Dave Begley: indecipherable intro...So there is a cost to this I think we should realise that. My question is this. Your theory about this disaster is based upon your models. Your models have mostly been wrong for the last 30 years. So how do we know that this impending disaster in the models are correct, seventy years from now, when everyone in this room is dead.

Dr. James Hansen: If you look at the paper we published, you will see that it's not based on models, it's based on the combination of the Earth's history, called paleoclimate, on climate models, and thirdly on observations of the real world.

And, you know, the physics is actually very simple.

When you add carbon dioxide to the atmosphere it absorbs heat radiation. It's like a blanket. So that makes the planet temporarily out of energy balance. More energy coming in from the sun than heat radiating to space because of this absorbing gases.

Well, we can now measure that energy imbalance. It's coincidental that I have sitting up here a slide.

You know the atmosphere of the Earth is very thin. It has a very small heat capacity. But the ocean is two and a half miles deep on average. It has a huge heat capacity. So when the planet is out of energy balance, most of that excess energy is going into the ocean.

About 15 years ago, nations cooperated in distributing about 3,000 floats around the world's oceans. They dive down to a depth of about two kilometers and come back to the surface and radio to a satellite their measurements. And this allows us to measure how the heat content of the ocean is changing. And what we find is that it's steadily increasing. It's increasing, and this graph just goes to the end of 2008 but the data goes up to the present and that increase is continuing and is slightly larger in recent years.

That rate of increase, which is about 6/10ths of a watt per metre squared on average over the entire planet doesn't sound like a lot, but it's equivalent to the energy in 400,000 Hiroshima atomic bombs per day, every day of the year. That much excess energy is going into the ocean, and it's warming the ocean. And that ocean is now melting the ice shelves. We're able to measure all these ice shelves around the Antarctic and Greenland. They are melting. And now the ?? of the ice sheets are beginning to shrink. And we're measuring that very precisely with gravity satellite.

So it's not a complicated story. It's a straightforward one, and it's scary just because of the inertia of the system. It wasn't easy to get these massive things to begin to change. They are beginning to change at increasing rates. So it's not some wild scare that we dreamed up. There's a lot of well-established physics and observations behind it.

I asked the first question. I reminded the Iowa native that he was in the home city of the Union Pacific Railroad and it has had recent significant layoffs due to a serious decline in coal car loadings. I then asked him, since his models have been mostly wrong for 30 years, why we should believe his models were any more accurate in predicting the disaster that is going to hit when everyone in the room was dead 70 years from now.

He asserted that his predictions were not based upon models but “observable evidence.” False. He dodged, stalled and avoided. He threw out some numbers and put up a slide depicting the Hiroshima bomb explosion. His answer was non-responsive. If I could have cross examined him at length I would have destroyed his answer, but he knew the format.