But there seems to be no signs of a major slowdown despite heat waves of the past 60 years.
![indicator3_2013_ProductionGrain[1]](http://wattsupwiththat.files.wordpress.com/2014/03/indicator3_2013_productiongrain1.png?quality=75)
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.”
From Thursday 20 March, this paper can be downloaded from http://iopscience.iop.org/1748-9326/9/3/034011/article
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Even if this was not a transparent bit bs, the answer the AGW hypesters offer is ridiculous:
Curb CO2, tax carbon and raise taxes.
I think this one should be filed next to, “The children in Endland won’t know what snow is” …
Zero sum thinking.
That’s funny. I don’t recall ever having to cut my grass in winter.
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?
Och aye, the usual suspects then: but I sis like the oxymoron about reduced sterility.
Kindest Regards
“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.
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
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.
“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.
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.
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?
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
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)..
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.
>”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.
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
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.
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.
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.
It seems that maize (corn) and soy beans grow rather well up to about 85F.
At least at our college the biologist are still using growth chambers and actually seeing what happens and not what some model says.
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”.
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.