The current “settled science” on the relationship between climate change and hurricanes is… some stuff may well happen. If you think such a prediction is hard to test, you’re right. But not to worry. Whatever does happen will be slotted firmly into the category of predicted after the fact. In their Oct. 28 “The Big Question” newsletter, oddly not available online, National Geographic asks “WILL EVERY HURRICANE SEASON BE LIKE THIS?” and comes down firmly on the side of “if climate change continues unabated, scientists predict that more intense hurricane seasons like this one are on the horizon.” How many? When? Can you quantify it? Can you predict it? Um no. But whatever happens we can pounce and say “Told you so… sort of. Vaguely.”
The piece on which the piece is based, by the Geophysical Fluid Dynamics Laboratory, offers “Global Warming and Hurricanes/ An Overview of Current Research Results” which asks “What changes in hurricane activity are expected for the late 21st century, given the pronounced global warming scenarios from IPCC models?” and “Have humans already caused a detectable increase in Atlantic hurricane activity or global tropical cyclone activity?”
The first question is a bit useless because the late 21st century is so far away that we can’t use any such prediction to test the theory. And also because “the pronounced global warming scenarios from IPCC models” are not real-world events or good facsimiles of same. But the second is a bit useful because if we can detect an increase in such activity, and separate out human from natural factors, it would tell us based on what people have already done what might plausibly happen based on what they might do next.
What then do they conclude? Well, for starters, “Sea level rise – which very likely has a substantial human contribution to the global mean observed rise according to IPCC AR5 – should be causing higher coastal inundation levels for tropical cyclones that do occur, all else assumed equal.” Which sounds like something rather than nothing, until you reflect that it’s not exactly rocket science that if sea levels are higher any given storm is likely to push water into something people built. And besides they just say “should” not “are”. Well, are they?
Then we get “Tropical cyclone rainfall rates will likely increase in the future due to anthropogenic warming and accompanying increase in atmospheric moisture content. Modeling studies on average project an increase on the order of 10-15% for rainfall rates averaged within about 100 km of the storm for a 2 degree Celsius global warming scenario.” OK. A thing will happen later. But how much will they increase and when? Even the conclusion that they will go up by 10-15% within about 100 km of a storm if there’s a 2° C increase is vague because we don’t know when and, again, it’s a model piled on a model. No real-world data at all. But at least we could check it if temperatures went up by that much and we could measure rainfall near storms and, crucially, we knew when to check. But we don’t.
Next “Tropical cyclone intensities globally will likely increase on average (by 1 to 10% according to model projections for a 2 degree Celsius global warming). This change would imply an even larger percentage increase in the destructive potential per storm, assuming no reduction in storm size. Storm size responses to anthropogenic warming are uncertain.” Which is hopelessly vague. First, an increase in intensity ranging from 1 to 10% is anywhere from nothing to maybe something: Unless we know how much intensity varies already and how strong future storms were going to be to within a few km/h of wind speed absent warming, there’s literally no way to tell whether they got 1% stronger. Nor, if they get say 5% stronger, can we tell if it’s because the models were right or they were wrong, having predicted 10% and not delivered. Additionally, we don’t know whether to assume a reduction in storm size. Or when it’s meant to happen. (The problem here isn’t just when do we hit 2° C, but is there a lag between doing so and this otherwise scrupulously vague outcome.)
If you’re feeling frustrated, wait, because you also get “The global proportion of tropical cyclones that reach very intense (Category 4 and 5) levels will likely increase due to anthropogenic warming over the 21st century. There is less confidence in future projections of the global number of Category 4 and 5 storms, since most modeling studies project a decrease (or little change) in the global frequency of all tropical cyclones combined.” Eh? Likely is a bit of a weasel word and “over the 21st century” is a rather imprecise time frame. But having said there will be more Category 4 and 5 storms they also say they don’t know whether there will be more Category 4 and 5 storms because modeling predicts a drop in storms. Meaning they’re predicting an increase and a decrease, of unknown magnitude over an unspecified period unless something else happens instead.
Now, what about the rather more precise question whether there’s already a human fingerprint on storms getting stronger if they are getting stronger. To which the story gives a resounding shrug. “In summary, it is premature to conclude with high confidence that increasing atmospheric greenhouse gas concentrations from human activities have had a detectable impact on Atlantic basin hurricane activity, although increasing greenhouse gases are strongly linked to global warming. Some possible human influences on tropical cyclones are summarized above. Human activities may have already caused other changes in tropical cyclone activity that are not yet detectable due to the small magnitude of these changes compared to estimated natural variability, or due to observational limitations.”
Several weeks ago we cited Geoffrey Sherrington’s challenge to alarmists to quantify their claims, to stop the arm-waving and instead say that an increase of X in this input will bring an increase of Y in this output so we can see whether there’s any science here. Instead we’re getting highly tentative statements of a qualitative relationship so vague it’s impossible to see how we might increase or decrease our shaky confidence in whatever it is.
How, you may be wondering, did National Geographic turn that set of suitably qualified scientific lack of conclusions into “scientists predict that more intense hurricane seasons like this one are on the horizon”? The usual way: verdict first, trial afterward.
Here it’s worth noting that National Geographic is so all-in on climate change that arguably it’s under water. Not only in banging the climate change strengthens hurricanes drum relentlessly, but also running with the story about how “as hurricanes are projected to become both more frequent and intense due to climate change” we’re going to see even more invasive species spreading, from apple snails to Burmese pythons to red lionfish to Asian swamp eels to any dang thing you don’t like. Indeed, two years ago it gave a sober and respectful interview to the author of a book claiming climate change had wiped out alien civilizations so we’d better watch out.
“We can say that, yes, there have probably overwhelmingly been civilizations before us. The next step is, does anybody last long, particularly when climate change is going to be a natural consequence of civilization-building?... The “cosmic teenager” idea is that we’re a very young species that’s just coming of age. What I argue is that climate change is our coming of age. I argue that there have been many civilizations before and, if you are a technological civilization like ours, you can’t help but trigger climate change. Every young civilization is going to trigger their version of the Anthropocene…”. (That the tail said the NG guy “curates Book Talk” rather than hosting or editing it doesn’t help.)
And if they can wipe out alien species nobody ever saw the slightest evidence of through climate change nobody ever saw the slightest evidence of on planets nobody can name, well, the hurricane thing is easy.