Last week, I wrote about the hundreds of American scientists who are thinking about running for office in the wake of Donald Trump’s election and inauguration. They’re looking to address a lack of scientific representation in government, to counter misinformation about issues like climate change and vaccinations, and to stand up against potential threats to funding and communication. In the words of Frances Colón, former Deputy Science and Technology Adviser to the Secretary of State, “many more scientists are realizing why their voices are needed.”

For Andrew Weaver, these are familiar emotions.

For most of his life, Weaver was a climate scientist. His name was on more than 200 scientific papers. He edited one of the top climatology journals for five years. He was a lead author on the 2nd, 3rd, 4th, and 5th scientific assessments from the Intergovernmental Panel on Climate Change (IPCC)—the reports that have repeatedly updated the world on the impacts of climate change.

But in 2013, he abandoned academia to run for office, as part of the Green Party of British Columbia. And he won, beating his rivals by a substantial margin, and becoming his party’s first ever provincial Member of the Legislative Assembly. He now leads the party, and is headed into another election in May.

I talked to Weaver about his experiences moving from academia into Parliament. An edited transcript of our conversation follows.

Ed Yong: Why did you decide to leave climate science for politics in 2013?

Andrew Weaver: In 1979, when I graduated from high school, the National Academy of Sciences put together a scientific assessment of what will happen if you double carbon dioxide levels. It pointed out that the best estimate was 3 degrees of warming, with a range of 1.5 to 4.5 degrees. In 1988, I was a postdoc in Australia and the IPCC was set up. Its first report said that the best estimate was in the range of 1.5 to 4.5 degrees. I took part in the 2nd, 3rd, and 4th versions. The 4th was published in 2007; there had been tens of thousands of papers, and the best estimate was a warming of 2.5 and 4.5 degrees.

By 2013, there had been 34 years of assessment, and the single most important metric of our collective understanding of how the world will warm hadn’t changed. At some point, one has to question whether we need more science to deal with this problem or whether we need political will.

But many politicians see politics as a career path, so getting re-elected becomes a top priority, and you make promises about what happens in the short term. Decision-makers today won’t see the consequences of their decision in their political lifetime, but those decisions have a profound effect on the environment that future generations have to live with. So the entire issue of global warming is one of intergenerational social equity. Do we care about what we leave behind, about future geopolitical stability, about other species?

I’ve lectured on this a lot and people would say: Politicians are all corrupt. I would argue: That’s what we got. You don’t like them, run yourself. Find someone you can get behind. But there’s only so many times you can do that.

When I was finishing the draft of the 3rd IPCC report, I was asked by the leader of the BC Green Party to run. I said no. Then, I said no again. And again. I think I said yes on the fourth time.

Yong: Why?

Weaver: From 2007 to 2009, I had been involved in British Columbia’s Climate Action Team. Gordon Campbell, the leader of the British Columbia Liberal Party, recognized that climate change was an issue that needed to be dealt with, and an enormous economic opportunity. He put in a suite of policy measures like an innovative carbon tax.

But in 2009, the British Columbia New Democratic Party planned to remove the tax as part of a cynical “axe the tax” campaign. And in 2010, Campbell was replaced by Christie Clark who campaigned to bring liquefied natural gas back to British Columbia, threatening to dismantle a lot of Campbell’s climate leadership. We had a two-party system and no one was doing anything. That’s why I ran with the Green Party.

Yong: What was your platform? Was it solely an environmental one?

Weaver: We based a lot of campaign literature on evidence-based decision-making. I ran on principle, honesty, saying what I believe in rather than people wanted to hear, and representing constituents not corporate interests. I ran with a party that had never elected anyone in any province anywhere in Canada to the legislature. We had one federal Member of Parliament but no provincial one. Polling historically had the Green Party of British Columbia at 6 percent of the vote. But I got 40 percent of the vote in Oak Bay-Gordon Head, which was one of the most conservative ridings in British Columbia. People are ready for authenticity and are sick and tired of the political establishment just doing things for themselves.

Yong: Did your success motivate more scientists to run for office?

