Q & A
Demonstrators in Washington, D.C., during the People's Climate Movement March on April 29, 2017. Photo: Zach Gibson/Bloomberg via Getty Images.

Is There Reason for Optimism on Climate Change?

For many, the Trump administration’s announced intention to withdraw from the Paris Agreement, a carbon-reduction pact joined by nearly every nation, cast a dark cloud over global efforts to respond to climate change. Does that cloud have a carbon-neutral lining?


The science is as conclusive as science gets. Anthropogenic climate change is happening, and as a recent paper in Science noted, “without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation.” The authors told the Washington Post, “What we’re talking about here are the kinds of changes that disrupt everybody’s lives.”

Despite the consensus among scientists, the Trump administration intends to withdraw from the Paris climate accord—something it can’t actually do until the day after election day in 2020. 

For many, the U.S. withdrawal was extremely discouraging—signaling a broad defeat for those who hope to limit the impact of climate change. But Yale’s Daniel Esty, Hillhouse Professor of Environmental Law and Policy, said in a conversation with Yale Insights that there’s reason for optimism. The accord, Esty said, flipped the organizing principle for efforts to transition to a low-carbon economy, from top down to bottom up. So while incentives set by national policy are helpful, especially in an economy as large as the United States’, it’s action at other levels of government and within the private sector that may be most critical.


Q: What is the status of the Paris Agreement?

The Paris Agreement is rolling forward despite Donald Trump’s threat to the pull the United States out. Not only are countries across the world taking steps to fulfill the “nationally determined contributions” they announced at the time of the 2015 Paris negotiation, but they are cascading obligations and responsibilities down from national governments to state or provincial and city governments. 

Thousands of businesses across the world have also signed up to advance the Paris Agreement in their own industries and in their own way. This includes more than a thousand companies across the United States that are a part of the “We Are Still In” coalition that is effectively thumbing its nose at the Trump Administration’s efforts to pull back from the global consensus that climate change requires action. 

Q: Are other countries experiencing the same resistance to climate science that we’ve seen in the United States?

There are some other countries where there’s debate over how urgent the climate change problem is, but nowhere else has there been the same degree of climate denial as exists in the United States. It really is troubling that one of the most important countries to have engaged has had trouble getting a serious climate change response moving because of the political breakdown that pervades Washington. 

It’s important to note that the United States—despite what Donald Trump has said he wants to do—has not backed out of the Paris agreement, and cannot do so for two more years. So there is every reason to believe that the United States is going to continue to be part of the solution in lots of places and in lots of ways, despite the president’s intention not to be a participant in the global response to climate change.

And what is exciting—it’s especially true in the United States—is that people are no longer waiting for a national policy. 

Q: What’s driving the action?

Many governors, mayors, and business leaders across the country believe that the climate change problem is real and demands attention. So they are launching initiatives to reduce the emissions that they might be seen as responsible for and to advance adaptation agendas. They are thinking about how to engage their workers, in the case of companies, and citizens, in case of cities and states.  

One of the important things about that 2015 Paris Agreement was the overt recognition that the prior strategy of global climate change action centered on national governments being in charge, and being the ones doing the work, wasn’t working. The 2015 agreement shifted from a top-down approach to a much more bottom-up implementation strategy. I think this is one of the reasons to remain optimistic. 

It turns out that presidents and prime ministers have relatively little day-to-day control over the choices and policies that determine the carbon footprints of their societies. In many regards, mayors who run public transit systems, or governors who establish economic development policies, are much bigger players when it comes to the actual emissions for any particular country. 

The Paris Agreement helped galvanize lots of actors across the world—in particular, players that were not part of prior conversations. It mobilized them. It was very important in that sense, but now the work of these mayors, governors, and corporate leaders, and leaders of other institutions like university presidents and religious leaders, has taken on a life of its own, and there’s a growing recognition that when so many people are committed to transformation, particularly towards a clean-energy future, there is a lot of momentum that will carry us through the ups and downs of political challenges.

To offer a couple of examples, Arnold Schwarzenegger, the former governor of California, launched a group called the R20 which has rallied leaders of subnational jurisdictions to finance and implement climate resilient economic development projects. Likewise, Michael Bloomberg, the former mayor of New York, helped launch a group called the C40 to help mayors of large cities work together on the best city-scale responses to the problem.

“It turns out that presidents and prime ministers have relatively little day-to-day control over the choices and policies that determine the carbon footprints of their societies.”

