What is Global Warming?

The cold fact

Global warming is an increase in the average temperature of the Earth's near-surface air and oceans. Although global warming has occurred in the past, the term is most often used to refer to the warming some scientists predict will occur as a result of increased emissions of greenhouse gases. An increase in global temperatures can in turn cause other changes, including a rising sea level and changes in the amount and pattern of precipitation. There may also be increases in the frequency and intensity of extreme weather events, though it is difficult to connect specific events to global warming. Other consequences include changes in agricultural yields, glacier retreat, reduced summer streamflows, species extinctions and increases in the ranges of disease vectors.

Remaining scientific uncertainties include the exact degree of climate change expected in the future, and especially how changes will vary from region to region across the globe. A hotly contested political and public debate also has yet to be resolved, regarding whether anything should be done, and what could be cost-effectively done to reduce or reverse future warming, or to deal with the expected consequences. Most national governments have signed and ratified the Kyoto Protocol aimed at combating greenhouse gas emissions.  

Ref.: www.wikipedia.org