In short
Global warming is the observed increase in the average temperature of the Earth's atmosphere and oceans in recent decades and its projected continuation into the future. Models referenced by the Intergovernmental Panel on Climate Change (IPCC) predict that global temperatures may increase by 1.4 to 5.8 °C (2.5 to 10.5 °F) between 1990 and 2100.
Cutting greenhouse gas
Most recently, researchers affirmed that only a clear cut of 80 percent by 2050 could have an even chance of curbing global warming in line with goals of the G8 countries. "Any delay in implementing emissions reductions will make a 2 degree target practically unreachable," said Nathan Rive of the Center for International Climate and Environmental Research in Oslo. But so far, no country policies have met the challenge.