Studies: Climate Change will threaten Global Wheat Harvest
January 31, 2012
A tired and recycled shibboleth dear to the hearts of aging climate deniers, as clueless about agriculture as they are about climate – “CO2 is good for plants…” – covered in the video above. The real world continues to provide tangible evidence of how wrong headed this is….
PARIS: More intense heat waves due to global warming could diminish wheat crop yields around the world through premature ageing, according to a study published Sunday in Nature Climate Change.
Extreme heat can accelerate wheat aging — an effect that reduces crop yields and is currently underestimated in most crop models — according to a study published online this week in Nature Climate Change. These findings imply that climate warming presents even greater challenges to wheat production than current models predict.
An important source of uncertainty in anticipating the effects of climate change on agriculture is limited understanding of crop responses to extremely high temperatures. David Lobell and co-workers used satellite measurements of wheat growth in northern India to monitor the rates of wheat aging — known as senescence — following exposure to temperatures greater than 34 °C (93.2° F)
In India’s breadbasket, the Ganges plain, winter wheat is planted in November and harvested as temperatures rise in spring. David Lobell of Stanford University in California used nine years of images from the MODIS Earth-observation satellite to track when wheat in this region turned from green to brown, a sign that the grain is no longer growing.
He found that the wheat turned brown earlier when average temperatures were higher, with spells over 34 ºC having a particularly strong effect. [...]
Lobell’s work suggests losses could be sooner and greater. “This is an early indication that a situation that was already bad could be even worse,” says Andy Challinor of the University of Leeds, UK.
Meanwhile, the New York Times is reporting on a separate Indian study with similar implications.
China and India, which constitute about 37 percent of the world’s population, face a future of sharply lower crop yields as a consequence of climate change, leading scientists in both nations warned recently.
Yields from rain-irrigated wheat could drop by 44 percent by 2050 under warmer conditions forecasted by climate models, the Indian farm scientist M.S. Swaminathan told reporters during the 97th Indian Science Congress last week.
Mr. Swaminathan is considered the architect of India’s “Green Revolution” for his work in the 1960s developing high-yield grain varieties that ended decades of severe famine.
“For every one degree Celsius rise in mean temperature, the wheat loss is estimated to be of the order of six million tons per year,” he said, according to The Hindu newspaper.
India’s total wheat production was about 75 million metric tons in 2009.
China could face a similar climate-induced grain crisis, Zheng Guoguang, director of the China Meteorological Administration, the official weather forecasting agency in China, warned in a December essay in an influential Communist party journal.
Yields of rice, wheat and corn could fall as much as 37 percent by 2050 due to increased drought conditions and other climate impacts, Mr. Zheng estimated. Citing Mr. Zheng’s essay, a statement by the Chinese Meteorological Association urged the country’s leaders to focus on adapting to, rather than mitigating, climate change.
“Since climate change is an objective fact, it is more realistic and urgent for China, a big developing country, to adapt to than mitigate climate change,” the statement’s author concluded. “So China should put adaptation as top strategy of addressing climate change and put enhancing grain production and ensuring food security as first task.”