Michael Bloomberg tends to avoid the press. The New York City mayor turned climate advocate is not a regular guest on cable news. But having helped close more than 300 coal-fired power plants in the U.S., cut New York City’s emissions by nearly 20%, and contributed more than $1 billion to climate action, he has a story to tell.
In 1981, Bloomberg launched what would become a media empire by providing data that informs financial decision-making. During his three terms as New York City mayor, from 2002 to 2013, he applied that same data-driven approach to advance pragmatic solutions on a wide range of issues, from crime to public health—even if, at times, that approach put him out of step with politics.
Since leaving office, he has brought the same thinking—and that billion-plus dollars—to climate change, with unmatched results that have accelerated action in the U.S. and around the world—supporting everything from stopping air pollution in the Deep South to protecting ocean ecosystems.
In the U.S., one of his most successful efforts was also one of his earliest. Beginning in 2011, he funded the Sierra Club’s Beyond Coal campaign, which called for the country to accelerate its move away from coal-fired power. His contributions, which totaled in the hundreds of millions of dollars over the following decade, helped pay lawyers and campaigners to advocate in city halls and courtrooms across the country for the closure of coal-fired power plants. Those efforts—combined with cheap natural gas and renewable energy—have helped push coal to just 15% of electricity produced in 2024, down from over 40% in 2011. “It really has been one of the most rewarding projects I’ve ever been involved in, and it would be hard to find a better return on investment,” he said in 2017. The campaign was so successful, he expanded it with Beyond Carbon, to advance the clean-energy transition, and Beyond Petrochemicals, to prevent the construction of new U.S. petrochemical facilities.
He’s also worked to empower local climate action—no matter the position of national governments. Through global initiatives like C40, a network of major cities committed to addressing climate change, Bloomberg has created platforms for mayors to share best practices and implement solutions tailored to urban environments. In his view, cities can serve as laboratories to test climate policies, which can later be scaled. “Cities have played a more important role in shaping the world than empires,” he wrote in a 2015 article in the magazine Foreign Affairs.
Since November, as many philanthropists have pulled back their funding of climate initiatives in the face of political pushback, Bloomberg has doubled down. Through his foundation, Bloomberg Philanthropies, he funded America Is All In, an initiative that supports state and local governments in their efforts to cut emissions. And Bloomberg Philanthropies is leading an effort with other funders to cover the hole left in the U.N. climate body’s budget when President Donald Trump announced that the U.S. would leave the Paris Agreement and cease any financial commitments made under it. Last year, the U.S. contributed $10 million to the body.
Ever mindful of the data, Bloomberg Philanthropies has also targeted several key areas of focus that the numbers show can make a big dent in the next stage of climate action: working with countries to help cut methane emissions and supporting cities to make their building stock less carbon intensive.
While less present to the general public, Bloomberg is keen to spread his message about market-based, financially rooted climate progress to other corporate and public-sector leaders. He serves as a special U.N. climate envoy, charged with engaging the private sector on the issue. He chaired the Task Force on Climate-Related Financial Disclosures, working to harmonize how companies disclose their climate-related financial risks. And he chairs the Glasgow Financial Alliance for Net Zero, which helps financial institutions advance the energy transition. Meanwhile, he drops well-timed op-eds in his namesake media outlet explaining the opportunities for acting on climate change.
“Economic growth and fighting climate change go hand in hand,” he has said repeatedly. To his credit, he’s spending the time and money to make sure the rest of the world understands that too.
Correction, March 27
The original version of this story misstated the status of Michael Bloomberg’s role at the Task Force on Climate-Related Financial Disclosure. He is the former chairman, not the current one.