On a Friday morning in April, Dan Stein, the founder of Giving Green, a climate philanthropy organization, found some big news in a surprising email. An anonymous donor had given his fund $10 million.

“I didn’t quite process the number of zeroes,” Stein said, adding he was “tickled, awestruck, surprised” by the gift.

Giving Green collects donations and disperses them to a handful of nonprofits that it believes have the potential to make a significant difference in preventing climate change and reducing the emissions of greenhouse gases. The $10 million donation is by far the largest single gift the nonprofit has ever received and it essentially fell out of the sky without warning.

The mystery gift went to Giving Green’s fund, which is housed at Giving What We Can, an organization inspired by effective altruism that asks people from all over the world to pledge to give away a percentage of their income or their wealth each year. The donor is anonymous with the gift coming from a donor-advised fund at Fidelity Charitable.

“At first, they also were nervous that it was a mistake, and they went back to Fidelity to verify it before they told us,” Stein said of Giving What We Can.

Looking back at their records and speaking with organizations they recommend, Stein and his team think the same donor may actually have given as much as $17 million more directly to those organizations in the last two years. Because the gifts are anonymous, it’s impossible to confirm, but Stein says the timing of the gifts, which came in two clusters, suggests they could have come from the same person or organization.

Fidelity Charitable said it does not comment on specific grants or donors.

Anonymous donations — even large ones — are not unusual, but such gifts are generally the work of behind-the-scenes relationship building, said Tory Martin, director of communications and strategic partnerships at the Dorothy A. Johnson Center for Philanthropy.

“Most of the time, if you’re getting millions of dollars, stewardship has happened. Cultivation has happened,” she said.

In general, giving anonymously is often perceived as the highest form of giving, with a donor deflecting attention from themselves, Martin said, adding the donor thinks “I’m doing this out of a sense of creating a better community and simply saying that this money should go towards other uses rather than sitting in my pocket or my bank account.”

But for any individual nonprofit, receiving an anonymous gift can present reputational risks if eventually the donor is discovered to be controversial.

Stein has no good leads on the mystery donor’s identity, though he doubts it is a corporation trying to greenwash donations since it wouldn’t get any public credit for the gift. He sees the donations as evidence that there are donors who want to give to climate change but don’t know where to donate. Providing highly researched recommendations is the reason he started Giving Green.

One recommended organization, Industrious Labs, advocates for decarbonizing heavy industries like aluminum and steel. Evan Gillespie, a partner at the organization, said those industries are often wrongly thought to be the hardest to abate. Giving Green reached out directly to them for what turned out to be a long vetting process that ended with Giving Green recommending them two years in a row.

“You have to make this leap of faith that, ‘Okay, we’re going to open up our most private thoughts about how this is going to work,’” Gillespie said. He credits Giving Green’s recommendation with providing a couple of million dollars in funding to them, which crucially is unrestricted.

On its website, Giving Green explains why they decided to recommend donating to Industrious Labs and its other partners and include detailed information about their campaigns, theory of change and future plans. Giving Green says its methodology is inspired by the tenets of effective altruism, a philanthropic social movement that grew out philosophy departments in the United Kingdom in the 2010s.

Proponents say they seek to maximize the good they can do in the world and give to what they calculate are the most effective charities and interventions. Some powerful and wealthy donors, especially from the technology sector, have embraced effective altruism and poured funding into areas like mitigating the potential worst impacts of artificial intelligence, preparing for pandemics, global health and animal rights.

Many effective altruists also pledge to give away a portion of their incomes while others have argued for the morality of earning as much money as possible in order to give it away.

“We think that the climate problem is an incredible generational issue and we think that we, as a society, should be doing things to stop it,” Stein said. “And that one thing that people can do is make donations, and that they should be trying to make those donations in an effective way.”

Charitable giving to climate change related issues has increased in recent years, though research from the nonprofit ClimateWorks shows it still remains a small portion of overall giving. ClimateWorks tracked $3.7 billion in philanthropic giving from foundations in 2022 to support reducing the impacts of climate change or adapting to those effects. Major gifts by individuals likely represent another $4.2 billion to $9 billion in 2022, though it is more difficult to track, ClimateWorks reported.

The National Committee for Responsive Philanthropy argues more funding should go directly to communities most impacted by the effects of climate change now, rather than to thinktanks or national environmental organizations. They also warn that investing in technologies that will take years to develop are “false solutions.”

“What movement groups have been saying is ‘System change, not climate change.’ And often when you’re looking at things that are cost effective, you are still thinking through things in an extractive mindset. Like trying to protect your bottom line. Save your funds for a rainy day. Only give as much as needed,” said Senowa Mize-Fox, the movement engagement manager for climate justice at NCRP. “Ultimately, what we always say is, the rainy day is here. The rainy day has been here. The climate crisis is happening right now.”

Stein said Giving Green intends to disperse the vast majority of the $10 million gift as soon as possible, with much of it going to the organizations they recommend. They’ll also direct smaller amounts to new organizations or programs within organizations that they support but aren’t ready to include in their top recommendations.

Associated Press coverage of philanthropy and nonprofits receives support through the AP’s collaboration with The Conversation US, with funding from Lilly Endowment Inc. The AP is solely responsible for this content. For all of AP’s philanthropy coverage, visit https://apnews.com/hub/philanthropy.

—Thalia Beaty, Associated Press