It is well known that strong to violent tornado activity in the US has decreased markedly since statistics began in the 1950s, which has also been a period of average warming. So, if anything, global warming causes FEWER tornado outbreaks...not more. In other words, more violent tornados would, if anything, be a sign of 'global cooling,' not 'global warming.'

Contrary to popular accounts, very few scientists in the world - possibly none - have a sufficiently thorough, 'big picture' understanding of the climate system to be relied upon for a prediction of the magnitude of global warming. To the public, we all might seem like experts, but the vast majority of us work on only a small portion of the problem.

Nature is not static, but causes its own, internally-generated changes - both in climate and in biological systems.

Al Gore likes to say that mankind puts 70 million tons of carbon dioxide into the atmosphere every day. What he probably doesn't know is that mother nature puts 24,000 times that amount of our main greenhouse gas-water vapor-into the atmosphere every day and removes about the same amount every day. While this does not 'prove' that global warming is not man-made, it shows that weather systems have by far the greatest control over the Earth's greenhouse effect, which is dominated by water vapor and clouds.

All scientists should be skeptics. The reason why is that, even with the best of scientific measurements, we can come up with all kinds of explanations of what those measurements mean in terms of cause and effect, and yet most of those explanations are wrong. It's really easy to be wrong in science ... it's really hard to be right.

We have no idea what's natural and what's man made. [...] There is no fingerprint of human-caused warming.

Twice I have testified in congress that unbiased funding on the subject of the causes of warming would be much closer to a reality if 50% of that money was devoted to finding natural reasons for climate change.