Adelaide’s January heatwave attributed to climate change
The findings are reported in the fourth issue of the American Meteorological Society’s report into extreme weather. The report looked at 33 extreme weather events around the world and analysed which could be attributed to human activity and which were the result of natural variability in weather patterns.
As David Mark reports, detecting the human hand in climate change is a developing area of climate science.
DAVID MARK: For decades, people have been attributing individual extreme weather events to climate change, but that invariably comes with a note of caution from scientists.
DAVID KAROLY: What scientists have done in the past was focus on changes in the mean climate as well as looking at long term trends.
DAVID MARK: David Karoly is a professor of atmospheric science at the University of Melbourne.
While scientists have been able to study those long term trends in events like heatwaves or heavy rainfall, they haven’t able to attribute individual events to human induced climate change.
But that’s changing.
The American Meteorological Society report, Explaining Extreme Events From A Climate Perspective examines 33 individual events around the world last year, including heatwaves, rainfall events droughts, cyclones and sea surface temperatures, and asks the question: which events are the result of human induced climate change. ……..
They can then compare the chances of an extreme event happening in the world as it is now as opposed to the simulated world without climate change.
Take the heatwave that hit Adelaide and Melbourne in January last year.
Professor David Karoly.
DAVID KAROLY: In Adelaide, five days in a row above 42 Celsius; in Melbourne four days in a row about 41 Celsius for the maximum, and those are extreme heat waves, and they had big impacts on lots of well, both on people and on infrastructure.
But what we found was that there were greater uncertainties in the signal of climate change affecting the Melbourne heatwave, whereas the results were much clearer and it was very likely that human-caused climate change significantly increased the chances of the heatwaves occurring in Adelaide by more than 25 per cent.
DAVID MARK: And then you get another study by Sarah Perkins-Kirkpatrick from the University of New South Wales which found that a late autumn heatwave was 23 times more likely as a result of increased greenhouse gases, so that seems like there’s a great deal of certainty there.
DAVID KAROLY: That’s correct………
DAVID KAROLY: Look, the take home message is that already climate change is affecting many extreme events across the world, both in 2014 and in other years. Particularly changes in temperature extremes, but also changes in a range of other events.
But in some extreme events natural variability is the dominant factor, and it’s hard to discern a clear climate change signal.
KIM LANDERS: Professor David Karoly from the University of Melbourne. http://www.abc.net.au/worldtoday/content/2015/s4346582.htm
No comments yet.
1 This month
of the week – Disrupting War & Militarism in Oceania. Active solidarity. Radical practice.
Antinuclear 
Leave a comment