Presidential hopeful Andrew Yang has delivered a climate plan that fleshes out his dreams for a geoengineered world. According to his proposal, which was released on August 26th, it’ll take 20 years, $4.87 trillion, and maybe even space mirrors to prevent a climate catastrophe.

Similar to other Democratic candidates, including former Vice President Joe Biden and former Rep. Beto O’Rourke, Yang wants the US to get to net-zero carbon emissions by midcentury — although he tries to one-up their plans by setting a goal of 2049 rather than 2050. Achieving net-zero emissions means that the country would successfully capture as much carbon as it puts into the environment. To get there, the US would need to significantly cut down on its use of fossil fuels, ramp up renewable energy, and employ methods to trap the planet-warming gases we’ve already released into the atmosphere over the years.

looking into “giant foldable space mirrors” that would reflect the sun’s light away from the earth

That last part is where Yang’s plan starts to get a little wonky, but it’s totally on brand for the startup entrepreneur. He’s the only candidate whose plan to avert the climate crisis banks on geoengineering (aka developing technologies to manipulate the environment). His plan would invest $800 million* in researching geoengineering methods like space mirrors. That’s right, he’s looking into “giant foldable space mirrors” that would reflect the Sun’s light away from the Earth as a “last resort.”

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It’s all part of Yang’s ambition to ensure that the US is the global leader in green technologies. “We’re the most entrepreneurial country in the history of the world. It’s time to activate the American imagination and work ethic to provide the innovation and technology that will power the rest of the world,” he writes in his plan.

Yang wants to spend $45 billion to create a “National Lab” underneath a new Department of Technology. Its central purpose would be to research new ideas on how to stave off climate change.

The $800 million* geoengineering line item will likely get the most attention, but by far the most expensive of Yang’s aims is to spend $3 trillion in financing loans for households to transition to renewable energy over the next 20 years. That alone is nearly twice as much as Joe Biden’s entire $1.7 trillion climate proposal. Yang’s plan also includes $200 billion to modernize the nation’s power grid and more than $330 billion to get ground and air transportation to net-zero emissions. To get some of that money back, Yang’s plan would place a carbon tax on polluters starting at $40 per ton of carbon emitted and increasing each year thereafter.

Yang’s plan includes a timeline to get new nuclear reactors online by 2027

Yang’s most controversial climate stance might be his support for ramping up nuclear energy. His plan includes a timeline to get new nuclear reactors online by 2027, and he wants to invest $50 billion in researching new technologies that he believes would eliminate many of the risks posed by older nuclear infrastructure.

“We can’t dismiss any ideas,” Yang writes. “We’ve waited too long, so we need to act fast and recognize that all options need to be on the table.” Yang’s comments echo critiques of Bernie Sanders’ recently proposed version of a “Green New Deal,” which is the first to explicitly exclude nuclear energy, geoengineering, and carbon capture technologies.

Some environmental activists have criticized these Yang-approved ideas on the grounds that they don’t wean the US off of fossil fuels or address the public health concerns connected with oil, gas, and uranium supply chains. “For us, the best way to deal with climate crisis is to reduce the amount of carbon emissions instead of putting on a Band-Aid approach,” says José Bravo, executive director of the Just Transition Alliance, a coalition of environmental justice and labor organizations. “We can’t move forward with any plan that does not take into consideration the legacy that dirty energy has left in our communities and the cleanup that needs to happen as well.”

Yang does have expert backing for some of his ambitions. The United Nations’ panel of climate scientists concluded that capturing carbon and increasing nuclear energy is necessary in order to reach global goals set by the Paris climate agreement. But the UN’s most recent report remains agnostic on the issue of geoengineering, citing insufficient research on its effectiveness and the consequences it might have on the planet.

Steven Cohen, director of the research program on sustainability policy and management at Columbia University’s Earth Institute, takes Yang’s plan with a grain of salt. “I think that he’s essentially on the right track to focus on science and technology, but I think that his faith in technology may be a little bit misplaced,” Cohen tells The Verge. According to Cohen, it’s not so bad that Yang wants to spur research into still-unproven technologies like carbon capture and geoengineering. “It’s one thing to do the research ... but another thing to count on it to save the world.”

*Correction 8/27: A previous version of this article stated that the budget for geoengineering was $200 million. The plan budgets $800 million for geoengineering. We regret the error.