James Hansen on Letterman

I have just finished reading the book Storms of my Grandchildren by NASA scientist James Hansen.

I found it inspirational. For example on page 73, chapter 9 'An honest effective plan'.

A simple clear urgent conclusion leaped out from our research on the appropriate target level of atmospheric carbon dioxide: Coal emissions must be phased out as rapidly as possible or global climate disasters will be a dead certainty.

Here is a Youtube clip of Hansen talking to Letterman.