Climate Change: Science, Policy and Solutions (Invited Keynote Presentation)

Climate change is the most serious environmental challenge facing society in the 21st century. The basic science is clear: the average temperature of the Earth's surface has increased about 0.8 degrees Celsius since the Industrial Revolution, and the frequency of extreme weather events such as heat waves, droughts and floods is also increasing, most likely as a consequence of this temperature change. There are scientific uncertainties that remain to be worked out, connected with issues such as the feedback effects of clouds and aerosols. Nevertheless, the consensus among experts is that the risk of causing dangerous changes to the climate system increases rapidly if the average temperature rises more than two or two and a half degrees Celsius, and that the associated costs to the economy are likely to be significantly larger than the costs associated with adopting the necessary measures to minimize such risk. The scientific community needs to better communicate the nature of the climate change risk to decision makers in government to improve the likelihood of reaching an international agreement that effectively reduces global greenhouse gas emissions.