Today, the House Science Committee is holding a hearing titled "Climate Science: Assumptions, Policy Implications, and the Scientific Method." Why? The stated purpose is to "examine scientific method and process as it relates to climate change." Examine, in this case, is best interpreted in the litigative sense: The House Science Committee's Republican majority has spent the past several years stacking these and other panels with climate skeptics in an attempt to discredit the premise of human-caused global warming.
Earth's average temperature is warming to catastrophic levels because humans are emitting too many heat-trapping gases like carbon dioxide and methane. Climate scientists agree on that premise, even though they argue about many of the particulars---for instance, how fast the planet is warming and how that warming will impact specific weather systems. Skeptics in Congress amplify those debates to undermine the science because they don't like how it gets used to write legislation.
Fine. Politics is politics. But imagine if other branches of science had such regulatory implications. Can you imagine the House Science Committee holding physicists to account for disagreements in the inflationary multiverse theory?
Every branch of science has dissidents. It could even be argued that dissent defines science---it is, after all, grounded in challenging one's assumptions about the world. However, most scientific dissent is arbitrated in published papers---not in the halls of government. Plenty of branches of science, in fact, sustain long arguments over agreed-upon assumptions that don't break the science itself. Let's examine a few.
In 1974, Stephen Hawking provided theoretical evidence that quantum mechanics cause black holes to slowly evaporate. To those who study black holes, this has implications about what happens inside. Is their internal pressure so great that space and time cease to exist? And if that's the case, what exists instead? The details of this debate get very abstract very quickly, but the implications reverberate throughout physics. "The problem is extremely important not only because of what it means for a specific system of black holes, but also with the basic pillars of modern physics, such quantum mechanics and general relativity," says Yasunori Nomura, physicist at UC Berkeley. And though the answer of this question could shake apart what many of the tenets holding together scientists' basic understanding of the universe, it's not a debate that warrants congressional review. Weird.
Scientists can't even agree which direction time moves---or if it moves at all. Of all the things that might warrant some raised eyebrows about the scientific method, you'd think this would be it. The debate centers around entropy, which is the tendency for matter and energy to have an increasing number of quantum states. Or, very generally, the fact that everything is always breaking down and getting colder. The flow of time depends on how much entropy exists in the universe, and how fast everything is entropy-ing. "Since local entropy change doesn’t affect the local flow of time, how could a universal entropy increase affect universal-time---particularly because there is no canonical universal time?" says Richard Muller, physicist at UC Berkeley. Some people have suggested that time as we experience it is actually running in reverse, that time doesn't exist at all, or that it only exists in our heads. Washington, DC itself is evidence for some sort of time warping, because how else do you explain how long it takes to get anything done there.
In all, your body has over 200 different cell types, but nobody really understands what tells DNA to create one cell and not another. "It is broadly agreed that this phenomenon, called cell differentiation, is due to the fact that all genes are not active in all cells at all times," says Fyodor Urnov, geneticist and associate director of the Altius Institute in Seattle. The debate revolves around the roles that various molecular adjuncts to DNA have in turning genetic code into usable proteins. "The key nuance lies in the complex problem of causality. All research science is about this: What causes what?" says Urnov. As an analogy: Nobody may ever know exactly how Donald Trump won the 2016 election. Was it simply electoral math? How influential was social media? What about those Russian hackers? James Comey? Benghazi? What causes what, indeed.
Physics, if you hadn't already noticed, is filled with contentious bickerers. Yet another thing they can't agree on is the universe. Or, universes. See, observational data shows that this universe has an absurdly low volume of background energy. Multiple, parallel universes would explain this. Most physicists actually agree on that crazy bit. "Accepting this picture, however, leads to a problem: The theory seems to lose a predictive power because, in the multiverse, anything that can happen will happen an infinite number of times," says Nomura. In other words, the multiverse as it is generally understood would make it impossible to predict anything. Or, as MIT physicist Alan Guth put it: "In an eternally inflating universe, anything that can happen will happen; in fact, it will happen an infinite number of times.” This would lead to unthinkable occurrences, like maybe the spontaneous appearance of a national health care plan that everybody can agree on.
Africa holds several key biological distinctions. Among them: It's where humans originated; And, it has more large animal species than any other continent. Combined, these facts have led many researchers to speculate that the migration of the former is the cause for the latter: Humans killed all the megafauna. The premise is that the large animals in Africa co-evolved with humans, while the animals on other continents didn't adapt to survive our intelligent, pack-hunting, projectile-weapon wielding wiles. "Some folks maintain that climate alone was sufficient and human population sizes were too small," says Beth Shapiro, paleogenomicist at UC Santa Cruz. But maybe this example isn’t really pertinent. After all, despite the efforts by many intelligent humans, large mammals like elephants and donkeys still survive.
Scientists have known since the 1890s that carbon dioxide traps heat, and have been accumulating evidence since the 1950s that atmospheric levels of carbon dioxide could cause the entire planet to warm. This is physics and chemistry applied planetwide, and as such, there's room for debate. And climate science has debates aplenty: How much carbon do the oceans absorb? How important are other greenhouse gases in relation to warming? How long will it take for carbon dioxide and the other greenhouse gases to release all their stored warmth? Even noted skeptic (and Republican-invited witness at today's House Science Committee hearing) John Christy, atmospheric scientist at the University of Alabama, agrees that human emissions cause warming---he just doesn't think it's enough to be a problem.
But if Congress were truly interested in resolving these disputes, you might expect that they would advocate for more funding to climate and Earth science (rather than do the exact opposite). After all, it's the one science that's solely focused on Earth's capacity to sustain life. But maybe it's a stretch to hope that even that could earn bipartisan support.
