Mauritius - Climate

The temperature range is moderate, from a low of 16ºC in the winter, to 35ºC in summer. Mauritius has a number of micro-climates so weather conditions can vary considerably across the island. The islands are in the Indian Ocean cyclone belt (the season runs from November to April). Most cyclones miss the islands but can bring vital rains at the ideal time for the country's main crop, sugar. Cyclones occasionally cause extensive damage.

Taken generally Mauritius enjoys a fairly healthy climate, especially on the higher levels. The diseases prevalent, though not directly caused by poverty, may be considered to be consequent on poverty; that is to say, on overcrowding, insufficient or bad food, want of clothing, and bad sanitation; but while putting poverty in the first rank as the chief predisposing factor in disease, the influence of climate can not be ignored. Malaria and dysentery, which accounts for over 25 per cent of the diseases treated in the Government hospitals, prisons, etc., is found to increase and decrease at the same time as the rainfall increases and decreases. This is not to be wondered at, as with the advent of rain in the early months of the year, during which the fields are manured, a considerable amount of organic matter is washed to the rivers, which, up to the present (1908), constitute the principal water supply of the greater number of the inhabitants. But the condition is made still worse when there happens to be a very high rainfall which sweeps, in addition, the more or less decomposing organic matters which have accumulated along the banks of the rivers.

A serious drought also tends to increase the amount of sickness, as then the rivers run low, become stagnant, and the water supply is again polluted. The death rate per thousand of population, which in 1897 was 29.5, had risen in 1901 to 40.3, and was still 40 in 1908. Bubonic plague first made its appearance in December, 1898, and 1,416 cases were treated in 1899; since then, though with considerable fluctuations, the epidemic has very much diminished, only 224 cases having been treated in 1907. But though the number was so much diminished, the percentage of mortality was still very great, only varying slightly from 81 to 74 per cent during the 10 years.

The cyclone season in Mauritius normally runs from November to May. Cyclones can cause extensive damage to property. There is a well-structured system of phased warnings.

The earliest record of a cyclone at Mauritius is as far back as 1695, when it was a Dutch possession. In 1754, it was visited by a severe storm, and in 1778 a violent cyclone wrecked 32 vessels, 300 houses, and a church at Port Louis. In 1868, again, during a violent cyclone a portion of an iron railway bridge across the Grande Riviere, 220 tons in weight, was uplifted bodily by the wind and thrown to the bottom of a ravine. In 1874, and again in 1879, in each year in the month of March, a cyclone was experienced; but from that date until April, 1892, there was nothing stronger than a moderate gale.

In 1882, however, on the 29th of April, occurred the most terrific cyclone the island has experienced. It was preceded by a heavy thunderstorm, which is rarely the case. It was remarkable for the lateness of the date on which it occurred, for the small size of its area, for its short duration, from its having approached from the northwestward (there being only two previous instances of this approach, viz., in 1863 and 1868), and from the extraordinary force of the wind and consequent damage to life and property, about 1,500 lives being lost, 4,000 people badly wounded, one-third of the city of Port Louis destroyed and 30,000 people rendered homeless and ruined.

In February, 1896, the island was again visited by a cyclone lasting three days, and more remarkable fer the extraordinary rainfall than for force of wind. On the 20th, when the wind was at its greatest velocity of 51.3 miles an hour, rain to the extent of 17.34 inches (onefourth of the total amount for the whole year) fell in 24 hours, causing great damage to roads, bridges, and property.

The impacts of climate variability and extreme weather events are becoming a concern to the Republic of Mauritius, including Rodrigues, St Brandon and Agalega. The climate of the South West Indian Ocean (SWIO) small island states is influenced by large ocean-atmosphere interactions such as trade winds. They are often affected by tropical cyclones and other extreme weather. Some of them like the Saint Brandon or the Cargados Carajos Shoals and Agalega Islands are threatened by sea-level rise as well. Annual rainfall over the outer islands indicate significant variation from year to year but long-term analysis do show decreasing rainfall trend, though lesser than the main island Mauritius.

One of the areas where Mauritius will suffer the brunt of climate change is with much more violent cyclones. The other part will be the erosion of the coast with the rising sea level. And whatever touches the coast means impacting the tourism industry. It also impacts the livelihoods of people, for those who depend on the lagoons for fishing and other activities.

Mauritius is a member of the Alliance of Small Island States and was a part of the high-ambition coalition that pushed for 1.5 degrees Celsius at COP21.