If you want to understand the perilous state of federal scientific research, ask Linda Birnbaum.

For 40 years, Birnbaum has worked as a toxicologist for the US government, rising through the ranks to direct both the National Institute of Environmental Health Sciences and the National Toxicology Program. She has authored more than 700 peer-reviewed publications and collected numerous awards and international accolades for her research on public health.

Now, as she prepares for an October retirement from the institute she says she has tried to “protect” from the ramifications of Donald Trump’s election, Birnbaum has words of warning about the dire path ahead she sees for public health. We ought to listen to what she has to say.

Birnbaum fears that the US regulatory system has become too politicized, too beholden to corporate money and power, and lacks the urgency and political will needed to address dire health crises around the globe. Many of those crises are tied to the climate emergency, which she considers the “biggest threat to humanity.”

“Everyone should be worried about that,” she told me. “The impacts on health are myriad and we’re seeing them now. It is not just about remote places like the Arctic, but about the health of people everywhere.”

Along with the obvious environmental damage, increasing flooding, fires, extreme heat and drought, combined with rising CO2 levels, also contribute to sicknesses and disease. The extreme weather also leads to a loss of micronutrients and protein in many food crops important for health, she says.

Those most at risk from complacency are children, who are particularly vulnerable to the air and water pollution associated with climate change.

Also troubling Birnbaum are the impacts of exposures to pesticides and other chemicals on children and other vulnerable populations.

From neurotoxic insecticides to a class of industrial chemicals known as PFAS, increasingly research shows that low level chronic exposures to a toxic soup of multiple pervasive pollutants jeopardizes the health of current and future generations, she said.

“We have a very small world,” Birnbaum said. “People need to understand that pollution is global, not local,” and “it’s not just high-level acute exposures that are doing damage”. Low-level exposure is also dangerous, and people have different susceptibility. “An old person and a healthy adult and a little child are impacted differently.”

Part of the problem is the way that resources are allocated. “Infectious diseases are where so much of the money goes but that is not the biggest killer anymore,” she said. “It’s these chronic low levels of exposure, and long-term effects of early life exposure, which are hard to identify and are causing so much damage.”

The Trump administration’s recent decision to continue to allow farmers to treat food crops with the insecticide chlorpyrifos, done at the bidding of Dow Chemical, is a prime example of how children’s health is taking a back seat to corporate interests, according to Birnbaum.

The science showing that chlorpyrifos harms brain development in children is “open and shut”, Birnbaum said, with concrete evidence that “exposure to chlorpyrifos impacts learning and memory and behavior in children”.

Similar comments got Birnbaum in trouble with lawmakers a year and a half ago, when she was accused by Republicans of violating anti-lobbying laws for calling for more protective public health policies.

The ensuing pressure, including an investigatory demand for her emails and other records, cost her an annual raise and curtailed her ability to speak freely.

Birnbaum said the pressure was not a factor in her decision to retire. She has a hand-picked leadership team in place, increased funding for the institute, and a strategic plan that she feels leaves the institute “in a good place”. She had planned to retire two years ago but the election of Trump made her decide to stay to ensure the institute stayed on course.

And after her retirement becomes official on 3 October, the 72-year-old Birnbaum says she will continue sharing her scientific knowledge, and is particularly interested in working with people running for office. “I am not walking away from science,” she said.

Let’s hope America doesn’t walk away from science, either.