Global News

Posted September 2007:

Guide to Climate Change

Climate forecast

In 2001, scientists predicted the Earth would warm by 1.4 - 5.8C by 2100.

Most of the warming, they believed, was a result of humanity's use of fossil fuels, like oil and coal.

Greenhouse effect

The greenhouse effect is the natural process by which the atmosphere traps some of the Sun's energy, warming the Earth enough to support life.

Most mainstream scientists believe a human-driven increase in "greenhouse gases" is increasing the effect artificially.

These gases include carbon dioxide, emitted by fossil fuel burning and deforestation, and methane, released from rice paddies and landfill sites.

The carbon cycle

Carbon dioxide (CO2) is the main greenhouse gas of concern. A finite amount of carbon is stored in fossil fuels, the sea, living matter and the atmosphere.

Without human influence, transfers between these stores roughly balance each other – for example, plants absorb carbon as they grow, but release it as they decay.

But when humans cut down trees or burn fossil fuels, they release extra carbon into the atmosphere, increasing the greenhouse effect.

Taken from BBC News http://news.bbc.co.uk/1/shared/spl/hi/sci_nat/04/climate_change/html/climate.stm