Q: What are the key hurdles on the way to that transformed future?

One of the big ideas that emerged with great force coming out of the Paris Agreement of 2015 was the importance of focusing on innovation. By innovation I’m thinking not just about technology development, but innovation in incentives and policies and finance and public engagement. 

In past years there was too little conversation about where the money would come from to do the things that need to be done to have a successful response to climate change. How do we pay to build a clean energy infrastructure? Now, there’s a growing set of initiatives to address that finance problem, including things like the Green Bank that’s been set up in Connecticut and green bonds that are being issued by a significant number of banks on Wall Street and other money centers.

Q: What’s the role of the private sector?

Companies are going to play a very critical role in delivering a sustainable future. I think that almost everyone in corporate America now understands what I have called the sustainability imperative

A growing number of business leaders realize that they need to do the right thing year in and year out without regard to how the political pendulum swings, and certainly for companies operating in multiple countries, you can’t let any one county’s political dynamic determine corporate strategy. Companies that operate all over the world have been among the leading centers of momentum for climate change, and among the steadiest of players continuing to push toward a clean-energy future. 

Q: What’s the business case for leading on climate change?

The business community knows that it cannot succeed if society is failing, or if the planet is burning. I would say that the business environment and the marketplace of the 21st century—is going to be defined in part by climate change as a societal challenge. That creates a business opportunity as well as a potential threat. The opportunity is that companies that address their own climate change challenges may be in position to provide goods or services that address the challenges of their customers. They may find growing markets, improved margins, and better profitability. 

I think the reality has now dawned on many companies that the world is going to have to address climate change; it is going to have to decarbonize. Therefore, companies need to think about how they can be part of the solution and not simply seen as part of the problem. 

Q: Are investors pushing the issue? 

We already see the beginnings of investor concern about carbon exposure. There is a growing focus on what’s known as environmental, social, and governance metrics, sometimes abbreviated as ESG. There’s also a rising demand for clear metrics on sustainability targets broadly and climate change action in particular. Increasingly, mainstream investors, not just the small number that are particularly environmentally focused, want to have sustainability performance spelled out in a verified way, since ESG needs to be factored into their investment decision-making. And they want to have their own capital deployed in a way that leans toward, rather than away from, a sustainable future. 

Q: Are there actors that are part of shifting the dynamic but are often overlooked?

The Pentagon has been a very vigorous thought leader with regard to how to take action on climate change. They do it because it’s important to national security and the military’s war-fighting capacity. 

It turns out a significant amount of effort in any war is devoted to moving energy to the troops on the front lines. If they can develop new technologies that reduce the energy flow to the battlefield, that’s a big deal. So the Pentagon has worked with great vigor and creativity on climate change and clean-energy opportunities for more than a decade.

Looking globally, China has shifted from being foot-draggers to being much more serious about addressing climate change. China was very constructive in getting the Paris agreement finalized. The Chinese leadership has concluded that what they would need to do to address climate change is very much the same thing that they need to do to address the rising problem of air pollution in Chinese cities. That means there a big domestic logic for having a major focus on climate change. Delivering reduced greenhouse gas emissions will deliver reduced air pollution. 

Q: The Trump administration’s stance on climate change and the Paris Agreement gets a lot of attention. Are there ongoing meetings and events that are worth mentioning? 

Just in the near term, there are a number of important climate-change events upcoming. There is a climate summit that California Governor Jerry Brown is hosting for leaders from across the world. There’s also Climate Week in New York City that happens along with the opening of the UN General Assembly each September. 

I think these events will demonstrate that leadership in the political world is not just national leadership, it’s state and local leadership as well, and it’s been inspiring to see what governors and mayors across the United States have done to ensure that their cities or their states are seen as helping to move the agenda forward. 

It’s also going to vividly demonstrate the new reality of the Paris Agreement commitment to broader engagement. We will see hundreds of different strategies that are unfolding in all levels of government, educational and religious institutions, as well as the private sectors. 

Beyond those events, in the end of November, the annual conference of the parties to the Framework Convention on Climate Change, the original 1992 climate change treaty, will take place in Poland. There’s an expectation that world leaders will signal that the momentum for action continues, despite a few places, most notably in the United States, where there has been an attempt to pull back. The very density of the new fabric of the response to climate change is very exciting.

Hillhouse Professor of Environmental Law and Policy, Yale School of Forestry & Environmental Studies; Former Commissioner, Connecticut Department of Energy and Environmental Protection