What we know about climate change

Scientists and economists gathered this week in Copenhagen to discuss climate change. At the end of their meeting they posted six messages, one being Earth's climate is warming faster than the Intergovernmental Panel on Climate Change projected in 2007. The full report from this group is due out in June 2009. This and many other efforts are preparation for United Nations Climate Conference in December 2009, also set in Copenhagen. The goal of that meeting: finding a solution for global warming (see this Independent article for more on December's UNCC).

Earth's climate and human impact on it is a widely complex topic, and that's why I'm grateful for Kerry Emanuel's book What We Know about Climate Change (2007). In a very slim volume, the MIT professor of atmospheric science explains the fundamentals of climate physics and climate modeling in a way that is both sophisticated and understandable. He outlines how we know for certain that human behavior is warming the planet, but he doesn't shy away from acknowledging the limitations of our best projections, noting "computer modeling of global climate is perhaps the most complex endeavor ever undertaken by mankind."

In an endorsement of What We Know, James Hansen of the NASA Goodard Institute for Space Studies says, "Emanuel's words are measured and authoritative. His book should help reduce the huge gap between what is understood by the scientific community and what is known by the people who need to know, the public and policymakers."