This is what Bordeaux or Nice will look like if the seas keep rising

Many inhabited cities will be eaten away by rising seas if climate targets are not met. These models make it possible to see it visually.

Environmental studies are often associated with modeling, that is to say projections into the future from extrapolated past and current data. Sometimes these simulations of the future themselves remain at the stage of data or graphics, maps. They are crucial, but then it can be difficult to visualize the future portrayed in numbers and curves. Some works therefore provide visually concrete representations – sometimes even calling on artists, such as a recent study which imagines the Earth in 2500.

A new publication, released on October 11, 2021 in Environmental Research Letters, looks at the rise of the seas caused by man-made climate change, and more specifically the impact of this rise on inhabited places. We already know that global warming will endanger many cities, but this research work, carried out by a collective of scientists and journalists called Climate Central, is based on an unprecedented collection of data and is accompanied by uplifting illustrations.

Unprecedented levels of exposure to rising sea levels

« Here we show that under high emission scenarios leading to a warming of 4 degrees Celsius and a rise in the global mean sea level of 8.9 meters in a period of 200 to 2000 years, 50 major cities, mainly in Asia, are expected to face exposure levels [à la montée des eaux] unprecedented (…) or even face partial or almost total losses of their area », Deplore the authors of this new study.

Global warming – caused by human activities – directly causes the seas to rise. Thus, since 1800, the planet has gained a little more 1 degree, and in parallel, the sea level has risen by 20 centimeters. But as warming progresses, that increase could be several meters.

This group of scientists therefore modeled the consequences of different degrees of warming on the seas, by applying the data to a Google Maps map that you can explore. It shows how the coasts are “eaten away” by the water as the number of degrees increases. This nibbling pushes back the maximum border of high tide on firm land. So, concretely, this means that the water of the seas reaches places that were not touched before.

France is not spared. Here is an example from the north of France.

In red, on the right, the part eaten away by the water. // Source: Climate Central (Numerama screenshot)

But Climate Central delivers even more striking models, visually speaking, via Google Earth.

Here is what four places in France could look like if global warming continues to at least 3 degrees. The simulations below are interactive: drag the middle slider to see the same place before or without warming to +3 degrees.

Bordeaux (cathedral)

Bordeaux (monument to the Girondins)

Nice

Anglet (riders’ beach)

Climate Central has conducted this type of Google Earth modeling for many cities around the world. You can go and see them all on the Picturing page.

In total, the border with high tide could encroach on land now occupied by at least 15% of the current world population – or one billion people. On the other hand, ” achieving the more ambitious goals of the Paris climate agreement will likely reduce exposure by around half »And could prevent coastal cities from having to deal with the implementation of adaptations to defend themselves against rising sea levels.

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