The histories of the islands Saint-Paul and Amsterdam are linked. Both are located to the south of the Cape Town – Malay archipelago route (South-East Asia), between Europe and the Indies.
Saint Paul Island was discovered in 1559 by Portuguese navigator Gysaerths. It was first named Nao Sao Paulo. As for Amsterdam Island, it was mentioned in Magellan’s ship’s log for 18 March 1522. Several sightings by explorers followed in the early 17th Century, before the Dutch governor Van Diemen named it after his ship, Nieuw Amsterdam, in 1633.
In 1842, the two islands were rediscovered by Franco-Polish Adam Mieroslawski, who suggested to the governor of the then Île Bourbon (Réunion) that these deserted islands should be taken over in the name of France. Possession was indeed taken on 1 July 1843. However, the United Kingdom contested this action. Mieroslawski died in 1853 and France officially renounced its sovereignty over the two islands. In 1892, however, the French dispatch boat La Bourdonnais retook possession of the islands, reaffirmed when another French warship, L’Eure, visited on the way back from Kerguelen in 1893.
A French government decree of 21 November 1924 tied the islands of Crozet, Kerguelen, Saint-Paul and Amsterdam to the Scattered Islands District dependent on the province of Tamatave in Madagascar, a French colony at the time. Then, in 1955, they became a district of the French Southern and Antarctic Lands (TAAF) thus forming a new Overseas Territory (TOM).
The two islands enjoy a temperate oceanic climate (no snow and ice in winter). The annual average temperature is around 12 to 14°C, with extremes oscillating between 2 and 26°C. Rainfall amounts to 1100 to 1200 mm per year, over a period of about 230 days of rain per year. The prevailing winds are northwesterlies and run at the northern limit of the Roaring Forties. The average annual wind speed recorded at sea level is 27 km/h. Gale force winds (> 60 km/h) are recorded on 163 days per year.
Saint-Paul and Amsterdam Islands belong to the same volcanic system, jointly linked to the Southeast Indian Ridge and a hotspot. They are located slightly to the south of the ridge. A transform fault, perpendicular to the ridge running between the two islands shifted them out of line with each other. The 2 islands are 100 000 years old sitting on a volcanic substratum dating back 300 000 years. Each of them shows two distinct magmatic episodes: construction of a palaeo-volcano, then formation of a neo-volcano whose eruptive materials more-or-less mask the previous one. A later explosive episode made a breach in Saint Paul Island and a fault destroyed a substantial northeastern part which fell into the sea. The spectacular result is a crater lake, over 1 km in diameter and 80 m deep, opened onto the ocean but protected by a bar of pebbles cut into only by a shallow channel (-2 to -3 m).