Faced with the evidence, many deniers have started to admit that global warming is real, but argue that humans have little or nothing to do with it.

Environmentalism isn't a discipline or specialty. It's a way of seeing our place in the world. And we need everybody to see the world that way. Don't think 'In order to make a difference I have to become an environmentalist.'

What about our children and grandchildren and their children and grandchildren? Do we not want them to live healthy and happy lives?

Education has failed in a very serious way to convey the most important lesson science can teach: skepticism.

Treaties, agreements and organizations to help settle disputes may be necessary, but they often favor the interests of business over citizens.

The damage that climate change is causing and that will get worse if we fail to act goes beyond the hundreds of thousands of lives, homes and businesses lost, ecosystems destroyed, species driven to extinction, infrastructure smashed and people inconvenienced.

Humans are now the most numerous mammal on the planet. There are more humans than rats or mice. Humans have a huge ecological footprint, magnified by their technology.