If Joe Biden wins the presidency, he will be faced with a hundred pressing problems and a thousand things to repair from the Trump years. Nevertheless, he will have little choice but to concentrate on the climate crisis.

Until now, for most people the danger has remained at a distance, except for scientists who have done their best to warn us about the speed and power of the storm headed our way. But amid the smoking pall that still hangs over the West and the recovery in Louisiana, after two powerful hurricanes in less than two months, there is no longer any doubt about the immediacy of the danger. And so everythingespecially the economic response to the trauma of Covid-19must flow in the direction of swift climate action.

In 2018 the Intergovernmental Panel on Climate Change told us that we had until 2030 to dramatically bend the curve of emissionsin fact, to cut them in halfif we had any hope of meeting the climate target wed set in Paris in 2015. Thats a wretchedly difficult goal, on the bleeding edge of the technically possible. And if we do not get started immediately, even that chance will slip away, and with it much of the prospect for a planet capable of sustaining civilizations like the ones were used to. If we want to avoid such a fate, the US will have to act quickly and, for the first time, actually take a leadership role in the international climate effort.

So what could President Biden do during his first days in office? He could accomplish a few important things by executive action: hes already promised to stop new oil and gas drilling and coal mining on Americas public lands. This is good news, since if those public lands were their own country, they would rank among the worlds five largest sources of carbon. He could also announce that the federal government will not just allow California to ban gas-powered cars by 2035 but will encourage other states to do so as well.

If Biden has a working Senate majority he may be able to do much more. The Green New Deal looked like an impossibly large legislative lift when it was first unveiled two years ago. But the young people from the Sunrise Movement, who brought it to the fore, have proved to be prescient. Given the scale of joblessness resulting from the Trump administrations bungled pandemic response, it suddenly seems plausible to undertake industrial policyin this case steering infrastructure dollars toward clean-tech sectorsat a level we havent seen since the 1960s. That seems to be how the EU, China, and other nations have decided to respondBeijings pledge to be net zero by 2060 is in essence a pledge to pursue renewable energy nonstop for decades to come.

One can imagine Biden, born and raised in Scranton, Pennsylvania, as the pitchman for an aggressive build-out of sun and wind power across the US, reactivating Rust Belt factories and signing union deals with clean-energy tycoons. But its not called global warming for nothing. So the Biden administration will need to work at least as hard to consolidate international action. The US remains the worlds largest economy, and therefore should have the persuasive power to convince intransigent leadersthink Brazils Jair Bolsonaroto shift their approach.

None of this is easy and all of it will require a willingness to do something that no administration, Republican or Democratic, has ever been willing to do: truly take on the fossil fuel industry, which has for so long dictated government energy policy. Twelve years ago, when Biden took office as vice-president, the power of corporations like Exxon and Chevron was still almost unassailable. But since then, two things have changed. First, the price of solar and wind power has dropped by 90 percent and clean energy now represents the most obvious economic choice. Second, a significant movement has arisen to erode at least some of the political power of the industry. The fossil fuel divestment campaign, for instance, has seen endowments and portfolios worth more than $14 trillion abandon fossil fuel ties.

To take advantage of the moment, Biden would need to abandon his instinct to move toward the middle. Thats because, at this late date, the middle is actually a choice: it means action too slow to catch up with the physics of climate change. And it is that physics that represents Bidens deadliest adversary.