Staggering Price Tag for States Hardest Hit by Rising Seas Revealed

Australia loves its coastline, but new research warns that rising seas could cost the country a staggering amount of money. Scientists from three universities have found that every coastal state and the Northern Territory could face huge damage bills before the end of this century. The total cost could top $850 billion, covering damage to homes, businesses, and land.

Researchers say more than 267,000 coastal properties and 2 million hectares of land could be flooded by 2100. That estimate is based on a scenario where global warming reaches about 2.7 degrees Celsius above normal pre-industrial temperatures. The United Nations has warned that warming of at least 1.8 degrees is already likely, and it could climb even higher under current policies.

Professor Tom Kompas, one of the study's authors, called the findings alarming. He studies environmental economics at the University of Melbourne. He said the damage will keep growing as long as burning fossil fuels continues to heat the planet.

Queensland faces the biggest property risk, with around 93,000 homes at risk and an expected damage bill of $214 billion. The Gold Coast is the single most exposed urban area in the whole country, with projected losses of $84.4 billion. Western Australia faces the largest total losses of any state, while communities in northern New South Wales and the Central Coast also face high property damage.

Sea levels have already risen more than 22 centimetres since 1900, and scientists expect them to rise another 14 centimetres by 2050. Every 10 centimetres of sea level rise triples the chance of a once-in-a-century flood happening. That means floods that used to be very rare could soon happen all the time.

Scientists often use the "1 to 100 rule" to explain how far seawater travels inland. For every centimetre the sea rises, water can move about one metre further onto the land. So just 10 centimetres of sea level rise can push water 10 metres deeper inland, flooding homes and other buildings in its path.

Climate Councillor Dr. Andrew Watkins said storms make things even worse when they combine with higher sea levels. "When you have that sea level rise, and then you get a storm surge where the storm is pushing the water up against the coast, it makes the water go even higher," he said. Add in waves at high tide, and the damage can be extreme.

A recent example is Ex-Tropical Cyclone Alfred, which caused serious erosion along the coastline between south-east Queensland and north-east New South Wales. More than 125,000 insurance claims totalling $1.36 billion were filed after that storm. Associate Professor Johanna Nalau from Griffith University said recovery from that event is still not complete.

One big question is who will pay for all this damage. Insurance companies usually do not cover damage caused by the sea itself. Dr. Nalau noted that most coastal properties have some insurance, but insurers are very aware of the growing risks from climate change.

Dr. Watkins said the cost of protecting coastlines is becoming too high for many local councils to handle alone. "A lot of councils are effectively having to dip into their own coffers to support resilience building," he said. Experts are calling for national planning that brings together local, state, and federal governments to find the best way forward for all Australians.