DW: What do you think about the energy policy of Germany as the COP23 organizer? There are still more than 70 coal power plants operating in Germany - we are actually only about 50 kilometers away from Europe's biggest coal mine. Isn't that a contradiction, especially when you consider Germany's goal of a 40 percent cut in carbon emissions by 2020?
James Hansen: Yes, Germany is a problem. Because it made an unrealistic assessment of the time scale on which we have to solve this problem. We can't set up new power plants that are burning brown coal, we have to phase out carbon emissions rapidly. Germany is actually useful in the sense that it's demonstrating just how difficult it is to switch to all renewable electricity - that is expensive.
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I think that Germany made a mistake when they decided to phase out nuclear power. But we don't want to expand the all-nuclear-power and light water reactors [either]. We have known for decades how to use much better technologies that are much safer and much more difficult to [weaponize].
Unfortunately Germany is not following a path on which they will be able to rapidly phase out carbon emissions. But we have got a worse problem in places like the United States. I don't want to spend too much time criticizing Germany.
Trump is withdrawing the US from the Paris Agreement. But this won't go into effect until November 2020. Do you think the United States will really leave the agreement?
Frankly I don't think it matters a lot. It is completely hopeless with the US government [anyway]. It was already hopeless with the preceding government, which pretended that it was solving the problem but was taking only baby steps. It allowed the building of tar sands pipelines, the development of fracking to get more gas out of the ground, tar shale to be developed in North Dakota, and drilling in the deep ocean, drilling in the Arctic.
Governments that say climate change is a problem and then propose half-baked solutions that don't solve anything are in some ways a bigger problem than the Trump-type governments. With those, everybody got to see what they were doing and that they were in the pocket of the fossil fuel industry. But liberal governments are not solving the problem either.
Then what is your formula to reduce carbon emissions?
We have got to get somebody in power who will admit the simple fact that as long as fossil fuels are allowed to be cheap, you cannot solve the problem. By subsidizing solar panels and such, you cover a few percent of our energy need [with renewables]. But fossil fuel use continues with no substantial reduction.
We have got to make the price of fossil fuel honest. That means you must have a rising carbon fee, the carbon tax. We argue that you need a carbon fee and dividend. You collect the money from the fossil fuel companies, but distribute it to the public in an equal amount to everybody. So the person who does better than average in limiting their fossil fuel use will make money.
That will spur entrepreneurs to develop clean energies and energy efficiency, and it will encourage people to pay attention to the carbon footprint. Unless we have that price on carbon, I don't see how we can solve the problem.
James Hansen, the former top climate scientist at NASA, is seen as "the father of climate change awareness" because of his early warnings in a famed US congressional testimony in 1988.