It’s May, which means “proxy season” in the corporate world. This is the time of year when publicly traded companies hold their shareholder meetings, and investors can vote on resolutions to change corporate policies. The votes can have plenty of clout because huge private investment firms such as BlackRock and Vanguard weigh in, as do major public shareholders such as California’s and New York’s employee retirement funds with billions of dollars in stock under their control. When they want something, CEOs listen.

Recently more and more of these resolutions have pushed companies to act on climate change and reduce greenhouse gas emissions. Two years ago, for instance, investor proposals forced Shell to sell off carbon-rich oil sands assets. Investors also made the company tie 10 percent of executive bonus pay to success in cutting emissions. And earlier this year BP, bowing to investor pressure, agreed to align future capital spending with the targets of the 2015 Paris climate accord, reducing emissions enough to keep global temperature rise below two degrees Celsius. That could mean cuts as high as 50 percent, depending on the country.

This year and going forward, investors should exert more of this leverage on these and other companies. That is because politicians, especially in the U.S., have abjectly failed to address the threats that climate change poses to health, national security and the environment. President Donald Trump has repeatedly said he does not see climate change as a problem, despite strong and steadily growing scientific evidence from the world’s researchers—and his own government agencies. This year the White House took steps to create a panel, chaired by someone who believes mounting carbon dioxide is good for the planet, to attack this overwhelming scientific consensus. On a local level, the state of Washington recently voted down a tax on carbon emissions.

The businesses that generate large amounts of greenhouse gases, in contrast, have proved willing to change their ways when investors insist on it. Of the more than 600 largest publicly traded companies in the U.S., 64 percent have now made commitments to reduce emissions, according to Ceres, a nonprofit group that tracks corporate sustainability. Many of those moves have come in response to proposals made at these annual shareholder gatherings. In addition to the actions taken by BP and Shell, Chevron has agreed to set an emissions-reduction target for methane, another powerful heat-trapping gas.

Companies’ desire to avoid embarrassing proxy-season showdowns has given rise to another investor force—a shareholder network called Climate Action 100+, whose members have $32 billion in assets under management and try to push corporate changes outside of these yearly meetings. One success earlier this year: international mining giant Glencore said it will not grow its coal-mining business any larger and will develop targets for emissions reductions. Climate Action 100+ is also pressing nonenergy businesses that generate a lot of emissions, such as steel manufacturers, to line up behind science-based reduction goals.

The motive of these investment funds is not unfettered altruism. While they hold oil company stock, they also invest in real estate along coastlines threatened by rising seas, in health care firms whose costs will increase, and in dozens of other sectors that stand to take a substantial hit if climate change is not brought under control. So they have to take a long-term and global view.

It’s time to push this wave of capital pressure even further. The Ceres report notes that most of the climate commitments it tracks are vaguely worded: only 36 percent of the agreements specify deadline-driven, quantitative targets for reduction. Companies also need to adopt sustainability targets for things like water use. More shareholders need to push for more of these specific goals and tie them to executive pay to ensure accountability.

Such demands can be tricky. The U.S. Securities and Exchange Commission has rules that prevent investors from micromanaging businesses. Exxon, in fact, has asked the SEC for permission to block a proposal calling for it to align emissions with the Paris accord. But the commission needs to give shareholders the right to protect their investments. And investor activists need to keep working to bring science and business together. Because money talks—or it walks—it can accomplish things that politicians won’t.