One area in which South African scientists are making a major international contribution is that of human-induced climate change – and Marion Island is proving a unique natural laboratory for that research.
“The signals of human-induced climate change on the environment are clear,” says veteran island researcher Professor Steven Chown of Stellenbosch University’s Centre for Invasion Biology.
For example, meticulous meteorological records since South Africa’s annexation of the island in January 1948 – the members of the top-secret “Operation Snoektown” had landed on Marion on December 29 the previous year – have shown that the mean annual temperature has increased by 1.5ºC since then – an enormously significant change in biological terms.
The entire stationary glacier that graced the centre of the island has disappeared in less than 30 years – it was still present “in all its glory” during Chown’s first visit in 1983.
The annual rainfall has plummeted, and – thanks to meticulous field notes by botanist Brian Huntley in 1965/6 – it’s been shown that many indigenous plants are migrating up the slopes to cooler habitats, with the current “winner” having climbed 388 metres in just 45 years. Whole plant communities are changing. Ominously, research on Marion is also showing that invasive alien species are all too ready and able to move into the vacated spaces, and that global warming is promoting their presence.
Replicated on a global scale, this unwelcome ability of alien invasives has immense implications for humankind.
Through tracking changes at Marion Island, local scientists’ findings can help influence political decisions, such as those being negotiated as part of a new international climate change agreement that might be finalised at the UN conference in Durban at the end of the year. - Sunday Argus