Elizabeth Warren’s biggest foe in her campaign for the Democratic nomination isn’t one of the nearly 20 candidates she’s competing against. It’s Amazon. The senator, who released a plan in March to break up Big Tech, attacked the e-commerce behemoth for the umpteenth time in a CNN town hall on Tuesday.

Giant tech companies have too much power. My plan to #BreakUpBigTech prevents corporations like Amazon from knocking out the rest of the competition. You can be an umpire, or you can be a player—but you can’t be both. #WarrenTownHall pic.twitter.com/73y1002QVv — Elizabeth Warren (@ewarren) April 23, 2019

Warren may be leading the charge, but she’s not alone. The idea of breaking up Silicon Valley’s giants—Amazon, Facebook, Google, and Apple—has become conventional wisdom on the left wing of the Democratic Party, and it’s increasingly gaining purchase within the establishment.

I’m not here to debate the merits of the antitrust case against Amazon. I’m interested in another consequence of Amazon’s size: Its impact on climate change. While breaking up the company might benefit its customers and smaller competitors, it would do little to reduce the company’s massive carbon footprint. Amazon’s retail division would still control half of the e-commerce market, and thus depend on just as many trucks, trains, and airplanes for deliveries; Amazon Web Services (AWS) would still control half of the cloud computing market, and thus require just as much electricity to power its server farms.

But if we’re to prevent some of the most irreversible, catastrophic effects of global warming, the company is going to have to make drastic changes to business model—under pressure, most likely. That was the message sent by more than 6,700 of Amazon’s 65,000 corporate and tech employees in the U.S. earlier this month, when they signed a letter calling on CEO Jeff Bezos and the Board of Directors to create “an immediate company-wide plan” on climate change.

“We have the power to shift entire industries, inspire global action on climate, and lead on the issue of our lifetimes,” states the letter, which outlines six principles for its recommended plan. “We believe this is a historic opportunity for Amazon to stand with employees and signal to the world that we’re ready to be a climate leader.”