During a sweltering rally in Las Vegas on Sunday, June 9, former President Donald Trump complained to his supporters about “sweating like a dog” in the triple-digit heat. Because climate change is breaking temperature records all over the world, one might have assumed that the aspiring leader’s next act would have been to express concern for the other people at his event.

Instead the Florida man told the attendees — ostensibly as a joke — that they needed to stay alive just long enough to cast their ballots for him.

“We need every voter. I don’t care about you, I just want your vote, I don’t care,” said Trump. Six people from the rally were later hospitalized for attending.

One person who definitely did not laugh at Trump’s joke is John Kerry. A former United States Senator and Secretary of State, as well as the Democratic presidential nominee in 2004, Kerry’s most recent job was as the first U.S. Special Presidential Envoy for Climate. A longtime environmentalist, it made perfect sense for President Joe Biden to tap Kerry for this role, especially as Kerry and his wife Theresa Heinz Kerry co-authored a determinedly optimistic book warning about climate change, “This Moment on Earth.”

In the 2008 book, the Kerrys spoke with ordinary Americans from all walks of life about the differences they were making to protect the environment. More than a decade-and-a-half after its publication, Kerry told Salon that he still firmly believes in the hopeful vision laid out in “This Moment on Earth,” and does not share the view of anti-capitalists that more radical measures are necessary.

At the same time, Kerry expressed tremendous alarm about the prospect of Trump winning the 2024 election. Trump’s advisers have already announced their backing of a broad-reaching right-wing policy plan called Project 2025; if implemented, Project 2025 would gut environmental regulations and place science deniers in positions of power over climate policy. That is no doubt the foremost reason that Kerry spoke to Salon.

“This is really as big a fight as you get in an election,” Kerry said during our conversation. “And I hope young folks all around the country who have the energy and obviously the vision and the passion to put themselves on the line for this must make it one of the real top voting issues of this next election.”

This interview has been lightly edited for clarity and length.

During a recent rally in Las Vegas, Trump told audience members who are suffering from the climate change-exacerbated heat that “I don’t care about you, I just want your vote.” Now he says that was a joke. But do you believe it can be dismissed as just humor given his ongoing denial of climate change?

It is remarkable, narcissistic, even if it was a joke. It Is just all about him. It is never really about them. Never really about people, and certainly never really about a serious issue like the climate crisis, which he denies, which he is at the forefront of trying to dismiss.

He met recently at Mar-a-Lago for a dinner fundraiser with a bunch of oil and gas people. He just looked at them and said, “I’m your guy for drill, drill, drill” and “If you want the things you need, you gotta raise a billion dollars for me.” He literally made an open quid pro quo demand of people! He is one of those people spreading lies, not only about the election, but about climate, about wind turbines supposedly killing people and giving you cancer.

Here are these people sweltering in a 100-plus degrees — something like 102, 103 degrees — everywhere is hotter and more dangerous. He is living at that moment in the middle of a very significant manifestation of how bad things are getting … and he’s making a joke about it. It really tells you all you need to know about him.

There is so much, it’s hard to keep up with all the negatives, but I think that everybody knows because he’s the guy who pulled out of the Paris Agreement, which did great damage to the reputation of the United States and slowed down the transition to clean energy in America. Everyone knows that he doesn’t care about the issue, and he doesn’t care about people. He cares about himself. What we need to do is get more facts out there so that people can embrace, at the foundation, of why they need to be moving in a different direction.

The reality is that this is a very dangerous time on a global basis on a number of issues — i.e. the challenges to democracy itself in Ukraine, Russia, China. There are a host of really big challenges right now, but one of the biggest is that not enough attention is being paid the unbelievable damage being done in many parts of the world as a consequence of the increased warming. I just was looking today, when I was getting up, it was raining massively down in Florida, and they had more water in the span of a day or so then they normally get in something like a millennium.

Joe Biden promised he would rejoin the Paris Agreement within hours of being sworn in. He did that. He created this new position of special presidential envoy. He set America on a path to increase our own ambition here at home, and try to reduce our emissions, which we have done last year. The emissions of our country lowered by 4%, and the economy grew by 2.5%. So that puts the lie to Donald Trump’s distortion suggesting that it’s going to hurt our economy to make this transition. The fact is that the fastest growing jobs in America have to do with clean energy, and there is now more money going into clean energy, creating more clean energy jobs, than there are in fossil fuels. So everything that he seems to say about this, either evinces a massive misunderstanding or a massive distortion.

