A major environmental group is reportedly set to funnel millions of dollars into research on solar geoengineering, a proposed fix for climate change that has garnered skepticism and even fears about unintended consequences.

Solar geoengineering encompasses a range of tactics to cool the planet down by reflecting sunlight, perhaps by artificially brightening clouds or thrusting reflective particles into the atmosphere. Rogue efforts to test these theories have raised alarm because scientists don’t know much about what other effects it could cause. It’s led to calls for more research to close those knowledge gaps before more trials move forward.

The Environmental Defense Fund (EDF) plans to dole out “millions of dollars” in grants for solar geoengineering research, The New York Times reports. EDF tells The Verge it shares concerns about solar geoengineering, which is why it’s supporting studies into the potential repercussions it could have.

“We are very concerned about unintended consequences of [solar geoengineering], which is why we are focusing on policy-relevant research that will help estimate potential impacts and develop the kind of policy-relevant science necessary to help governments make informed decisions,” Lisa Dilling, associate chief scientist at EDF, said in an email.

EDF declined to say just how much money it would invest into solar geoengineering studies. It also declined to say who its funders are for this initiative, although The New York Times names the LAD Climate Fund — led by partners who’ve held leadership roles at Cisco Systems — as one donor.

Next steps include working with scientists to “develop a research agenda with a near-term focus on impacts” and creating a “governance structure,” Dilling says. After putting those guardrails in place, EDF plans to award research projects expected to share their results in journals and conferences.

Heated talks at the United Nations Environment Assembly in March failed to result in new international guidelines for solar geoengineering. Since 2010, there’s been an outdated global moratorium on certain kinds of large-scale geoengineering. The language is vague, excluding small-scale experiments that have moved forward in recent years.

Last week, Alameda, California, voted to prevent University of Washington scientists from testing new technology to spray sea salt particles. It’s part of a strategy to make clouds more reflective called Marine Cloud Brightening (MCB). More than 30 scientists authored a paper in the journal Science Advances in March proposing a research roadmap for MCB.

“Interest in MCB is growing, but policymakers currently don’t have the information they need to reach decisions about if and when MCB should be deployed,” lead author Graham Feingold, a researcher with NOAA’s Chemical Sciences Laboratory, said in a press release at the time.

A decidedly less scientific solar geoengineering outfit sparked backlash last year. Mexico moved to bar future experiments after one geoengineering startup launched weather balloons filled with sulfur dioxide within its borders. The co-founders picked up shop and tried it again in Nevada, grilling fungicide in a parking lot to create the sulfur dioxide gas. 

As a pollutant, sulfur dioxide can lead to acid rain. Sending reflective particles into the atmosphere, called stratospheric aerosol injection (SAI), could also widen the Antarctic ozone hole. Those are just a few reasons why experts are worried about moving ahead with solar geoengineering without a better understanding of the potential fallout.

And at the end of the day, environmental advocates want to make sure solar geoengineering doesn’t detract from efforts to transition to cleaner energy — which is the only way to get a real grip on climate change.

“Reducing greenhouse gas emissions as rapidly as possible is essential to addressing climate change. It remains EDF’s top priority,” EDF’s Dilling says.