Climate change heralds an uncomfortable future for Victorians
It’s easy to think of climate change as a far-flung concern, well away from our daily lives. But what are the predictions for Melbourne and Victoria? How will they affect our cities and houses?
Dr Penny Whetton, principle research scientist at CSIRO, says we can expect the average temperature to be 1 degree warmer by 2030, compared to the start of this century. It could get much hotter as the decades go on.
“If we continue the growing trend in global emissions, we’re looking at between two and four degrees warmer by 2070. And then warmer again later in the century,” she says.
Among the most uncomfortable consequences will be heatwaves. “If you think about the severe hot spell in Melbourne in February 2009,” Dr Whetton says, “that type of weather is going to become more frequent.”
Under a high emissions scenario, days over 40 degrees could be three to six times more common by 2070.
Such extremes not only damage infrastructure, such as electricity and rail networks, but also human health. The heatwave preceding the Black Saturday bushfires caused 374 deaths in Melbourne. To limit the consequences, we’ll need to design our buildings for low-energy summertime cooling, not only winter warmth.
Temperature rise is just one part of the change. On rainfall, Dr Whetton says most of the science suggests we can expect less. “But as temperatures increase, when conditions are right for a thunderstorm or a downpour, the atmosphere holds more moisture,” she says.
“We’re looking at longer dry spells and less rainfall, but when rain comes, we’ll have heavier downpours. That’s the pattern for Victoria and most of southern Australia as well.”
Drier conditions overall will make farming more difficult and probably lead to higher prices for fresh fruit and vegies. Bigger storms will cause more flash floods, unless we upgrade our drains and culverts.
Then there’s sea level rise: the predictions for the end of the century vary from about 30 centimetres to around one metre.
“The increase in sea level is due both to oceans becoming warmer and expanding, and to ice on land melting,” Dr Whetton says. “The largest ice sheets that concern us are in parts of Antarctica and Greenland. We don’t know a lot about how rapidly the ice can melt, but sea level rise is likely to continue for many hundreds of years.”
Under its Future Coasts program, the Victorian government is planning for a rise of “not less than 0.8 metres by 2100”. That’ll mean protecting beaches and properties against erosion and storm tides, as well as restricting new development in low-lying places.
But Dr Whetton says we still don’t know what the biggest impacts on cities will be. “We might feel it most through the impact on the hinterland – the climate change predictions are quite a worry for food production in the Murray-Darling basin,” she says.
“It’s likely we will find ways to adapt to a 1- or 2-degree warming, although we don’t know for sure. A 3- or 4-degree warming is going to be significantly more challenging. If we want to avoid the bigger climate change, then it’s not about adaptation. We need to reduce greenhouse gas emissions globally.”