New research finds coastal flooding may cost up to 20% of economy
Exposed human population and assets are estimated to increase about half in that time.
Under a scenario of high greenhouse gas emissions and no flood defences, the cost of asset damage could equate up to 20% of the global economy in 2100, Ebru Kirezci PhD candidate, University of Melbourne, and University of Melbourne Professor Ian Young write.
"Without a dramatic reduction in greenhouse gas emissions, or a huge investment in sea walls and other structures, it’s clear coastal erosion will devastate the global economy and much of the world’s population.
"In Australia, we predict the areas to be worst-affected by flooding are concentrated in the north and northeast of the continent, including around Darwin and Townsville.
"Sea levels are rising at an increasing rate for two main reasons. As global temperatures increase, glaciers and ice sheets melt. At the same time, the oceans absorb heat from the atmosphere, causing the water to expand. Seas are rising by about 3-4 millimetres a year and the rate is expected to accelerate.
"These higher sea levels, combined with potentially more extreme weather under climate change, will bring damaging flooding to coasts. Our study set out to determine the extent of flooding, how many people this would affect and the economic damage caused.
"One outstanding result is that due to sea level rise, what is now considered a once-a-century extreme sea level event could occur as frequently as every ten years or less for most coastal locations.
"Under a scenario of high greenhouse gas emissions and assuming no flood defences, such as sea walls, we estimate that the land area affected by coastal flooding could increase by 48% by 2100.
"This could mean by 2100, the global population exposed to coastal flooding could be up to 287 million (4.1% of the world’s population).
"Under the same scenario, coastal assets such as buildings, roads and other infrastructure worth up to US$14.2 trillion (A$19.82 trillion) could be threatened by flooding." ■