"coastal aquifers turned salty and the northern permafrost melted"
High Arctic Permafrost
Creative Commons Attribution Share AlikeHigh Arctic Permafrost - Credit: Mila Zinkova

Global warming is the increase in temperature of the Earth's near surface air and seas.  Through much of the twentieth century, increases in temperature were recorded, and it is widely believed that the rise was the result of human-caused CO2 emissions leading to the Greenhouse Effect.

Possible consequences include the warming of the Arctic, the melting of ice caps and permafrost, rising sea levels, expanding deserts, species extinction and extreme weather.