On Monday evening, the New York Times published a draft version of an interagency special report on climate science that’s chock-full of observations that climate change is already observable here in the United States. The report was made public back in January via the non-profit Internet Archive, but didn’t grab any sort of widespread attention until the NYT got involved this week. Each and every one of the draft’s pages are emblazoned with the words “DO NOT CITE, QUOTE, OR DISTRIBUTE,” commands that were disobeyed presumably out of fear that the Trump Administration would attempt to quash the report’s contents.
That may have been a legitimate concern. The President’s tweet labeling climate change as a Chinese hoax is well known, but that rejection of mainstream science extends into his cabinet, too. Scott Pruitt, the head of the EPA, rejects the well-established fact that carbon dioxide is a greenhouse gas, and is causing a rise in surface temperatures. Energy secretary Rick Perry touts a more watered down form of climate skepticism by saying that he doesn’t believe human activity is “the primary control knob” of our climate. This week, Secretary of State Rex Tillerson sent a message to American embassies around the world instructing diplomats to evade questions about U.S. commitments to combatting climate change in the wake of Trump’s decision to pull the country out of the Paris accord. One at least can understand why scientists might be concerned that this report, part of a congressionally ordered quadrennial National Climate Assessment, might not get the green light from the Trump Administration.
One of the most interesting parts of the leaked report concerns the various connections between climate change and weather. But before we dive in, a little bit of housekeeping. First and foremost, it’s important to remember that weather is not climate. The two affect one another, but when we discuss climate and changes in climate, we’re doing much more than simply noting that it was hot on Tuesday. Climate occurs over years, decades, and centuries, while weather can seldom be accurately predicted even a week out. Conflating these two concepts is one of the most common—and yet most easily avoided—pitfalls in the heated (sorry) climate change debate. When Senator Jim Inhofe brought a snowball onto the Senate floor, he made his climate skepticism look foolish, not justified. When Al Gore remarked in his newly released film, An Inconvenient Sequel, that “every storm is different now” thanks to climate change, he watered down (again, sorry) his case that we’re already seeing warming’s effects. This gets to one of the central difficulties most of us have when it comes to grappling with climate change: it occurs on a time scale that’s foreign to the manner in which we’re accustomed to thinking (and it certainly occurs on a much longer time scale than the length of time policymakers are in office). Because of that, we often see politicians and activists on both sides of the debate putting their feet in their respective mouths.
Still the fundamentals of climate change are easy to grasp. Gases like methane and carbon dioxide work to trap more of the sun’s radiation in our atmosphere, much like the glass of a greenhouse, and increases of their concentrations lead to rising surface temperatures. That causal chain is “settled,” as much as science can ever be.
But there’s still much that’s unsettled in climate science, thanks to the enormous complexity of the system scientists are studying. There are a mind boggling number of variables at play here, and they interact with one another in ways both known and unknown, the results of which can often confound the predictions of our best models. Climate change is real and it’s happening in large part because of humanity’s industrialization, but things get quickly get fuzzy when we move further into the field.
That’s why it’s so interesting to see this special (draft) report taking on one of the most difficult to pin down aspects of climate change: its relationship with weather. We can already measure summers getting hotter across much of the globe and winters getting milder, but the day-to-day weather effects are harder to predict. Researchers are increasingly focused on climate’s effects on extreme weather, not only because these events can wreak havoc on civilization centers and are therefore important to forecast, but also because it should be easier to draw a link between these events and climate change than it would for milder weather.
Still, even these kinds of observations can be fraught. For example, the report claims with “high confidence” that climate change is projected to cause increases in precipitation rates in hurricanes and typhoons, and projects with “medium confidence” increases in intensity. And yet “[the] current 11-year (2006–2016) absence of U.S. 7 major hurricane landfall events (sometimes colloquially referred to as a “hurricane drought”) is unprecedented in the historical records dating back to the mid-19th century,” the report acknowledges a few pages later. Scientists have differing explanations for this historic luck for the United States that range from landfalls being essentially random, to a 2016 study’s hypothesis that “conditions conducive to hurricane intensification in the deep tropics occur in concert 19 with conditions conducive to weakening near the U.S. coast.” Another study cited by the report calls into question “uncertainties in the historical data,” a perennial problem for climate scientists when you consider that we only started paying close attention to these phenomena recently.
Climate science is most convincing when it is framed in general terms, and this report is no exception. “There are no alternative explanations, and no natural cycles are found in the observational record that can explain the observed changes in climate,” the report says. The evidence for these changes are all around us, “from the top of the atmosphere to the depths of the oceans,” and the more we study it, the more bad news we seem to uncover. We’re well past the point of equivocating about whether this is actually occurring, or whether humans are responsible for it—the experts we trust to delve into this problem have answered those questions definitively.
Nevertheless, much of the public and most of the current Administration seem loath to take positive action on climate change. In an attempt to convince the non-believers, many environmentalists are placing an emphasis on the rising risks of extreme weather, and it’s not hard to see why: if you can definitively link the visceral impacts of natural disasters with the more nebulous concept of climate change, you’d be able to make more people care about this problem. That said, establishing that causal link between a warming planet and any specific storm is very difficult, and if done incorrectly it could easily make people more mistrustful of the more well understood aspects of climate science.
That’s not to say that this isn’t a subject deserving of further research—for aforementioned reasons it absolutely is, and this draft report is full of examples of those sorts of studies. But greens like Gore that use extreme weather to try and persuade skeptics play a dangerous game, and they often do so with little regard for what the actual scientists are saying.