On the same day that Alexandria Ocasio-Cortez won an upset victory in her primary against Wall Street-friendly incumbent Joe Crowley — one of the most powerful Democrats in the House — a New Yorker nearly 50 years her senior fed rumors that he would seek the highest office in the land.

Aside from pouring $80 million to support a set of handpicked Democratic congressional hopefuls, billionaire former New York City Mayor Michael Bloomberg once again seems to be angling to run for president. Business Insider columnist Daniella Greenbaum took the opportunity to assert: “Democrats need to choose: Are they the party of Alexandria Ocasio-Cortez or the party of Michael Bloomberg?”

She sided with the latter, but the question is a valid one. The differences between Bloomberg and Ocasio-Cortez are difficult to stuff into a single paragraph, but let’s try: He’s one of the richest men in the world who made his fortune on Wall Street and, in his tenure as mayor, went out of his way to make the financial sector feel at home. She’s a democratic socialist who until last year bartended in Manhattan and campaigned to make housing a human right — something Bloomberg made a more difficult goal to attain for her future constituents.

But one key difference might be less obvious and a bellwether for climate politics post-2018 if a blue wave sweeps Democrats back into power on Capitol Hill: how they plan to tackle climate change.

Since leaving his post, Bloomberg has adopted climate change as one of his pet causes, becoming one of the world’s most well-known advocates for quelling rising temperatures. He’s funded efforts to shutter coal-fired power plants and when the Trump administration announced that it would pull out of the Paris Climate Agreement, Bloomberg offered to pick up the tab instead. He even co-authored a book on the subject with former Sierra Club head Carl Pope, cheerily titled “Climate of Hope.”

Bloomberg comes to climate action, as he writes therein, as an “unrepentant capitalist.” In his view, climate change is simply a collection of market failures, the solutions to which are encumbered by political failures. “Working together, businesses, governments, and civil society are already repairing many of these market flaws,” Bloomberg and Pope reason, optimistically. “We simply need to do more of it faster. Markets, like gardens, feed and enrich us. But they also require tending. Weeds need to be pulled out and fertilizer added in.”

They suggest centering the profit motive — something “many environmentalists have traditionally seen as an enemy” — as a main driver of climate action. “Only when self-interested acts are also climate-friendly acts will success be possible. In other words: reducing carbon must offer profit opportunities for us to win the battle against climate change,” they conclude. “The federal government doesn’t have a lot to do with climate change. … State governments, only a little,” Bloomberg told CBS News recently. “It’s city governments and the private sector. Mostly the private sector.”

He does do some hedging in the book. “I don’t have much sympathy for industries whose products leave behind a trail of diseased and dead bodies,” he clarifies, but the most restrictive action he imagines is to “put them out of business by driving down demand, through taxes that address their true societal cost, regulations that mitigate the harm they cause, and public awareness advertising that makes plain the dangers they pose.”

Contrast that with Ocasio-Cortez’s climate stance, informed in part by the fact that several parts of her district are vulnerable to sea-level rise. Per her platform:

It’s time to shift course and implement a Green New Deal – a transformation that implements structural changes to our political and financial systems in order to alter the trajectory of our environment. Right now, the economy is controlled by big corporations whose profits are dependent on the continuation of climate change. This arrangement benefits few, but comes at the detriment of our planet and all its inhabitants. Its effects are life-threatening, and are especially already felt by low-income communities, both in the U.S. and globally. Even in NY-14, areas like Throgs Neck, College Point, and City Island are being affected by erosion and rising sea levels. Rather than continue a dependency on this system that posits climate change as inherent to economic life, the Green New Deal believes that radically addressing climate change is a potential path towards a more equitable economy with increased employment and widespread financial security for all.

To get there, Ocasio-Cortez isn’t looking to the private sector, but suggests “waging a war for climate justice through the mobilization of our population and our government.” She sets as a goal a complete transition by the U.S. to 100 percent renewable energy by 2035.

