Conclusion: Avoiding a four degree world - Australia’s role

Abstract

Despite years of international negotiations and growing public and scientic concern, both global fossil fuel use and carbon dioxide emissions have continued to increase at an accelerating rate. In May 2013, atmospheric concentrations of carbon dioxide rose above 400 ppm for the rst time in human history (see: keelingcurve.ucsd.edu). Similar levels were last experienced some 3.2 to 5 million years ago, when global average temperatures were between 3°C and 4°C warmer and as much as 10°C more at the poles and sea levels ranged between 5 and 40 meters higher than present. The rst 12 years of the 21st century were all among the top 13 warmest years since 1850, when records began, and 2012 was the..