Massachusetts is known around the world as a leader in science, technology and medical research — thanks, in large part, to more than $6 billion in federal funding. But that money may now be at risk under the Trump administration, which has threatened to both cut funding and downplay how science research informs federal regulations.

On Sunday, hundreds of scientists rallied in Copley Square to share their concerns about the future of research under a Trump administration. They point to his cabinet picks, like Rick Perry and Rex Tillerson, who have longstanding ties with the fossil fuel industry, and his new head of the Environmental Protection Agency, Scott Pruitt, who sued that very agency 14 times while he served as Oklahoma attorney general.

And as the Trump administration continues its effort to roll back regulations, scientists like Andrew Rosenberg, director of the Center for Science and Democracy at the Union of Concerned Scientists, are worried that the work they do will be reduced and ignored.

When you turn away from science-based public policies and providing information to the public, that says to scientists, you know the work that I do, isn’t going to have an impact on society,” Rosenberg said.

Rosenberg has worked as a federal marine and fisheries researcher under different administrations, but he says what’s happening now feels very different.

To say that we’re not going to release any science reports unless it’s vetted by political personnel, we don’t want any scientists speaking out, we want to know the names of the people on particular kinds of issues -- I’ve never seen that before,” says Rosenberg.

President Trump has pledged to cut back regulations by 75% because many business groups say these rules cripple industry growth by being too restrictive and costly. Meanwhile, Congress is considering the Regulatory Accountability Act, a bill that would restructure how federal agencies inform their policy decisions. For some conservatives who say that science has been overly politicized, that kind of change is long overdue.

Diane Katz, a policy expert at conservative think tank, The Heritage Foundation, says the federal government should scale back certain areas of science research — that too many special interests have broken the system and that scientists shouldn’t be so deeply involved at the policy-making level.

“I don’t think that’s what scientists should be doing. And I think that’s what they are doing. They’ve become policy makers, and they’ve moved away from being scientists.” Katz said.

“I find that there is a real loss of scientific integrity in the federal government. I would argue that much of the science that’s being done by federal government ought not to be. It ought to be done in the private sector. It ought to be as independent as much as possible because it does cast — whether it’s on the left or the right, suspicion and doubt and uncertainty on scientific inquiry when it’s driven by a political process.”

It’s too early to predict how Trump’s proposed reductions will play out, but scientists are bracing themselves for deep cuts in the discretionary budget. The lion’s share of research funding comes from the National Institutes of Health, and the Department of Defense mostly funds development. In the greater Boston area alone, approximately 112,000 people are employed by colleges and universities, and if research grants don’t come through, there will be a ripple effect in the local economy.

Tony Janetos, environmental scientist and director of Boston University’s Pardee Center for the Longer Range Future, says not knowing whether or not federal grants will be available can throw off long-term research plans that are already in motion.

“This is, in large part, how we support graduate students, how we support post-doctoral fellows, how we support research scientists, so there’s this whole ecosystem for research scientists in all fields who are really quite dependent on the ability to compete for federal research funds.” Janetos said.

Janetos adds that he’s concerned about the recent rhetoric in Washington that facts don’t matter.

“Well, you know, Mother Nature doesn’t care, and so facts actually do matter and understanding the way the physical world intersects with everything else matters a lot.” Janetos said.

In Cambridge, MIT biology professor and cancer researcher, Angelika Amon, says it’s a scientist’s civic duty to be involved in how policies are made.

How can making your citizens’ live longer, live better, live healthier lives be not in the government’s interests? I think we are in the business of finding new cures for diseases. We’re in the business of educating people here at universities. I think it should be one of the prime goals of a federal government to support those kind endeavors,” Amon said.

Amon is worried that a political climate in which facts and evidence are constantly in question is problematic not only to the science community but to society as a whole.

As scientists, we are in the truth-seeking business. Every day of my life, I go out there and I study a particular problem.” Amon says. “I gather data and I try to establish fact and I’m trying to get as closely as I can to the truth, and so to me as a scientist, it’s really very distressing that the truth and facts have become relative terms.”