Evrim Yazgin
Cosmos science journalist
Sea-level rise due to climate change has already begun to effect low-lying communities and ecosystems around the world.
An Australian researcher has published a summary which warns about the potential effects of sea-level rise on the country’s southeastern coast.
Kathleen McInnes is a research scientist at the Climate Science Centre, part of the CSIRO – Australia’s national science agency. McInnes’s paper focussed on the Gippsland region is published in the journal Proceedings of the Royal Society of Victoria.
“Global mean sea level has risen by approximately 25 cm since 1880,” McInnes writes. “Sea-level rise is a major concern for low-lying coastal communities… and coastal environments are increasingly likely to experience hazards such as coastal inundation and erosion over the coming decades.”
Such rising sea levels can cause havoc on communities and ecosystems.
Earlier this month, the first local extinction due to sea-level rise was reported in the United States.
Gippsland is a region which is particularly at risk from rising seas.
“There are many parts of the Gippsland coastline that are low-lying and therefore likely to experience more frequent inundation over coming years from high tides and storm surges,” McInnes tells Cosmos. “And there are places that are wave exposed that are experiencing enhanced erosion.”
McInnes says the effects of rising sea levels could impact local communities.
“Settled areas around the Gippsland Lakes are not only very low lying, but this region has the added potential of coincident flood events from the various river systems draining into the Lakes and so a combination of oceanic high sea levels and riverine flooding during high rainfall events are of particular concern. Such events will all likely become more extreme as the climate continues to warm,” McInnes explains.
The researcher adds that additional factors could see the relative sea level in Gippsland rise even higher than the global average. Oil and gas extraction in Gippsland over decades has seen “land subsidence” which makes the relative sea level higher and “will affect hazards such as inundation depth and extent during extreme sea level events.” Additionally,
McInnes notes the “influence of the East Australian Current” which brings warmer water to Australia’s southeast coast, raising sea levels further due to decreased ocean density and the relative narrowness of the gap between continental plates off the coast.
Gippsland covers a region of more than 41,000km2 –about the size as the Netherlands. It stretches from the Australian Alps to the eastern coast of Victoria and encompasses a rich array of habitats and wildlife.
Biochemist Perran Cook, from Melbourne’s Monash University, says the low-lying ecosystems of Gippsland are under threat from rising seas.
Among these are the region’s lakes and waterways, some internationally recognised as Ramsar wetlands in line with the treaty, the Ramsar Convention on Wetlands. These are unique wetlands important for conserving biological diversity, especially waterfowl.
“Obviously the wetlands are right at sea level, so as they rise that affects them,” says Cook, who was not an author on the Proceedings of the Royal Society of Victoria paper.
Cook says that conservation efforts in the region include “monitoring and reporting on the condition of the Ramsar wetlands. They have to report that to the Ramsar committee and undertake remediation action.”
“There has been dredging to create sandbanks for terns to breed on, for example. The Catchment Management Authority of East Gippsland have been doing that. As the sea level rises, those sandbanks will go under and they have to artificially create more to preserve that habitat.”
Cook adds that more can be done, but this has to be assessed on “balancing the cost and the return on investment.”
“The big thing is stopping climate change. Even though it’s not direct like doing on-ground action in the lakes, it’s about reducing CO2 emissions. That’s the bigger picture,” Cook says.
“You need to build solar, wind farms. People sometimes say the wind farms and solar are destroying the place. Well, actually, you put them up in agricultural areas which are already damaged and you’re going to save these areas that you care about.
“If you want to save these low-lying areas, and if you value them, then you’ve got to build renewables quick smart.”