“We need a Marshall Plan for renewable energy in the United States,” she told me last week, shortly before the election, suggesting that a massive $146 billion investment to rebuild Puerto Rico — per a proposal by Sens. Bernie Sanders, I-Vt., and Elizabeth Warren, D-Mass. — could provide “an example for how we can approach the ravages of superstorms and climate change moving forward. … We can show the world what recovery in an era of extreme climate change looks like.”

Climate change hasn’t been a big part of the conversation about the blue wave. But if it’s successful, and the party finds itself with enough seats to push through ambitious legislation next January, what to date have been seen as minor differences between Democrats on climate could become the grounds for legislative battles. That is, if Ocasio-Cortez’s election marks a new era for the Democratic Party, what will that mean for its climate politics?

After all, there’s a lot of room for Ocasio-Cortez to maneuver in the space that opens up when Bloomberg suggests the government deal with some companies like this: “Put them out of business by driving down demand, through taxes that address their true societal cost, regulations that mitigate the harm they cause, and public awareness advertising that makes plain the dangers they pose.”

While there’s been ample attention paid to insurgent candidates’ bold stances on “Medicare for All” and abolishing Immigration and Customs Enforcement, no natural analog has emerged when it comes to preventing the potential end of human civilization.

Ocasio-Cortez is one among many left-leaning candidates with ambitious climate proposals who could breathe fresh air into a policy field long-dominated by market tweaks, half-measures, and lofty talk of megawatt hours and parts per million of carbon dioxide — not to mention wealthy white men. Kaniela Ing, Abdul El-Sayed, and Randy Bryce are all calling for some version of a Green New Deal and strict restrictions on fossil fuel corporations, framing climate change as both an equity issue and an economic opportunity for working-class Americans. Similarly, Jess King, Rashida Tlaib, Ben Jealous, Kevin de León, and others are looking to go after the fossil fuel industry and have all sworn off taking money from them.

Before getting into the details of these proposal, it’s worth giving some context for just how dire the climate problem is, and how vast the changes science demands really are.

Conservative estimates suggest that greenhouse gas emissions in industrialized nations like the U.S. begin rapidly declining after 2020. For just a two-thirds chance of meeting the Paris Agreement’s 2 degree celsius warming target, emissions in such places need to draw down to zero by 2050. And even that scenario assumes that so-called negative emissions technologies that can suck carbon out of the atmosphere will be by that point deployable at scale. Though most climate models assume these technologies will soon or already exist, they currently don’t — at least not in any meaningful way. Without them, the timeline for decarbonization gets much shorter and means shutting down every coal- and gas-fired power plant and taking every single oil-fired, combustion engine car off the road worldwide within a decade. Alas, Kevin Anderson, deputy director of the U.K.’s Tyndall Center for Climate Change Research, told me last year, “We have to mitigate as if these negative emissions technologies do not work.”

Bloomberg and others like him have held up the Paris Agreement as our saving grace; even without the White House on board, citizens, businesses, and local governments can stay on track. Altogether, though, the track the Paris Agreement leaves us on currently is for around 3 degrees of warming. That would leave around 4.5 billion people vulnerable to heat waves, decimate large chunks of the world’s arable land, and render coastal cities like New York virtually uninhabitable by the end of this century. Getting in the neighborhood of 2 degrees means countries “ratcheting up” their commitments over the coming years. And even that 2 degree target will still lead to warming that is too high for many people — especially those in low-lying island nations or agricultural communities vulnerable to climate-fueled drought. That’s why representatives from the Global South have for years chanted “1.5 to survive” to U.N. climate talks, calling for a more ambitious, 1.5 degree target that grows farther out of reach every year.

Climate scientists aren’t prone to mince words about how tall the task of staying below even 2 degrees will be. Anderson estimates we have about a 5 percent shot at getting there. Like Ocasio-Cortez, he says it will require a massive mobilization “similar to the Marshall Plan we had in the reconstruction of Europe after the Second World War, when the continent was basically flattened and we had to start almost from scratch,” noting that such a program would need to both scale up clean energy and radically scale down fossil fuels, not just expect one to outcompete the other on the free market. “It’s that scale and rate of change that will be necessary to deliver an infrastructure that will allow us to meet our 2 degree commitment.”

