Scientists are identified nine key 'tipping points' that could cause irreversible damage to the earth within the next century. Once these scenarios reach the point of no return the effects will be long-term and could include crop failure, famine and flooding from rising sea levels.

Experts say it is still possible to avoid disaster by reducing man-made greenhouse gas emissions, which are blamed as the cause for climate change. The definition of tipping point is a "small small increase in temperature or other change in the climate could trigger a disproportionately larger change in the future."

The nine identified tipping points are:

- Arctic sea ice: some scientists believe that the tipping point for the total loss of summer sea ice is imminent.

- Greenland ice sheet: total melting could take 300 years or more but the tipping point that could see irreversible change might occur within 50 years.

- West Antarctic ice sheet: scientists believe it could unexpectedly collapse if it slips into the sea at its warming edges.

- Gulf Stream: few scientists believe it could be switched off completely this century but its collapse is a possibility.

- El Niño: the southern Pacific current may be affected by warmer seas, resulting in far-reaching climate change.

- Indian monsoon: relies on temperature difference between land and sea, which could be tipped off-balance by pollutants that cause localised cooling.

- West African monsoon: in the past it has changed, causing the greening of the Sahara, but in the future it could cause droughts.

- Amazon rainforest: a warmer world and further deforestation may cause a collapse of the rain supporting this ecosystem.

- Boreal forests: cold-adapted trees of Siberia and Canada are dying as temperatures rise.

» The Independent