Important food grains will have significant reduction in yield as the
climate warms because rising temperatures boost the metabolic rate and
population increase of insect pests, according to a study published in
"Climate change will have a negative impact on crops," said Scott Merrill of
the University of Vermont, one of the authors of the study. "We're going to
see increased pest pressure with climate change."
The research team observed how the insect pests of rice, maize, and wheat
would respond to various climate scenarios. Their findings showed that
increasing global temperatures would lead to an increase in crop losses due
to insect pest attacks, particularly in temperate areas. Losses are
projected to rise by 10-25 percent per degree of increase in temperature.
The researchers explain that the losses are due to the increase in insect
metabolism and population growth rates. When it becomes hotter, the insect's
metabolisms increase, so they tend to eat more. In terms of population
growth, insect population grows best in an optimal temperature. If it is too
cold or too hot, the population growth is slow. Thus, the losses will be
greatest in temperate areas, but less severe in the tropics.
"Temperate regions are not at that optimal temperature, so if the
temperature increases there, populations will grow faster," said Merrill, an
ecologist who studies plant-crop interactions. "But insects in the tropics
are already close to their optimal temperature, so the populations will
actually grow slower. It's just too hot for them."