Critics of climate change science are few in number but their attacks are aggressive. Photograph: Corbis

In the weeks before and after the Copenhagen climate change conference last December, the science of climate change came under harsh attack by critics who contend that climate scientists have deliberately suppressed evidence "” and that the science itself is severely flawed. The Intergovernmental Panel on Climate Change (IPCC), the global group of experts charged with assessing the state of climate science, has been accused of bias.

The global public is disconcerted by these attacks. If experts cannot agree that there is a climate crisis, why should governments spend billions of dollars to address it?

The fact is that the...