The duration, frequency and intensity of extreme heat events have increased across large parts of Australia, a climate report has found.
The Bureau of Meteorology and CSIRO’s biennial State of the Climate report also found May-July rainfall had reduced by around 19 per cent since 1970 in the south-west of Australia.
The report offers a snapshot of how Australia’s weather has changed over the last two years.
What’s happening with Australia’s climate?
- Australia has warmed by around 1C since 1910
- There has been an increase in extreme fire weather, and a longer fire season, across large parts of Australia since the 1970s
- May–July rainfall has reduced by around 19 per cent since 1970 in the south-west of Australia
- April–October growing season rainfall has reduced by around 11 per cent since the mid-1990s in the continental south-east of Australia
- Rainfall has increased across parts of northern Australia since the 1970s
Source: State of the Climate report
According the latest report, there has been an increase in extreme fire-weather days, and a longer fire season, across large parts of Australia since the 1970s.
Temperatures in Australia — both in the air and on the sea surface — have warmed by 1C since 1910, the report said.
It may not sound like much, but according to the Bureau of Meteorology’s Karl Braganza, it is a big deal.
“It’s not significant when you think about the shift from night to day, but we’re talking about a shift in the actual climatology of Australia,” Dr Braganza said.
“If you move from one climate zone to another in Australia — where there’s only a degree or two of difference — you’ll notice quite a different environment.”
So is anything changing globally?
Last year was the warmest on record for the globe since reliable surface air temperature records began in 1880 — 15 of the last 16 years have been the hottest recorded.
Sea levels globally have risen more than 20cm since the late 19th century — one third of this rise is because of ocean warming and the rest from water stored on the land and melting land ice.
It is that melting land ice that could cause a huge shift in sea levels.
Take the ice on Greenland, for example. CSIRO’s Steve Rintoul said if that melted, there would be enough ice to raise global sea level by seven metres.
What makes this even more challenging is that scientists are not sure at what level of temperature rise this melt would happen.
“It could be as low as 1.5C [or] it could be as high as 3C, but once we cross that threshold we have committed ourselves to losing most of the ice on Greenland,” Dr Rintoul said.
What do we do about it?
Scientists say there is not a moment to lose and we must reduce the consumption of fossil fuels and consequently lower CO2 emissions.
BOM’s Dr Braganza said even if countries kept emissions steady today, there would still be more warming over the next few decades.
The findings do not differ significantly from the 2014 report — and Dr Braganza says that is “an affirmation of the past report”.
“There’s little or nothing from the previous report that needs revising,” he said.
“We’ve seen trends, particularly warming trends continuing and we expect those warming trends to continue.”