A U.S. government agency has recommended, for the first time ever, that federal money go towards research into climate change geoengineering, a historically controversial field of study that seeks to find disruptive technologies capable of altering Earth’s atmosphere. The endorsement arrived in the form of a short, two-paragraph section of a 119-page report by the U.S. Global Change Research Program, which coordinates federal funding for climate change research. The document outlines spending priorities and plans through 2021.

“If you ask me, there should have been research funding in this area decades ago,” says Ken Caldeira, an atmospheric scientist with Stanford, who was on a committee of the National Academy of Sciences charged with making recommendations to the federal government on climate engineering. Those recommendations were cited in support of including geoengineering in the Global Change research plan. The reason there’s not been any thus far, according to Caldeira? “It’s a political hot potato,” he tells Inverse.

Geoengineering is generally defined to include two categories: technologies that pull atmospheric carbon directly out of the air, and technologies that manipulate the atmosphere so that it reflects back more energy from the sun. The latter is sometimes referred to as either “albedo modification” or “solar radiation management.”

The formal call at the federal level for research into both sorts of geoengineering is a big deal. The mere mention of atmospheric manipulation in 2009 by White House science adviser John Holdren set off a media controversy that quieted the feds on the subject for years.

The result has been that federal science on geoengineering is all but non-existent, even as private entities and foreign governments have charged headfirst into this new frontier. Bill Gates, for example, has bankrolled the Fund for Innovative Climate and Energy Research with $8.5 million of his personal money. Caldeira administers that fund along with David Keith of Harvard University; both are also beneficiaries of the fund for their respective research activities. Keith and his company, Carbon Engineering, are already pulling carbon dioxide straight out of the air at a demonstration project in Squamish, Canada, sucking about a ton of CO2 out of the atmosphere every day.

“While climate intervention cannot substitute for reducing greenhouse gas emissions and adapting to the changes in climate that occur, some types of deliberative climate intervention may someday be one of a portfolio of tools used in managing climate change,” the U.S. Global Change Research Program report notes. “The need to understand the possibilities, limitations, and potential side effects of climate intervention becomes all the more apparent with the recognition that other countries or the private sector may decide to conduct intervention experiments independently from the U.S. Government.”

There’s a distinction between supporting research into geoengineering and being in favor of geoengineering proposals themselves, although that point is often lost in the public discourse, says Caldeira. “Even if you think we would never want to deploy one of these systems, somebody else might want to and it would be important to understand what the consequences would be if somebody else did. Furthermore, situations could change, and what seems like a bad idea today could seem like the best available option somewhere down the road.”

The conflagration of technologies that pull carbon out of the air and those that otherwise manipulate Earth’s atmosphere hasn’t been helpful, he says. Scrubbing carbon dioxide from the atmosphere is considered geoengineering, but if you use the exact same technology to pull CO2 from a smokestack, it’s not. “Carbon dioxide removal is entirely equivalent to reducing emissions, because if you release carbon dioxide in one place and take it out of the atmosphere somewhere else, that’s exactly — from a climate systems perspective — the same as not having emitted it from before,” says Caldeira. “It’s not introducing any new risks into the climate system, in fact it’s removing risks from the climate systems. And all the risks are just the typically local environmental risks that might be true also for carbon capture and storage from a power plant.”

Solar radiation management, on the other hand, is “a form of radical adaptation to high greenhouse gas concentrations in the atmosphere,” Keith says. Proposals include injecting massive quantities of sulfuric gasses into the stratosphere, which would cause the atmosphere to reflect more light back to the sun and result in (relative) global cooling, with similar effect as a large volcanic eruption. This sort of atmospheric modification could have severe unintended consequences, and does nothing to address non-temperature effects of climate change, including ocean acidification. It’s highly risky but will become more attractive if aggressive climate change interventions are delayed. If the world gets to a point where that sort of last-ditch solution starts to look like a reasonable idea, solid research into potential impacts will be valuable.

The mention of geoengineering in the U.S. Global Change Research Program planning document does nothing to guarantee actual funding, and the political future of geoengineering is far from certain, says Caldeira. “We’re in this very unpredictable political state here in the United States now with the Trump administration coming in.”

President-elect Donald Trump has signaled through his words and cabinet appointments that climate change research will be a low priority — potentially even a non-priority — for his administration. However, it’s very possible that geoengineering projects of both types — which could mitigate against the consequences of greenhouse gas emissions without reducing the amount of fossil fuel burning — might be relatively attractive to Trump, who has championed “clean coal” and oil and gas industries in general.

“With Trump, people’s confidence in the ability to predict the future of our political system is way down, and anything could happen, from the entire global change budget getting cut, to this being one of the elements of the global change research program that the Trump people like,” Caldeira says. “So I think it’s just impossible to predict at this point.”