As Executive Secretary of the United Nations Framework Convention on Climate Change, Costa Rican diplomat Christiana Figueres presided over the negotiations between nearly 200 nations that resulted in the 2015 Paris Agreement. The agreement marked the first comprehensive, worldwide commitment to reducing greenhouse gas emissions, with a goal of limiting the increase in global average temperature to 2 °C above pre-industrial levels. Today, Figueres continues to advocate for action on climate change through her Mission 2020 initiative. Two recently discovered species, a tropical moth and a wasp, are named after her.

Shortly after this interview was conducted, President Donald Trump announced that the U.S. will withdraw from the Paris Agreement.

The Politic: The 2009 Copenhagen Summit was generally portrayed as an unsuccessful attempt to reach an international agreement regarding climate change, but the Paris Agreement has been called a historic success. So I’m wondering, what factors allowed the Paris Agreement to be so much more successful, and what steps did you take to look at the conflicts in the Copenhagen Summit?

Christiana Figueres: Well, let me see. I think there are three buckets to this. One bucket is the procedural bucket where we, the secretariat while I was there, after Copenhagen, between Copenhagen and Paris, we did learn a lot of procedural mistakes that had been made in Copenhagen and proceeded to improve upon all of them. There’s another bucket that has to do with technology, technologies of a solution to climate change, that is not within our control or power, as opposed to the first bucket. And there’s no doubt that part of the success of the Paris Agreement is because the technologies, i.e. renewable energy technologies, by 2015 were so much cheaper and so much less risky as an investment than they were in 2009. So that’s another big bucket that was not under control but that had a huge effect.

The third bucket that is perhaps the most interesting and that is one that we paid a lot of attention to was the context in which the negotiation, or as I call it the conversation, took place on the path toward Paris. It was very evident that in Copenhagen, there was a deep lack of trust and a mutual blaming, basically developed countries and developing countries blaming each other. There was a confrontation between the global need and the national interest, and there was much more of a sense of a burden than an opportunity.

All of this, we changed and transitioned over time. So we definitely encouraged and fostered much more trust among countries by improving transparency and reporting. We made sure that countries were not looking only at the global need but rather at their national interest and national development plan. And that is why the INDCs, the Intended Nationally Determined Contributions, are a very important part of the Paris Agreement, because they represent how each country will contribute to the global needs but from the national perspective. And in so doing, we turned around the conversation from being a burden sharing to being actually an opportunity creation, to really create the opportunity for the transformation for all countries.

As I understand it, the Paris Agreement seeks to limit global temperature increase to less than 2 degrees Celsius above the pre-industrial levels. What would be the consequences of not meeting this goal?

The consequence of going above 2 degrees, from an insurance industry perspective, as the insurance industry has already been pretty clear, is that we would be moving into a world that is systemically uninsurable. And the reason why that is so is that we would cross over thresholds that are irreversible and into an imbalance in nature and reflected into the economic system. That would be very, very difficult to manage and that would be exponentially damaging to the entire economy.

Given that by some estimates global temperatures are already 1 °C above pre-industrial levels, what effects would we have to accept as a consequence of the existing additional degree of warming? And what, if anything, can be done to mitigate these effects?

I think one has to be very honest and frank to know that we cannot fix climate change. We cannot solve climate change. We have already been, for 150 years, on a path of increasing [greenhouse gas] concentrations and therefore of increasing average temperature. And we already have baked into the system enough greenhouse gas emissions that we will continue to see temperatures rise over the next few decades. So that does mean that we will see consequences such as increased drought in some areas, increased flooding in other areas. We will certainly see the bleaching of coral reefs. We will see glaciers melting. We will see all kinds of changes, particularly in the water system around the world, that will still continue to occur because we’re still increasing the greenhouse gas emissions over on a global level.

Now the interesting part is that over the last three years, we have had a flattening of global total greenhouse gas emissions while we have seen an increase in GDP. So we have begun to see that it is possible to delink economic growth from greenhouse gas emissions. And it is precisely that delinking of those two curves that are at the foundation of the Paris Agreement.

Some analysts have expressed concern that the NDCs countries have submitted so far will not be sufficient to limit global temperature increases to under 2 °C and that NDCs are not legally binding. What do you think should be done to encourage countries to commit to their NDCs?

The Paris Agreement does not attempt to enforce anything. That is not the purpose of the Paris Agreement. The sum total of the NDCs are definitely below a two-degree effort, and that is well-known, and was known before the Paris agreement was adopted. There was never any attempt to say that the sum total of the NDCs would get us to the maximum temperature of 2 degrees. So those who expressed concern should not express concern about something that we didn’t know. We actually did know. The way that we dealt with that is precisely because it’s an invitation for countries to come forward with the current effort that they have visibility over, and we knew ahead of time that that would not get us to the level of effort that is necessary.

Therefore, the logic of the Paris Agreement is not to be a static agreement as previously in the Kyoto Protocol, for example, but rather to be a dynamic agreement. So the Paris Agreement invites all countries to put forward their best effort under the first trench, if you will, of their efforts, their first nationally determined contribution, and then, on a five-year rolling period, to increase their ambition every five years as they understand that they can actually go further because technology will be advancing during those five years, cost of those technologies will be decreasing, capacity will be increasing, policy will be increasing, finance will be increasing. And in response to all of those factors, being actually mobilizing forces, driving forces of climate change action. Countries will be able to increase their ambition over time. But that is already structured into the Paris Agreement.

