Rising Levels Of CO2 May Lead To More Food Production

Bringing drought and increased temperatures, climate change has been widely portrayed as a force that will leave staple food crops struggling in many areas where they are grown today. But a new study has shown that increasing levels of carbon dioxide in the atmosphere may actually lead to greater yields of key crops like wheat, rice and soybeans.

Scientists say higher levels of carbon dioxide in the air helps plants build up greater biomass but can also reduce the amount of water needed to help them grow.

While the effects of a complex changing climate makes it difficult to predict exactly how crops in different parts of the world will grow, overall rising carbon dioxide levels could be beneficial.

Average levels of carbon dioxide in the atmosphere have risen by more than a quarter since 1960, and now sit at around 400 parts per million.

Plants take in carbon to build their tissues through photosynthesis, and if there is more carbon around, the process is easier.

Until now most research looking into climate change has focussed on changes in temperature and rainfall.

Many studies indicate that as temperatures rise, crops across the world will suffer as average temperatures become unsuitable for traditionally grown crops, and droughts, heat waves or extreme bouts of precipitation become more common.

But a large team of researchers have tried to predict the combined effect of a variety of changing factors caused by climate change to take into account the increase in carbon dioxide.

They introduced artificially heightened levels of carbon dioxide to farm fields, and measured the results on crop production.

Although the results are complicated, their research suggests some crops might grow better in 2080.

Researchers have introduced artificially heightened levels of carbon dioxide to farm fields, and measured the results on the production of maize, soybeans, wheat and rice. Here, experimental plots at the University of Arizona’s Maricopa Agricultural Centre

The study looked at how rising temperatures and carbon dioxide along with changes in rainfall and cloud cover might combine to affect how efficiently maize, soybeans, wheat, and rice can use water and grow.

It confirmed heat and water stress alone will damage yields, but when carbon dioxide is accounted for, all four crops will use water more efficiently by 2080.

Based on the current biomass of these crops, the researchers predict water-use efficiency will rise an average of 27 per cent in wheat, 18 per cent in soybeans, 13 per cent in maize, and 10 per cent in rice.

‘To adapt adequately, we need to understand all the factors involved,’ said lead author Delphine Deryng, an environmental scientist at Columbia University’s Centre for Climate Systems Research, the NASA Goddard Institute for Space Studies and the University of Chicago’s Computation Institute.

She said the study should not be interpreted to mean that increasing carbon dioxide is a good thing, but its direct effects must be included in any calculation of what the future holds.

Taking it all into account, the study projects that average yields of current rain-fed wheat areas, mostly located in higher latitudes including the US, Canada and Europe, might go up by almost 10 per cent, while consumption of water would go down a corresponding amount.

But average yields of irrigated wheat, which account for much of India and China’s production, could decline by four per cent.



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