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….

The Economic Times:

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.

Nature Asia-Pacific:

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)

New Scientist: 

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.

India continues to suffer from high inflation in food prices and widespread chronic hunger. Such problems will be vastly worse if global temperatures continue to rise, Mr. Swaminathan said.

“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.”

5 Responses to “Studies: Climate Change will threaten Global Wheat Harvest”

  1. neilrieck Says:

    While poking around the net I stumbled upon some articles claiming that the optimum temperature for maximum photosynthesis is 76 F (for most plants) and that the output drops by 10% for every degree increase. It totally stops at 86 F because the plants close their stomata to limit water loss.

    On top of this, water is much more important to photosynthesis than CO2. Why? The first stage of photosynthesis involves the photolysis of water (a photon splits water into H and O). This releases energy which powers the remainder of the chemical reactions.

  2. prokaryotes Says:

    Sidenote about to storys also covering topics on plants and direct/indirect human interactions..

    Improtant read about Monsanto’s new seeds “..we’re back to square one — or rather to square toxic.”

    Above story is basically about the failed engineering about pest resistances.

    Bee Colony Collapse Disorder May Affect Our Food Supply (Because of pesticides)

    And now consider is estimated that about one half of every metric ton of fertilizer applied to fields never even makes it into plant tissue, but instead ends up evaporating or being washed into local waterways.

    These chemicals are energy intensive to produce, create vast amounts of waste, and contribute to greenhouse gas emissions. Producing one unit of N requires 1.4 units of carbon and 3 units of carbon are required to manufacture, transport and apply 1 unit of P as P2O5 fertilizer. For every ton of phosphoric acid produced, five tons of phosphogypsum are generated. Over the past 50 years, more than 700 million metric tons of phosphogypsum have accumulated in Florida alone, huge stacks at times covering more than 300 hectares at more than 60 meters high with settling ponds that threaten local water sources. The production of nitric acid, the primary feedstock for synthetic commercial fertilizer, is also a source of nitrous oxide, a greenhouse gas 310 times more potent than carbon dioxide, and accounted for 15.9 Tg CO2E in 2005, the equivalent emissions of 2.9 million vehicles.

    According to the World Health Organization, some 3 million people a year suffer from severe pesticide poisoning. Pesticide exposure can lead to cancer, birth defects and damage to the nervous system. Drinking water contaminated by pesticide runoff is a main source of exposure.

    Excess fertilizer use and runoff causes eutrophication in waterways which threatens animal and plant health. The surplus nutrients stimulate excessive plant growth, such as algal blooms, which consume nearly all the available oxygen in the water and cause other plants and animals to suffocate. Surplus nitrogen and phosphorus from fertilizer runoff, animal manure, soil erosion and sewage have created a “dead zone” of more than 7000 square miles in the Gulf of Mexico near the mouth of the Mississippi River. These huge algal blooms are starving out shellfish and threatening commercial fisheries and area economies-the U.N. reported nearly 150 dead zones throughout the world’s oceans in 2007.

    Solutions: Reduced fertilizer use

    Nitrogen (N), phosphorus (P), and potassium (K) are the primary major nutrients required for plant growth and are the main components of most fertilizers.

    • neilrieck Says:

      With all due respect, reducing overall fertilizer use at this time will tip the planet in the direction of mass-starvation. Many people are unaware of the fact that the current population explosion was enabled by industrialization of framing (where fossil fuels are used as starting material during fertilizer production). See this link to learn more:

      Now a carbon tax would have made fertilizer a little more expensive; this would force farmers to be a lot smarter while applying it. For example, since fertilizer washes away with rain, then, based upon local conditions, farmers would apply lower amounts of fertilizer, multiple times. This way, fertilizer uptake would be increased while fertilizer washout would be decreased.

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