Top scientist's fears for climate

By Roger Harrabin
BBC environment analyst

One of America's top scientists has said that the world has already entered a state of dangerous climate change.

In his first broadcast interview as president of the American Association for the Advancement of Science, John Holdren told the BBC that the climate was changing much faster than predicted.

"We are not talking anymore about what climate models say might happen in the future.

"We are experiencing dangerous human disruption of the global climate and we're going to experience more," Professor Holdren said.