Australian airports and coastal infrastructure only metres above sea level could be at risk of inundation this century as emerging science suggests climate change impacts may happen earlier than expected, researchers at Risk Frontiers and Macquarie University say.

The Intergovernmental Panel on Climate Change (IPCC) projects 50-90 centimetre sea level rises for Australia by 2090, relative to average levels between 1986-2005.

But the projection may be an underestimate, with some studies suggesting a further two metres at least could be added to global sea levels in the case of potential West Antarctic Ice Sheet collapses.

“For airports, the planning implications are stark when you compare the current projection of less than a metre of sea level rise and the potential of at least a two-metre rise later this century,” they say in an article published on The Conversation website.

The article is written by Risk Frontiers Senior Risk Scientist Thomas Mortlock, Risk Frontiers GM Andrew Gissing, Macquarie University Associate Professor Ian Goodwin and Risk Frontiers Senior Geospatial Scientist Mingzhu Wang.

“Taking the most low-lying major airports in Australia as an example, our modelling suggests a collapse of the West Antarctic Ice Sheet would see their near complete inundation – without any adaptation in place.”

Cairns airport is less than three metres above sea level, while those at Sydney and Brisbane are less than four metres above. Townsville and Hobart airports may face issues with a five-metre rise.

The researchers say most Australian airports have conducted risk assessments based on the IPCC projections.

Infrastructure at more elevated locations are also at risk and may also be inoperable more frequently when the combined effect of storm surges, waves, elevated groundwater or river flooding are considered.

The researchers say that uncertainty generally comes with a cost, and proactive planning makes economic sense.

“Given the deep uncertainties associated with the timing of ice-sheet collapse, we suggest airport and other critical coast infrastructure is subjected to risk analysis for a two to three metre sea level rise,” they say.

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