John Holdren is the longest-serving presidential science adviser in U.S. history. He’s also probably one of the most influential, having advised President Obama on key energy issues for the last eight years. “Mr. Holdren has this president’s ear,” is how The New York Times put it in 2014.

A physicist by training, Holdren is among the chief architects of the Obama administration’s Climate Action Plan.

This makes him one of the more controversial science advisers, as well. The plan has been lauded by environmentalists, but is loathed by conservative politicians, some of whom have filed suit against it. The future of the plan, which rests almost entirely on executive authority, is now very much in doubt.

Holdren spoke to Yale Environment 360 about the difference between “dangerous” and “catastrophic” warming, the incoming Trump administration, and how to talk to people who deny the existence of climate change. “Part of the reason that I retain some optimism about the future is that there are these fundamental forces pushing us toward doing the right thing,” he said.

e360: There’s obviously a lot of concern out there right now about a new administration and what’s going to happen to the steps President Obama has taken on climate. How do you feel about this?

Holdren: We don’t know at this point what the next administration is going to do. I think everybody saw the interview with The New York Times in which President-elect Trump said his mind is now open on climate change. That is certainly progress compared to some of what went before.

I don’t know what’s going to happen, but what I know is that a lot of what is going on in the positive sense on climate has a lot of momentum to it. It has momentum because it makes sense to people. People understand that renewables have been getting cheaper. People understand that energy efficiency saves them money. People understand that climate change is happening around them. Just the increase in torrential downpours and the flooding associated with that is so conspicuous, so damaging, that I think anybody that did want to roll back the sensible things we’re doing would find there was a lot of opposition to it.

You know, the business community is on board now in a way that goes way beyond what was true before. You have so many of the Fortune 500 companies with policies aimed at reducing their own greenhouse emissions and supportive of government policies to help that along. You’ve got the environmental community. You’ve got a substantial fraction of the economic community, who understand that the damage to the economy from not addressing climate change will be far, far greater than the costs of addressing it. There are a lot of constituencies out there who will act to defend the positive things that are going on. That gives me reason for optimism.

e360: Still, we have a president-elect and many high-ranking members of Congress who’ve said they don’t believe in climate change. What’s your analysis of what’s gone wrong here?

Holdren: I think a number of Republicans believe that if the public ever accepted the reality of what climate science is telling us, the country would embrace a regulatory regime which Republicans would not welcome. There has been a leaning toward questioning the science, which is really based on fear of over-regulation. I think that’s particularly unfortunate because economists on all parts of the political spectrum have agreed for a long time that the single most effective thing you could do to reduce greenhouse gas emissions would be a market-based approach, which puts a price on carbon emissions and then lets the market decide how to reduce it. And if you wanted to make such a thing revenue-neutral, you could reduce capital gains taxes or reduce income taxes in proportion to the revenue you got from a carbon tax. The reality is that some of this thinking, which is reflected in the positions of some folks on the Republican side of the aisle, is actually out of date.

It isn’t true that accepting the science requires a draconian regulatory regime.

e360: How can we get out of this situation where people can still say, “I don’t believe in climate change”? And what is the role of scientists who have been sounding the alarm on this for really a long time now?

Holdren: I have long held the possibly naïve view that giving people more information will help. There have been a number of studies lately that have indicated that that may not be right. One of the conclusions I draw from that is we need to focus more on the solutions and their attractiveness irrespective of whether you are convinced that humans are altering the climate to our detriment.

Let me give you a couple of examples: One of the big drivers of the reductions in emissions that have been achieved in recent years is that renewable energy and natural gas have been cheaper than the more greenhouse-gas-intensive alternatives, particularly coal. That has been driven by the market above all. If the climate-friendly energy sources are also less expensive, and that trend appears to be continuing, then you don’t need to “believe” in human-caused climate change to embrace them.

I think everybody who’s paying close attention to climate understands now that we need to do a lot on the preparedness, resilience, and adaptation sides, because no matter what you do on the mitigation side, you can’t stop climate change overnight. Adverse impacts are already occurring, so we need to do what we can to reduce our vulnerability. Well, it turns out a lot of those strategies are win-win strategies in the sense that they would make sense even if the climate weren’t changing. There have always been powerful storms. There have always been droughts. We have always under-invested in preparation for those kinds of events. The fact that climate change is increasing the frequency and intensity of those events strengthens the argument for investing in preparedness, resilience, and adaptation, but the argument stands even without that.

Part of the reason that I retain some optimism about the future is that there are these fundamental forces pushing us toward doing the right thing. One is a set of economic forces. Another is a set of historic underinvestment in infrastructure, which we should be improving in terms of its resilience in any case.

e360: Well, if these are underlying trends, what difference does public policy make?

