Sir John Houghton
AGE: 75
OCCUPATION: Oxford University climatologist
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 0
PRO: He's the co-chair of the scientific assessment group of the influential Intergovernmental Panel on Climate Change. Houghton, a Christian and an author deeply involved in the dialogue between religion and faith, looks at global warming through the twin lenses of science and theology.
CON: When it comes to cutting emissions, oil and gas prices often trump scientific evidence and high-minded discussion. The IPCC has also been accused of being too compromised by political interference from heel-dragging nations like China and the U.S.