Key Findings of the IPCC's Fourth Assessment Review 2007

 Warming of the earth’s climate system is unequivocal.

 CO2 atmospheric concentration--280 ppm in 1750 rose to 379 ppm in 2005. And the average global temperature rose by 0.74 degree Celsius.

 Direct observations of changes in temperature, sea level, and snow cover in the northern hemisphere during 1961–90 indicate increased temperatures, rise in the mean sea levels, and decreasing snow cover.

 Global average sea levels rose by 1.8 mm/year over 1961–2003.

 Eleven of the twelve years—1995-2006—rank among the twelve warmest years since 1850.

 Both the hemispheres have observed a decline in the mass of mountain glaciers and snow cover. Precipitation has been found to be more variable, with increased frequency of heat waves, droughts, heavy
precipitation events, and floods.

 Projected changes in the climate indicate an increase in global temperatures in the range of 1.8°C to 4.0°C over the twenty-first century and sea level rise is projected to be between 0.18 m and 0.59 m by 2100.