Either way, we can’t afford four years of that.

One of the stories from your book “This Moment on Earth” that I feel is really inspiring from that book is Rick Dove, the retired Marine and Vietnam veteran who became a Riverkeeper on the Hudson River. It speaks to how a lot of Americans, at least at that point, embraced environmental issues, even if they didn’t want to be identified with the term “environmentalist.” Looking back 16 years later, do you feel that humanity’s understanding of these issues is better, worse, or about the same as when you wrote that book?

I think without any question — without any question — humanity’s understanding of the issue has grown markedly, not the least reason for which is Mother Nature herself is sending daily messages like the kind I just described down in Florida. All over the world, people are suffering the consequences of the increased warming. You could look in India where it nearly reached 50 degrees Centigrade [122 degrees Fahrenheit]. I predicted, frankly, just about two and three months ago, I said, “Look, we’re going to have somewhere in the world where we’re going to be cracking 50 degrees.” It’s only June and we’re already doing that.

The implications on the planet for everybody — farmers in South Dakota, in Minnesota, Wisconsin, anywhere around our country — are finding that their crops are behaving differently, are growing differently. There are water challenges. There are fire challenges. There is drought. There is too much water when you have these flooding rains, and that comes from the fact that the ocean is warming, because 90% of the heating of the planet goes into the ocean.

As the ocean warms, there is more and more moisture that goes up in the atmosphere as it travels around. It dumps this massive amount of moisture in the form of these bomb blast rainstorms, and people suffer for it: flooding, dying and fires. People are dying. The quality of air is taking the lives of about 7 million people a year around the planet because it’s so bad. People get lung cancer. People with emphysema or other problems with breathing, like COPD, have much more increased and repetitive health incidents. I think there is a massive new awareness in the world, and there are more and more activists too.

People like Rick [Dove] and others are trying to do things. The problem is many people are feeling a sense of helplessness because they work like hell to try to make things happen, and then you have somebody going out doing something that’s massively damaging in one form or another. I’m encouraged that people are aware of that. Regrettably, supposed leaders are not leading, and I’m talking about people in the other party.

For instance, the IRA — the Inflation Reduction Act, which is one of the most important and consequential pieces of legislation in a long, long time and has had a major impact in growing the response to the climate crisis – not one single Republican voted for that in the House or in the Senate. That’s just crazy. You can’t politicize this issue. You’ve got to humanize it, and respond to the crisis that humanity is facing in a broad base. I think more and more people are aware of that, and more and more people are frustrated that they’re not responding.

Now, one quick addendum: Some people say climate doesn’t poll very high. A lot of people aren’t picking it as the first issue in their minds. That’s true, and they don’t, but that’s because the first issue on their minds is their job or their income level measured against inflation. People are anxious to respond to that, but at the same time, one of the single biggest threats we face globally — every country on a shared universal basis — is the crisis of climate, which is going to cost many lives and cost many more billions of dollars in cleaning up the mess or responding to the crisis in an emergency, rather than responding to it in an orderly, thoughtful, constructive way that builds out the infrastructure we need to be able to not only withstand the current level of storms, and of dangers, but also to avoid some of them in the long term.

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There’s a spectrum of debate within the Democratic Party on these issues, with some like Rep. Alexandria Ocasio-Cortez (D-NY), who strongly criticize capitalism as a system, as well as Sen. Bernie Sanders (I-VT). They argue that climate change is proof that capitalism fundamentally has failed. What do you and President Biden think of this point of view? 

First of all, President Biden and I both share a deep sense of the genuine concern and the passion of AOC and of Bernie to try to deal with this issue, but I think that capitalism can contribute in a number of different ways. Capitalism can provide some of the solutions to the crisis.

Right now, the rate at which the solar industry is growing, the rate at which the wind turbines and wind farms are being deployed, the rate at which new technologies are coming online like hydrogen, green hydrogen, better electrolyzers to make that hydrogen, the chase for clean energy by looking for some newer technologies that might make a difference — like battery storage is getting longer — the motive to try to come up with a good product that could sell and make a positive difference to people’s lives is very strong, even within some of what happens in capitalism.

There is always a robber baron capitalism that unfortunately haunts the economic structure. That’s been true since the first days of human beings. But that’s something we can control if we want to. That’s something we could do something about, and it’s something we do something about when we get the interstate commerce regulation to be on the side of consumers, or we get new products that are protected, or require seat belts in cars — just to pick one sort of idea that was put in place years ago. There was a big fight, I mean a really big fight, as people resisted doing that.

