From Watts Up With That?

Brief Note by Kip Hansen — 26 June 2023

The United States’ National Aeronautics and Space Administration (NASA) has a unit called the Scientific Visualization Studio (SVS).  They have been pumping out a new visualization every Monday for two decades. 

Earlier this month they released a video:  Sea Level Through a Porthole.  It was originally released June 16, 2023 [ it was “updated”  June 20, 2023, though the web page does not say what the update consisted of ].

Nearly every media report used a title similar to:  “NASA has released a chilling animation showing just how far sea levels have risen in the three short decades…”

When I see a repetition of a title like that, I suspect that it originated in a press release – but I was unable to find the first use.  Here’s a screenshot of the opening screen of the video:

The video proceeds to show “rising sea level”, water lapping gently at the glass of the porthole, until the sea level has risen 3 1/2 inches in 30 years. 

The purpose of this Brief Note is in its title: Is the visualization “scientific”?  By this I mean:  Has it been produced in such a way as to more clearly communicate some scientific fact to the general public?  The alternative is that it has been produced to mislead or evoke emotions in the general public; for example,  it been produced as propaganda.

The first test is to examine the facts presented (italic quotes are from the SVS page)

“As the planet warms and polar ice melts, our global average sea level is rising. Although exact ocean heights vary due to local geography, climate over time, and dynamic fluid interactions with gravity and planetary rotation, scientists observe sea level trends by comparing measurements against a 20 year spatial and temporal mean reference. These visualizations use the visual metaphor of a submerged porthole window to observe how far our oceans rose between 1993 and 2022.”

How big is a porthole?  In my experience (half a lifetime at sea) portholes in ships built through the 19^th century generally had a glass area 8 to 18 inches in diameter, with glass from 1 to 2 inches thick.   Larger than 24 inches would be exceptional.   On the Titanic:  “The largest portholes were found in the first class … the size of the glass was about 24 inches maximum… The smallest portholes had a nine-inch glass diameter, mostly used in third class and crew accommodations in the bow and close to the waterline.”

The “porthole” in the visualization, according to the scale, is shown to be 40 inches.  Not realistic at all – it seems to be a size pulled out of a hat.

The “fright-value” of the visualization would have been far greater if they used the more common porthole size limited to 8 to 12 inches, similar to these shown on the HMS Royal Scotsman:

There is one row just above the rubbing strake (just above the green-painted waterline).  None, of course, are below the water line, and none would show water rising on the outside of the glass unless the ship was slowing sinking.

The use of a “porthole”, even if presented at an unusually, non-realistic, size, is an obvious attempt to invoke fear of sinking into the sea or fear of rising water – childishly transparent.

And the amount of “sea level rise” depicted?  That is a controversy.  If NASA’s SVS had used the long-term tide gauge measurements which show a steady near-perfectly linear SLR for over a century of 1.7-1.8 mm/yr,  to show 30 years of SLR, they would have shown only a 5.4 cm rise, or 2.13 inches.   But, being NASA, they chose to use the not-measured-but-calculated “satellite sea level rise” of 3.3 mm/yr.

The difference between the two SLR trends, tide gauges vs. satellite is too complicated to take up here, but simply put, the satellite “measurement” isn’t a measurement – but a complicated calculation that returns not a physical level of the sea surface (what normal people would call sea level) but is something quite different, eustatic sea level. as explained by the Sea Level Research Group at the University of Colorado.  [see end note for the full explanation] 

The SVS animation shows the 3 ½ inches (about 90 mm) of the non-physical  eustatic sea level as if it were the level that the seas have actually risen in 30 years, which it is not. (again, see End Note)

Bottom Line: 

At least this one visualization is not scientific:  It uses an intended-to-frighten unrealistic premise (sea surface rising as if seen through a porthole of a sinking ship), uses a very out-of-scale size for a porthole, and uses the Eustatic Sea Level rise – which is not a rise in a physical level — in place of actual sea level rise.

But I am happy to admit that in general, the surfaces of the world’s ocean have been rising as the world has warmed coming up out of the Little Ice Age at about NOAA’s  long-term linear figure for SLR, about 1.7 to 1.8 mm/yr.  (see here).

If NASA’s SVS had wanted to be realistic and scientific, they could have used my animation below—it shows 30 years of Sea Level Rise at the American Merchant Mariners’ Memorial at Battery Park New York:  It takes 15 seconds (if it doesn’t run or have a play arrow, open it in a new tab and watch) Its 15-second length will seem like forever:

Oh, you didn’t see it?  I added in the last image a small vertical red bar, its very small, up and to the left of the monument plaque, which is the amount that local relative sea level has actually risen at The Battery in New York, about 3.4 inches/87 mm.  It is lost in the blackened surface of the sea wall caused by the rising and falling of the tides.

The little red bar includes 1.6 in/40 mm of negative vertical land movement (subsidence, the land moving downward). Only 1.8 inches (47 mm) of that barely discernible change is the surface of the sea rising.

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END NOTE:  What do they mean when they use GMSL in relation to satellite measurements?

“The term “global mean sea level” in the context of our research [determining GMSL using satellites]  is defined as the area-weighted mean of all of the sea surface height anomalies measured by the altimeter in a single, 10-day satellite track repeat cycle.  It can also be thought of as the “eustatic sea level.” The eustatic sea level is not a physical sea level (since the sea levels relative to local land surfaces vary depending on land motion and other factors), but it represents the level if all of the water in the oceans were contained in a single basin. Changes to this eustatic level are caused by changes in total ocean water mass (e.g., ice sheet runoff), changes in the size of the ocean basin (e.g., GIA), or density changes of the water (e.g., thermal expansion). The time series of the GMSL estimates over the TOPEX and Jason missions beginning in 1992 to the present indicates a mostly linear trend after correction for inter-mission biases between instruments. The GMSL rate corrected for GIA represents changes in water mass and density in the oceans. These changes are thought to be predominantly driven by thermal expansion of the oceans and land ice melt (Greenland and Antarctic ice sheets and glaciers).”

Googles shows that I have written quite a bit about this here at WUWT.

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Author’s Comment:

NASA’s SVS has quite a team – producing visually impressive graphics, many of them videos.  Some of them are helpful, some of them are unhelpful.   Some of them are egregious pieces of propagandistic nonsense, seeming meant to obscure the facts rather than illuminate them.   This one was an easy target – silly in its conception and execution. 

I will be covering others in future Brief Notes

Propaganda has ALWAYS been forwarded with powerful emotion-evoking images.  Not a good thing when politics is substituted for science. (see the Crichton Lecture).

If you have a favorite example among NASA’s SVS misleading visualizations, please mention it in comments.

Thanks for reading.

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