Rising sea levels will submerge Kakadu

CSIRO modelling reveals grave threat to Australia’s World Heritage asset.

Northern Australia’s World Heritagelisted Kakadu National Park could be overwhelmed by rising seawater in fewer than 90 years, according to a report published in the CSIRO journal Marine and Freshwater Research.

Kakadu, a landscape of coastal floodplains, wetlands, woodlands, monsoon forests and ‘stone country’, is highly vulnerable to climate change. With rising sea levels, saltwater inundation and storm surges are predicted to wreak havoc on the ecosystem. Changes in seasonal rainfalls and temperature increases will also take their toll.

The region faces “a diabolical problem that requires complex and possibly counter-intuitive solutions”, conclude the report’s authors, Peter Bayliss and colleagues from the CSIRO’S oceans and atmosphere business unit.

The iconic national park is a biodiversity bonanza. It is home to 10,000 species of insects, more than 280 kinds of birds, 117 reptile species, 60 types of mammals, 53 species of freshwater fish and more than 1,700 different species of plants. Introduced species including aquatic weeds and feral pigs have taken their toll. Many endemic species are already endangered or vulnerable.

Using 2013 as the baseline, the researchers modelled the impact of climate change in the Kakadu region now, in 2070 and in 2100. They determined that 60% of its freshwater floodplains will be subjected to sea-level rise and saltwater inundation by 2070, and 78% by 2100. By 2132 all current freshwater floodplains in the region will be an average of 2.15 metres under seawater.

Sea levels “are predicted to keep rising even if climate change is stabilised, and will continue to do so for many centuries because of the long time scales of the oceans and ice sheets”.