Accordingly, he’s leery of relying predominantly on market-based approaches to get the job done, calling “the “dominant neoclassical, market-based approach … fundamentally flawed for guessing system-level changes.” Anderson notes that there are “root and branch” changes required of capitalism to deal adequately with the climate crisis and “even then, whether you can say it looks and sounds like capitalism [after that], I don’t know.”

Insurgent candidates’ climate plans, then — involving large-scale government investment and economy-wide transformations — aren’t just populist and politically salient in the sense that they’re promising jobs and a higher standard of living. They’re also more firmly in line with the science than the market fixes Bloomberg imagines.

So what alternatives are on offer from insurgent candidates?

Randy Bryce, running for the Wisconsin House seat Paul Ryan will vacate later this year, comes at his jobs-focused climate and energy platform with firsthand knowledge. “I’ve worked in the copper mines up in the upper peninsula” of Michigan, he told The Intercept. “You get done with a shift, and you’re covered in this black and red color — we call it the red death. I would take one shower and think that everything was clean, but it took three showers to get everything off.

“But as far as putting up the wind turbines,” he says, “you’re outside. And at the end of the shift, you’re still exhausted, but you feel a lot better.” Unlike the rooftop solar business, wind turbine work is largely unionized, in many cases by the same unions that erect pipelines, like the United Steelworkers and the Laborers International Union of America. Bryce told me that his union — Iron Workers Local 8 — “practically wrote the book on how to erect wind turbines,” but had to give up much of that work in Wisconsin after Republican Gov. Scott Walker passed policies that were hostile to renewable energy.

He’s calling for a Green New Deal that would create “tens and thousands of new jobs,” end subsidies to fossil fuel companies, prosecute Exxon Mobil for misleading the public about the existence of climate change, and get the U.S. entirely off fossil fuels by 2035. Bryce’s evolution on the issue reflects the shifting politics: Having supported pipelines in the past for the jobs that they provided to union members, he’s now opposed to any new oil and gas infrastructure. “You have to get to the root of the problem, and that’s dependence on fossil fuels,” he says. “Let’s get people to work doing things that are going to help our future. Rather than clinging to things in the past, I’d rather move ahead. The thing at the end of the day is to feel good about a job, as opposed to working on something that’s going to leak and cause damage,” he told The Intercept, referring to pipelines.

Michigan gubernatorial candidate Abdul El-Sayed, a 33-year-old doctor who’s worked as the health commissioner for Detroit, approaches climate issues from a public health perspective — and with a firsthand knowledge of how austerity politics can work against good policy. He took his job in the city’s health department as it was under emergency management, where a state-appointed board took over Detroit’s finances in order to help reign in its nearly $20 million in municipal debt through a series of painful budget cuts.

“The whole mindset is that once we get through the emergency, then we can think about the future. But right now, we’re under emergency circumstances,” El-Sayed told me by phone. “It kills any kind of future-oriented thinking.”

He describes climate change as a threefold problem for Michigan, involving ending our reliance on “a system of energy production that will ultimately poison us and poisons our kids,” creating jobs as older industries falter, as well as updating and, in some cases, creating infrastructure for the 21st century. “We don’t have time, and we’ve got an opportunity to solve three problems at the same time if we’re willing to embrace the future,” he says. Recognizing the budget constraints placed on states — and Michigan in particular — part of his plan to do that includes setting up something called the Pure Michigan Bank, a state infrastructure bank to enlist private capital in public projects in which the “payout is owned and operated by the public,” he says. He also hopes to rejigger what Michigan’s state budget prioritizes, through things like ending its $10 billion in refundable business tax credits.

“The money is there,” he says. “The question is whether we want to allocate it toward what we want to use it for or funnel it to large corporations that will offshore and automate our jobs away.”