Robert O. Mendelsohn is a professor of forest policy and economics at Yale University’s School of the Environment, with a research focus on the valuation of the environment. In this interview with Jill Stoddard, Editor-in-Chief of the Global Observatory, he discusses the global forces creating unprecedented changes over the next few centuries, including climate change, and why he is optimistic about the future.

The interview has been edited for length and clarity.

I read a quote from you recently: “The trick is to have 19th-century emissions without reverting to a 19th-century standard of living.” I’m curious about what that future looks like. How do we balance growth with what science is telling us about earth’s resource limitations? And what do we owe our fellow planet dwellers, if anything? I do feel some days quite desperate about the climate crisis, and I’m assuming you feel that way too.

I actually am much more optimistic about what’s going to happen than most people. A lot of my own research looks at the alternative scenarios that climate scientists are telling us might happen and trying to imagine what the world will be like then. And it turns out, the world is not going to stay looking like 2020. We have to refashion what the future will look like to accommodate changes, and climate is only one of the things that is changing.

But the climate changes are not going to happen overnight. They are happening slowly. Adaptation has to anticipate these changes but not far before they happen. The world has to be somewhat different to deal with a two-degree climate change—but this future world has not yet been created.  Between now and the second half of the century, most of the capital we see around us is going to be gone and replaced. It’s not that the existing capital needs to be destroyed tomorrow. And the question is, how do we want to replace it? We’re going to create a new world in the second half of the century, and it should be ready for how the climate’s going to be different. But it’s got to get ready for a lot of other things, too: more people, a larger economy, new technology, and evolving values.

Climate change is going to last for a century or more. It’s more of a marathon than a 100-yard dash. We’re going to lose land if there are huge changes in ocean levels, partly because we know that has happened before. However, this change is not like facing a tsunami that happens suddenly, what you’re facing is the sea level rise that we’re seeing already, but just a little faster.

On the adaptation side, this means you have time. Things are surprisingly adaptable if they happen slowly— it’s only if they happen very rapidly that they are incredibly damaging. For example, some existing cities are in the way of these rising oceans. But if high ocean levels do not happen for 150 or 250 years, these future cities don’t yet exist.  Where should we build these future cities? Clearly on high-elevation land.

It wasn’t that long ago, 150 years ago, there were one billion people, and now we’re talking about having 10 billion. That is a huge change. We’re using up almost all the freshwater that’s available on the planet. All the high-quality land is being used. We’ve driven wild things to very tiny spots—there’s very little wildlife and wildlands left. All these things have consequences. We are now facing planetary not just local constraints. This is something new for humankind.

I believe very much in the climate science. I’m not at all skeptical about the science part of it. But it’s a multi-dimensional world, and we shouldn’t boil it all down to, “it’s just climate change.” It’s a mistake, because you’ll find you could fix the climate and then suddenly you realize that the world is not fixed. The traditional air pollution, our use of all this land, our use of almost all the freshwater are still going to be constraints. We have to think about those things as part of the plan for the future as well.

If sea level rise progresses in a constant way, in a way that is plausible, it might be a long-term consequence that Florida itself has to be abandoned. And so that’s an example of adaptation: Florida goes. You’re still talking about hundreds of years from now. For most cities, however, like New York City, there are high places, so adaptation would imply you’d just move to higher parts of the existing city, away from the lowest stuff, which would be abandoned. It’s a gradual retreat from the lowland and then a gradual realization that the lowland is not worth keeping at all.

There are some low-elevation countries like Bangladesh, where there’s no place to go…

It’s devastating to think about the long-term effects in countries that are entirely at low elevations. It’s not quite the same thing as a tsunami, which would instantly kill people. But in the long run, it could lead to some countries being abandoned. But time is really important to keep straight. What do you have to cope with right away? How big is the change you have to deal with now, and how big a change do you have to deal with way into the future? There are adaptations to do now and others to do later as the problem evolves. It’s a question of: are there things we would do in advance to ease the pain?

If we built things like seawalls to protect the city of Miami, for example, it would help in the short term. But as the sea continues to rise, you’d have to build ever taller walls. And at some point, the walls would have to be so tall that if you lived in Miami, the allure of living there would start to disappear. The city would gradually fade away. And one of the things we would not want to do is subsidize people to stay in Miami and remain in harm’s way because that’s just going to make it worse. So we want to think about, as we protect ourselves, are we making things better? Or are we making things worse?

