It has become very difficult for anyone to argue that observed global warming is natural variability. We have good reason for being able to say that the world will be warmer by about a quarter of a degree in the next decade. It's the same reason we had 10 years ago when we said that the 1990s would be warmer than the 1980s: The planet is out of equilibrium.
James HansenThe scientific excitement in comparing theory with data, and developing some understanding of global changes that are occurring, is what makes all the other stuff worth it.
James HansenScientists will say we can't blame global warming for any single event. In a sense that's right, but the fact that the frequency and intensity of these events is increasing you can blame on global warming.
James HansenWe are on the precipice of climate system tipping points beyond which there is no redemption.
James Hansen