Understanding Sea Level Rise

Sea level rise is complicated. But some people think its future course is oh so simple, and the recent visit by a certain Mr. Wakefield showed just how determined he is to stick with what I call the “simpleton’s view.”

It started with a post I did about Willis Eschenbach’s mistaken claim about sea level rise at individual tide gauge stations, that they show steady rise at a constant rate, surely not speeding up (accelerating). Looking at data from 63 tide gauges around the world, Eschenbach said “NOT ONE of these 63 full tidal datasets shows statistically significant acceleration …” I showed that Willis was wrong, using exactly the same data he had used. To his credit, Willis didn’t keep insisting he was right about that. He still maintains that any acceleration you can find is unimportant (I disagree), but at least he didn’t insist that his initial analysis was right after it had been shown wrong.

One of my example cases was Boston, which prompted Mr. Wakefield to comment here, saying this:

Your Boston graph is cut way too short, why did you do that? Data for it goes back to 1920s, and shows NO acceleration.

He then linked to a graph of the Boston data (from NOAA). I could tell (and so could others) that he was “spoilin’ for a fight.”

The choice to use only data since 1950 was Willis Eschenbach’s, not mine, so he couldn’t criticize me for it (Eschenbach is, apparently, on “his side” — he seems to have divided us into “sides”). Perhaps that disappointed him.

He followed with further comments, levelling further criticisms on further topics. If we’re going to argue about multiple issues, it’s only fair to take them one at a time. Since his very first claim was that Boston data “shows NO acceleration,” I decided to deal with that first, so I did yet another post about the Boston data specifically, this time using all of it. I showed, beyond a reasonable doubt, that the tide gauge data from Boston does show acceleration recently (and deceleration too, earlier), it’s definitely doing more than just following a straight line plus random noise. Now he could either provide counter-evidence, or drop that pretense and admit his mistake; then maybe we could move on to some of those other things.

No such luck. He didn’t seem persuaded, but had no evidence to offer, he just wanted more proof:

OK so assuming this is from sea level rise and not a local caused short term phenomenon, do a few other stations, like in Australia and Brest, France. Both very long measurements.

So far, we couldn’t even get past his first claim of “NO acceleration.”

So I did yet another post, about the data from Brest, France and Australia. I not only examined data from Brest, France and “a few other stations” in Australia, I even formed a composite of 81 Australian stations’ data. I also insisted that we deal with this issue — acceleration in tide gauge data — before moving on to others. There it was, acceleration (and deceleration). Maybe he would now be convinced? Then we could get to some of the other issues, having finished with this one?

Not a chance.

He attempted to refute my demonstration, in three ways. First, he linked to graphs (from NOAA) of some of those other stations, and said “Not even NOAA plots an accelerating curve through those.” Of course not; they didn’t try to, they make it quite clear that they’re just fitting a straight line (whether it’s following a straight line or not) to estimate the average rate of sea level rise over the whole record. Second, he linked to a paper by researchers who not only bungled their analysis, one of them has a history of just making up stuff. Third, he commented about some of those other issues besides tide gauge data from individual stations.

So I told him, in no uncertain terms (as I already had), to stick to the subject at hand — we can get to the other issues after we finish with this one. All he had to do was either provide some real evidence, or admit that yes, there are individual tide gauge stations which don’t just follow a straight line, they even show acceleration. Not a huge concession, but it would at least put this one issue to rest. It was time to “put up or shut up.”

He kept trying to turn the discussion to other issues. I wasn’t having it. Deal with the issues one at a time, and deal with this one before we get to the others. That’s not asking too much, and it prevents the kind of “discussion” where we can never make progress on anything because when one issue gets too “hot” for him, he just switches to another.

Evidently he had no real evidence to offer, and wasn’t willing to admit the truth, and since I wasn’t allowing discussion of other issues while this one was still on the table, the frequency of his comments has dwindled. We’ve waited long enough, we’re done with him.

