4 Degrees or More? Climate Change: The Critical Decade - a speech by Professor Hans Joachim Schellnhuber

This was the 1st keynote address to the Four degrees or more? conference Australia in a hot world which is currently meeting in Melbourne. After a day and a half of listening to climate scientists detailing the present climate impacts and future projections, understandably I, and many others, felt a little depressed.

But most of these scientists and other delegates are possessed of a human optimism that the challenge can be overcome. That human society has the technical and engineering capability to avoiding a 4 degree or higher world, to limit global warming to 2 degrees celsius as agreed to in Copenhagen in 2009 and affirmed in Cancun in 2010.