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Global Food Crisis Will Worsen as Heat Waves Increase

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Damian Carrington, The Guardian

The world's food crisis, where 1 billion people are already going hungry and a further 2 billion people will be affected by 2050, is set to worsen as increasing heat waves reverse the rising crop yields seen over the last 50 years, according to new research.

Severe heat waves, such as those currently seen in Australia, are expected to become many times more likely in coming decades due to climate change. Extreme heat led to 2012 becoming the hottest year in the U.S. on record and the worst corn crop in two decades.

New research, which used corn growing in France as an example, predicts losses of up to 12 percent for maize yields in the next 20 years. A second, longer-term study published on Sunday indicates that, without action against climate change, wheat and soybean harvests will fall by up to 30 percent by 2050 as the world warms.

"Current advances in agriculture are too slow to offset the expected damage to crops from heat stress in the future," said Prof Andy Challinor, at the University of Leeds. 
Credit: flickr/USDAgov
 

"Our research rings alarm bells for future food security," said Ed Hawkins, at the University of Reading, who worked on the corn study. "Over the last 50 years, developments in agriculture, such as fertilizers and irrigation, have increased yields of the world's staple foods, but we're starting to see a slowdown in yield increases."

He said increasing frequency of hot days across the world could explain some of this slowdown. "Current advances in agriculture are too slow to offset the expected damage to crops from heat stress in the future," said Prof Andy Challinor, at the University of Leeds. "Feeding a growing population as climate changes is a major challenge, especially since the land available for agricultural expansion is limited. Supplies of the major food crops could be at risk unless we plan for future climates."

Hawkins, Challinor and colleagues examined how the number of days when the temperature rose above 32C affected the maize crop in France, which is the UK's biggest source of imported corn. Yields had quadrupled between 1960 and 2000 but barely improved in the last decade, while the number of hot days more than doubled.

By the 2020s, hot days are expected to occur over large areas of France where previously they were uncommon and, unless farmers find ways to combat the heat stress that damages seed formation, yields of French maize could fall by 12 percent compared to today. Hawkins said there will be some differences with other crops in different locations, but added: "Extreme heat is not good for crops."

The second study is the first global assessment of a range of climate change impacts, from increased flooding to rising demand for air conditioning, of how cutting carbon emissions could reduce these impacts, published in Nature Climate Change. "Our research clearly identifies the benefits of reducing greenhouse gas emissions – less severe impacts on crops and flooding are two areas of particular benefit," said Prof Nigel Arnell of the University of Reading, who led the study, published in Nature Climate Change.

Sprinklers water crops in Bakersfield, California, during a heat wave.
Credit: David McNew/Getty Images

One example showed global productivity of spring wheat could drop by 20 percent by the 2050s, but such a drop in yields is delayed until 2100 if firm action is taken to cut greenhouse gas emissions.

River flooding was the impact which was most reduced if climate action is taken, the study found. Without action, even optimistic forecasts suggest the world will warm by 4C, which would expose about 330 million people globally to greater flooding. But that number could be cut in half if emissions start to fall in the next few years. Flooding is the biggest climate threat to the UK, with over 8,000 homes submerged in 2012.

Another dramatic impact was on the need for air conditioning as temperatures rise. The energy needed for cooling is set to soar but could be cut by 30 percent if the world acts to curb emissions, with the benefit being particularly high in Europe. However, climate action has relatively little effect on water shortages, set to hit a billion people. Just 5 percent of those would avoid water problems if emissions fall.

"But cutting emissions buys you time for adaptation [to climate change's impacts]," said Arnell. "You can buy five to 10 years [delay in impacts] in the 2030s, and several decade from 2050s. It is quite an optimistic study as it shows that climate policies can have a big effect in reducing the impacts on people."

Ed Davey, the UK's secretary of state for energy and climate change, said: "We can avoid many of the worst impacts of climate change if we work hard together to keep global emissions down. This research helps us quantify the benefits of limiting temperature rise to 2C and underlines why it's vital we stick with the UN climate change negotiations and secure a global legally binding deal by 2015."

