Global Warming Definition from Google Search : What is Global Warming

an increase of the earth’s temperature by a few degrees resulting in an increase in the volume of water which contributes to sea-level rise
www.nwrc.usgs.gov/fringe/glossary.html

increase in the average temperature of the earth’s surface.
www.nrdc.org/reference/glossary/g.asp
An increase in the near surface temperature of the Earth. Global warming has [...]