The Oxford Dictionary’s word of the year for 2016, “post-truth,” may as well be repeated for 2017.

Science and truth are under siege all around us. High-level decision makers in the United States are casting doubt on scientific understanding, defending false information and making decisions in the absence of evidence.

This weekend, thousands will join the March for Science in Washington, D.C. and sister cities all over the world. They will march because the alternative to making decisions based on evidence is making decisions based on emotions and political motives, which can lead to dangerous outcomes. They will march because the Trump administration is proposing to defund critical scientific research programs, which sound decision-making depends upon. They will march because too many Americans – 70 percent – cannot name a living scientist. They will march because facts underpin our democracy and justice system, and because science is the foundation of environmental and health protection.

They’ll also march because science has never been quite so threatened in the United States.

Where is truth under siege?

From the size of the inauguration to questioning the credibility of reputable media outlets, the Trump administration has shown that evidence does not carry much weight. Cabinet members have called into doubt the extent to which human activities have contributed to climate change, which has been well established in the scientific literature. Climate deniers are being considered as the president’s science advisor. And the administration has proposed significant budget cuts to climate science and technology research, such as to climate research at EPA and its Office of Research and Development; NOAA’s satellite division; the Advanced Research Projects Agency (ARPA-E), which funds research in energy technology development; and NASA Earth science missions, among others.

What is contributing to attacks on the truth?

Those that are ignoring facts and undercutting science typically have an incentive – financial or otherwise – to do so. For example, corporate interests that depend on a high-carbon economy seek to influence policy outcomes through campaign finance and close ties to cabinet officials. There are others that seek out different ideas because the truth contradicts their beliefs.

Technology advancements have undermined truth, too. Now with various forms of social media, it is easy to spread information and create “echo chambers“ in which once-fringe ideas can be reinforced by others, become louder and shut out accurate information.

What are the consequences?

When facts are redefined, we find ourselves on a slippery slope. Data can be manipulated to support arguments, and policy is no longer informed by facts. It can also create a debate where there isn’t one. While American understanding of climate change has greatly advanced over the years, we could see a retreat in understanding as people try to make sense of the “alternative facts” from elected officials.

It can also harm scientific innovation and basic research, which had previously been supported on both sides of the political aisle. The recent budget proposals would make it more challenging to predict extreme weather events and climate impacts, making it difficult for officials to plan for fires, floods and water availability, and for scientists to keep track of changes in the Earth’s climate. Universities, national laboratories and international research efforts also often depend on federal funding for science, so budget cuts could have a knock-on effect well beyond Washington, D.C.

What can scientists to do?

Scientists have a number of vehicles available to address mistrust in science. First, they can better describe the implications of their research -- how it will affect people, infrastructure and ecosystems that communities rely upon. Otherwise, it is easier to discount science because its relevance remains unclear.

Second, it is essential to find well-trusted scientists who are also good communicators. One example is Katherine Hayhoe, a climate scientist and co-director of Texas Tech University’s Climate Science Center. She’s been lauded for not only having tremendous scientific expertise, but powerful communication skills to reach audiences like conservative religious communities.

It will also be important for scientists to separate their findings (e.g. warming is occurring at a certain rate) from assertions about what to do about them (e.g. adopt certain policy proposals, such as carbon pricing). The latter is about acceptable levels of risk and decision-making preferences, which people may disagree upon. It is easy for people to conflate disagreements about solutions with our very solid understanding of climate science.

Scientists can also speak up against the attacks on their research areas. Already, 30 top scientists sent a letter to EPA Administrator Scott Pruitt after he questioned the role of human activities in climate change. Many will march this coming weekend. Scientists can also take measures to protect science by sharing documents and backing up data.

But we all know that one-off marches, letters and data backups will not be sufficient. Some have also called for scientists to be much more engaged in their communities, offering their time to churches, schools, elected officials and those who don’t understand climate change.

Scientists can also become decision-makers themselves! 314 Action recently formed to help those with scientific backgrounds run for office so that policies are made by those who value evidence-based decisions.

Science and Government at a Crossroads

Scientific inquiry will not be cowed down with these attacks and continue to march onwards. The question is whether the government will use it to inform their policymaking.

The climate certainly isn’t going to act differently because some individuals in Congress and the cabinet don’t believe scientific consensus. Huge sections of the Great Barrier Reef are bleaching and dying. We have seen record-shattering low levels of Arctic and Antarctic sea ice. Sixteen of the warmest 17 years on record have happened this century. At the end of the day, facts will be the final arbiter of what happens to the climate and society.