An increase in the average temperature of Earth’s near surface air and oceans since the mid-20th century 4th assessment report of IPCC: global temperature increased 74+0.18 degree C during the 20th century. Caused by greenhouse gases Water vapour, Co2, Methane, Nitrous Oxide, Ozone, CFCs (in order of abundance) Since the industrial revolution, the burning of fossil fuels has increased … Read more  Global warming