Guest post by David Middleton
When the observations don’t match the models, adjust the observations…
Satellite snafu masked true sea-level rise for decades
Revised tallies confirm that the rate of sea-level rise is accelerating as the Earth warms and ice sheets thaw.
Jeff Tollefson
17 July 2017
The numbers didn’t add up. Even as Earth grew warmer and glaciers and ice sheets thawed, decades of satellite data seemed to show that the rate of sea-level rise was holding steady — or even declining.
Now, after puzzling over this discrepancy for years, scientists have identified its source: a problem with the calibration of a sensor on the first of several satellites launched to measure the height of the sea surface using radar. Adjusting the data to remove that error suggests that sea levels are indeed rising at faster rates each year.
“The rate of sea-level rise is increasing, and that increase is basically what we expected,” says Steven Nerem, a remote-sensing expert at the University of Colorado Boulder who is leading the reanalysis. He presented the as-yet-unpublished analysis on 13 July in New York City at a conference sponsored by the World Climate Research Programme and the International Oceanographic Commission, among others.
Nerem’s team calculated that the rate of sea-level rise increased from around 1.8 millimetres per year in 1993 to roughly 3.9 millimetres per year today as a result of global warming. In addition to the satellite calibration error, his analysis also takes into account other factors that have influenced sea-level rise in the last several decades, such as the eruption of Mount Pinatubo in the Philippines in 1991 and the recent El Niño weather pattern.
The view from above
The results align with three recent studies that have raised questions about the earliest observations of sea-surface height, or altimetry, captured by the TOPEX/Poseidon spacecraft, a joint US–French mission that began collecting data in late 1992. Those measurements continued with the launch of three subsequent satellites.
“Whatever the methodology, we all come up with the same conclusions,” says Anny Cazenave, a geophysicist at the Laboratory for Studies in Space Geophysics and Oceanography (LEGOS) in Toulouse, France.
[…]
“As records get longer, questions come up,” says Gavin Schmidt, a climate scientist who heads NASA’s Goddard Institute for Space Studies in New York City. But the recent spate of studies suggests that scientists have homed in on an answer, he says. “It’s all coming together.”
If sea-level rise continues to accelerate at the current rate, Nerem says, the world’s oceans could rise by about 75 centimetres over the next century. That is in line with projections made by the Intergovernmental Panel on Climate Change in 2013.
“All of this gives us much more confidence that we understand what is happening,” Church says, and the message to policymakers is clear enough. Humanity needs to reduce its output of greenhouse-gas emissions, he says — and quickly. ”The decisions we make now will have impacts for hundreds, and perhaps thousands, of years.”
- Nature
- doi:10.1038/nature.2017.22312
So… They accomplished accelerated sea level rise by slowing down the past…
Of course, Bill Cosby invented the word “riiiiight” in a sketch about accelerated sea level rise…
Oddly enough, Dr. Nerem and company predicted that they would soon detect the irascible acceleration in sea level rise. So, I guess the soon-to-be-detected acceleration will be tacked on the the adjusted acceleration and Bill Cosby will probably not get credit for the inundation of our coastlines when they are submerged under 7.5 meters of adjusted sea levels.
Until then, sea level rise looks just as tame as it ever did…
Featured Image: Cartoons by Josh
The best available dataset is the one that can be adjusted to fit the desired narrative. This is why surface data works for temps and satellite data works for SLR and not the other way around.
I’m not sure what to think about sea level rise anymore. If rock warms, it expands too, doesn’t it? Thermometers need bulbs to accentuate the expansion of the liquid. I hate to say this but it will take a model to understand exactly what rising sea levels are all about. I’m guessing that when heated seawater expands more than rock, but I’m pretty sure they both expand.
https://legacy.earlham.edu/~debowke/Thermal_Expansion.htm
Still waiting for those coastal property values to drop.
Still waiting for that rush on “floody” pants and galoshes.
Still waiting.
This is “science” at its worst. They expect to see something so they look to see what they can change in the underlying data to show it. If the built-in calibration adjustment to the instruments had shown the rate increase in the first place then they’d not have needed to remove it. Nor would they have done so.
This is exactly the kind of “human bias” that make most adjustments cool the past, giving more alarming warming. Statistically, AGW is on poor footing when the adjustments all go one way like that.
CSIRO estimate of global sea level rise-
“We have used a combination of historical tide-gauge data and satellite-altimeter data to estimate global averaged sea level change from 1880 to 2014. During this period, global-averaged sea level rose about 23 cm, with an average rate of rise of about 1.6 mm/yr over the 20th Century.”
http://www.cmar.csiro.au/sealevel/sl_hist_few_hundred.html
although as they state the Port Arthur tide gauge can only demonstrate an average sea level rise of 0.85mm/yr between 1841 and 2000 which leaves plenty of wriggle room for the Noah’s Ark planners to adjust the data to suit their meme.
That settles the science. Just look at the facts. Over 150 years ago sea level rise was only 0.85mm a year and nowadays it’s 1.6mm a year so we’re all gunna drown if we don’t tax CO2.
So… SLR has gone from insignificant to slightly less insignificant in just 150 years? We’re doomed. Man the lifeboats… Better yet, rearrange the deck chairs.
A bit off-topic, but as long as we’re talking statistics I guess I can throw this in here. I’ve downloaded the NOAA GHCN daily files from the NOAA ftp site, and have been especially looking at the GSN station data from the GHCN data set. NOAA describes GSN as ” a subset of about 1000 stations chosen mainly to give a fairly uniform spatial coverage from places where there is a good length and quality of data record.” But from my look at some of these files, some of them leave a lot to be desired. For example, file IN020081000.dly, has only PRCP (precipitation) data, and the record ends in December 1970. There are four other files that are the same, and several more that have serious gaps in the record.
It’s enough to make me wonder if I’ve downloaded the wrong data, but the NOAA site refers to it as the daily summaries, updated every day. The timestamp on the file is 18 July, so it seems to be the right stuff — but I’m wondering why a file with 47-year-old precipitation data is included in one of the supposedly high-quality GSN stations.
The story has made it to the pages of the penultimate in science authority — Scientific American! /sarc
https://www.scientificamerican.com/article/satellite-snafu-masked-true-sea-level-rise-for-decades/