Profiting from companies that are overloading the atmosphere with carbon and changing the atmosphere is wrong.

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.

A world where one tenth of the population gets to be extremely wealthy, and six tenths very poor, is not, in the long run, a stable place.

We've lost half the summer sea ice in the Arctic. We've wiped out an enormous percentage of the world's coral reefs. We see huge changes in the planet's hydrology already, the cycles of drought and flood both amped up because warm air holds more water vapor than cold. These things are happening with a one-degree increase and going to two degrees won't be twice as bad, the increase in damage won't be linear, it most certainly will be exponential. So it was precisely the wrong moment to elect Trump.

We spend a lot of time playing defence against bad things. So, in the US, one of the focusses has been this huge Keystone Pipeline project, another has been the coal ports on the Pacific Ocean.

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.

I've got no advice. You guys know where you are and what will work. Just know that there are people all over the place working on this and that there's a great deal of solidarity around the world and we should try to build this big, sprawling movement that looks like the kind of energy system that we want - building lots of solar panels on lots of rooftops that are all interconnected.