Scientific advisors to the U.S. government have for the first time urged Congress to fund federal geoengineering research to battle climate change.

The shift in stance appears in an updated roadmap for federal funding of climate research that was published earlier this week by the U.S. Global Change Research Program. The report notes that the research could provide “insight into the science needed to understand potential pathways for climate intervention or geoengineering and the possible consequences of any such measures, both intended and unintended.”

Two main geoengineering approaches for fighting climate change exist. One is sucking carbon dioxide out of the atmosphere to reduce its warming effects, the other increasing how much sunlight the Earth reflects. The new roadmap proposes that both approaches should be investigated.

The idea of using man-made techniques to ease the effects of climate change is not a new one—but while popular among many scientists, it has proven controversial. Skeptics have warned that testing geoengineering approaches at scale is risky, because no one understands what their effects might be.

In 2015, a report from the National Academy of Sciences warned that geoengineering may only partially offset the impact of greenhouse gases, and may also introduce its own problems. But at the same time it also called on scientists to develop experiments that would test geoengineering technologies to determine their efficacy. Now, it seems, White House science advisors are inclined to agree.

Meanwhile, Science raises the concern that a decision to push on with geoengineering approaches could provide the incoming Trump administration with an excuse to avoid cutting emissions. If we can suck CO2 out of the atmosphere and reflect sunlight, the theory goes, why would we need to stop burning fossil fuels?

The new report is pretty clear on that issue. “Climate intervention cannot substitute for reducing greenhouse gas emissions and adapting to the changes in climate that occur,” it says, but “some types of deliberative climate intervention may someday be one of a portfolio of tools used in managing climate change.”

(Read more: The New York Times, Science, “Scientists Suggest Testing Climate Engineering,” “A Cheap and Easy Plan to Stop Global Warming,” “Geoengineering Could Be Essential to Reducing the Risk of Climate Change”)