Raise in Temperature

The phrase global warming refers to the documented historical warming of the Earth's surface based upon worldwide temperature records that have been maintained by humans since the 1880s.

There is a increase in the temperature of the Earth's near-surface air and oceans for quite some time. THis is mostly caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation

An increase in global temperature will cause sea levels to rise


The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet's lower atmosphere and surface


http://www.eoearth.org/article/Global_warming