review
…….However, this study hypothesizes that the increase in CO2 might be responsible for the increase in greening and rainfall observed. This can be explained by an increased aerial fertilization effect of CO2 that triggers plant productivity and water management efficiency through reduced transpiration. Also, the increase greening can be attributed to rural–urban migration which reduces the pressure of the population on the land…….
doi: 10.1007/s10113-013-0473-z

It’s getting worse all the time and we are doomed.

Jimbo

Is it also possible that more warmth (as opposed to heatwaves) at higher latitudes will INCREASE global food supply? Canada? I was told that global warming would make itself mostly felt as you headed away from the tropics and towards the poles, and at night. Less frost damage?
Increased heat waves over the Alps could lead to more glacier melt.
Getting hit by a car driving at 170mph will likely kill you.
Can I have my money now?

ddpalmer

“Our results show that maize yields are expected to be negatively affected by climate change, while the impacts on wheat and soybean are generally positive, unless CO2 fertilisation effects have been overestimated,” continued Deryng.
So what if CO2 warming effects have been overestimated? Wouldn’t that also invalidate the whole premise?
[sarc]Or did they decided not to consider that possibility because with no warming for 17 years it is obvious that the CO2 warming effects are real and fully understood?[/sarc]

Berényi Péter

Climate mitigation policy would help reduce risks of serious negative impacts on maize worldwide

Getting rid of the mindless ethanol mandate in gas entirely would make even more good to global corn supply. The Fischer–Tropsch process is always available to manufacture transportation fuel from abundant coal as needed.

knr

‘according to a new study led by researchers at the University of East Anglia’
That is as likely to encourage you to read further as
‘according to a new study led by researchers at Disneyland ‘
So people who been show to use poor scientific practice , lose data when it suits them and spin for all their worth and who would be out of job without climate ‘doom’ make a wild claim based on a wild guess. Perhaps I have insulted the researches at Disneyland.

Gamecock

“global crop production” “global food supply”
There is no such thing as “global food supply.” Food supply is local to regional. A tomato in Texas is of no value to people in India. We get the same absurd claims for “global water supply.” I see it as collectivist dreams to control all.
Global climate is another collectivist invention. The earth has many climates, not one. “Global climate” means you don’t know what climate is.

Jimbo

There is a way to increase US corn crops.

2013
“…40% of the U.S. corn crop is used to produce ethanol…”
http://www.aei.org/article/energy-and-the-environment/alternative-energy/production-of-corn-ethanol-as-an-automotive-fuel-source-should-cease/

We reap what we sow. Are the seeds of future starvation being sown now?

François

We all keep in mind -more or less (?)- parallel charts comparing world temperature anomalies and CO2 levels. Is the equivalent available for food production and agricultural subsidies?

observa

The Institute of Physics you say? Got news for those physicists and aint it about time they began asking the hard questions-
http://quadrant.org.au/opinion/tony-thomas/2014/03/finally-real-climate-science/
Hallelujah! Ring the bells and deck the halls of the AGU
(hat tip Andrew Bolt)

observa

Woops…the APS

Jim G

Brian hatch says:
March 19, 2014 at 8:08 pm
“Dr hubert lamb of east anglia uni said in the 1970s that the global cooling then happening would cause crop failure and famine. are both right?”
As average temperatures go down the growing belt narrows (in the north it moves south and in the south it moves north) and food production capabilities decline, or so the story went back then.
The reverse should be true if temperatures rise.