The underlying problem that we are having with mitigation is that we don’t have a global government that’s capable of doing global mitigation. We should be doing mitigation now. Even with my optimistic view of what climate change will do, it’s causing damage, and that damage will get worse. We want to avoid really high temperatures, because the more we push the temperatures up, it’s going to steadily become more and more harmful. I am surprised by how broken global mitigation is. It’s partly because it’s expensive, but it’s mostly because what you’re doing is something that saves everybody. You pay for it, and the whole world benefits. But do you care about the whole world?  How much would you pay to benefit everyone else? The self-interested strategy is to get your neighbors to do lots of mitigation, you pretend you’re going to, but you don’t, because it’s expensive. Europe is a little bit better behaved—they’re actually trying to do something—and California is trying to do something by itself. But it’s incredibly difficult to get cooperation across 197 countries.

We are not evolved enough to worry about the globe individually, and we need to do this as a group of governments, and the problem is the group of governments is the United Nations. The UN can do things that are cheap, but it can’t do things that are expensive—countries are not willing to give the UN those kinds of resources, and that’s a major problem, and that’s the reason mitigation is failing. I think the best way to start is to show that we can actually work together, start doing some mitigation projects and then gradually make it more expensive.

Where is the cooperation happening?

If you want to talk about inexpensive mitigation, developing countries are willing to do it. China has more renewable energy in place than any other country in the world. They don’t want to spend vast amounts of money on it, but they are willing to spend money on it.

So instead of “zero emissions by 2050,” what if we focused on what we’ll do in the next five years? What can we get done to remove emissions by spending just $20 per ton of carbon? I’m guessing you could get the entire world to agree to that. India would say, yeah, okay, then let’s do some solar stuff in India. I think you’d see global cooperation is possible.  For the poorest of the poor countries in the world, the rich countries wouldn’t mind spending some money in those places to make a difference. What the world will not agree to do is a crash program that’s super expensive—more expensive than what we spent on COVID-19—that has to go on for 50 years. People are happy to talk about it, but you see nobody implementing it, and it’s killing us, because we’re not doing the cheap stuff.

To me, that’s the tragedy of our current approach to mitigation. In the pursuit of the perfect solution, to have no emissions by 2050, we are actually doing nothing. We’re letting emissions that are going to be sitting in the atmosphere for hundreds of years get out there, when we could have spent a relatively small amount of money to remove some of them. That we’re not doing more mitigation is a major failure. Part of the reason for this is that there are two political forces out there—one force wants to do nothing at all, and the other force wants to do everything all at once. And the ideal solution is actually somewhere in between, and we’re not talking about that in-between space. Both sides agreed they don’t want to do the in-between space. And that’s a pity, because we could act.

I think we need more examples of successful mitigation, even if it’s small scale, just to show we can do this, that this isn’t going to kill us to do modest mitigation. The world won’t fall apart to spend a  small amount of money on this.

The problem is that we’ve made some mistakes as we’ve gone into the 20th century. We are in a new world that we didn’t know much about before. We’ve got to figure out what those mistakes were and correct them. And the idea is to change what the world looks like so that we are living more consistently with the environment we’re going to see in the future. The mistake is not that we’ve gone from the 19th century to the 20th century. Because most of us really wouldn’t want to be back in the 19th century, with a much lower standard of living. Most of us would find that less pleasant.

The first thing to do for the US, for sea level rise, is learn to live with the environment we have. A lot of Florida cities are built way too close to the water. Subsidized flood insurance made that seem safe. The United States is the only one in the world that’s done subsidized flood insurance, and so without intending to, we’ve encouraged people to live in low-elevation places—not the 100-year flood plain, the 10-year flood plain. We’ve taken flimsy summer homes and converted them into fancy coastal mansions. When a hurricane hits us, it causes 10 times more damage than when it hits any other part of the world. If I had to point to something and say, “What would I blame more? Climate change or our flood policy?” There’s no question, it’s the flood policy. The government has already decided to fix this, and is slowly getting rid of subsidized insurance. But now the question is whether we have invested enough in physical flood protection. The clear answer is no. We need to do a lot more to protect the cities we have against flood. We need to adapt to the flood risks we face today. As time progresses, we will need to protect against the future risks we face then.

What do we owe our fellow planet dwellers as we build this future? Looking especially at island countries, which are facing an extinction of their culture, their way of life.

