Porritt’s Sea Level Rise

By Paul Homewood



In the Jonathon Porritt article in the Telegraph, which I highlighted yesterday, you may recall his claim: According to the Intergovernmental Panel on Climate Change, average sea levels will have risen by no less than a metre by 2100. That’s the best case. You probably don’t want to think too much about the worst case. That’s still 80 years away.

It is of course a common assertion designed to frighten people, and sadly it cannot be challenged in terms of accuracy because the IPCC have said as much.

But that does not mean it is correct or likely.

Since satellite monitoring started in 1992, global sea levels have officially risen at the rate of 3mm a year, with little sign of acceleration:




The recent blip above the trend line is mainly due to weak El Nino conditions last year. Current data is three months out of date, and current La Nina conditions, which tend to lead to lower sea levels, are therefore not yet reflected in the chart.


Obviously at this rate, sea levels will only rise by 240mm by 2100, not the full meter claimed.

We also know from Jevrejeva’s study in 2013 that tide gauges are in agreement with satellite data, that the sea levels rose by 3.1mm a year between 1993 and 2009 (in other words, no acceleration since 2009), and that the rate of rise since 1970 has been 1.8mm a year.






Much is always made by climate alarmists that seas are rising faster now than in the 20thC. However, as the Jevrejeva chart shows, this is a flagrantly dishonest argument. In reality, the rate of rise since 1992 is little different to the period from 1850 to 1950.

What brought the 20thC rate down was the slow down in sea level rise seen in the second half of the 20thC, a time when global temperatures were falling.

Meanwhile closer to home, sea levels have not risen at all in the last decade at North Shields.


mean trend plot



Quite simply, the data consistently shows us that sea levels are not going to rise by a meter or more this century, despite what Jonathon Porritt might say.



December 20, 2020 at 05:42AM

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