According to the same studies, events previously considered rare are becoming more frequent, with increasingly severe impacts on communities, infrastructure, and coastal areas.

The new information appears in the journals "Nature Climate Change" and "Science Advances," with two studies demonstrating that rising sea levels caused by human activity have altered the probability of extreme weather events.

More frequent events

The research team combined observations from tide gauges with climate model simulations to analyse the frequency of extreme sea-level events between 1900 and 2005. The group concluded that the median frequency of an extreme event that occurs every 100 years has increased by approximately 12 times.

In other words, the study concludes that a phenomenon that used to happen once a century may now occur every eight years. However, in Portugal, the factor may be even more worrying. Although researchers were unable to access Portuguese tide gauges, analyses were conducted on the Spanish coast, from which conclusions can be drawn for the Portuguese coast.

Portugal has faster increases

One of the researchers, Dangendorf, states that Portugal experiences faster increases in extreme sea-level events than other regions worldwide. However, the reason is not linked to more intense storms, only to the rise in sea level.

In this sense, Portugal is subject to high tides and storm surges reaching the country more easily, which means that moderate storms can cause flooding, something that did not happen as frequently in the past.

The researcher also notes that existing statistics have become obsolete and do not describe the current risk the country faces.

Human factors

The study, published in Science Advances and led by Daniel Gilford, analyses the problem by calculating how often water levels exceed the limits considered extreme.

According to the study, sea level rise is caused by humans, who are responsible for 58% of daily occurrences recorded between 2000 and 2018. Thus, scientists presume that, on average, human activity has led to an increase in the number of days with extreme events by nearly threefold since 1970.