Australian news, and some related international items

Is climate change playing a role in Australia’s drought?

How bad is this drought and is it caused by climate change?

How do we define drought? What causes them? And are they getting worse?, Brisbane Times, By Peter Hannam , NOVEMBER 3, 2019

“………..Is climate change playing a role?

If droughts can be hard to pin down, explaining their connection to climate change adds to the complexity.

The facts are that scientists cannot say definitively that a specific drought is caused by climate change, but they can say definitively that climate change makes the effects of droughts stronger and more damaging.

Andy Pitman, director of the ARC Centre of Excellence for Climate Extremes, recently ignited a brief firestorm over his comment to a business forum that “there is no link between climate change and drought”.

Some media jumped on his views, prompting his centre to issue a belated correction saying he erred by leaving out one word, as in “there is no direct link between climate change and drought”.

The indirect links, though, should be cause enough for concern in a country with Australia’s variable rainfall……..

Climate change is blamed for accelerating the winds that circle around Antarctica, drawing storm tracks further south so some miss the mainland.

By contrast, for some areas in southern Australia, rainfall is increasing during the warmer months. That shift, though, comes as little consolation for farmers now reliant on winter harvests……

While it’s not clear how annual rainfall totals will change in a warming world, future droughts will be hotter when they do arrive, says Ben Henley, a climate researcher at the University of Melbourne.

“We’re really quite concerned in southern Australia,” he says. “Even if we get the same degree of annual rainfall, if that’s falling in the hot time of the year, that’s more likely to be evaporated off.” …..

Is this the new normal?

Cutting-edge research includes work to investigate whether droughts such as the current one are likely to become more prolonged and more frequent…..

One smoking gun is that rainforests are now burning.

“By June 2018, they reported that all types of trees were dying, leaving a desert-like landscape of sand dunes replacing the normally vegetated scene,” the paper says.

As plants dry or die,the risk of major bushfires increases. And, as plants also help moderate the local climate through a process called evapotranspiration, when they die another hand brake on the heat is removed.

Some researchers believe the ambient conditions that led to the Millennium Drought have not yet broken down, says Greg Holland, an emeritus senior scientist at the US National Center for Atmospheric Research and formerly with the bureau.

“It’s quite possible … we never came out of it,” he says, adding a couple of wet years in 2010 and 2011 may have been “a bit of an hiatus in the middle”.

Indeed, while drought is measured against historical averages, it may be time to redefine what we considered as normal. “One smoking gun is that rainforests are now burning,” he says…….

November 4, 2019 - Posted by | AUSTRALIA - NATIONAL, climate change - global warming

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