Confronting the nation’s coastal urban cities as it approaches 2055, 30 years on, will be both higher sea levels and air and water temperatures.

A repost from 11 September 2025

And 50 years from now (in 2075) sea levels will be substantially higher (and continue to further rise into the 22nd century). A high level of confidence exists in projections of future sea levels and temperatures along with less certain, but reasonable, projections of intensification of rainfall in most of our coastal cities.

More than 80% of Australia’s population lives, works, and plays within 30km of the coast. They attract much of the nation’s international business and tourists, and will remain centres of continued population growth with residents demanding access to healthy waterways.

It is imperative that the nation fully understands future consequences of climate change on the specific functioning of the waterbodies around which each of these cities has been built.

What is missing is a national appreciation of what our major estuary urban centres will begin to look like under conditions that are “highly likely” to occur in 30- and 50-years’ time. Sea-level trajectories recently made available by BoM indicate acceleration in rate of sea-level rise around Australia. A general increase of 26cm by 2050 and 83cm by 2100 (an estimate for 2075 is 46cm) is predicted.

We must expect losing tailwater for drains as low tide rises closing the “drainage window” of stormwater........

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