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.

In the closed system that is the earth’s hydrosphere, the water that fills the ocean comes from many sources

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?

What’s happening to all of my ice?

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).

It seems pretty clear that Thermosteric expansion is the leading contributor to both sea level rise, and its accelerating pace

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.

How long can you tread water?

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.

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4 Responses

  1. Robert Wells says:

    Unfortunate, but it still makes sense beyond warming and sea level rise to switch to nuclear, solar, and wind as much as possible. My rooftop solar is working out very well, both financially and psychologically, supplying about half of my plug-in hybrid driving, 100% of house power usage, and enough extra to light and heat my greenhouse in winter, given that our utility acts as a system battery in the form of accumulated energy credits. Financially, if I assume the system holds 2/3 of its value/cost, it breaks even in 3.5-4 years in a discounted/inflated cash flow. Inflation is actually worse than I assumed, making me more confident in the value of the system. Essentially, the system investment is like a mutual fund that pays a huge 10%+ dividend yearly and has some kind of value when sold (as part of our house). I reinvest the dividend. We’ll be way ahead in the black in 10-15 years when we age out of the house.

    If we do it right, we don’t necessarily have to rely only on climate change logic to justify switching to renewables.

    S.T.B.U.? What’s that?

    • GeoMan says:

      Sucks To Be Us — or, in my case since I’m older than dirt and by the time the doodoo really hits the fan I’ll either be pushing up daisies or slobbering in my oatmeal — it should actually be S.T.B.M.K.A.GKs

      • Robert Wells says:

        Indeed. …Kids and Grandkids… Another factor, which I don’t know if these experts take into account, is the fact that we are already on the shoulder of post-glacial sea level rise which has been ongoing for millenia. Human-caused warming is on top of that.

        • GeoMan says:

          Yep to all the above. Sea level has been going up for over 10k years since the last major ice retreat, and we are surely leaving some unique challenges for our progeny.