Holdren: Policy can accelerate the good trends. Again, let me give you some examples: We’ve had a policy of investing in research and development on clean energy and energy efficiency. One of the results of that policy has been a 90-percent-plus reduction in the cost of light-emitting diodes, LED bulbs. The investments in clean energy R&D have contributed to the reduction in the price of wind and solar. Also important has been the tax credits, the production tax credits [for wind and solar], which we just got extended in law for five years with bipartisan support in the Congress. You can reinforce positive trends with policy.

e360: What do you think the most important policy measures that have been taken over the last eight years with regard to climate change are? I know you don’t want to speculate, but how hard or easy would they be to undo?

Holdren: First of all, and this is sometimes forgotten when people think that the whole interest of the Obama administration in climate change originated with the Climate Action Plan in 2013, the down payment took place in the Recovery Act [of 2009]. There was $80 billion for clean and efficient energy, the biggest boost for clean and efficient energy in the history of the country, probably in the history of the world, which again had a big effect. It led to advances in technology, reductions in cost that have been extraordinary.

Then you look at the rest of the first term, we had the first set of combined fuel economy CO2 emissions standards for light-duty vehicles, followed by heavy-duty vehicles.

Now, of course, in the second term, we had in 2013 the Climate Action Plan with its three pillars – reduce domestic emissions, build up domestic preparedness, resilience, and adaptation, and the third international pillar, work with countries around the world both bilaterally and multilaterally to get them to do the same. That has been immensely effective. It led to the joint announcement by [Chinese] President Xi and President Obama in Beijing in November 2014 saying, “We are the two biggest emitters. We are the two biggest economies. We are going to lead.” That made possible Paris. It transformed the international discussion.

e360: There’s been talk recently that China will be stepping into the leadership role that the U.S. has occupied for the last several years. Do you buy that?

Holdren: There is no doubt in my mind that the Chinese are serious. The Chinese are not doing what they’re doing because we urged them to do so. They are doing it because they understand that climate change is already adversely impacting China. It’s adversely impacting their agricultural production. It’s adversely impacting the East Asia monsoon, aggravating historic problems of flooding in the south and drought in the north.

The other thing about China is most of the leadership was trained in engineering. They can do arithmetic. They are absolutely convinced and committed, so the question of whether they will take over the lead internationally in addressing the climate change challenge is partly up to us. They’re going to keep going. We should keep going as well.

e360: You’ve said that the goal of avoiding dangerous anthropogenic interference with the climate system is gone. We’re already experiencing that, and the question is can we avoid catastrophe? Where do we draw the line between dangerous and catastrophic?

Holdren: I’ve likened the current situation with respect to climate change to driving a car toward a cliff in the fog and the car has bad brakes.

Energy represents an enormous capital investment. In the global energy system, replacement cost is probably $25 trillion or even $30 trillion. That’s an investment that turns over in the normal course of things in 30 to 40 years. That’s the average lifetime of these energy facilities – refineries, transmission lines, power plants, drilling rigs. You can’t take a $25 trillion investment and turn it over overnight. So there’s this enormous amount of inertia in the energy system. That’s the bad brakes in the car. And the fog is we don’t know exactly where the tipping points that could really turn it into a catastrophe are, but there are quite a few of them that are understandable in terms of how they would work.

For example, we are busy not only heating the ocean, but acidifying it. Nobody can figure out at what point the oceans could exhibit changes that become catastrophic for human society.

We know with pretty high confidence that we’re likely to have lost the majority of the world’s coral reefs by the middle of the century we’re now in from a combination of heating and acidification.

e360: Doesn’t that lead us to the idea that, well, we don’t have 30 years to turn this around?

Holdren: I’m not saying, “Business as usual is fine.” We’re not in business as usual at the moment. We are moving faster to turn that over. We are retiring coal plants. China is retiring coal plants at a rate that was unimaginable a few years ago. It’s showing in the data, in the emissions data. We’re not in business as usual. But still, no matter what we do, we can’t stop it overnight.

e360: You mentioned retiring coal plants. A lot was said during this past campaign about coal. What future does coal have?

Holdren:First of all of course, we’re not shutting down the whole coal industry. What has mostly been shut down are the dirtiest and least efficient plants and probably the costliest mines. The long-term future of coal is going to depend on whether we can master CO2 capture and sequestration. About which I’m more optimistic than many.

Without that, the long-term future of coal is continuing decline and its replacement by cleaner things. In the short- to medium-term, natural gas and in the longer-term, some combination of nuclear and renewables.

e360: What do you say to people who say that natural gas will get us to the same disastrous place, it’s just going to take a bit longer?

Holdren: We can’t burn natural gas indefinitely as a society and expect to surmount the climate challenge. I think those of us who have welcomed the degree to which natural gas has been replacing coal in electricity generation are aware that it is an interim solution and not a permanent solution, again, unless and until you capture and sequester the CO2.