The United States’ NDC calls for a 28% reduction in greenhouse gas emissions by 2025 [relative to 2005 levels]. In practical terms, do you think this will require dramatic changes to energy infrastructure? Or in general, what do you think needs to be done to achieve this goal?

The United States calls for a 26 to 28 [percent] reduction. That is what they put into their nationally determined contribution. So they chose a range of 26 to 28. And that, of course, is based on much of the regulations that are in place in the United States. It is based on the fact that due to natural gas and to shale gas, much of the coal of the United States, or perhaps even all of the coal of the United States, is no longer competitive with gas, and therefore that is the reason why 250 U.S. coal plants have already been retired since 2010. That is also the reason why renewable energy is having a much better run in the United States, why there is actually much more investment going into renewable energy certainly than in coal, and why more jobs are being created in renewable energy than in all of the fossil fuels ahead of time because the technologies of old, starting with coal, are simply no longer competitive. They’re not competitive on a financial level, and they certainly are not competitive with respect to all of the external implications such as health effects with coal, or such as the water needs of coal plants. They simply just do not add up any more.

So we are seeing in the United States but also across the world, we’re seeing a remarkable transition toward renewable energy, perhaps illustrated by a Kentucky coal mine that was closed and where they decided to build the state’s largest solar farm on one of the coal mines. And it’s really to provide not just 50 to 100 megawatts but actually to provide new and clean jobs there, exactly at the same place, because these are the jobs of the future. So the fact is that we are in a transition, and you can look at as many different examples around the United States, perhaps in Texas—might surprise some people—where Denton, a city in Texas, has actually announced its intention to generate 70% of the city’s generation from renewables by 2019. And Texas itself has installed more wind power capacity than Canada and Australia combined. Google, a very emblematic U.S. company, has announced that it will reach its goal of being 100% renewable very soon. They’re already at 98% renewable around the world, not just in the U.S. operations but around the world, and they will soon be at 100% renewable. And perhaps my last example is the fact that Tesla, that is a U.S.-based company, investing into the new technology of cars. Tesla has already been recognized by the market as having a higher value in the market than General Motors, a company that is only just beginning to encourage into new technologies of transportation. So many different examples of why in the United States but also around the world, renewables are moving in very quickly and are out-competing fossil fuels.

Do you think one particular source of renewable energy might have benefits over others?

No. That very much depends on what the energy regime is of any country. Obviously, a country with a lot of solar potential will want to explore its solar potential. But for that, you need land. So you need both high degrees of insulation as well as land capacity that you can turn into solar farms. Those that have wind will be able to use that. So these technologies don’t, per se, compete with each other. It all depends on what the resource is that is available to a country. And in the best of all cases, countries should be investing, if they have all of them, should be investing all of them because they are actually quite complementary to each other in the dispatch.

President Trump has obviously been slightly antagonistic towards climate change solutions, but geoengineering is something he considers feasible for America. Do you think geoengineering is a potential solution or a potential way to cut greenhouse emissions in the future?

You know, there are several people that are working on geoengineering. I myself am not an enthusiast, for a couple of reasons. One, because I think we have many other technologies that are much cheaper and much safer right now, and I don’t see the logic of jumping to a technology that is much more expensive and much more risky without having exhausted the capacity and the potential of cheaper and safer technology. So my personal preference is to make the best use out of those technologies that we know well, that do not have any negative risk, any risk, and we have to use them to their greatest potential.

What do you think are the most important global issues that the UN must work to solve, and where do you think the UN is succeeding at the moment?

Well, obviously, the most urgent has to do with peace, the negotiations of peace in all of the different areas in which we have the absence of peace, or open conflict. Obviously, that is the reason why the United Nations was created, and that is one of the main responsibilities of the United Nations. And I think we are getting, slowly but surely, to the point of realizing that conflict must not just be resolved but it must also be avoided, and that there are many environmental factors, social factors that lead to conflict that can be dealt with before they explode into conflict. Prevention is the word of the day.

It seems that in some countries, voters such as those who supported Brexit and Donald Trump are increasingly skeptical of the benefits of international cooperation. For those skeptical voters, what would you say is the strongest argument in favor of the necessity of transnational organizations like the UN?

I would say that it’s very evident that we have reached planetary boundaries on the use of all natural resources, and that our lives depend on these natural resources quite fundamentally. And because we have reached planetary boundaries, that forces us to look across the national boundaries into a collaborative framework of how are we going to make the best use of those resources, how are we going to optimize them, how are we going to get the best economic growth for the least use and the least waste of natural resources. And that can actually best be done on a transboundary basis.

Where do you get your news?

My news. Where do I get my news? From several sources, obviously, but very seldom print news; mostly Internet, and some radio, and some television.

What place would you most like to visit?

Home. I want to go home. Costa Rica.

Which living person do you most admire?

Not sure that I have favorites among the living. My favorites among the no longer living are my father, Mandela, Mahatma Gandhi.

What is your advice for college students?

Follow your passion.

And finally, what keeps you up at night?

Speed and scale. The speed and the scale of the decarbonization process, specifically.