气候学家谈论哥本哈根大会

TONY JONES: Now you've proposed what you call a uniform rising price on carbon; effectively a global carbon tax. Now it's a simple approach but it would require carbon tariffs to be levied againstthose who refuse to put a price on carbon. But isn't that a serious problem? Won't it lead to trade wars?

JAMES HANSEN: No, in fact it is far simpler. As we saw in the Kyoto Protocol, you cannot get all the countries to agree, you have to bribe them one by one to try to get them to sign up to the Kyoto Protocol or a Copenhagen follow up.

But, in the case of a carbon price, which is simple and honest, it's a much easier task. All you need to do is get the major players to agree to put a carbon price on. And then if any countries don't want to do it, well then you put a tariff on the products that you import from those countries that are made with fossil fuels.

In effect, most countries would then decide, well, we would rather have our internal carbon tax because then we get to collect the money rather than the other country. That is much simpler than cap and trade.

TONY JONES: Can we talk about the science of global warming and climate change now, because as we've gotten closer to Copenhagen, the sceptics have become much louder. There's been a fierce backlash against the science. What do you think is going on here?

JAMES HANSEN: Well, the science, as you know, has become very clear. The evidence for climate change around the world is widespread. The Arctic Sea ice melting, glaciers receding all around the world, climate zones are shifting, the subtropics are expanding, and that's affecting Australia, by the way, as well as the south-west United States and the Mediterranean region, and that's a reason why we have more extremes, including heatwaves and fires.

But also, when we have rain, it is heavier, because warmer atmosphere holds more water vapour. We see the climate change all over the planet, there's no question about that.