Thermosteric Sea Level Rise
The SciTechDaily website had an interesting article (28 May 2026) that summarized an international study about how climate change is affecting global sea level rise. The team included researchers from the Institute of Atmospheric Physics at the Chinese Academy of Sciences, Tulane University, the NSF National Center for Atmospheric Research, the University of St. Thomas, and scientific collaborators in France.
The SciTechDaily article has the title “Scientists Just Confirmed What’s Driving Sea Level Rise And It’s Alarming”. I have to admit, however, that I wasn’t personally all that alarmed — their reasoning is based upon something that some of us have known, or at least suspected, for years.
Before we continue, here are links to some of my earlier posts that may provide a bit of background information:
Click here for an Index to Climate Change posts
Click here for “Carbon Dioxide and Climate Change for Dummies”
Click here for “Climate Change?”
Click here for “Climate Change and Sea Level Rise”
Click here for Going Up?
The short version is relatively simple. There are several factors that are contributing to the earth’s rising sea levels: everyone’s favorite loss of glacial ice, including from retreating alpine glaciers and the melting of the ice at both poles; the lesser but still measurable excess water returning to the ocean from the land; and the mostly-ignored-by-everyone thermal expansion of the ocean as it heats up.
The main thrust of the article is to let us all know that the rise in sea levels due to warming of the ocean itself has a name (“Thermosteric,” which I did not know), and that this contributor plays a major role in the upward expansion of the ocean (it surely cannot go down), and the inevitable flooding of coastal areas (unfortunately, it can go sideways).
A couple quotes from the article may help (bolding is on me):
The study … found that global sea levels have risen by an average of 2.06 millimeters per year since 1960. More concerning, the pace has accelerated sharply in recent decades, climbing to 3.94 millimeters per year between 2005 and 2023.
Researchers determined that ocean warming is the single largest contributor, responsible for 43% of total sea level rise since 1960. When seawater heats up, it expands and occupies more space, causing ocean levels to increase even without adding extra water.
Melting ice is also playing a major role. Mountain glaciers account for 27% of the rise, while the Greenland Ice Sheet contributes 15% and the Antarctic Ice Sheet contributes 12%. Changes in land water storage make up the remaining 3%.
One of the unfortunate issues discussed at the end of the article (and likely the source of the alarm) is again something which some of us have been saying for years, and is indeed mentioned in several of my earlier blog posts.
The point the article is trying to make is that because of how slowly water changes temperature — coupled with the massive inertia of the earth and its systems — no matter what we do in the short term, sea level will continue to rise for generations, possibly even for hundreds of years.
Another quote from the study:
The findings also highlight the long-lasting nature of climate-driven sea level rise. Scientists say that even if greenhouse gas emissions eventually stabilize, oceans will likely continue rising for many generations.
That is because oceans warm slowly and store enormous amounts of heat deep below the surface. Massive glaciers and ice sheets also respond gradually to rising temperatures and continue melting long after warming begins. Because of this long-term inertia in Earth’s climate system, researchers expect sea level rise to continue for centuries.
Oops.
So apparently, the flooding of coastal areas is inevitable and just beginning, no matter what we do in the short term.
S.T.B.U.
