How can you think cosmically about global warming?  The first thing to do is appreciate how the Earth works, and that the Earth has been through many cycles of being hot and cold.  The Earth has been frozen over like a solid snowball several times in the past.  It’s been super-hot several times in the past, but these cycles happen very, very slowly.  We’re talking over tens of hundreds of millions of years for these cycles.  Because of the amount of fossil fuels we are burning, we are making this happen incredibly fast.  And so when people try to confuse the issue by saying, “Oh, the Earth has already been through this, it’s just one more cycle," that’s just obfuscation.  That’s really a lie.  

What we’re doing today is so fast that we don’t know even how to think about the long term effects of it.  So I think that if we could put in into context, if we could understand what the difference is, for example, between a one degree change, which we’ve had now -- about a one-and-a-half degree change -- and a four degree change, which we could just have in a few decades. It could be disastrous, catastrophic: huge storms, totally unpredictable weather, violent weather.  That’s what four degrees means.  

Without any perspective on how the Earth has behaved over different periods when it was at those temperatures, I don’t think people really appreciate the seriousness of the issue.  There’s still people out there saying, "Oh, a few degrees warmer, that would feel great. You know, I live in a cold climate."  That would not feel great.  It’s not that the whole average just slowly moves up.  It’s that there are wild swings, and if you average them all out, you get four degrees.  But if you look at them day-to-day, you get terrifying weather.  Not only that, but you’re going to get large numbers of refugees. I think people also don’t appreciate this. Everybody likes to live on the coasts.  That’s where population density is all over the world. Those are the people who are going to get flooded out first.  

Consider New York City by 2050: Lower Manhattan could be largely flooded out, permanently, or at least in the big storms.  People should realize that when this happens there are going to be millions of refugees looking for a safe place to live.  Where are they going to go?  Are we going to have a huge military to fight against foreign refugees who try to come here?  These are the issues that we have to look at.  It’s not just weather, it’s all the implications, the diseases that are going to show up in the northern hemisphere. We think of them as tropical. How are we going to deal with that?  What if there’s an epidemic?  These are huge issues.  And by describing this as four degrees, you’re just not getting the picture across to people.  

So thinking cosmically is giving us perspective.  Not only on what has happened, but on what could happen and on the amount of power that we have today, that if we allow these things to happen, we won’t have again.