The trend causing 'deadly' heat in Australia's major cities

Parts of Australia’s largest cities could be uninhabitable due to heatwaves, new research has found.

Temperatures will regularly soar to 40 degrees Celsius in Brisbane and Melbourne, with even worse expected for Sydney where residents can expect to swelter through 50-degree days.

The hotter conditions could be a common occurrence by 2060, but things could get even worse in urban areas without action to make cities greener, a study from Monash University found.

Australia has the most urbanised population on Earth, and heatwaves are already responsible for killing more of us than all other natural disasters combined.

Estimates suggest an extra 6214 people will die due to climate change related heatwaves by 2050 in Victoria alone.

Now scientists warn a phenomenon known as Urban Heat Island (UHI) effect, which makes cities hotter than surrounding areas, could make things even worse.

Cities are particularly susceptible to UHI due to the abundance of dark surfaces like concrete, asphalt and roofing which absorb solar radiation and increase temperatures.

Other contributors are a combination of tall buildings and narrow streets which can trap heat on the street, and waste generated by human activity.

Despite the gloom, there is a solution.

Trees key to reversing deadly heat trend

The Temperature Check: Greening Australia's Warming Cities study found that lower income areas are more susceptible to the phenomenon, and a major reason is that they have fewer trees and thus less shade than other suburbs.

Despite the key role that vegetation plays in reducing heat, the number of trees in Australia’s capital cities are declining, with Hobart the only exception.

The study’s co-author Dr Lucy Richardson told Yahoo News Australia that things are “pretty dire”.

“It's a serious thing and trees take time to grow,” Dr Richardson said.

“If we want to do this, we need to start now.

“I heard someone say the best time to plant a tree was 30 years ago.”

While the UHI effect has been averaged out across the capital cities, in some areas the temperature could be much higher.

Blacktown in NSW was identified as having a high UHI, increasing temperatures by an average of 5.8 degrees, however some parts of the suburb actually heated by an extra 16 degrees.

“Could you imagine that, nearly 65 degrees is just not liveable,” Dr Richardson said.

“It’s a serious thing.”

Laws to protect trees 'ineffectual'

Australian Conservation Foundation, who released the Monash study, said current laws to protect native trees are “ineffectual”.

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The charity’s campaigns director Paul Sinclair said this habitat could be cooling our cities and providing habitat for wildlife.

“In the first 17 years that Australia had a national environment law, 20,212 hectares of urban threatened species habitat — that’s 11,400 MCG footy grounds — was destroyed,” he said.

“Decisions made by Australian governments in the coming months will either lock in permanent and escalating damage to the ecological systems that sustain human health and livelihoods, or they will promote a healthier, fairer and greener world.”

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