Thresholds

There are certain thresholds which could cause the rate of climate change to accelerate very rapidly with spiralling effects, causing uncontrollable "runaway warming": 

• Rising temperatures could cause the huge stores of carbon dioxide and methane in forests and soils to be released. Similarly from melting tundra permafrost.
   

• Rising sea temperatures could trigger release of vast quantities of methane (a very potent greenhouse gas) from crystal structures in the sea.
   

• Peat bogs, which are believed to contain one third of the carbon stored on land, have been found to be releasing CO2 to the environment at a rapidly accelerating rate - up to 6% per annum - encouraged by the amount of CO2 already present in the surrounding air.
   

• People in hotter areas of the world will use more air conditioning and those in colder areas (such as the UK if the Gulf Stream “switches off”), more heating. All round, this means more energy consumption, contributing to even greater climate change.
   

Geologists have found that sudden increases in warming have happened before –  within a time-span of a few years, e.g. 65m and 250 million years ago (believed due to either extreme volcanic activity or an asteroid), resulting in the extinction of most species.