Climate Change

Climate change to make pests hungrier, cause more crop loss

Warmer climate will increase the metabolic rate of insects making them devour more crops

By Akshit Sangomla
Published: Friday 31 August 2018
Pests are responsible for destroying one fifth of the global crop output annually. Credit: Sivakumar B/Pexels Pests are responsible for destroying one fifth of the global crop output annually. Credit: Sivakumar B/Pexels

Insects are going to be hungrier and their population will increase manifold. Reason? Climate change. A new study, published in the journal Science on August 31, says warmer climate will increase the metabolic rate of insects, which is the rate at which they digest what they eat. This will make them hungrier and so they will devour more crops causing more crop losses.

Also, the rise in temperatures will lead to an increase in population of these pests.

The scientists studied the effects of pests on food crops like rice, wheat and maize, which are staple crops in most countries. All reasons for crop loss, be it due to infestations or as a result of pesticide usage to prevent such infestations, were taken into account by the study group. And that’s when the group found that global warming will reduce agricultural production significantly in the near future. A research paper, published in the journal Proceedings of the National Academy of Sciences on August 15, 2017, finds that with each degree rise in temperature the yields of wheat, rice and maize will go down by 6 per cent, 3.2 per cent and 7.4 per cent.

The paper predicts that for every degree rise in temperature the losses will increase by 10 per cent to 25 per cent. Temperate climatic zones will be the most affected as these provide the best conditions for insects to reproduce. Temperatures that are too high like in tropical climates or too low are not conducive for insect population growth. In tropical regions, the insects’ crop eating ability will increase, while their population growth rate will decrease leading to a balance.

There are around 10,000 species of insects who eat and damage crops, according to a research paper published in the journal Indian Journal of Entomology in 2015. Of these, only 10 per cent are considered to be major pests. These insect pests are responsible for destroying one fifth of the global crop output annually. In India the losses due to insect pests have come down from 23.3 per cent in the post green revolution era to 15.7 per cent now. This loss calculates to around US$ 36 billion annually.

According to the Food and Agricultural Organisation (FAO) of the United Nations (UN), pests, including insects, lead to considerable losses to food crops globally. The total loss of food grains is around 1.3 billion tonnes per year. The FAO also says that only 5 per cent of research funds are actually diverted towards studies on crop losses as compared to a massive 95 per cent spent on increasing agricultural production. There is a decline in land and water resources around the world that could have provided a push for greater focus on prevention of crop losses and damage through pests, diseases and other means, says the FAO.

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