If you were running a solar company you may be okay - you may be able to keep growing. The question for physics is: Can you grow fast enough to begin to catch up with the damage?

It drives me crazy to see so much of this planet's life so casually endangered. The first steps are so easy (drive smaller cars, for instance) that it's very hard to understand why we haven't taken them. But I know that this is the issue our generation will be judged by.

I think the best way is to keep stressing, that, as we build out a new energy system, one of the best things about it, if we do it right, will be that it will be more local, more democratic, more distributed, and, in the long run, much more economically sensible.

That's why people are standing up again to fight the Keystone pipeline in Nebraska and South Dakota and Montana. Everyone is well aware of what this industry is about. It engages not only in those kind of practices, polluting people's water, but it has polluted our political life now for a quarter century.

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.

I think that some of it is electoral - helping candidates that are willing to take dramatic actions, not just to say a few words about how climate change might be a problem.

It now appears that the fracturing of that ice is happening much more quickly than people previously thought, apparently at a slow melt.