Rising sea levels, should we be concerned?

Caribbean Maritime’s cover story in the previous edition of the magazine focused on decarbonization. But there is a counter argument. This magazine does not set out to deliberately court controversy, and this is not the aim of this article. This article seeks to offer a different and, perhaps, contrarian perspective to a global concern about rising sea levels.

By Gary Gimson

There is a near consensus that global sea levels are on the rise and that this is the result of anthropomorphic global warming which in turn is melting glaciers as well as Arctic Sea and Antarctic Sea ice.

So, despite this widely held concern are Caribbean Sea levels really rising fast and, if so, by how much? Is this something new? Should we be worried and, if they are, should we as a region just mitigate for any possible rise rather than undertake a wholesale decarbonization program costing many billions of dollars?

Examine

But first let’s examine whether Caribbean Sea levels have risen by much in the past or whether sea level rises are something new. The highly respected Geneva-based World Meteorological Organization says the waters of the Caribbean Sea rose by an average of 3.6 mm a year between 1993 and 2021.

Notwithstanding the possibility that sea levels will rise faster in the future and based on a purely straight-line calculation, it would therefore take the Caribbean Sea 277 years to rise by one meter. Something to get overly worried about? Maybe, maybe not.

If indeed Caribbean Sea levels are on an unstoppable upward trajectory, are all islands really at serious risk? Fortunately, many Caribbean islands are quite hilly, even mountainous, so a sea level rise of, say, one meter will make some difference but would not be devastating. Others, for example, may not be so lucky such as The Bahamas and the Turks & Caicos.

Increase

Looking further back prior to 1993, graphs seem to show a steady increase in Caribbean Sea levels since at least 1800. As this sustained rise is observational, this rise can be quantified, and we can broadly agree that this is fact. If sea levels have been steadily rising for the last two hundred years or probably longer, could the recent small rise just be a continuum of this trend?

Undertake a simple Google search and there are plenty of gloomy forecasts and dismal modelling, some of it even quite scary, about the possible rise in the region’s sea levels between now and, say, the end of this century. Nearly all these forecasts seem to mention the word ‘could’.

But let’s also keep in mind that a forecast is merely a forecast. Forecasts can be and are often wrong – little more than crystal ball gazing mixed with confirmation bias and therefore some way off the mark. We only need to look at the apocalyptic predictions made by virologists/scientists at the start of the recent Covid-19 pandemic to see how wrong forecasting by ‘experts’ can be.

Sadly, most of us won’t be around to see if these forecasters are correct about end-of-century Caribbean Sea levels. But then again neither will the forecasters.

Low lying

If you want to look at facts rather than forecasts when it comes to rising sea levels, then the low-lying Maldives provide a perfect example of where the two can diverge. Back in 2009 the then prime minister of the Maldives, Mohamed Nasheed and 13 of his ministers held an underwater cabinet meeting to highlight his nation’s plight as a collection of coral islands threatened by rising sea levels. Since that well-publicized event, which claimed that the country would be under water within 30 years, the Maldives government has continued to encourage the construction of very many new hotels on these seemingly vulnerable islands and apparently nearly halfway on their road to oblivion. It would seem that these hotel investors are not too bothered about the possibility of rising sea levels – even in a country whose highest point is only four meters above sea level.

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