I base my views on the overwhelming scientific consensus that global warming is a very serious problem. This consensus has become stronger as more data have come in, as demonstrated in the most recent updates from the Intergovernmental Panel on Climate Change (IPCC). The IPCC’s reports are based on input from a broad range of disciplines and go through a rigorous peer-review process, a process that is inherently conservative, in the sense of eliminating extreme examples on which there is no scientific consensus.