There is no ideal Christmas; only the one Christmas you decide to make as a reflection of your values, desires, affections, traditions.

We've been in lots of places that I suppose, by Oxford standards, would be considered illiterate, but everyone's completely conversant with the idea that here is a number, and that number is above it, and that's too high. It's not a very complicated idea.

The flaw is the business plan - digging up and burning way more carbon than physics says we can deal with. So, I suppose it's some kind of mid-point between writing them nice letters asking them to stop and figuring out a way to take down the entire system- which I don't have any idea how to do.

The models that have been constructed agree that when, as has been predicted, the level of carbon dioxide or its equivalent in other greenhouse gases doubles from pre-Industrial Revolution concentrations, the global average temperature will increase, and that the increase will be 1.5 to 4.5 degrees Celsius or 3 to 8 degrees Fahrenheit... In Dallas, for instance, a doubled level of carbon dioxide and other gases like methane, would increase the number of days a year with temperatures above 100 degrees from 19 to 78 each year.

The Arctic and the Antarctic are melting quickly. We may have waited too long to get started. But this is a day for optimism because the battle is fully joined, and the idea that big oil is unbeatable is no longer true.

There's always the danger that people will simply sign online petitions, the way they used to just mail in checks, and there's the greater possibility we'll just spend our whole lives staring at screens and never get anything done.

My goal was to have as many of the primary sources as I could made available for people to look at and understand. Climate change is probably the most important thing that's ever happened, and yet people's understanding of it and its history remains a little fuzzy.