How to cool the planet using crops

Washington, Jan 16: In a new research, scientists have determined that by carefully selecting which varieties of food crops to cultivate, much of Europe and North America could be cooled by up to 1 degree Celsius during the summer growing season.

Temperatures going down by 1 degree Celsius are equivalent to an annual global cooling of over 0.1 degree Celsius, almost 20 percent of the total global temperature increase since the Industrial Revolution.

The growing of crops already produces a cooling of the climate because they reflect more sunlight back into space, compared with natural vegetation.

Different varieties of the same crop vary significantly in their solar reflectivity (called `albedo'), so selecting varieties that are more reflective will enhance this cooling effect.

Since arable agriculture is a global industry, such cooling could be extensive.

The research, carried out by Dr Andy Ridgwell and colleagues at the University of Bristol, argues that we should select crop varieties in order to exert a control on the climate, in the same way that we currently cultivate specific varieties to maximize and fine-tune food production.

According to Dr Ridgwell, "We have evaluated the effect of our approach in a global climate model. By choosing from among current crop varieties, our best estimate for how much reflectivity might be increased leads us to predict that summer-time temperatures could be reduced by more than 1degrees C throughout much of central North America and mid-latitude Eurasia."

"Ultimately, further regional cooling of the climate could be made through selective breeding or genetic modification to optimize crop plant albedo," he added.

The team emphasized that unlike growing biofuels, such a plan could be achieved without disrupting food production, either in terms of yield or the types of crops grown.

"We propose choosing between different varieties of the same crop species in order to maximize solar reflectivity rather than changing crop type, although the latter could also produce climatic benefits," explained Ridgwell.

Over the next hundred years, making these kinds of decisions would be equivalent to averting the carbon footprint of 195 billion tonnes of CO2 emitted into the atmosphere, according to the researchers.

Since society has so far remained unwilling to make the drastic reductions in fossil fuel use needed to cut carbon dioxide emissions, simple alternatives such as growing more reflective crops are a realistic way of helping reduce the severity of heat waves and droughts in these regions, they added. (ANI)

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