India’s grain production is vulnerable to climate change, say scientist who have found that the yield of the country’s rice crop can significantly decline during extreme weather conditions.

Researchers from Columbia University in the US studied the effects of climate on five major crops in India: finger millet, maize, pearl millet, sorghum and rice.

These crops make up the vast majority of grain production during the June-to-September monsoon season -- India’s main grain production period -- with rice contributing three-quarters of the supply for the season.

Taken together, the five grains are essential for meeting India’s nutritional needs, researchers said.

The study, published in the journal Environmental Research Letters, found that the yields from grains such as millet, sorghum, and maize are more resilient to extreme weather.

Their yields vary significantly less due to year-to-year changes in climate and generally experience smaller declines during droughts.

However, yields from rice, India’s main crop, experience larger declines during extreme weather conditions.

“By relying more and more on a single crop -- rice -- India’s food supply is potentially vulnerable to the effects of varying climate,” said Kyle Davis, an environmental data scientist.

“Expanding the area planted with these four alternative grains can reduce variations in Indian grain production caused by extreme climate, especially in the many places where their yields are comparable to rice,” Davis said.

“Doing so will mean that the food supply for the country’s massive and growing population is less in jeopardy during times of drought or extreme weather,” Davis.

Temperatures and rainfall amounts in India vary from year to year and influence the amount of crops that farmers can produce.

With episodes of extreme climate such as droughts and storms becoming more frequent, it is essential to find ways to protect India’s crop production from these shocks, Davis said.

The team combined historical data on crop yields, temperature, and rainfall.

Data on the yields of each crop came from state agricultural ministries across India and covered 46 years (1966-2011) and 593 of India’s 707 districts.

The researchers also used modelled data on temperature and precipitation. Using these climate variables as predictors of yield, they then employed a modelling approach to estimate whether there was a significant relationship between year-to-year variations in climate and crop yields.

“This study shows that diversifying the crops that a country grows can be an effective way to adapt its food-production systems to the growing influence of climate change,” said Davis.

“And it adds to the evidence that increasing the production of alternative grains in India can offer benefits for improving nutrition, for saving water, and for reducing energy demand and greenhouse gas emissions from agriculture,” he said.