A warming that could go up to 6°C locally compared to the period 1981-2010 ; an alternation of longer and more severe droughts with denser rainy episodes; a higher proportion of intense cyclones… For the first time, Météo-France is assessing the impact of global warming by 2100 in the south-west of the Indian Ocean, which includes Réunion, Mauritius, Madagascar, Mayotte, the Seychelles and the Comoros.
Four years of research were needed to complete the BRIO project (“Building Resilience in the Indian Ocean”), whose data was presented for the first time on the sidelines of the Swiocof forum (South-West Indian Ocean Climate Outlook Forum) in September in Victoria, capital of the Seychelles. It provides precise local data, with a resolution of three kilometers, on the effects of global warming which is already affecting the area.
In Reunion, Météo-France observes an increase in the average temperature of 0.9°C over the last fifty-three years, as well as a warming of the Indian Ocean (at the surface of the water) from to 0 .5°C to 0.6°C between 1968 and 2018, with an acceleration of warming over the past ten years. The level of the Indian Ocean rose by an average of 5 millimeters per year over the period 1993-2017, or 12 centimeters over this period.
Projections based on IPCC
To establish their projections until the end of the century, the BRIO teams started from scenarios of the Intergovernmental Panel on Climate Change (IPCC). The pessimistic scenarios correspond to a doubling of greenhouse gas emissions by 2050, with the unrestrained use of fossil fuels. ” The most optimistic scenario is that where States and their economies achieve a reduction in gas emissions by arriving in 2080 at “net zero emissions” thanks to carbon sink technologies”. details Emmanuel Cloppet, interregional director of Météo-France for the Indian Ocean. The intermediate scenario foresees a maintenance of current greenhouse gas emissions until the middle of the century before a decrease.
In the worst case scenario, temperatures will increase by 2100 by 3°C to 5°C in the South West Indian Ocean compared to the period 1981-2010. This warming will be even higher on the African coast and in the lands of Madagascar with an increase of 5°C to 6°C. It is less on the islands, surrounded by the ocean which better absorbs the rise in temperature. In the optimistic scenario – now considered very unlikely given the current trend in emissions – warming will be limited to 1.5°C at the end of the century. And at 2°C for the median.
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