All the things that we've done as a species have had a limited scope. We're talking about melting the ice caps, raising the level of the seas dramatically, changing the distribution of every other species on Earth, perhaps wiping out one-third or half of them. The changes at work are geologic in scale. The level of change required to deal with it is enormous, too. It will require change in every country. It will require a degree of global cooperation that we haven't seen before.

I think the world on the other side of fossil fuel is more local - the logic of sun and wind is diffuse and spread out, not concentrated like the logic of coal and oil.

A third of summer sea ice in the Arctic is gone, the oceans are 30 percent more acidic, and since warm air holds more water vapor than cold, the atmosphere over the oceans is a shocking five percent wetter, loading the dice for devastating floods.

When we think about global warming at all, the arguments tend to be ideological, theological and economic.

Those of us in the west have figured out a lot of ways to damage the lives of poor people in this country and around the world over the years.

We just see a sort of cascading amount of data of the damage that is being done by those increased temperatures.

Renewable energy is far more labor-intensive than fossil fuel production.