Temps de lecture :6 minutes
The US’s stance on climate change has shifted beyond recognition. President Barack Obama’s science adviser John Holdren tells Graham Lawton how the US will put its house in order, secure a deal at the make-or-break summit in Copenhagen, and lead the world’s fight against dangerous climate change
How will you persuade the American people that climate change is a problem and win support for policies to tackle it?
The polls show that 70 to 75 per cent of the American public accepts that climate change is real, that humans are largely responsible, and that we need to do something about it. But it doesn’t rank particularly high on their concerns: the top concern tends to be the economy. So it’s recognised as a problem but needs to move up.
President Obama has made it clear that the same strategies can help reduce the risk of climate change, reduce dependence on imported oil and help drive recovery with new businesses and jobs in clean energy. He is saying we can get a lot of things done simultaneously by making the right investments and developing the right policies, including the policies in the energy climate bill that recently passed in the House of Representatives (see backgrounder).
What does the bill hope to achieve? Does it contain binding targets for reducing greenhouse emissions?
Absolutely. The target is for emissions in 2020 to be 17 per cent below those of 2005. This would amount to being a few per cent below what they were in 1990.
The bill is now being considered in the Senate. Could it be thrown out or watered down?
I think that we are going to get a bill out of the Senate, which may even improve some aspects of it. I think everybody understands that legislation of this sort will have some strengths and some weaknesses. This certainly has some things that, if I were king, I would have written differently.
Is the emissions target based on scientific calculations of safe climate limits?
I would argue that there is no safe limit. In my view we’re already experiencing dangerous [climate change], by any reasonable definition of the word dangerous. The question is, will we be wise enough and effective enough to avoid catastrophic interference in the climate system? President Obama’s goal is to get the US on a trajectory that is compatible with a global emissions trajectory that avoids unmanageable changes. That amounts to trying to avoid exceeding a global average surface temperature increase of 2 °C.
What does that mean in terms of atmospheric CO2 concentrations? Is a limit of 450 parts per million low enough?
From a scientific standpoint, 350 ppm is better than 450 ppm. The reason 450 ppm has become the mainstream view is that it is close to the best we can do and, at the same time, maybe the worst we can tolerate.
In my judgement, the most important thing to get done right now in the US is to get legislation passed that has a cap-and-trade mechanism in it, which, of course, will be adjusted over time. Those adjustments are likely to make the targets more ambitious. This is because two things are going to happen. One, the damage from climate change is going to continue to escalate. And two, once you have a real price on greenhouse gas emissions, you’re going to see innovation in response. It’s going to make it clear to people that it is easier and less expensive to reduce emissions than they had feared.
What about carbon capture and sequestration?
I think it’s going to work, and I think it needs to work. We remain, as a planet, roughly 80 per cent dependent on fossil fuels. That’s not going to change overnight. Without CO2 capture and sequestration it is going to be extremely difficult. We need to boost our investments in research and development, and indeed this is part of the Obama policy.
What about geoengineering? Where do you stand on that?
Geoengineering is not under consideration in current policy, but from the scientific standpoint we need to understand it – like we need to understand all other aspects of this problem. We have to understand what its potential is, what its risks are, and what its costs are likely to be.
My own view is that most of the schemes that have been put forward so far look costly and burdened with side-effects that make them problematic, and they look limited in their effectiveness.
For example, most of the approaches do not address the absorption of a lot of the excess carbon dioxide in the oceans, the consequent acidification of the oceans, and the potential damage to our ocean food chains, coral reefs, and so on.
There are approaches to geoengineering that are widely understood to be quite innocuous. White roofs, for example: basically, making our urban areas more reflective. That’s geoengineering, and nobody’s wringing their hands very much about that approach. Carbon sequestration is not something I’d put in the category of geoengineering.
We’re fiddling with a very complicated system, trying to counter the consequences of other large human influences, inadvertent ones, in that system. And it’s a dicey business, because we’re doing it without a complete understanding of how the machinery works.
My bottom line on geoengineering is: of course we have to look at it. Understanding it is likely to lead us to the conclusion that many of the approaches would not be attractive – but we have to be sure that we’re not overlooking anything.
What about biofuels, and nuclear?
I think biofuels have an important role to play, but we have to choose carefully what approaches we use to grow the feedstocks, and what approaches we use to convert them to fuels.
The corn ethanol programme can be viewed in a couple of ways. The most positive way is as a stepping-stone, in which we’re getting experience with a biofuel system that will serve us well when we move to cellulosic ethanol, which makes much more sense from the energetic and greenhouse gas standpoint.
As to nuclear, I believe, and the President believes, that nuclear energy has to remain part of the menu of options by which we reduce our greenhouse gas emissions. Certainly it will be easier to solve the climate challenge if we can get a significant contribution from nuclear energy.
On a global level, what needs to happen as we approach the United Nations climate summit in Copenhagen in December?
I believe that if the US can go to Copenhagen with a specific policy in place, the chances are very good that we can get an agreement in which major developing countries make commitments that will move them onto a declining emissions trajectory. They are still waiting for concrete evidence that the US is going to move, but I think if the US does move, we will see a degree of progress at Copenhagen that will surprise people.
And if you fail?
If we don’t get the legislation passed, it’s going to be a much more difficult lift at Copenhagen.
So the US legislation is key to success in Copenhagen. Will it really be in place?
If I were a betting person, I would bet that it will happen, but I have to admit that it’s going to be a challenge. The president understands how important it is, and so far he has got a rather good record in convincing Congress to do the things that he thinks are most important. That’s not to say that there aren’t senators who will vote against it: there are.
How many senators’ votes do you need?
We only need 60 votes, and we have 60 Democrats. My sense is that, if the vote were taken today we’d probably fall short by 12 to 15. But I think we’re going to get those votes. One thing you have to understand is that among people who oppose it, there are some who oppose it because they think it’s too strong, but others who oppose it because they think it’s too weak. It’s going to be an interesting juggling act to get the votes it needs to pass.
How do traditional opponents of climate-change legislation view what is going on?
There has been a huge change. In 1997, the private sector was mostly sceptical; now it is overwhelmingly in favour. You’ve got oil companies and electric utilities saying we need this. Some of the important labour unions are saying we need this. There are religious people saying we need to protect the climate on grounds of stewardship of the creation. So you’ve got this convergence.
Do your climate plans require ordinary Americans to make lifestyle changes?
Nothing in these policies actually requires sacrifices. They’re based on making energy cleaner and more efficient. There is a tremendous amount of low-hanging fruit; ways in which you can reduce emissions drastically with no sacrifice. Now, there are ways in which I think some lifestyle changes would make sense. If more people had opportunities for living closer to where they worked, you could regard that as a lifestyle change which everybody would consider beneficial. I think most people would prefer not to spend 2 hours a day in traffic jams. That’s a lifestyle change: I’ll take it, thank you.
Interview: America turns red, white and green
New Scientist, n°2719
3 august 2009
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