You must become a climate champion, a single-issue voter. You must take whatever action you can. You must use whatever influence you have wherever it would make a difference, even if it is only to educate the people around you.

On our current path, all our great Gulf and Atlantic coast cities are at risk of meeting the same fate as New Orleans.

The great political tragedy of our time is that conservative leaders in America have chosen to use their superior messaging and political skills to thwart serious action on global warming.

Some 3 million years ago, when the earth was a little more than 3°C warmer than preindustrial levels (about 2.2°C warmer than today), Antarctica had far less ice and sea levels were a stunning 25 meters higher than today. If we stay on our current emissions path, the planet will almost certainly be that warm by the century's end.

Time is short. We have at most a decade to sharply reverse course.

In 2003... the White House conspired with an oil-company funded think tank to block a major government scientific report that sought to spell out the dangers of climate change to Americans.

The first few feet of sea-level rise alone will displace more than 100 million people worldwide and turn all our major Gulf and Atlantic coast cities into pre- Katrina New Orleans - below sea level and facing super-hurricanes.