Effects of Climate Change on Insect Pests of Forests, Grasses and Crops

Abstract

Human activities have increased the atmospheric concentrations of greenhouse gases and aerosols since the pre-industrial era. The atmospheric concentration of greenhouse gases reached their highest recorded levels in the 1990s, primarily due to the combustion of fossil fuels, agriculture and land use changes. Global atmospheric CO2 concentration has increased by approximately 30% since the industrial revolution and is believed to be responsible for an increase of ~0.6°C in mean annual global surface temperature. If no climate policy interventions are made, the concentrations of atmospheric CO2 may increase upto 405-460 ppm, 445-640 ppm and 540-970 ppm by 2025, 2050 and 2100 respectively. Similarly global mean temperature may increase by 0.4-1.1°C, 0.8-2.6°C and 1.4-5.8°C by corresponding periods respectively. It is very likely that 20th century warming contributed significantly to the observed rise in global average sea level and increase in ocean-heat content. Snow covers and ice extent decreased. Precipitation was very likely increased by 5 to 10% over most mid and high latitudes of the northern hemisphere continents. Changes in stream flow, floods and droughts were observed (IPCC, 2001). Apart from the effects mentioned above, agriculture including plants-insect-parasitoid systems is likely to be affected by the climate change.