During President Biden’s first formal meeting with the nation’s labor leaders, Mark McManus played the skunk at the garden party: Joking that he “drew the short straw,” the president of the pipefitters union complained about Biden’s job-killing veto of the Keystone XL pipeline. Biden countered that the decision should have come as no surprise to McManus’s members in the United Association; he had campaigned on a pledge to cancel the project, a potent symbol in the fight against climate change.

The two-hour meeting in the Oval Office last month was otherwise cordial. But the exchange highlighted the tension between Biden’s pledge to be “the most pro-union president in history” and his promise to environmentalists to aggressively confront global warming, which Biden has called “the existential threat of our time.”

Many tribal activists and those from such groups as the youth-led Sunrise Movement — who want the country to stop burning fossil fuels immediately — were heartened when Biden vetoed Keystone XL, a major oil project, on his first day in office and paused new leases for oil and gas drilling on federal lands. They are also urging Biden to halt pipeline construction in the Midwest and on the East Coast.

But some labor leaders want Biden to slow down, noting the pay disparity between jobs in fossil fuels and renewable energy.

“You get guys that are coming off of fossil jobs in the Dakotas or the wind belt, and are making, you know, eighty, ninety, a hundred thousand a year,” said Brad Markell, executive director of the AFL-CIO Industrial Union Council. To put wind turbines up, “they’re looking at thirty to thirty-five thousand, with either no or substandard benefits.”

“The green sector is like any other new sector. … They want to pay as low as they can,” Markell added. “But that just can’t be the way this green economy thing is going to go down.”