It’s tricky to live on an island. Even an island like Venice. It’s expensive, and there’s no place to go when things get tough. Individual islands may not have enough fresh water given how many people are trying to live there now. The Pacific Islands, especially the atolls, are incredibly vulnerable places. You’re much more dependent on the climate, and much more vulnerable to climate change, so they’re going to suffer more damage than anybody else. And they actually had very little to do with the emissions. In that sense, it’s completely unjust.

The islanders will probably want to stay where they are as long as they can. So you can do things like build seawalls that will extend how long they can stay. You could help them with their water issues. Part of that is just going to be development and part of it is adaptation. If you can make people wealthier, eventually they could decide for themselves to either stay on a risky island or live someplace else. The world can help with that.

So a third leg of climate policy in addition to mitigation and adaptation is more compensation-oriented. What COP 27 is trying to discuss. This compensation could be in the form of development aid. You could send cash. But I personally would like to see us help victims get on their feet, so they themselves can decide what to do with themselves.

What you’re talking about—how do you put a price on “x”? Culture, home, history? Is sorting that out necessary to get this kind of justice?

I think the justice element is pretty obvious. There’s a small minority of people who are very vulnerable and had nothing to do with the emissions. It’s kind of hard to say, “You’ve lived on this island and you have to leave. We don’t care.” It wouldn’t take that many resources to help poor islanders or poor people in very hot places. We can help them maintain their current lifestyle for a while and ultimately we can help them leave when it is no longer possible to stay. Especially if you carefully target who actually is the most vulnerable, it’s something that is affordable and should be within our understanding of our humanitarian responsibilities. I personally would like to see that happening—a climate humanitarian fund that’s targeted specifically at the severe victims of climate change.

But you actually raised another point which I want to answer. Which is most of the impacts of climate change are not on the economy. Most of the things about climate change that I think are devastating are non-market. You’re going to live in a hotter place—is that okay? The ecosystems themselves are going to change a lot in response to climate, so the world is going to look a lot different. And one of the questions is, what’s the value of that? What weight should we give it? Those are important questions to ask. If we replace the forest with desert, there’s no question that would be a huge loss.  But if you’re replacing the forest with a different forest, it isn’t obvious anymore. You might say, “Well, I don’t like that.” But the question is, would your grandchildren care?

Because these are slow-moving forces, it could be we as humans will adapt more than we can imagine. So these non-market things are important. And I think it’s one of the things we don’t have a good grasp on. I have a feeling if you told people that we should bring things back to the way the landscape used to look like in 1900, most people in Massachusetts and Connecticut would revolt and say, “No, no. The way it is now is the way it should be.” They wouldn’t want it to go back to being just farmland.

You wrote recently for Brookings on voluntary carbon markets, where credits are purchased voluntarily to offset emissions. They have grown rapidly in the last few years but have issues. Do you think they are worth saving?

I’m deeply concerned that a lot of the voluntary carbon market is ineffective. The carbon market is reducing only a small fraction of the carbon emission it claims to be reducing. If we can take that goodwill of “we’re willing to spend some money on this” and actually use it differently, we could guarantee that there will be a lot more carbon removed. I think carbon markets are worth saving if they improve. The current model based on small projects is not working because we can’t verify whether the project would’ve been done anyway even without the carbon market. The forestry offset market is saving trees that would have been saved anyway. If we’re going to spend $100B in developing countries on mitigation every year, and we follow this model, most of that money is going to be wasted. I want that money to be well spent and actually lead to mitigation.

This means the mitigation programs including the voluntary carbon market have to change the way they’re doing it. We have the tools in regulations to get mitigation done and we have successfully applied those tools to reduce emissions of sulfur dioxide and particulates and other pollutants. You need to return to firms as the target of control. What are the total emissions of a particular firm or a particular facility? Then you tell them they’ve got to reduce these emissions. If firms reduce emissions faster than the historical record in each industry, they get carbon credits they can sell. You redesign the voluntary market to look more like how a regulation would look. And then you’d be sure you’re causing meaningful reductions in emissions. Firms cannot just do business as usual and get credit.

Of course, the goal is to impose global regulations on greenhouse gas emissions. That’s the first best choice, to get global regulations in place. But in the meantime, if all we can do is subsidize emissions, then we want to make sure that these subsidies are being well spent.