Climate change in the sub-Antarctic: An illustration from Marion Island

The oceanic climate of Marion Island (sub-Antarctic; 47degrees S, 38degrees E) is exceptionally thermally-stable, yet between 1969 and 1999 annual mean surface air temperature at the island increased by 1.2 degreesC. Warming has occurred in all months excepting June. Annual precipitation decreased since the mid 1960s, so that the 1990s was the driest of the five decades that precipitation has been measured at the island. All months excepting October have become drier. The interannual variability in annual total sunshine hours was large, and irregular, but a significant proportion of that variability could be ascribed to an average increase of 3.3 hours each year between 1951 and 1999. Hours of sunshine increased for all months in that period. It is argued that the Antarctic region has not taken its rightful place in studies of the biological and ecological effects of climate change and that sub-Antarctic islands, especially, have much to offer in this field. Climatic change will directly affect the indigenous biota sub-Antarctic islands. An even greater threat is that a warmer climate will increase the ease with which the islands can be invaded by alien species and examples are given of how climatic change and invasive organisms influence the biota and ecology of Marion Island.