CO2 Could be the Boon and Not the Bane of Agriculture


Scientists have been issuing dire warnings on the catastrophic implications of  greenhouse gas emissions. Carbon Dioxide including surface level ozone, methane, Nitrous oxides and fluorinated gases are among the most notorious greenhouse gases. Sources of CO2 in the atmosphere are various such as volcanoes, the combustion and decay of organic matter, respiration by aerobic organisms, burning of fossil fuels, clearing of forests, cement production etc.  Nature has evolved its own methods of mitigating the presence of atmospheric CO2 through various physical, chemical, or biological processes known as “sinks” such as plant life, which absorbs CO2 during photosynthesis and marine life which can absorb dissolved CO2 among others.

However, these sinks are effective only upto certain levels beyond which they are unable to combat the  enormous levels  of greenhouse gases pumped daily into our atmosphere driven by the rise in population and industrial activity.  Rising CO2 levels have the ability to inflict monumental damage to the environment in various ways such as rising temperatures, rising ocean levels and melting glaciers.   The Greenhouse gas effect has been a worrying phenomenon and the future of the planet has appeared to be increasingly bleak.  But a recent report in Nature Climate Change on a study conducted by scientists into the worldwide implications ofCO2‘s ability to augment agricultural productivity has given us some light at the end of tunnel.

Studies have now indicated that increased levels of atmospheric CO2 could augment photosynthesis and thereby reduce leaf-level transpiration, the process by which some of the water that plants draw from the ground gets released back into the atmosphere.

Consequently, growing seasons and loss of water will be reduced leading to an increase in crop water productivity, which is the amount of food produced for each unit of water expended.

What this means is that despite the climate disruptions, the rising CO2 levels could actually end up increasing crop yields and reducing water consumption at large scales, thus ensuring water and food security. Clearly, there are various complex factors that come into play and drive climate change. To that end, scientists used data from a huge network of field experiments and global crop models, and arrived at spatially defined viewpoint on the productivity of crop water under elevated CO2 levels and associated projected climate change. Several staple crops such as wheat, maize, rice, and soybean were studied and the results indicated that depending on the crop type, global crop water productivity increased by 10 to 27 percent by the 2080s.  This also included arid regions which exhibited large increases depending on the crop variety.