We as citizens in a democracy have to make sure we’re dominating the playing field with our actions, with the laws we’re passing, with the vision and the values that we’re putting in place to protect people. We did that with smoking, but when we banned smoking on airplanes, it took us a real huge fight, and these things shouldn’t be that hard a fight. I’m very sympathetic when Bernie and AOC express a frustration with the system where too much money often gets into the system and prevents good things from happening, or it takes much longer than it should. That’s the downside and the bad side of it. But the upside and good side of it is that we’re able to cure a disease, or we’re able to put a drug like Paxlovid in order to deal with COVID.

If you look around you, you’ll see this sort of balance driving it. But I share the anger and frustration that comes about because there are these powerful vested interest forces that resist the propagation of good regulation, of good restraints to bad behavior. But I don’t think it’s automatic that it has to happen. If you have good people with good laws and good accountability and good transparency and good prosecution, you can create a balance that works pretty effectively.

More than targeting capitalism per se, put the focus on the denial and on the delay, and on those who are being swayed by those vested interests that only want to make more money and ignore the consequences of some of the choices that they make. That’s a reality. And so I think that if we could get people to face up to the truth and to put the truth more in circulation and to honor that truth, we’d be a lot better off.

What are the consequences in terms of climate change if President Biden loses to Trump, especially if Project 2025 is implemented? 

The consequences of Project 2025, if they were implemented, would be absolutely unimaginable and destructive. It would cost an enormous number of lives and would have gigantic long-term consequences for the planet itself.

That is not hyperbole. I say that because we know exactly what Donald Trump tried to do the first time, and Project 2025 is specifically geared to make sure they can do what they didn’t achieve in the last round, and that they can put the people in place who they know are absolutely committed to this destructive path. This is really as big a fight as you get in an election, and I hope young folks all around the country who have the energy and obviously the vision and the passion to put themselves on the line for this must make it one of the real top voting issues of this next election.

Remember, Donald Trump pulled out of the Paris Agreement. Donald Trump took all the money out of a lot of climate activity. He never proactively led efforts, which is another role of the presidency. It’s not just to propose something, it’s to lead. It’s to mobilize people to actually get something done. And he was a counter-mobilizer. He tried to undo things — pulling out of the Iran nuclear agreement, pulling out of the trade agreement which had America putting its best, the gold standard, the way we think people should do business on the table, and leaving nothing in its place.

Now there is one other reality though about this, if Donald Trump were to win: The marketplace has now made big decisions based on the reality of the climate crisis. Ford Motor Company, General Motors, Mercedes, BMW, Volkswagen — you run around the world to the automobile manufacturers, they have spent billions of dollars retooling their factories in order to produce electric vehicles. I absolutely guarantee you, they are not suddenly — because a president might be changed — going to go back and say, “Oh, okay, let’s undo all the changes we made in our factories, and how we ought to reproduce. We ought to go back to producing internal combustion engine cars.” That’s not going to happen.

There are a lot of practical, real reasons why it’s not going to happen. First of all, the largest marketplace of the world, which is on a global basis, is not even going to think about that. They’re going to produce electric vehicles. And in order to be competitive, in order for the United States to be able to win the economic battles, we’re going to have to have products that are competitive with the other ones that the rest of the world wants and is ordering and making.

Believe me, the other automobile manufacturers of the world would be laughing to the bank, although they’ll be sad for the climate from a business point of view. Donald Trump would destroy American competitiveness in this new industry. I think the market just isn’t going to let that happen, so in addition to the power sector, people likewise want clean electricity. Companies themselves have made commitments to try to achieve net zero by 2050. They’re not suddenly going to turn around and adopt policies that will undo their ability to be able to do what they know they need to do, as a matter of good business, as a matter of corporate citizenship, but also because they’ve got kids and grandkids and they don’t want to leave the world in a worse place than it is today, which is where it’s heading to some degree.

I think Donald Trump would have a critical negative impact on decision-making and on the deploying of things. That would slow some things down. But he can’t undo this direction that has been adopted by the marketplace of the world.

What has President Biden done to address climate change compared to the changes that scientists say are necessary? One example that comes to mind is I’ve interviewed scientists who believe that there should be a declaration of a climate emergency. What are your thoughts on that? 

