Wednesday, 29 June 2022


 ukcp18-fact-sheet-sea-level-rise-and-storm-surge.pdf (

Take a look at the screen grab of the factsheet below and there is the following: "UK tide gauge records show substantial year-to-year changes in coastal water levels (typically several centimetres). We recommend that coastal decision makers account for this variability in risk assessments, particularly for shorter-term planning horizons."

You can enlarge the above screen grab for easier reading, or go to the link. I have written to the Met Office to ask if they believe this to be correct and am waiting for a response. 

Below is the record for Portsmouth, and while it is true to say that there is year to year variability of several centimetres, this is both up and down and, when it is averaged out, the actual rise is much lower (only around 2mm). So what point are they trying to make? Could it be to give the impression that sea level is rising by "several centimetres" a year? 


  1. All locations in the world vary in their sea level rise. When planning for sea level rise, it is wise to consider acceleration of future sea level rise.

    Global sea level has been rising over the past century, and the rate has increased in recent decades. In 2014, global sea level was 2.6 inches 67 mm above the 1993 average—the highest annual average in the satellite record (1993-present). Sea level continues to rise at a rate of about one-eighth of an inch 3.2 mm per year.

    Higher sea levels mean that deadly and destructive storm surges push farther inland than they once did, which also means more frequent nuisance flooding. Disruptive and expensive, nuisance flooding is estimated to be from 300 percent to 900 percent more frequent within U.S. coastal communities than it was just 50 years ago.

  2. The interesting fact is that tide gauges do not appear to show any accelerating rise - see my previous post. The "increase" comes from satellite measurements which appear to undergo a number of ad hoc changes from the raw data. As far as flooding is concerned I am very dubious of the claims you are making about the increase.

    1. It is your right to be as dubious as you wish. The potential damge from sea level rise alone is just massive. WIth that kind of damage, our world economy will have to deal with this. Glaciers and ice sheets shrinkage from around the world support the rise in sea level data.

      “What’s striking is its (the study’s) consistency with future projections of sea level in the IPCC,” Watson said. “Those estimates state that there could be up to 98 centimeters (39 inches) of sea level rise by 2100. We’re certainly tracking on that upper bound of the IPCC projection and that projection to 2100 has significant impacts.”

      That’s because sea level rise isn’t just a linear problem, it’s one predicated on tipping points for major damage in coastal areas unless efforts are made to adapt. Currently more than 1 billion people live along shorelines around the world and $11 trillion in assets sit below the 100-year flood mark on coasts, though that number could balloon to as much as $210 trillion by 2100. Sea levels have risen by about a foot since 1900 and the rise is projected to continue accelerating into at least the next century.

  3. It is generally accepted that sea levels have risen by about 20cm over the past century, and tide gauges have so far not seen any increase in that trend. The satellite measurements seem to show a slight increase, but there is a lot of controversy over the accuracy of this data, which has been subjected to manipulation that has not been revealed to the wider scientific community - something that should make us very suspicious! Of course if sea level continues to rise, then eventually coastal cities will have a big problem, but mankind will have to deal with that as it arises. A 20cm/century rise is much easier to deal with than a 100cm/century one. The higher figure appears to be a forecast based on speculative computer programs based on scary guesswork. OK it could happen, just we could be hit by a meteor, or a super volcano erupts. Surely the sensible thing to do is to keep monitoring sea level and make sure sea defences in vulnerable places are kept up. If that becomes too difficult or costly then we will have to move away from those areas.

  4. [The higher figure appears to be a forecast based on speculative computer programs based on scary guesswork]

    Your past suspicions have been based in dubious sources themselves. WUWT isn't looking to do real science. They are looking to create doubt. It doesn't take much effort to spin up suspicioun. Science on the other hand takes practical skepticism in a positive methodoloy. Half of sea level rise is from expansion of the warming oceans. 90% of the global warming is absorbed by the oceans.
    The two major causes of global sea level rise are thermal expansion caused by warming of the ocean (since water expands as it warms) and increased melting of land-based ice, such as glaciers and ice sheets. The ocean is absorbing more than 90 percent of the increased atmospheric heat associated with emissions from human activity.

    With continued ocean and atmospheric warming, sea levels will likely rise for many centuries at rates higher than that of the current century. In the United States, almost 40 percent of the population lives in relatively high-population-density coastal areas, where sea level plays a role in flooding, shoreline erosion, and hazards from storms. Globally, eight of the world's 10 largest cities are near a coast, according to the U.N. Atlas of the Oceans.

  5. You have made a sweeping statement about WUWT, but that website has reports from hundreds of scientists. You seem to be dismissing all that as "not real science". It is simply foolish to take that view. Ask yourself the question - why do the world's tide gauges not show any sign of accelerating sea level rise beyond what has been going on for the past century? If the water is expanding and the glaciers are melting, surely we should see this in the tide gauge readings.

  6. Nasa disagrees with you about tide gauges not showing acceleration.

    Which are more accurate in measuring sea-level rise: tide gauges or satellites?
    Both methods produce accurate results, though they measure different aspects of sea-level rise. Both show, for example, that sea-level rise is accelerating. But tide gauges provide direct observations, over 75 years or more, for specific, sparse points on Earth’s surface.

    Satellites cannot yet match this long-term record; the altimetry record so far is just shy of 30 years. But satellites provide something tide gauges can’t: nearly global coverage, more thoroughly recording planet-wide trends and explaining the changes behind them.

    Satellite altimeters can measure the height of the ocean from space to centimeter or millimeter accuracy when averaged over the globe. Both measurement methods capture regional trends in sea-level rise, and tide gauges also can provide an approximation of global trends, helping to calibrate satellite measurements.


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