A blanket of carbon di-oxide hangs trapped in the earth’s atmosphere, mainly as a result of burning fossil fuels and burning of forests to create farms and pastures. Surviving in the earth’s atmosphere for up to centuries, this carbon di-oxide is warming the earth and bringing it onto the verge of climatic changes. Global temperatures having already increased by more than 0.7°C above pre-industrial times; and there is substantial scientific evidence available to show that an increase of more than 2°C over pre-industrial levels will pose severe risks to natural systems – and agriculture is one of the most vulnerable sectors to be affected – in more ways than one. Though it is difficult to predict what would happen in the long term, scientists have put together several evidence-based hypotheses on the short-term effects on agriculture.
One of the major changes is expected to be in production patterns of agricultural crops. As increased warming melts glaciers and icecaps, oceans will expand; raising sea levels by a meter or more over the next ten years. A meter’s rise would affect half the rice land in Bangladesh, and a two-meter rise would drown much of the Mekong delta, which produces half the rice in Vietnam. Melting of Himalayan glaciers will affect the flow of rivers Ganges, Indus, Yangtze and Yellow, making them more erratic, and affecting crop production. Some scientists believe that climate change will lead to changes in precipitation patterns, causing heat waves, droughts, strong winds and heavy rain, all of which will affect crop growth. In Africa, such drought and aridity would contribute to farmers losing 40%-80% of their maize-sorghum-millet crop land, as these crops are sensitive to high temperatures. Cereal production that is estimated to be 10% less in 2050 than in 2000 simply means less food to eat.
At the same time, colder places would warm up, shifting some agri-zones towards the poles. This would be evident in countries like the United States, where cooler areas of the country will become more habitable for some crops, expanding the area in which certain crops could be grown. But for crops that are already in the warmest productive temperatures, the yields could reduce. A report from the Intergovernmental Panel on Climate Change states that if climate change reduces the global arable land, then the total yields could decrease.
While carbon di-oxide supports plant growth, and may increase the yield in some places, the drawback is lower nutrient and protein levels in the crop. Additional fertilisers would be required to balance nutrition levels; failing which consumers would experience what is called ‘hidden hunger’.
There is no doubt that reduction in greenhouse gas emissions is the first goal to be achieved to reverse the adverse effects of climate change on agriculture. But along with this, immediate solutions such as development and adoption of crops that can tolerate high temperature and drought conditions should be taken up. Investment in improving crop management techniques is required. Asian countries need to invest in agricultural adaptation in agricultural research and infrastructure. In addition, sharing of knowledge by establishing centres of excellence and linking national research institutions across Asia-Pacific needs to be taken up to combat these adverse effects, to the extent possible.