Reprinted with permission from The Guardian

Comments

By Lewis Cleverdon
on January 20th, 2013

Carrington fails to identify the extreme threat posed by these findings in two regards. First, the great medieval European famines, that killed a substantial fraction of the population, arose from crop failures of a mere ten to fifteen percent, being exacerbated by the hoarding of stocks that we still see in modern times - viz Russia etc. since 2010. Projected declines of grain yields of 30% by 2050 are thus utterly catastrophic in terms of serial mega-famines.

Second, the article’s tone implies a smooth curve of declining yields, giving a distant critical shortage threshold. In reality, the inter-annual volatility of extreme weather events brings that critical threshold very much closer in time due to the inevitable convergence of crop failures in major producer countries. In this sense we can endure ‘averaged’ shortages equivalent to being poked in the ribs on a hundred occasions - but a single stab wound is liable to be lethal.

In addition, the article overlooks a recent prior study that addresses the near-term prospects of loss of food security : “Food Security: Near future projections of the impact of drought in Asia”  ( available online at www.lowcarbonfutures.org ). Excerpt from the press release:

“Research released today shows that within the next 10 years large parts of Asia can expect increased risk of more severe droughts, which will impact regional and possibly even global food security.

The report, led by the University of Leeds and published by the UK-based Centre for Low Carbon Futures, highlights China, Pakistan and Turkey as the most seriously affected major producers of wheat and maize and urges policymakers to focus attention on climate change adaptation to avert an imminent food crisis.

On average, across Asia, droughts lasting longer than three months will be more than twice as severe in terms of their soil moisture deficit compared to the 1990-2005 period. This is cause for concern as China and India have the world’s largest populations and are Asia’s largest food producers.

The research was led by Professor Piers Forster from the School of Earth and Environment at the University of Leeds, who is also a lead author on Intergovernmental Panel on Climate Change (IPCC) reports that have directly informed UN climate negotiations of the latest science.  The study was based on climate change projections from 12 leading climate modelling centres around the world and finds clear signals of climate change emerging within the next 10 years.

Commenting on the results of the analysis Dr Lawrence Jackson, a co-author of the report, said: “Our work surprised us when we saw that the threat to food security was so imminent; the increased risk of severe droughts is only 10 years away for China and India. These are the world’s largest populations and food producers; and, as such, this poses a real threat to food security.”

Prof Forster said: “The message for policymakers is clear. The threat to food production in Asia from drought risk brought on by climate change could be felt in the next 10-15 years. Given the slow rate of progress achieved over the 20 years up to the recent United Nations Conference on Sustainable Development (Rio +20), we cannot wait for actions to address the changes in the physical climate if we want to feed the growing Asian population and limit impact on global food security. “

Note: “. . . if we want to feed the growing Asian population and limit impact on global food security.”  It is thus darkly ironic that the Guardian’s Environment journalist should be pushing so complacent a view of the prospects of catastrophic famine. It robs the debate over commensurate climate action of the essential evidence that the strategy of mitigation by emissions control alone is wildly deficient - being at best too slow to avoid ruinous geo-political destabilization by many decades. And of course it utterly fails to focus the requisite attention on the bipartisan US climate policy of a ‘brinkmanship of inaction’ with its Chinese rival for global economic dominance.

Regards,

Lewis

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By Shaolin PitBoo (Shetland)
on January 20th, 2013

Yet another reason to start growing hemp, the hemp seeds contain everything the body needs to live a long and healthy life. Its oils are being used to “CURE” cancer, among many other diseases, it can be used to make paper (1 acre of hemp is worth 1.5 acres of trees, in the production of paper, trees take tens of years to grow, where as hemp can grow every season), it can be used to make clothing, rope, bio-fuel and even boi-degradable plastic… all this can be achieved once we get rid of the petrochemical companies, and their iron grip on mankind!! PEACE!!

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