“We’re now at a stage where we have to get this done, and that is up to business,” Steyer told Fortune. “Businesses’ function is to serve the needs of society and get done what is needed.”

After his Democratic presidential campaign, Steyer returned to his roots as an investor. He cofounded Galvanize Climate Solutions, alongside longtime investor Katie Hall.

Galvanize’s venture arm has invested in early-stage companies including Watershed, a carbon accounting firm that tracks carbon emissions for companies like Spotify and Walmart. The firm also invests in publicly traded companies and sustainable buildings.  

In September, 59-person Galvanize closed a $1 billion fund focused on growth and equity investments. A representative for Galvanize declined to disclose how much the firm had in assets under management. When asked to share what the firm’s returns have been so far, Steyer said it was too early to tell since it hadn’t sold any of the companies it invests in.  

Ordinarily an investment firm specializes in a certain type of investing like venture capital, which targets startups, or private equity, which acquires stakes in existing businesses before reselling them later. But Galvanize is interested in all manner of investments so long as they may alleviate some of climate change’s dangers, meaning that Steyer has opted to work within the system. “We don’t have the time to change American finance,” he says. “Is American finance perfectly set up to address the climate? No. But that doesn’t matter.”

Climate change represents a significant opportunity that will make investing in green technologies very lucrative for savvy investors, Steyer said. Investing in clean tech and renewables may seem like easy money, given the widespread negative impact of climate change, but it’s left some of the biggest investors badly bruised. Kleiner Perkins, once the gold standard of venture capital firms, invested some $630 million into green startups more than a decade ago that ended up either flopping or taking years to yield any returns, for example. 

“We have to win in capitalism, not because it’s nice, but because this is where the opportunity is, this is where the returns are,” Steyer says. 

When he first started advocating for climate investing, it was met with a tepid reaction, he recalls. “I certainly went to Wall Street conferences, and talked about investing along these lines in 2014 or 2015,” Steyer said “People really didn’t believe in it.”

Although business must play a big role in tackling climate change, Steyer is clear that the problem can only be addressed with government help. The public sector has a critical role in shaping policy, which he says “definitely still matters,” and in providing much of the early funding for research into new technologies and infrastructure. However, the private sector must ultimately bring those technologies to market. 

“Businesses scale, and we need that kind of scale,” Steyer says. “We need it to be profitable—and it’s going to be incredibly profitable. We need that to happen, and I want to be one of the people pushing that… We’re at the execution phase.”

Last year, Congress passed one of the largest spending packages ever for climate change with the Inflation Reduction Act (IRA). The new legislation earmarked $390 billion for climate-related spending including $14 billion for the Environmental Protection Agency to reduce greenhouse gas emissions; $12 billion for the Department of Energy to expand loans for the U.S.’s power grid; and a $7,500 tax credit for certain models of electric vehicles. 

“There’s going to be important research done that’s funded by the government that is done in schools and labs, and research facilities around the country,” Steyer says. “But all the part about turning that into a commercial, globally impactful organization will be done by private enterprise. That’s how it works.”

Steyer has been involved in politics for years

Steyer has long been a big-money donor to climate change causes. In 2014 he started NextGen Climate Action, a political organization that spent around $100 million in the 2014 election cycle to advocate for policies to address climate change. His political donations were so influential he is credited with playing a major role in helping elect former Virginia Gov. Terry McAuliffe by spending $11 million on his campaign in 2013, according to the New York Times. In that article he was referred to as a Democratic version of Charles and David Koch, the brothers whose political contributions have helped shape the Republican Party. 

In 2016, Steyer continued his efforts by spending $25 million on a campaign in seven battleground states to encourage young people on 200 college campuses to vote. He called it the largest youth voter outreach program ever. Steyer remains an influential donor to Democratic campaigns. President Joe Biden reportedly held a fundraiser at Steyer’s San Francisco home. 

By 2019, though, Steyer, no longer content to work behind the scenes of political power, decided to become a candidate himself. In July of that year he announced he was entering the Democratic presidential primary and, in particular, influenced Democratic candidates to talk more about climate change, which was “getting very short shrift” during the race. “A lot of times people think the debate is about positions,” Steyer says of the primary race, in which he spent at least $125 million of his own fortune, according to Bloomberg. “That’s not true. The debate is about priorities. The president can deal with a very small number of things and I honestly felt as if this [climate change] had to be elevated.” 

For the most part Steyer feels he succeeded in his goal of helping to make Joe Biden focus more on climate change in his winning campaign. “When he [Biden] originally started, it was a tangential part of his campaign. But it became a central part of his campaign and central part of his winning because I think that was a big part of his success with people under the age of 35.”