(TED Talk) Amory Lovins: A 50-year plan for energy

[NickB79]

49. The Arctic ice cap is on track to disintegrate by 2020

Positive feedback on a massive scale then sets in, with the permafrost thawing and gigatons of methane being released. In fact, we're already seeing large methane releases today, with only a 1C temp increase in the past century: http://www.guardian.co.uk/environment/2010/jan/14/arctic-permafrost-methane

Scientists have recorded a massive spike in the amount of a powerful greenhouse gas seeping from Arctic permafrost, in a discovery that highlights the risks of a dangerous climate tipping point.

Experts say methane emissions from the Arctic have risen by almost one-third in just five years, and that sharply rising temperatures are to blame.

The discovery follows a string of reports from the region in recent years that previously frozen boggy soils are melting and releasing methane in greater quantities. Such Arctic soils currently lock away billions of tonnes of methane, a far more potent greenhouse gas than carbon dioxide, leading some scientists to describe melting permafrost as a ticking time bomb that could overwhelm efforts to tackle climate change.

After which, temp. increases of 3-5C by 2100 are pretty much locked in. And if you can seriously tell me that a 3-5C temperature increase in the next century isn't a serious threat to human civilization, we have nothing left to discuss: http://www.heatisonline.org/contentserver/objecthandlers/index.cfm?id=6041&method=full

Dr. Scholze said the effects of a 2C category were inevitable. This is the temperature rise that will happen, on average, even if the world immediately stopped emitting greenhouse gases. This scenario predicts that Europe, Asia, Canada, central America and Amazonia could lose up to 30% of its forests.

A rise of 2C-3C will mean less fresh water available in parts of west Africa, central America, southern Europe and the eastern US, raising the probability of drought in these areas. In contrast, the tropical parts of Africa and South America will be at greater risk of flooding as trees are lost. Dr. Scholze says a global temperature rise of more than 3C will mean even less fresh water. Loss of forest in Amazonia and Europe, Asia, Canada and central America could reach 60%.

A 3C warming could also present a yet more dangerous scenario where the temperatures induce plants to become net producers of carbon dioxide. "As temperatures go up, plants like it better and they start to grow more vigorously and start to take up more carbon dioxide from the air," Dr. O'Neill said. "But there comes a point where the take-up is saturated for a given vegetation cover, then the ecosystem starts to respire more than it's taking up."

Dr. Scholze's work shows that this so-called "tipping point" could arrive by the middle of this century. His scenarios echo research from the UK's Hadley Centre, a world leader in climate change modelling. In a report published last year called Avoiding Dangerous Climate Change, scientists at the centre predicted that a 3C rise in average temperatures would cause a worldwide drop in cereal crops of between 20m and 400m tonnes, put 400 million more people at risk of hunger, and put up to 3 billion people at risk of flooding and without access to fresh water supplies.