Democrats appear to be on the cusp of retaking the United States Senate after runoff elections in Georgia, an outcome with potentially momentous implications for science and climate policy.

Democratic control would likely make it easier for President-elect Joe Biden to win Senate confirmation of his appointees, for Congress to revoke controversial rules finalized in the last months of President Donald Trump’s administration, and for lawmakers to pass new legislation aimed at curbing climate change and boosting federal research investments.

Democratic candidate Raphael Warnock beat Senator Kelly Loeffler in yesterday’s election, becoming the first Black Democrat elected to the Senate from the South. Democratic challenger Jon Ossoff is leading in his race against sitting Senator David Perdue and “very likely” to win, according to a projection by The New York Times. If the results stand, Republicans and Democrats would each control 50 seats in the Senate that convenes later this month, with Vice President-elect Kamala Harris providing the tie-breaking vote that gives Democrats control. Republicans have held control of the Senate since 2015.

The most immediate change would be in the Senate’s leadership. Sen. Chuck Schumer (D-NY) would replace Sen. Mitch McConnell (R-KY) as Majority Leader, giving Democrats extensive power to decide legislative priorities and which bills advance to final votes. Although Schumer’s job as Senate leader means he will have to balance the many competing demands of his caucus, he has recently shown a keen interest in boosting federal spending on research. Earlier this year, he was a key player in crafting bipartisan legislation, The Endless Frontiers Act (S. 3832), that calls for a giving the National Science Foundation (NSF) a sweeping makeover. It calls for giving the agency a new name, an additional $100 million over 5 years, and  responsibility for maintaining U.S. global leadership in innovation. Schumer has also said he would work with the Biden administration to advance climate legislation and boost federal spending on clean energy research.

Each of the Senate’s 20 permanent committees, which do most of the work of crafting legislation, would also get new leaders.

The powerful Senate Appropriations Committee, which sets annual spending levels, is expected to be led by Sen. Patrick Leahy (D-VT), a longtime advocate of environmental protection. Although the panel often works in a bipartisan manner, Leahy will likely play a key role in trying to help the Biden administration realize its spending priorities.

It is too early to say for sure which Democrats would end up leading committee subpanels that set the budgets of key research agencies, including the National Institutes of Health (NIH), the National Science Foundation (NSF), NASA and the Department of Energy (DOE).

Sen. Maria Cantwell (D-WA) is expected to chair the Commerce, Science, and Transportation Committee. The panel has a wide set of responsibilities, including overseeing the regulation of technology companies and handling transportation infrastructure—both issues that are likely to demand attention in the new Congress. It also sets policy for research agencies including NSF, the National Oceanic and Atmospheric Administration and the National Institute of Standards and Technology. Cantwell, a former technology industry executive, has a strong interest in research and climate issues, which could influence the panel’s work.

Senator Patty Murray (D-WA) is in line to chair the Health, Education, Labor and Pensions Committee, which among many other things oversees NIH, the Centers for Disease Control and Prevention, and the Food and Drug Administration. It also plays a key role in setting education policy. Murray has been an advocate for biomedical research spending and diversifying the scientific workforce. She has opposed restrictions on research using human embryonic stem cells.

The environment committee would be led by Sen. Thomas Carper (D-DE), a vocal advocate of federal action on climate change and strong pollution laws. He has helped write numerous legislative proposals to curb global warming and would likely play a key role in any effort to pass new climate legislation.

Senator Joe Manchin (D-WV) would lead the Energy and Natural Resources Committee, which could also be involved in efforts to write new climate legislation. Manchin, who represents a state that has historically been highly reliant on coal mining, has been an outspoken supporter of developing technologies aimed at trapping carbon dioxide produced by fossil fuel burning before it enters the atmosphere.

Revocation and reconciliation

Control of the Senate would also make it easier for Democrats to use some rarely-practiced legislative maneuvers to revoke recent regulations they oppose, and to push through legislation that might otherwise be blocked by a minority of Senators. In each case, Democrats would have to assemble just 51 votes to achieve their goal.

Using a seldom-invoked law, the Congressional Review Act (CRA), Democrats are expected to try to undo a host of regulations adopted late in the Trump administration. To cancel a rule, the CRA requires just a simple majority vote of both the Senate and the House of Representatives, and the agreement of the sitting President. Democratic control of the House, Senate, and the White House would make using the law possible (although Senate Democrats would likely need to gain the support of at least one Republican lawmaker in some cases). Potential targets would include Trump rules that weakened air pollution and endangered species laws, and a new rule limiting the kinds of research the Environmental Protection Agency can use when writing new regulations.

A second process, known as reconciliation, would allow Senate Democrats to pass certain kinds of legislation with just 51 votes—avoiding the 60-vote threshold typically needed to advance bills. Perhaps the most famous example of reconciliation came in 2010, when Senate Democrats used it to advance President Barack Obama’s health care law. Now, analysts have suggested Democrats could use reconciliation to advance bills, such as new climate change or environmental protection laws, unlikely to gain the support of 60 Senators. But reconciliation has limits: It can only be used for matters that have a direct budgetary impact. And any measure passed through reconciliation is vulnerable to later being repealed the same way—with just 51 votes.

Even as Senate Democrats savor the prospect of flipping the Senate, they know their influence could be relatively limited and fleeting. They will face a hefty number of competing priorities, including taming the COVID-19 pandemic and rebuilding the economy, that will leave limited bandwidth for addressing other issues. Divisions within their own ranks—including over climate policy—could make it difficult to realize an ambitious agenda. And with the next elections set for 2022, it’s possible Senate Democrats will have just 2 years to exercise power.