Oldspeak: “Yields of several major crops are likely to be seriously affected by rising temperatures, scientists say, with spells of extreme heat posing the greatest risk.” – Tim Radford
“1 in 8 people on the planet is suffering from chronic undernourishment. 16 million in developed countries, and 852 million in developing countries, or 52 times more people. The richest fifth of the world’s people consumes 86 percent of all goods. Extreme inequality couldn’t be more clear than that. Knowing that it’s easy to see who will suffer most, as if they weren’t suffering enough now, in the coming anthropocentric global warming caused calamities of water scarcity and famine. We are seeing the beginning stages of it in the American West, and it’s full blown and out of control in places like Uganda, where they’re “….. …seeing drought. Serious drought that has not happened before. This drought has caused famine in parts of the country. In other parts, there has been too much rain… It has been very hot these days. Over the years it has gotten hotter with more unpredictable weather.’ -Benon Twineobusingye, Senior Human Resource Manager, Ugandan Government. Again, this is not something far off in the future, it is happening RiGHT NOW. Socio-economic factors are utterly irrelevant to the abrupt impacts of climate change. There’s no where else for us to go. “Developed” countries will be plunged into the warming induced unpredictability and instability as the “developing” countries are, even The Ministry Of Love said so. in the description of our “civilization” is the fundamental problem. “Development”. Development has allowed humans to decouple our existence from the well being of Great Mother who has graciously provided her invaluable natural capital to us; only to be reduced to mere “resources”, “property” and “externalities”. This dangerously imbalanced world cannot continue to function normally. The fever is mild now, but when it gets higher look out! -OSJ
By Tim Radford @ The Daily Climate:
LONDON – Rampant climate change driven by ever-rising levels of carbon dioxide in the atmosphere poses a serious threat to world food supply, according to a new study in Environmental Research Letters.
The hazard comes not from high average temperatures, but the likelihood of heat extremes at times when crops are most sensitive to stress. The message: Those communities that rely on maize as a staple are more at risk than most.
Delphine Derying of the Tyndall Centre for Climate Change Research at the University of East Anglia in the UK and colleagues looked at one of the big puzzles of the coming decades: What will global warming do for crop yields?
Timing is everything
It is not a simple question. Climate change means more evaporation, more precipitation, longer growing seasons, more warmth, and higher levels of the carbon dioxide that plants exploit by photosynthesis (the process they use to convert light into chemical energy), so the consequence ought to be greater yields. But as every farmer knows, what matters most is the timing of all that warmth, rain, and those dry spells in which the harvest can ripen.
There is a second consideration. Climate is the sum of all events. Rather than a steady overall rise in daily temperatures, an increasing number of ever-larger regions are predicted to experience ever more intense extremes of heat, and sometimes cold. Plants can be very sensitive to extremes of heat at flowering time. If the thermometer goes up, the pollen becomes increasingly sterile and less seed is likely to be set. So an extended heat wave in the wrong season could be calamitous.
Business as usual
The Tyndall team included the assumption that nothing would be done about climate change – that is, that governments, industry and people would continue with a business-as-usual scenario. They then chose three well-studied and vital crops – spring wheat, maize and soybean – and tested predictions under 72 different climate change scenarios for the rest of this century.
They allowed for the already-established benign effects of carbon dioxide-driven warming, one of which is that plants can make more tissue and at the same time use water more efficiently, and therefore respond more effectively to drought conditions. They also looked for the outcomes in places where yields could be most vulnerable: For example, the North American corn belt.
What they found was that – if carbon dioxide fertilization effects are not taken into account – then maize, wheat and soya yields are all likely to fall, in all five top-producing countries for each of these crops.
When they factored in the benefits of more CO2 in the atmosphere, the picture changed. There would be positive impacts on soya and wheat, but not on maize.
There is another proviso: So far, the benefits of extra CO2 have been confirmed in experimental plant laboratories. The experience in the fields 60 years in the future may be rather different. And in any case, these positive impacts could be severely offset by extremes of heat at the moment when the crops were most vulnerable, so overall, harvests remain at risk.
The best answer, the scientists argue, is to attempt to limit climate change. “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,” Deryng said.
Tim Radford is an editor at Climate News Network, a journalism news service delivering news and commentary about climate change for free to media outlets worldwide.
The Daily Climate is an independent, foundation-funded news service covering energy, the environment and climate change. Find us on Twitter @TheDailyClimate or email editor Douglas Fischer at dfischer [at] DailyClimate.org
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