Rising temperatures, extreme weather events, rising water levels... Faced with climate change, overseas territories are on the front line. The consequences for local populations and ecosystems are already observable today, and will become more and more serious with a high level of warming.
The disappearance of coral reefs
This is the corollary in particular of the progressive rise in ocean temperature. Bleaching phenomena, meaning the death of animals responsible for the development of coral reefs, are increasing on a global scale and the Caribbean is not spared.
In September 2023, the American Oceanic and Atmospheric Observation Agency (NOAA) placed the coral reefs (…) of the northern Antilles on maximum alert, for “severe bleaching and risk of probable mortality”. (…) A threat of death hangs over our coral reefs!
As a reminder, coral reefs shelter 25% of marine biodiversity; are responsible for the formation of large quantities of sand; form a natural barrier against swell and waves; provide a large part, directly or indirectly, of the fisheries resources exploited for human consumption; benefits research, particularly medical research (treatment of certain cancers or the fight against aging).
The increase in volume, frequency and end of seasonality of sargassum strandings
These volumes of sargassum which drift in the ocean and wash up on the coasts of Saint-Martin are also attributable to the combined effects of deforestation and overexploitation for agricultural purposes of large areas around large tropical rivers and the rise ocean temperatures. These strandings have a direct impact on coastal ecosystems and in particular on coral reefs and mangroves, on the coastline and induced effects on public health when they are not collected quickly enough.
Changing rainfall patterns
Saint-Martin, known as a "dry island", that is to say without any free fresh water resources (rivers and lakes), is already experiencing recurring drought conditions, penalizing the possibilities for agricultural development and prohibiting this resource in the necessary access of populations to drinking water. Climate change will and is already causing a profound change in the rainfall regime with a decreasing annual water balance. However, this change in the rain regime seems to suggest less violent but longer rains with the induced effects on the absorption capacity of the soil, the development of gullying phenomena, runoff also consequences of the artificialization of the soil. In this sense, a decreasing annual water balance is not incompatible with a potential increase in flooding phenomena, as evidenced by the episodes experienced in October 2023 in Guadeloupe as in Saint-Martin. For comparison in 2022, August was the highest cumulative rainfall month of the year with 135 mm over 14 days. 2023, October was the highest cumulative rain month of the year with 348 mm over 19 days!
Increasing temperatures and frequency of heat peaks
The trends in the evolution of temperatures will not escape the global warming phenomenon. In this sense, by 2055, an increase of +1,6 to 2,4°C is expected depending on the scenarios and of +2,5 to 3,5°C by 2080 across the Caribbean, far from the objectives which would make it possible to reduce or contain the effects induced by climate change.
The increase in frequency and intensity of “sand mists” phenomena
This meteorological phenomenon is recurrent in Saint-Martin. These mists form above the Sahara during the spring under the influence of hot winds then lifting large quantities of desert dust which cross the Atlantic. The increase in the frequency of this phenomenon is observed and attributable to both the increase in agricultural practices and climate change. The mists of the Sahara are worrying for human health since they carry fine particles which degrade air quality and can cause respiratory problems.
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