January 22, 20256 min readWhat Trumps Blitz of Executive Orders Means for ScienceAfter his second inauguration, President Donald Trump signed a host of executive orders, some with important implications for scienceU.S. President Donald Trump speaks while signing executive orders in the Oval Office of the White House in Washington, D.C., on Monday, Jan. 20, 2025. Jim Lo Scalzo/EPA/Bloomberg via Getty ImagesSoon after being sworn in as the 47th President of the United States on Monday, Donald Trump signed a slew of executive orders that could reshape science at home and abroad. The orders which direct the actions of the federal government but cannot change existing laws are designed to shift policies and priorities on several scientific issues, including climate and public health. They also aim to cut the government workforce, which includes scientists, and potentially reduce its authority.It remains unclear how much weight many of the orders will carry, but policy specialists who spoke to Nature say that they clearly mark the direction Trump intends to steer the United States during his second term in the White House.A lot of the power of executive orders is in the messaging, says Gretchen Goldman, president of the Union of Concerned Scientists, an advocacy group based in Cambridge, Massachusetts. And the message thus far is clear, she says: The administration is trying to undermine the government experts themselves, as well as the processes by which we make science-based decisions in government.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.Here Nature examines some of the executive orders that are most relevant to science.Changing climateTrump signalled in one order that similar to his first presidency from 2017 to 2021 he would pull the United States out of the 2015 Paris climate agreement. Citing both national security concerns and the impact of high energy prices that devastate American citizens, Trump also declared a national energy emergency at home, an action that could enable his government to greenlight fossil-fuel-based energy projects.Trumps emergency order, one of many focusing on energy issues, would allow US agencies to identify energy projects where federal regulations and laws protecting, for instance endangered species, are holding up progress, according to the president. Agencies would then be authorized to move more quickly to approve projects, including through the use of any lawful emergency authorities.But there are limits to what Trump can accomplish, because in many ways, the economy trumps Trump, says Mark Maslin, an Earth-system scientist at University College London. For instance, Maslin says, its now much cheaper to invest in renewable energy sources such as solar and wind than it used to be, and that means that investments in those technologies will continue.Comparatively, Trump will have an easy time withdrawing the United States from the Paris accord, which commits nearly 200 countries to limiting Earths warming to 1.52 C above pre-industrial levels. During Trumps first presidency, his administration had to wait more than three years before formally withdrawing from the pact because of the rules of the agreement. Joe Biden, who succeeded Trump as US president, quickly rejoined. This time, the exit process will require only one year.Although the Paris agreement will continue to function without the United States the worlds second-largest emitter of greenhouse gases many scholars worry that a US exit will inevitably reduce pressure on other countries to act. This follows Earth reaching its highest temperature on record last year, and scientists say that countries must increase efforts to curb emissions if they are to achieve the global goal.Anything delaying or halting that effort will lead to lives lost on the ground, Goldman says.In withdrawalAs expected, Trump also signed an order to withdraw the United States from the World Health Organization (WHO), a United Nations agency responsible for global health that the new president alleges mishandled the COVID-19 pandemic. He has also said that the United States pays a disproportionate amount of dues to the agency compared with other member nations.Trump announced that the United States would leave the WHO in May 2020, during his first presidency, but because the process takes one year, Biden blocked it on his first day in office in 2021.Public-health researchers say that leaving the WHO will cripple the countrys ability to respond nimbly to emerging health threats and curtail the countrys reputation as a global-health leader. Because its annual contribution makes up more than one-tenth of the organizations budget of billions of dollars, the United States withdrawing from the WHO could also kneecap the agencys mission. It is a very worrisome signal to the global community about our seriousness as a partner in protecting health, says Jennifer Nuzzo, an epidemiologist who directs the Pandemic Center at Brown University, in Providence, Rhode Island.The WHOs member countries share information and expertise on infectious-disease outbreaks and other threats, and without this key knowledge and data for instance, the DNA sequence of an emerging virus the United States will be slower to respond to crises, Nuzzo says. In addition, the withdrawal creates opportunities for other countries to step in and assert themselves in ways that might not be compatible with US interests, she says. For example, the United States has been a leading voice calling for stringent biosecurity measures in the construction of new pathogen-research centres around the world, she adds.A US pullout from the WHO could also imperil collaboration with the US Centers for Disease Control and Prevention (CDC), says David Heymann, an infectious-disease epidemiologist at the London School of Hygiene and Tropical Medicine and a former assistant-director general at the WHO. The flagship US public-health agency runs more than a dozen WHO collaborating centres in areas ranging from influenza surveillance to antimicrobial resistance. It would be a loss for CDC, but it would be a loss for WHO, he says.It is unclear if Trump can withdraw from the WHO using an executive order, because the United States accepted membership in the agency in 1948 through a law passed by the US Congress. It might, therefore, require Congress's approval to leave. Lawrence Gostin, a specialist in health law and policy at Georgetown University in Washington DC who directs a WHO collaborating centre, said on the social-media platform X that he is considering challenging the order in court.Deep cutsSeveral of the orders Trump issued on 20 January focus on the federal workforce, which includes roughly 280,000 scientists and engineers. The Trump administration is seeking to reduce its size and regulatory power.In one, Trump says there will be a 90-day hiring freeze for the federal government, with the directive to reduce the size of the federal workforce when the order expires. Other orders might coax federal employees to leave their jobs themselves: for example, Trump is seeking to mandate that federal employees return to the office full time, and requiring agencies to recognize only two sexes, male and female, which would, for example, prevent employees from listing their preferred gender on official documents.All of this is part of a broader effort to slash spending and the size of government. For many observers, the message for science is clear. This is the world were going to be in, says Robert Atkinson, the president of the Information Technology and Innovation Foundation, a non-profit think tank based in Washington DC. Were not going to be expanding science. Were actually going to be cutting it.Yet another executive order focuses on a change to the rules governing civil servants those hired on the basis of their expertise rather than as political appointees. Stating that all federal employees who work on policy-influencing positions must be accountable to the president, the order reinstates a policy formerly known as 'schedule F' that the Trump administration attempted to put in place during his first term in office. It would have made it easier for the administration to fire tens of thousands of workers, including many government scientists, and replace them with political loyalists. The Biden administration revoked that order and also put in place a new rule designed to enhance civil-service protections. The Trump administration is nonetheless moving forwards with its schedule F changes which are already being challenged in court by a union representing public employees.It represents an unprecedented politicization of the civil service, says Don Moynihan, a political scientist at the University of Michigan in Ann Arbor. Traditionally, we have this clear dividing line between political appointees and the career civil service. Schedule F seeks to blur, if not completely erase, that dividing line.While some areas of science and technology, such as AI and quantum computing, are expected to benefit under the second Trump administration, the barrage of Day 1 executive orders did not inspire confidence in researchers or policy specialists. I actually am more worried now than I ever have been, Atkinson says. I think the stars are aligning in a way that could really hurt the science community at the federal level.With additional reporting by Ewen Callaway and Miryam Naddaf.This article is reproduced with permission and was first published on January 21, 20245.