Weaver: I’m now leader of the Green Party of British Columbia and I’m running again because there’s been such enormous growth in support of our party. We’ll have 5 scientists who will run in the next elections and have PhDs—in chemistry, physics, environmental sciences, and medical sciences. I don’t know of any other scientists running in the other parties.

Obviously, we don’t want to have 85 candidates who are all scientists, but it’s nice to have more than one. We have a lot of lawyers, and in law, the person with the best argument wins. But in science, the person with the best evidence wins. I think the public is ready for a more bottom-up, evidence-based approach to decision-making. And as a scientist, I’ll argue my case passionately, and I’ll hope that I’m right, but if I find evidence that I’m wrong, I’ll switch and do something different. We need more of that in politics.

Yong: Okay, give me one example where you changed your mind on a policy matter because of new evidence.

Weaver: Here’s one. In British Columbia, we’re building the Site C dam. Back in 2010, I was a strong proponent for it. I advocated for it. It was hydropower that was going to displace fossils fuels. But the new evidence is that since then, the power demand in British Columbia hasn’t increased, the price of wind and solar has plummeted, and the price of dam construction has gone through the roof. It would be economic folly to build Site C. And when we build it, we’re going to have a massive glut of power that we’re going to have to sell to the US, which will kill out clean energy sector. Now we’re wasting taxpayer money on this monolith.

Yong: In my last piece, one of my sources—a scientist and former congresswoman—said that she never felt like she understood people better than when she went round knocking on doors and talking to them as a politician. Did you also find that? Did you experience any culture shocks when you moved out of academia and onto campaign trails?

Weaver: I’ve never been an ivory tower person. I coach soccer. My friends are plumbers and electricians. My parents lived in poverty, and my mother was a refugee immigrant to Canada. So I didn’t find a shock on the doorstep, and I didn’t find it difficult to make the transition at all. The politics I deal with now are far easier than what I had to deal with in the university system. Henry Kissinger once said that politics in university is so vicious because the stakes are so low—and it’s true. It’s very passive-aggressive. In the political realm, people are more aggressive; you know what people think because they’ll tell you.

Yong: It seems that many scientists feel that science is above politics, or at the very least, distinct from it. Did you have to contend with that attitude when you ran for office?

Weaver: I received a lot of support from the climate science community, because they’ve been under attack for quite some time. But there are other colleagues in other fields who had that attitude. I don’t tolerate it. To think that science is above politics is an elitist attitude that has no place at all in a 21st-century economy. You’re looking down at the will of the people. Every single one of those scientists is getting their money from the taxpayer. They have a responsibility to tell the taxpayer how their money is being used. I tell my colleagues that the average person has no idea what you’re doing, and you better get engaged. If you don’t your funding will be gone. That what we saw at the federal level here—a complete collapse of funding.

Yong: What do you make of the influx of American scientists who are contemplating a move to politics in the wake of the recent election?

Weaver: I don’t want to wade into U.S. politics. But based on what I’ve been saying, you have very big issues to deal with and science is the least of those. The kind of post-truth approach is making America irrelevant on the international scene. People are asking what has happened to the great country that we know. So to those scientists, I say: Good on you. I say good on you. Continue forward, and you’ll enjoy it when you get in. It’s the most rewarding profession you can have.

Yong: Wait, it’s the most rewarding profession you can have? More than being a scientist?

Weaver: Yes. As a scientist, you get excited about little things. When I got my first paper published in Nature, I was over the moon. But that pales in comparison to the satisfaction you get when you can make someone’s life a little better. In science, we pursue knowledge so society can have a better life, but incremental advances of knowledge are more abstract. In politics, it’s immediate. You see it in people’s faces.

Yong: Would you ever go back to science?

Weaver: I never believed that politics should be a career path. In February, I’ll be proposing term limits for politicians in British Columbia, and I would only run a third and final time. I’ll have my job at the Unvieristy of Victoria, but it may be that my role will be less to conduct experiments or modeling and more of an administrative role. It would be tough after being out for 8 to 12 years to get to the forefront of the field again. And I think it’s time for new ideas and new people.