Next Saturday, in Washington, DC, and in hundreds of rallies around the world, scientists and their supporters will stage what is likely to be the largest gathering of its kind in history. The March for Science, an idea hatched by a few enthusiastic people on Reddit, has mobilised scientists and their supporters as never before.

As a colleague observed: “You know you’re in trouble when scientists take to the streets.” He’s right. I’ve worked closely with scientists for decades and, by training and temperament, they tend to be happiest in the lab, testing and retesting experiment results – among the last groups of people you might expect to find protesting.

So, why are they grabbing placards now? Because an unprecedented attack on science, scientists and evidence-based policymaking is underway in the US federal government.

Nowhere is the attack more ferocious than on the issue of global warming, where the Trump administration has taken a wrecking ball to the modest but important policies put in place by President Obama. First among them is the Obama administration’s signature Clean Power Plan, the nation’s first-ever limit on carbon dioxide emissions from power plants, which Trump has vowed to repeal. He has also pledged to “reopen” (which could well mean “weaken”) hard-won vehicle fuel economy standards that have already begun lowering carbon emissions and oil consumption. Meanwhile, in a tragic example of wilful blindness, Trump has abolished a rule requiring federal agencies to consider how large federal projects affect climate change and how climate impacts, such as sea level rises and drought, might affect the long-term viability of the projects themselves. This is akin to erecting a building on a fault zone without considering earthquakes.

Thankfully, bureaucratic hurdles make it hard to accomplish these goals with a stroke of the president’s pen. But if the administration succeeds, it may increase by billions of tons the emission of global warming gases and other pollutants that endanger our health; burden our children with much higher costs of fighting climate change; cede the United States’ clean energy prominence to other countries and make it much harder to meet the goals the US set as part of the 2015 international Paris agreement on climate.

There is nothing subtle about Trump’s antipathy to science. As a candidate, he dismissed decades of established scientific evidence by calling global warming a “hoax” and he has displayed an unprecedented disregard for facts and evidence throughout his brief presidency, even on matters as trivial as the size of the crowd at his inauguration.

He picked cabinet members for crucial posts who prominently display their ignorance about or disdain for science. Scott Pruitt, his choice to lead the US Environmental Protection Agency, has stated publicly that he does not accept that carbon dioxide emissions are a primary cause of climate change. Trump’s budget director, Mick Mulvaney, thinks funding research on global warming is a waste of taxpayer dollars.

The anti-science approach extends far beyond climate science. In one of Pruitt’s first official acts, for example, he overruled the recommendation of his own agency’s scientists, based on years of meticulous research, to ban a pesticide shown to cause nerve damage, one that poses a clear risk to children, farmworkers and rural drinking water supplies. What’s more, Trump hasn’t even yet followed in the time-honoured tradition of appointing a presidential science adviser. His proposed budget cuts government science across the board, reducing vital research and data gathering on topics such as sustainable farming methods, weather prediction, the fate and transport of air pollutants and clean energy technologies.

The attack on science is coming not only from the Trump administration. Private groups, such as the fossil-fuel funded Heartland Institute, have mailed extraordinarily misleading booklets entitled Why Scientists Disagree About Global Warming (sic), vowing to make sure that every school science teacher receives this disinformation presumably to weaken the consensus the climate change is real and burning fossil fuels is its primary cause.

Even more worrisome, Congress is using a radical tool called the Congressional Review Act to eliminate numerous public safeguards that took years to develop and is actively working to pass bills that make it harder for federal agencies to issue science-based safeguards for public health and safety. One bill, for example, would prevent academic scientists – but not industry-funded scientists – on federal advisory boards from weighing in on scientific issues within their expertise.These attacks are profoundly unacceptable to many scientists and collective outrage over them has propelled the March for Science and the People’s Climate March planned for the following Saturday.

Yet something even bigger also seems to be brewing. For a long time, many of us have believed that facts speak for themselves, and scientists could remain on the sidelines to avoid “politicising” their work. The recent election and its aftermath have clearly triggered a dramatic re-evaluation of these norms. We have learned – the hard way – that we can’t take respect for facts and science for granted and a large and growing “fact-based” community is rising up. This grouping includes those who rushed to airports to protest against the ban on Muslim immigration and the public and private attorneys who demonstrated in court that the policy had no facts to support it. It includes those who have packed town hall meetings to block a repeal of the Affordable Care Act and shown that the replacement bill fixed no problem at all (except perhaps the tax increases that were levied on the rich to pay for expanded healthcare).

This fact-based community includes journalists who are calling out falsehoods despite being branded enemies of the American people. It includes political leaders from both parties who have insisted upon a thorough investigation into allegations of Russian influence over the election and taken seriously the information assembled by career intelligence officials.

What unites these disparate acts is the principle that demonstrable facts and evidence – not fake news, alternative facts, supposition or innuendo – must form the backbone of public decisions. It is what separates a democracy from a theocracy, monarchy, or dictatorship, all forms of government in which “the truth” is whatever the ruler says it is.

My organisation, the Union of Concerned Scientists, with its more than 500,000 members and supporters, has joined with allies from the climate, environmental justice and labour movements to help organise both the March for Science and the People’s Climate March.

As the demonstrations are likely to show, an enormous number of people understand what is stake. The greatest attack on science in memory may wind up spurring the greatest mobilisation of scientists, and allies far and wide, we have ever seen.

Kenneth Kimmell is president of the Union of Concerned Scientists, a US-based nonprofit organisation



