My response to a friend who, having heard about the Climategate scandal, decided that global warming was discredited:

Climategate is real but so is warming. Carbon trading is a big scam, but that does not mean the problem is not a reality. Natural forces produce CO2 and hence warming trends, but human activity disrupts the normal feedback cyles and magnifies it into a runaway train. The figures are clear that if CO2 production continues at its present, or even significantly reduced, rates, there will be global disaster. What would be a tragedy would be if those people who committed to preventing that were persuaded to give up because of some overenthusiastic scientists who wanted to push things too fast. Put punitive taxes on the overproducers and stop letting them dictate the discussion!