Warm climate spells doom for bread basket

Warm climate spells doom for bread basket

Indian scientists unfazed by US, Mexico research finding

India’s bread basket faces a serious threat from rising temperature due to climate change, according to a new study that suggests a sharp dip in wheat productivity in India if mercury goes north.

Extreme heat can accelerate wheat aging, reducing yield.

Extreme heat can accelerate wheat aging, an effect that reduces crop yields. The overall decline could be as much as 50 per cent with two degree increase in temperature and is way above than what has been anticipated in existing crop forecasting models.

The new research implies that climate warming presents even greater challenges to wheat production in Punjab, Haryana, Uttar Pradesh and Bihar than current models predict.

The team comprising scientists from Stanford University and International Maize and Wheat Improvement Centre in Mexico studied the wheat growing regions of Indo-Gangetic plains with satellite data for nine years to pick up the signs of early maturity in wheat and compare it against rising temperature.

The findings – published in “Nature Climate Change” on Sunday – suggests that existing models underestimate the effects of heat on wheat maturity, which in turn puts a limit to grain filling and grain yields. Crop forecasting models underestimate this risk.

High temperature affects crop growth at many stages of development and through several different mechanisms.

If the temperature rises beyond 34 degrees Celsius, warming can slow down the grain-filling rates because leaf photosynthesis apparatus is damaged in extreme heat, resulting in acceleration of maturity.

In the last 100 years, global mean temperature went up by 0.74 degrees Celsius and the rate has become faster in the recent past. As many as 12 warmest years ever recorded were between 1990 and 2006, according to the United Nations’ Inter-Governmental Panel on Climate Change.

Even changes that were once considered rather extreme like increase by 4 degrees Celsius than pre-industrial level, could now happen as early as 2060.

As the new study underscores the importance of reworking the crop forecasting models with greater emphasis on temperature trend, Indian wheat scientists said that they knew about the threats and were currently working on strategies to overcome the same.

A gamble

“Wheat production in India is always a gamble against temperature. We succeed due to the blessings of the snow-capped Himalayas, which lowe­rs the temperature in mid-February and March,” S Na­grajan, former director of In­dian Council of Agriculture Re­search’s Directorate of Wheat Research (DWR) in Karnal told Deccan Herald.

“We need to take such studies into cognisance but should not be nervous. Even though increase in temperature is disadvantageous to wheat, so far there is no evidence to show that climate change is adversely affecting our wheat productivity,”said Nagarajan, currently with M S Swaminathan Research Foundation in Chennai and reviewing an India-Australia research programme on wheat.  India maintains second position in wheat production in the world since last ten years. In 2009-10, the wheat production stood at 80.70 million tonnes.

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