In the last five years, the earth has become hotter than it has ever been in recorded history. Global warming is the theory that due human's activity on the planet making it hotter. This phenomenon is also called the Greenhouse Effect, because it heat the planet like a greenhouse. Global warming is not yet conclusively proven, but scietists all agree that if they wait until global warming will be scietifically proven, it will be too late. CO2 (carbon dioxide) is riseing when fossil fuels are burning. We all use theme every day for transport, heating the house or whatever. Riseing CO2 and heating means melting ice and riseing sea level.
The fact is that global temperatures have in last 200 years risen about 1oC. If we compared that fact with Earth's long history we can see big change. Scietists predict that if the Earth heats up by between 1-3oC in the next 100 years, which is probable, then the see level will rise betwen 15cm and 120cm in that time, or up to 20cm by 2030. This means that major us cities such as New York, Boston, Miami and Washington could soon find themselves submerged in water.