Why is he (and so many others) insistent on denying that sea level rise is doing anything but rising at a constant, unchanging rate? My opinion: because they don’t want us to do anything about man-made climate change. They can’t deny that sea level is rising — just ask the people of Miami. Every year when the highest tides come (around October) the streets flood; they didn’t used to but now do because of sea level rise. Undeniable. And it’s already costing; the Miami area is already spending about half a billion dollars installing pumps to keep the water off the streets. It’s going to get worse, because the sea will keep rising.

We have every reason to expect that over the years to come it will rise even faster. The present rate, all by itself, spells trouble, not just for Miami but for major metropolitan areas around the world. The threat to Norfolk, Virginia (home to the largest naval base in the world) is enough that the U.S. Navy regards it as a threat to our military readiness. If it rises as far and as fast as the best evidence suggests, then by the end of the century the entire city of Miami will be under water. Trillions of dollars of real estate will be lost. That’s the kind of blow to the economy which will hurt everybody, although it will surely hurt the people who live there most.

So those who want to do nothing about man-made climate change are determined to deny that sea level rise will do anything but keep going at its present rate. A few years ago the North Carolina state legislature even considered legislation (!) to require than any planning to deal with sea level rise could only consider its rising at the current rate, nothing faster. They quickly became a laughingstock. The present rate is bad enough — very bad — but expected future rates are devastating, the kind of trouble that gets attention. No more Miami.

Denying acceleration of sea level rise also gives them something to criticize, namely projections of what future sea level rise might actually bring. By disparaging that, they cast doubt on the competence of climate change researchers in general, which of course serves their purpose to obstruct doing anything about it. Doubt is their product.

There are some important lessons to be learned.

Some deniers will never concede anything, even the obvious. No matter how many times they’re shown wrong, they’ll keep repeating the same nonsense endlessly. That’s why some of their “arguments” are better described as “zombie arguments” — even if you kill them, they just come back from the dead.

Deniers tend to use the “change the subject” tactic — a lot. When the topic under discussion gets too hot for them, rather than admit any mistake they just switch to another.

Focusing on a single issue, until it’s dealt with anywhere near completion, is anathema to deniers. That’s why they tend to argue about as many issues at the same time as they can get away with. Sometimes it becomes ridiculous, raising so many criticisms that it would require massive amounts of time just to discuss them all — it’s a rhetorical technique called the “Gish gallop.”

One of the most effective ways to counter denier propaganda is to force them to stay on topic. When they can’t change the subject to avoid it, they either devolve into ludicrous claims, or just go silent.

The future of sea level rise is a complex issue. As the earth warms ocean waters expand due to absorbing more heat, and how much they do depends on how much the world warms. That depends on what we do. As more and more of the world’s land-based ice melts it adds more water to the oceans, and that’s something we have a very hard time anticipating. It’s complex, but we do know that there are very troubling signs that the great ice sheets in Greenland and Antarctica are starting to destabilize. If either one disintegrates, it’s goodbye to coastal regions and their billions of inhabitants. Human inhabitants.

Alas, the deniers and the fossil-fuel industry have too many politicians in their pockets. Like Florida governor Rick Scott, who seems to have insisted that workers in his own state’s environmental protection agency not even mention the words “global warming.” Like Florida senator Marco Rubio, who denies the danger while the people of Miami are screaming for help from the state and national governments that are supposed to be protecting them.

When you talk to politicians in south Florida, like the mayors of the cities being affected, they do not deny the danger. The people can see it, right before their eyes.

And that’s another one of the problems — that people (including voters) don’t take the issue seriously enough unless it hits them in the face in their own home towns. The sad part is that by the time that happens, we’ve already wasted decades when we could have been working to reduce the damage. Because scientists have been warning us about this, for 30 years now. They say that “forewarned in forearmed,” but when early warning is discredited by know-nothings, too many people take the easy way out and set the issue aside. Instead of being forearmed, we end up disarmed, just when we most need to prepare for what’s to come.

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