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Dangerous sea-level rise

14 Oct 2020 | Science Notes

A new review by Kenneth Richard of No Tricks Zone shows highlights of four studies published this year on changes in sea levels around the world since the end of the last ice age. All of them show evidence of rapid sea level rise. So the end is nigh? Alas no. This rapid rise wasn’t recent. It happened after the end of the last glaciation, and lasted from about 10,000 to about 6,000 years ago. After that time the process reversed and sea levels began falling, and in some places still are. What’s more, the rates of change during the earlier period are rapid: Depending on the location the seas could rise as quickly as six meters in a century. Today the prospect of 20 centimeters in a century is called a climate emergency. To the many billionaire climate activists with waterfront mansions we can only say, learn how to build a dyke. And be glad you don’t live in an era of rapid sea level rise.

The studies Richard reviews look at relative sea-level changes around Japan, New Zealand, Greenland and Brazil. In the first two, sea levels peaked at 2 to 3 meters above present levels approximately 6,000 years ago, then began a decline lasting until today. Along the coast of Brazil the peak was between 2.5 and 5 meters higher than the present. And the latest evidence from Greenland suggests the peak could have been as much as 32 meters above the present level along the southern coast. But there it happened much earlier, about 13,800 years ago. The sea level then fell to a minimum level about 6,000 years ago, and has been rising ever since.

Perhaps you think this passage reflects confusion or sloppy copy-editing. After all, how could sea levels be rising around Greenland while they were falling around Brazil and New Zealand when all the oceans are, essentially, one vast body of water? But remember that what we are measuring is relative level, and the height of land changes too. Which is why Sweden can slowly be rising while Venice is sinking: the continent of Europe is still tilting in response to the melting of the ice at the end of the last ice age that removed an enormous weight from the northern part.

For this reason, places where sea level is not rising do not tell us it’s not rising anywhere. But places where it is rising do not tell us it is rising everywhere, let alone that it is doing so as part of a man-made catastrophe that will sweep us all away.

Or a natural one that might. Fortunately for Venice the new floodgates appear to be working and, once completed, will prevent the city from submerging as its local relative sea level continues to rise. Which is more evidence that all the climate policies in the world won’t do what adaptation and engineering can accomplish at a fraction of the cost.

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