This whole question of fossil fuel and leaving it in the ground, there’s a short-term and there’s a long-term aspect. In the short term, we can’t leave it all in the ground because the United States and the world as a whole are still 80-plus-percent dependent on fossil fuels for our primary energy. As I’ve already argued in terms of just the capital investment in that energy system, you can’t change that overnight. If someone says, “Leave it in the ground” meaning leave it all in the ground starting now, I say, “That’s simply not feasible.”

If, on the other hand, somebody says, “By leave it in the ground, I mean we know that we cannot afford from the standpoint of climate to burn all the fossil fuel that’s out there” – that’s a different matter. There have been very good studies that show if you burn all the fossil fuel that’s out there, both the Greenland ice sheet and the Antarctic ice sheet go away and sea level goes up by about 65 or 70 meters [213 or 230 feet].

I subscribe to the leave it in the ground notion – as a long-term proposition, we’ve got to leave a lot of the fossil fuel that’s out there in the ground, or else learn how to burn it and put the CO2 back in the ground.

There was some controversy because in a public speech I gave, I was asked in the Q&A period if it is technically feasible to leave it all in the ground. I answered it as a technical question, the way I’ve answered it here: No, it is not feasible to leave it all in the ground starting now. Somebody tweeted that I had disparaged the Leave It In The Ground movement. The next thing I know I had 23,000 emails complaining about this — 23,000 emails, all identically worded, an orchestrated campaign.

e360: Do you think that the movement has been politically effective?

Holdren: Well, most of the people associated with the Leave It In The Ground movement actually want to stop federal leasing of fossil fuel development on federal lands, saying sort of that’s the least we can do. That’s not the same thing as leaving it all in the ground. It just says, “The United States government should be a leader in accelerating the reduction of the use of fossil fuels.” That is at least an interesting argument.

I’m basically of the view that almost every discussion of different ways to address the climate challenge is helpful because the discussion calls to people’s attention that there is a climate change challenge. What is the best way to deal with this challenge? That’s the debate I wish we were all having, rather than a continuing debate about whether or not it’s happening, which has become kind of ridiculous in the face of the evidence.

e360: You’ve spent a lot of time dealing with people on Capitol Hill. Do you have advice for your colleagues moving forward? What should scientists be doing?

Holdren: Scientists, number one, should keep talking about the science and what it’s telling us, what the implications are. That includes the implications of delay. How much more damage are we buying into if we say, “Let’s deal with this later,” rather than dealing with it now. It’s becoming possible to talk about that. The other thing that is becoming possible is to talk about impacts in a much more regional way. The third U.S. National Climate Assessment, which was released in 2014, succeeded in disaggregating things regionally and sectorally to a much greater extent than any previous assessment had done.

I went around the country that year, and talked to state, local, and tribal leaders. And I was actually astonished by the number of people, including mayors, governors, who came up to me and said, “For the first time, this is a report about climate science that’s useful to us because it brings it to the level that we have to operate at.” What’s going to happen to fisheries? What’s going to happen to farming? What’s going to happen to forests? How is it different in the Northwest and the Southeast?

That’s going to be important for scientists: to focus on what’s happening where people live and in relation to what they do for a living or what they enjoy.

e360: What arguments do you find really get to people?

Holdren: The local gets them, the relation to things they care about. The productivity of farms, forests, and fisheries. Hey, that matters. The prevalence of oppressive heat and humidity. That matters to folks.

One of the things I found very effective is explaining to people that the global average surface temperature is simply an index of the state of a very complicated system, just like your body temperature is an index of the state of a very complicated system. When your body temperature goes up 2 degrees C, you know it’s telling you that something’s amiss in the system. What could be going on can be extremely complicated and extremely dangerous.

e360: One last question. I don’t think that the president-elect is reading environmental websites, but if you could offer some advice to the incoming administration, what would it be? Maybe he will read it – if I tweet it, or something.

Holdren: We have a transition process. I don’t think we should be talking about the details of the transition. But I’ve written down a lot of advice and my colleagues have written down a lot of advice. I just have to hope that at least some of that advice will be taken.

I got such advice when I came in from my predecessor, John Marburger, who not only wrote a superb transition book for me, but met with me personally at great length. You don’t have to take all the advice of your predecessor. No one expects that to happen in a new administration with a different political cast. But there are things that ought to make sense regardless of political leaning. We hope that those will register.

Elizabeth Kolbert, who conducted this interview, is a regular contributor to Yale Environment 360 and has been a staff writer for the New Yorker since 1999. Her most recent book, The Sixth Extinction: An Unnatural History, won the 2015 Pulitzer Prize for General Nonfiction and was based in part on reporting she did for Yale Environment 360.

First Published by Yale Environment 360