The president is evaluating that very closely. He has done more than any president in the history of our nation to move the needle to the place it needs to be in order to respond to the climate crisis. Within hours of being sworn in as president, he rejoined the Paris Agreement. On that same day, I took my oath of office as the first U.S. Special Presidential Envoy for Climate.

Under President Biden’s instructions, we began robust diplomacy on a global basis to bring people to the table to raise their ambition to reduce emissions. And it worked. We did it. The president hosted a major climate summit of the 20 largest emitting nations in the world, the 20 largest economies, and we wound up getting Russia, China, India, a whole bunch of countries to raise ambition on a global basis.

In addition, the president passed this most significant legislation on the climate in history. The IRA has had more impact at creating new jobs, new industries within the climate sector in an effort to try to reduce emissions than any legislation before. He also passed a $1.2 trillion infrastructure piece of legislation. He personally went to each of the Conference of the Parties (COP) meetings of the last years — excuse me, I misspoke on that, he was not able to come, but he sent a massive group of people to come to Abu Dhabi — and it resulted in probably the strongest outcome of a COP since the very beginning. This was on a par with Paris.

It had a major impact because that resulted in the declaration that all of us need to transition away from fossil fuels. We need to be accelerating it in this decade. We need to be laying out our plans to hit 2050 net zero, and we need to do it according to the science. Everything we do needs to follow the science, and that means holding the Earth’s temperature to 1.5 degrees [Celsius.]

Here is the best way to measure it: When I came into office, when President Biden was sworn in and came into office, the world was headed to about four degrees of warming or more. That’s where we were going, to 3.7 to 4 degrees [Celsius] of warming. Now, because of the measures we have taken in the last three years, the International Energy Agency tells us that if we did everything we have promised, everything laid out at each of the COPs since Paris, we would be at 1.7 degrees of warming instead of heading towards 2.5, which is where we are.

So what is the difference? The difference is that not everybody is doing what they said we should do. Not everyone has implemented or is implementing to the full measure necessary. So we know we can get there. We know we could win the battle, but we also know because too many countries are still dependent on coal, they’re not transitioning fast enough, and we have to continue to lead the effort to get them to transition fast.

It’s sort of like the frog being boiled in the pot. As you bring the heat up, the frog is not aware of the impact, and then boom, it’s too late. What we’re witnessing is a kind of frog effect on a global basis where we’re in the cauldron and it is getting hotter, and if people don’t take seriously the consequences to the human body of being outdoors in that extreme heat, it can have profound health impacts — including dying.

It does every year. We lose human beings who don’t or can’t take care to protect themselves from being out in that extreme heat — if you’re not getting enough water, if your body isn’t able to replace the sweat that you put out and you literally overperspire. Unfortunately, I don’t think it’s just at a rally that this is something to be concerned. It’s everyday life everywhere where you’re having that kind of heat. Last year, it was over 110 degrees for 31 straight days in Phoenix, Arizona.

Now we’re seeing much greater heat levels in every part of the planet today, including in the Arctic and the Antarctic, where both are melting at record rates, and the two poles are the fastest heating. They are warming faster than any other part of the planet, so the massive loss of ice, which is melting and flowing into the ocean, which is creating its own challenges to ocean life, has real consequences for all human beings. People need to understand the connections. You have to connect the dots for all of these things. The climate crisis is also a health crisis, and people need to pay very close attention and learn more about the consequences of extreme heat.

Is there anything about climate change and the future of humanity that you think people need to know more about?

Responding to the climate crisis does not require that everybody give up things they love to do or having a high quality of life, or that your job is going be under pressure. On the contrary, responding to the climate crisis is the greatest economic opportunity that we’ve had since the Industrial Revolution in the 1800s. We’re going to see new products, we’re going to see cleaner air. It will be safer for people. Their health will be better.

The upsides of this transition are extraordinary, and we should be embracing it and moving faster in that direction because it’s going create a massive amount of new economic activity, new products, and all of those products are going to be products that have a sustainable life if they do it properly.

I see the upside of this. The downside is where Donald Trump and his friends are, who don’t want to do something about the climate crisis. They’re going to wind up costing everybody else a lot more money, and they’re going to wind up costing lives. That’s the measure here. It seems to me, practically speaking, that most Americans know that it makes more sense to opt in the direction of addressing the climate crisis and getting the benefits of a safer, cleaner, healthier world that we live in as a consequence.