No doubt about it, the sea is rising. Fast. It’s already high enough that coastal cities flood even without storms or torrential rainfall, they can flood from extemely high tide alone. This is a huge problem, already costing hundreds of millions of dollars for cities like Miami. It will cost even more, a lot more, in the future — the near future.
It’s also high enough that when storms come, especially those that bring big “storm surge” which leads to flooding, the sea is already higher than it used to be so that makes the flooding far worse. Ask the folks in New York and New Jersey. They know.
But Albert Parker/Boretti just wants to talk about one thing. He’s not denying that sea level is rising (very few are that stupid). He wants to tell us that sea level isn’t accelerating, i.e. that the rate of rise itself isn’t increasing. But he can’t back that up with anything but smoke and mirrors.
What evidence does he present? He urges you to visit the trends page at PSMSL (Permanent Service for Mean Sea Level). There, you can view a map of sea level trends for a variety of time spans, and you can choose the time span yourself (there’s a slider below the map). Only locations with enough data are included (at least 70% of years within the specified time span).
Parker begins with European stations and a time range from 1900 to 1975. That gives this:
Then he extends the time range to 1900 through 2014, which gives this:
Then he says this:
· Surprise, surprise, no major changes …..
· Do you spot any significant change?
· Those that are claiming the sea levels are rising sharply than ever before at an accelerating rate are simply not telling the truth.
· This may realize (for now) downloading and analyzing the PSMSL data, or even analyzing the data online.
· In a few years’ time, also this data base will be corrupted and the truly measured data will be replaced by computations or reconstructions.
There are fascinating aspects to his “analysis.” Foremost is that fact that there isn’t any.
It’s just “look at this” followed by “look at this” followed by “Surprise, surprise, no major changes.” Then comes the inevitable “Do you spot any significant change?” Yes, I do. But then, I looked closely and I know what I’m looking for. Most readers don’t, and don’t.
Also interesting is the comparison of 1900-1975 with 1900-2014. If you’re looking for changes, why compare two time spans that overlap (in fact, the 2nd time span includes all of the 1st). Why not just compare the separate time spans 1900-1975 and 1976-2014. Even better, make that later one 1976-2015 (since there’s another year in the PSMSL database).
Of course, including 2015 would require downloading the data and anlyzing it yourself, because their “trends” tool doesn’t include it yet. Downloading data and analyzing it yourself … what kind of blog would do such a thing?
We would. We’ll take every station in the PSMSL, extract the data from 1900 onward, and select only those which have more than 80 complete years of data (that’s 69% of the time span). Then we’ll remove the seasonal cycle and fit a continuous piecewise linear trend, allowing a trend change in 1976. That will estimate the rate of sea level rise in the two separate time spans. We can even estimate the change in the rate of sea level rise.
Station #1, for instance, is Brest in the northwest of France, and has 102 complete years since 1900 — plenty to meet the selection criteria. It gives this:
Here’s a close-up on the trend fit alone:
But we don’t just want to do a single station. There are 89 which meet the selection criteria. Here’s a histogram of their changes in sea level rise rate:
A couple of those are way out there — I don’t trust ’em. So let’s remove those:
Either way, removing outliers or not, the bulk of them show positive increases in sea level rise rate. The vast majority, in fact. If we test whether or not they are, en mass, positive or negative, we can’t rely on the super-strong statistical significance of a t test because they’re obviously not following the normal distribution. Rather, we should rely on the super-strong statistical significance of the non-parametric Wilcoxon rank sum test.
We can also make a little map of the change in sea level rise rate for European stations. It won’t have the coastal borders like that from the PSMSL trends page, but it will show how sea level rates have changed rather than just what they are (up arrows for increasing sea level rise, down arrows for decreasing):
Somehow, Albert Parker/Boretti managed to take these data and claim “no major changes.” Perhaps more amazing is that he probably actually believes it.
Sea level rise is one of the biggest problems we’ll face in upcoming decades, in fact it’s a problem now. How bad it’s going to get is highly uncertain. But as recent research shows, we could be in for a truly terrible century. Of course there’s tremendous uncertainty … but uncertainty is not your friend.
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