It’s been a long campaign season, and many of us are ready for a respite from barbed political banter. So let’s take a high-altitude look at what this looming election might mean – for our planet.

Perhaps you’ve noticed that the planet rarely features in candidate debates or stump speeches. Political discourse tends to skirt substantive environmental issues and even sidestep empirical science.

For centuries, we’ve relied on evidence gleaned from observing and experimenting to guide policy-making and technological innovation. Yet increasingly, political rhetoric dismisses scientific evidence as if it were a capricious belief – or even “a hoax.”

We are seeing more and more instances, Frederick Rich writes in his new book “Getting to Green,” of ” ‘faith-based knowing’ replacing evidence-based reasoning.”

This phenomenon is spreading to such a degree that journalist Christian Schwägerl recently deemed it a “global contagion.” We’re entering what some call a post-fact society, where emotions and ideology squelch scientific evidence. Hence we have elected leaders and even a presidential candidate who claim not to be big believers in climate change.

Observatories around the world have tracked parts per million of CO2 in the atmosphere for half a century, and several locations routinely record readings now over 400 ppm – a level the earth has not experienced in about 15 million years. This is quantifiable evidence of change, just as dropping a brick demonstrates that gravity is not a belief but a scientific phenomenon that we disregard at our peril.

The dismissal of science in political discourse is deeply disturbing, not only because it denigrates centuries of scientific advances but because that collective process of reasoned inquiry is a cornerstone of our democracy.

Author Shawn Otto explains it this way:

“If anyone can discover the truth by using reason and science … then no one is naturally closer to the truth than anyone else. Consequently, those in positions of authority do not have the right to impose their beliefs on other people. The people themselves retain this inalienable right. Based on this foundation of science – of knowledge gained by systematic study and testing instead of by the assertions of ideology – the argument for a new, democratic form of government was self-evident.”

Science offers a rational common ground where people of different beliefs and partisan views can reach consensus based on, well, reality. Absent that, we risk straying into the ideological la-la-land where some politicians now dwell – a delusional state that can devolve into decidedly undemocratic governance.

One need look no further than Maine’s governor – who wants political activists with whom he disagrees “to be jailed” – or U.S. Rep. Lamar Smith of Texas, whose ongoing subpoena quest is eerily reminiscent of Joseph McCarthy.

To help voters who still value the role that science plays in understanding and improving our world, Scientific American has teamed up with the nonprofit sciencedebate.org to assess presidential candidates’ responses on 20 scientific topics.

A small sampling of these reveals the stark contrast in scores (where 0 is worst and 5 is best) between the primary party candidates:

• Developing a long-term energy strategy – Clinton 5, Trump 0

• Addressing climate change – Clinton 4, Trump 0

• Ensuring access to clean water – Clinton 4, Trump 0

• Improving ocean health – Clinton 4, Trump 0

• Protecting biodiversity – Clinton 3, Trump 0

The assessments are based on central tenets of the party platforms and statements made by both candidates. Trump’s scores reflect his expressed intent to lift moratoria on drilling in federal areas, revive coal (despite market forces favoring natural gas), rescind the Clean Power Plan, eliminate the U.S. Environmental Protection Agency, and “cancel” the Paris climate agreement – a move that 376 members of the National Academy of Sciences claim would produce “severe and long-lasting (consequences) – for our planet’s climate and for the international credibility of the United States.”

As these scores signal, this election matters on a planetary scale, and not just for the next four years. “The 2016 presidential election can really be seen as the most important referendum on climate change and on positive action to make the planet a livable place,” University of California-Berkeley physicist Daniel Kammen recently noted.

More fundamentally, this election will decide whether we base policy on scientific evidence or on ideology. The current presidential race, the editors of Scientific American note, has taken “antiscience to previously unexplored terrain” – with a Republican candidate who has claimed that “the concept of global warming was created by and for the Chinese in order to make U.S. manufacturing noncompetitive.”

Such fact-defying rhetoric obscures a truth that Trump recognized before he placed ideology over science. Prior to that, in 2009, he signed onto a full-page advertisement in the New York Times with dozens of other business leaders affirming that our economic well-being depends on planetary health.

May their words echo in our heads when we cast ballots on Nov. 8: “Please don’t postpone the earth. If we fail to act now, it is scientifically irrefutable that there will be catastrophic and irreversible consequences for humanity and our planet.”

Marina Schauffler is a freelance writer and editor who is online at naturalchoices.com.