I’ve decided to apply some area weighting to my sea level estimate based on my new method.
I’ve spoken before about my new way of aligning tide gauge stations. Maybe it’s time for me to outline some of the details, and share my program (written in R) for doing the computation.
Dangendorf et al. have made a new estimate of global sea level since the year 1900, based on data from tide gauges around the world. I’ve compared it (which I’ll call Dang) to the most trusted data set (in my opinion) from Church & White (which I’ll call CW), to the dataset I have criticized from Jevrejeva et al. (which I’ll call Jev), and to my own reconstruction (which I’ll call me) based on my own method of correcting for VLM (Vertical Land Movement). The first thing to note is that my own data doesn’t include proper area weighting, and can only be considered seriously flawed. But it is my own, so we’ll see how the new kid on the block compares to it, as well as to well-known data sets. Here’s the new data from Dang:
Dave Burton, you still don’t understand.
You finally commented on this post, showing a graph of San Diego data and saying:
As you can see, there’ve been >112 years of continuous measurements, and still no detectable acceleration.
Not true. I detected acceleration. You don’t believe it. Then you gave us this:
Dave Burton has visited, and commented extensively on this post. He takes exception to the sea level data I used, and suggests that sea level has been rising at a steady, unchanging rate “since the late 1920s.” To quote him:
Neil, many locations have seen a little bit of acceleration “since the 1800s” — but not since the late 1920s.
Is that true? I’m skeptical.
It’s been a while since Foster & Rahmstorf (2011) took global temperature time series and removed our best estimate of the changes due to known fluctuating factors, the el Niño Southern Oscillation (ENSO), aerosols from volcanic eruptions, and variations in the output of the sun. After removing fluctuations of known origin, what was left over was a very steady rise in global temperature.
I’ve improved (I believe) the method by allowing for more detail in the response to ENSO. I now allow both a “prompt” (not necessarily immediate) and “more delayed” response, as well as a seasonal pattern to the ENSO response. I’ll probably expound on those details at some point, but not now. Now, let’s look at the results.
The streets flood even without storm, rain, wind, even on a calm sunny day. It didn’t used to happen, but now the highest spring tides of the year (around October) bring flood waters, septic systems back up, waste oozes onto streets and lawns, saltwater leaks into groundwater and spoils drinking supplies. It’s not a pretty sight, and it’s not confined to Miami and New Orleans, it’s all along the coast.
It’s an undeniable sign sea level is rising. But one wonders: how fast?