For me, the most serious problem is how America became so vulnerable to the assertion of blatant falsehoods that drive policy and are not corrected by the so-called immune system of democracy, a free press and a free democratic discourse.

Researchers at the Naval Postgraduate School have told us that the entire Arctic ice cap may totally disappear in summer in as little as five years if nothing is done to curb emissions of greenhouse gas pollution.

ManBearPig, half man, half bear, half pig

Making consumer choices that reward eco-friendly products and companies is a great way to start.

We sometimes emphasize the danger in a crisis without focusing on the opportunities that are there. We should feel a great sense of urgency because it is the most dangerous crisis we have ever faced, by far. But it also provides us with opportunities to do a lot of things we ought to be doing for other reasons anyway. And to solve this crisis we can develop a shared sense of moral purpose.

I have felt for a long time that the pathway to solving the climate crisis is through the building of a massive grassroots army of men and women who will go out there and win the conversation on climate, and persuade businesses, and universities, and towns to switch to renewable energy and to reduce emissions. And the big change from ten years ago is that people are way more receptive, not only to the message that we have to act, not only to the message that now we can act, we have the solutions now - that's the biggest change - but also willing to make a commitment that we will act.

You see that pale, blue dot? That's us. Everything that has ever happened in all of human history, has happened on that pixel. All the triumphs and all the tragedies, all the wars all the famines, all the major advances... it's our only home. And that is what is at stake, our ability to live on planet Earth, to have a future as a civilization. I believe this is a moral issue, it is your time to seize this issue, it is our time to rise again to secure our future.