Phys.org reposted a press release from NASA’s Jet Propulsion Laboratory (JPL), titled “Rising sea level could exceed estimates for US coasts, NASA study finds,” which claims climate change is causing larger than expected sea-level rise.
This claim is not supported by a comprehensive reading of the available evidence
The JPL study referenced in its press release was published in Nature Communications, Earth & Environment.
“New results show average sea-level rise approaching the 1-foot mark for most coastlines of the contiguous U.S. by 2050. The Gulf Coast and Southeast will see the most change,” reports the subheading of the Phys.org article.
A number of federal agencies contributed to the report, including NASA, the National Oceanic and Atmospheric Administration, and the U.S. Geological Survey.
After examining 28 years of satellite data, they estimated seas could rise between 10 to 18 inches, depending upon the coastline, over the next 30 years. [emphasis, links added]
The study makes three significant mistakes. First, the accelerated rate of sea-level rise (SLR) the researchers perceived in recent years appears to be an artifact of switching between different satellites during the period of measurement, not an increase in the rate of rise.
As discussed in Climate Realism, sea-level data reported from recently launched satellites indicate seas are rising approximately 3.4 mm/year.
By contrast, tidal gauge stations have recorded a rise of approximately 1 to 2 mm annually, a rate that is little changed over the century or so for which we have adequate records.
The dataset of the newest set of satellites does not correspond to the data recorded by earlier satellites, which were largely consistent with tide gauge data.
The most recent satellites record significantly higher rates of sea-level rate of rise than the earlier satellites.
The earlier satellite measurements agree quite well, but they show a much lower trend than the most recent satellites.
Neither set of the satellite record shows any accelerating trend.
Whence the difference? It seems likely that the researchers involved simply combined the two dissimilar datasets, and plotted a new trend showing acceleration, which is either a mistake, evidence of incompetence, or worse, deliberately misleading.
As Willis Eschenbach explains:
[R]egarding the question of whether there is acceleration shown in that spliced satellite record, I’ll say the three most important words that any scientist can ever say:
We. Don’t. Know.
We don’t know for a few reasons. The first is that it’s a spliced dataset, and the changes in the trend line all occur at and after the splices. Makes a man suspicious, particularly given the differences in the initial individual datasets. (See Figure 1.)
Essentially, we have data measured by four different satellites in four different orbits, each with different sensing equipment.
It is no surprise that there would be differences in the data that aren’t part of what was to be measured.
More to the point, to get the 10- to 18-inch sea-level rise by 2050 warned by JPL, the rate of sea-level rise would have to accelerate significantly.
It’s 2022, 28 years to 2050. At 3.4 mm/year using today’s satellite SLR rate, the expected rate of rise would be 95.2 mm or about 3.75 inches by 2050.
Sea-level rise would have to accelerate three times the rate today to match the low-end estimate of 10 inches of rise by 2050, and by nearly five times to rise by 18 inches.
Yet there is no evidence the rate of sea-level rise is accelerating at all, much less by three to five times the current rate.
Eschenbach continues:
The second is that the record is only 27 years long, so we really don’t have enough data to draw many conclusions. This is particularly true since the variations from a straight line are quite small.
Third, the rise was right along the linear trend line up until 2005. So, there was no acceleration before that time. Then the rate of rise started decreasing around 2005 … deceleration rather than acceleration? Why?
And then, according to the spliced dataset, it started rising faster around 2011. Again, why? Assuredly those three, first a straight line, then deceleration, then acceleration, are unlikely to be caused by a monotonic rise in CO2. Nor do they conform to any expected pattern of acceleration.
What else did JPL miss? The fact that some of the cities whose data were used have a serious problem with subsidence – a sinking of the land, which creates a false impression of sea-level rise.
The peer-reviewed study “Local land subsidence in Miami Beach (FL) and Norfolk (VA) and its contribution to flooding hazard in coastal communities along the U.S. Atlantic coast,” notes subsidence is a serious problem with Norfolk, VA – interestingly, JPL used a picture of Norfolk flooding is its press release, seen in the featured image for this story and provided by the city of Norfolk.
What can explain the sad state of affairs resulting from scientists, some considered among the top in their field, missing simple things like combing discontinuous records to produce artificial trends in the sea-level rise data?
Or the fact that some widely acknowledged factors, like land subsidence, are not accounted for in their projections of rising seas?
Arguably, in the rush to jump on the “climate change crisis” bandwagon, JPL ignored problems with their spliced-together dataset and failed to consider the full range of factors, other than actually rising seas, which could be contributing to measured sea-level rise.
By their slipshod work, JPL did the public a disservice and made fools of themselves.
Top image: Norfolk, Virginia, is pictured here with an inundated roadway. Credit: City of Norfolk
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