- 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 the levels of Co2 in the atmosphere from 280 ppm to 390 ppm.