The Democratic Party leadership that set up Hillary Clinton as the 2016 nominee is one of the all-time failures in American political history. Not only did they bobble an easily winnable presidential election, they have overseen a virtual collapse of the party at the state and local levels. Now a climate denier will take office at a time when aggressive climate policy is literally a matter of life and death. (By the way, global sea ice coverage is right now something like eight standard deviations below the average.)

But more than that, Democrats must admit that their previous climate record was also pathetically inadequate. If they wish to preserve the United States in its current form, or perhaps even at all, hardcore climate radicalism must become an ironclad party commitment.

Clinton's disastrous performance is no less than a screaming emergency for climate policy. President Obama's Clean Power Plan, various regulations on coal pollution and energy efficiency, subsidies and research spending on green technology, the Paris climate accords, all are probably getting flushed down the toilet. Instead of making at least reasonable forward progress on climate change, we're going backwards at speed.

This is at a time when, in order to keep warming below 2 degrees Celsius (itself a highly damaging level of warming), world emissions in developed nations ought to be ratcheting down by something like 10 percent per year. Four or eight years of a climate denier president almost could not come at a worse time. It means that, especially if President Trump screws up the delicate international politics, we are probably going to sail past 2 degrees, and into the territory where self-reinforcing climate feedbacks — decreasing albedo, release of frozen methane, deforestation, and so on — become a live possibility. In that case, warming could sail up to 4-6 degrees Celsius or even higher no matter what happens to emissions.

This would be an incomprehensible disaster. Sea levels could rise by 6 feet or more by 2100, accelerating fast after that; crop yields would be savaged; flooding and drought would be commonplace; murderous heatwaves would become the new normal; and many if not most animal species would be driven to extinction. It would quite literally threaten the existence of the United States as an organized community (and, needless to say, kill billions in poorer nations). At that point psychotically risky geoengineering schemes — the most realistic of which wouldn't even prevent some of the worst parts of climate change — would be the only option.

All this means that when Democrats do manage to claw back power, climate policy is going to have to be aggressive on the order of a total war mobilization to get emissions down in time.

But the thing about Obama's regulations is that they also were not remotely close to good enough. From 2007 — the U.S. emissions peak, at least for now — to 2014, carbon dioxide output dropped by about 10 percent. Yes, the Clean Power Plan was the most aggressive climate policy in American history, but it is a feeble half-measure compared to the scale of the problem. This is because the supposedly "wonky" elite Democrats have consistently failed to take the implications of climate science seriously. During their huge majority in 2009-10, they halfheartedly tried to pass a cap-and-trade bill that was so punched full of holes it barely would have done anything, then promptly gave up. Even Obama has consistently boasted about his fracking and pipelines record.

For all their boasting about being in touch with data and policy, Democrats can be every bit as willfully ignorant as conservatives generally are on science. It's not much better for someone to mouth the correct scientific facts when they ignore the implications of those facts the moment they run into a slight political headwind.

Therefore, Democrats need to get radical, and the only political direction available is left. Strong climate policy means expropriation of some of the most valuable assets in the world. To counterbalance certain enraged resistance from capitalists, Democrats must return to their New Deal labor party roots. Hillary Clinton lost in part because her weak appeal to the working class — of all races — could not counterbalance Donald Trump's ethnic nationalism and anti-trade shtick. As I have argued before, strong social democracy is the most promising policy agenda for peeling off enough working-class whites and activating enough non-voters to win while preserving the party's margins among black and brown voters.

And despite the scale of the threat, climate change is a solvable problem. Put a high and rising price on carbon, and plow the proceeds into a tidal wave of green energy research on anything that looks promising, including weird longshots like thorium reactors and carbon capture. Direct huge government investments in zero carbon energy and transportation, and forcibly shut down coal and natural gas plants as fast as possible. Work to stabilize and manage forests and agriculture so as to reduce emissions. Mandate rapid increases in fuel efficiency, and eventually abolish gas-powered automobiles altogether. Offset harm done to the working class with social insurance, income supplements, and jobs programs.

It's arguable whether a return to labor unionism and social democratic policy will be a political winner. Climate radicalism, on the other hand, is a matter of brute necessity. There simply is no alternative. If Democrats don't win a national election and put through some really aggressive policy sometime in the next decade (in concert with other world powers), the United States of America might not make it to its 300th birthday. So let's get cracking.