Question: what effect does global warming do

James M Monk answered on 14 Jun 2011:

Global warming is caused by greenhouse gasses such as CO2, methane and water vapour. Greenhouse gasses are opaque to (some) infra-red light, which reduces the Earth’s ability to radiate heat into outer space. The greenhouse effect causes the Earth to be warmer than it otherwise would be because it radiates less of its heat (which is provided by the Sun).

The greenhouse effect occurs naturally – without it the Earth would be about 30 degrees C cooler than it is, which is below freezing, so we need the greenhouse effect to survive. Industrialisation has caused the amount of greenhouse gas in the atmosphere to increase in the past hundred years or so, resulting in a stronger greenhouse effect. This is causing the average temperature of the Earth to increase.