Do you believe in gravity? I know it sounds like a silly question, but stay with me: whether you believe in gravity or not—and why you do—is critical to the future of the planet.
Let’s assume that you do believe in gravity. Why do you believe in gravity? I suspect there are three reasons. The first reason is that it is consistent with your observations, where you remain grounded on the earth when you walk across the room and a ball thrown in the air falls back to the floor. The second reason is that there is a theory developed by scientists that explains those experiences but also explains how airplanes can fly and why astronauts float weightless in space and the earth orbits the sun. The third (and most important) reason is that it is very useful as a guide to living your life: you avoid walking off of ledges because the theory of gravity and your observations consistent with the theory of gravity predict you will fall and hurt yourself seriously if you didn’t believe in gravity.
That’s the real value of believing in gravity: it helps you avoid bad outcomes in living your daily life. People who don’t believe in gravity tend not to live very long in a gravity-based universe. So we generally treat the theory of gravity as if it were a fact in our world.
Do you also believe the earth orbits the sun? If so, why? Our own personal daily observations of the sun don’t tell us that this is true; if anything, it appears to the casual observer that the sun orbits the earth. More careful observation about changes in the pattern of the sun tracking across the sky each day and across the seasons, however, led brave scientists to develop new theories about that relationship that eventually blossomed into a belief that the earth actually orbits the sun. Further observations solidified this theory, and this is now treated as a fact in our world. Like our belief in gravity, this allows us to avoid bad outcomes in living our daily lives: we can predict when the seasons will shift, know when to plant and harvest our crops, or know why human snowbirds migrate from the Midwest to warmer climates during the winter months (which has important economic consequences). So we behave as if the earth orbiting the sun is a fact.
Not all people actually believe that the earth orbits the sun—about one-quarter of Americans answered otherwise in a 2012 survey, while one-third of Europeans got the question wrong in a 2005 survey. But we operate our society (and our weather satellites, our air traffic control system, and many other systems that depend on this crucial fact) as if it were true. The fact that some people don’t believe the earth orbits the sun hasn’t really affected our reliance on the combination of scientific theory and empirical observation to treat it as a fact. Our nation was forged in the Enlightenment, so we have constructed a society and a government that is deeply rooted in science and rational discourse for collective decisions.
Which brings us to the politicized question “do you believe in climate change?” and its close cousin, “do you believe humans are causing climate change?” Some people, like our new President and his nominees, say that we just can’t know for certain what is causing climate change. Others, like myself, believe we should rely on the same rationale for climate change that we apply to other scientific questions such as the existence of gravity and whether the earth orbits the sun. And my reason for doing so is the same: it will help us avoid really bad outcomes that could otherwise be avoided. As for gravity, physics and facts don’t really care about your belief if you try to walk across the airspace between two buildings. Physics and real-world facts apply to people regardless of whether or not they believe in gravity.
And so it is for climate change and our human role in it: based on the classic combination of observations and theory, scientists have reached the clear conclusion that humans are one of the primary causes of climate change that is increasingly becoming evident from a wide range of empirical observations. We no longer simply call it global warming, however, because that simple phrase fails to capture the many ways in which an increase in average temperatures associated with emissions of greenhouse gases is causing a range of other changes that may sometimes not seem to be consistent with warming. Colder winters in some areas, more extreme rainfall events, and sea level rise are all consistent with the theoretical models that relate an increase in greenhouse gases from human activity with changes that matter in our daily lives. A snowball inside Congress doesn’t negate either the theories behind climate change science nor the role that humans play in climate change. It is just a prop that is more like a magic trick that may appear to defy the laws of gravity: it presents a distracting illusion that is of little value once you step off of that ledge.
Gravity doesn’t care if you believe in it. And neither does climate change. Physics and facts have a powerful way of defeating mere belief when the latter is not grounded in either. As a society, we have to acknowledge that physics and facts—rather than belief—will determine the effects of our future actions regardless of what we do or don’t believe. We otherwise run the risk of running our collective lives off a steep ledge and falling into disaster. And that is precisely what the new President and his cabinet nominees want us to do: to step off a huge ledge as a society based on their belief that climate change is not a fact. They will try to distract us with magical illusions, but physics and facts will have the last word.
To say that climate science is uncertain or inconclusive or that there are disagreements about whether climate change is serious or primarily caused by humans is to substitute public misunderstanding of basic scientific theory and facts for the well-developed and tested views of scientists who have been studying the problem thoroughly for decades. Physics and facts don’t care that one-quarter to one-third of Americans and Europeans don’t believe that the earth orbits the sun. The earth orbits the sun and societies that don’t believe it are doomed to misery and deprivation due to their ignorance. The same is true for climate change: it is happening, it is caused primarily by humans, it is already causing misery and deprivation, and we can do something about it if we rely on physics and facts.
The new President and his administration owe it to all Americans to rely on physics and facts when making climate, energy, and environmental policy—no matter what they or their economic interests or their political supporters believe. Otherwise, we will all soon be falling off that ledge. And changing our belief about gravity won’t help once we start falling.