Sea levels are rising, despite what social media users say

If you only have a minute… 

• Social media users have been claiming that a recent study disproved the idea that sea levels are rising due to climate change. But that’s not actually what the scientific study says. It actually looks at locations where human and geological factors have offset this rise.

• Rising sea levels are actually due to temperatures rising globally. An increase in temperatures is causing glaciers and the polar ice caps to melt. Moreover, when water is warmer, it expands and takes up more volume.  

The fact-check, in detail

If the surface area of certain islands is growing, then it must mean that sea levels are not rising due to climate change, or so claim some social media users, citing a recent study published in March by Taylor & Francis, an important, UK-based scientific publisher. The scientists behind this study examined the changes in island shorelines in southeast Asia, the Indian Ocean and the Mediterranean from data collected between 1990 and 2020.

The posts on Facebook and X citing this study say that rising sea levels can’t be a real thing because the study shows that the shorelines on certain islands are expanding. However, most of these posts are drawing from an article about the study by German media outlet Report24. According to this outlet, the study shows that claims made by people who believe in “climate hysteria” are wrong. 

In a Telegram post, Silvano Trotta, a figure who backs a number of conspiracy theories, took real numbers from the study— but then applied them out of context. “While 88% of islands have seen no real change between 1990 and 2020, only 12% have changed drastically. According to analysis of data collected by satellite, about 6% of islands expanded seaward, while 7.5% lost some of their coastline (primarily due to erosion).” 

Using these numbers, Trotta then claimed that these islands were not being “engulfed by the sea”, as he says so-called “alarmists” would have you believe. However, Trotta’s claims don’t take into account an important part of the study, which is that in some cases, the shorelines of these islands have been artificially expanded, often by human construction. 

“Human-induced land reclamation has been shown to cause notable expansions of island shorelines, effectively overshadowing the impacts of natural factors such as sea-level rise and wave action,” reads the study, giving the example of the Zhoushan archipelago, located not far from Shanghai. Significant seaward expansion has been observed there, however, this is largely because of human land reclamation to increase areas designated for harbors, towns and industrial activities. 

So while some shorelines have expanded, it seems to be mostly due to human factors. Moreover, human activity can also increase sea level rise, says Gilles Ramstein, a paleoclimatologist who spoke to our team. 

“If you look at the Mekong River Delta [in Vietnam],” he said, “the global increase in sea levels means that there is more salt in the earth. This, in turn, adds salt to the water. This is aggravated by the fact that the Delta is sinking under the weight of construction, ten times faster than the sea rises.”

“Rising sea levels continue to pose a threat” 

One quote in particular from the study was cited by many social media users to support their theory that sea levels rising isn’t a big deal: “Contrary to initial assumptions, our empirical data does not conclusively link the widespread erosion of island shorelines primarily to historical sea-level rise, suggesting that human activities might mask the effects of sea-level rise.”

However, this quote doesn’t actually deny that sea levels are rising and that they are having a big effect on the planet. You’ll see this if you keep reading. In the very next sentence, the authors of the study make it clear that they aren’t questioning the threat posed by rising sea levels: “Based on a thorough analysis of current data and consideration of future sea-level scenarios, we believe that sea-level rise will continue to pose a significant challenge to island communities and recommend these communities to adopt scientifically validated strategies as these could be crucial for their sustainable survival and development.”

The report goes on to say, in the conclusion: “Regardless of the historical or current impacts of sea-level rise on islands, the latest IPCC AR6 WGI assessment reports with high confidence that all evaluated coastal climatic impact drivers, including relative sea-level rise, coastal flooding and coastal erosion, are projected to intensify in almost all regions globally by mid-century.”

Sea levels have risen by around 9.4 centimeters since 1993, according to numbers from NASA, which reported that there has been an acceleration in the rise over the past decade. Global warming has also caused extreme meteorological events like El Nino, which also contributes to an increase in sea levels. 

The French Ministry of Ecological Transition just released a report on the threat to 500 French coastal communities caused by rising sea levels.