Coastal flooding due to climate change could put homes, business and roads worth $226 billion at risk, a new report suggests.

The Climate Council released its latest report – Growing Risks, Critical Choices – which details the impact of climate change on health, property, farming and ecosystems.

Based on a 1.1 metre sea level rise – the highest range of projections – about 250,000 coastal homes, $87 billion in commercial buildings and $67 billion in roads and rail could be at risk.

Even with a much smaller rise, of about 50cm, the report suggests a coastal flooding event in southeast Queensland alone could cause $4 billion in damage to homes.

Deaths from heatwaves in Australian cities are projected to double over the next four decades.

And a rise in drought frequency is estimated to cost $7.3 billion a year from 2020.

Even with rapid and deep cuts to carbon emissions, by the end of the century annual average temperatures were expected to rise 1.2C to 2.3C above pre-industrial levels, but 3.4C to 5.7C under a business-as-usual scenario.

Scientists now believe that a 2C target – which Australia is committed to – should no longer be considered a “safe” level of climate change.

National governments should instead aim for 1.5C.

“With just 0.85C of warming globally we have already witnessed adverse consequences,” the report said.

The report concludes that the globe must “almost completely decarbonise” within three decades to effectively tackle climate change.

“A low or no-carbon future … is healthier, more resilient, more equitable, and more economically viable than a business-as-usual future,” the report says.

The Abbott government has announced a goal to cut emissions by 26-28 per cent on 2005 levels by 2030 – lower than the Climate Change Authority’s proposal of 45-65 per cent.

But even the council’s more ambitious proposal, the report said, should be seen as a bare minimum to avoid a 2C rise.