GLOBAL WARMING

Global warming refers to the risingaverage temerature of earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about 0.8 °C (1.4 °F) with about two thirds of the increase occurring over just the last three decades. Warming of the climate system is unequivocal, and scientists are more than 90% certain most of it is caused by increasing concentrations og green house gases produced by human activities such as deforestation and burning of fossil fuels These findings are recognized by the national science academies of all the major industrialized countries.

An increase in global temperature will cause sea level to rise and will change the amount and pattern of precipitation, and a probable expansion of subtropical desert.  Warming is expected to be strongest in arctic and would be associated with continuing melting of glacier. Other likely effects of the warming include more frequent occurrence of unexpexted weather events including heatwaves, droughts and heavy rainfall events,extinction of species due to shifting temperature regimes, and changes in crop yields. Warming and related changes will vary from region to region around the globe, with projections being more robust in some areas than others. In a 4 degree celcius world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world. Hence, the ecosystem services upon which human livelihoods depend would not be preserved.