Why This Summer Has Been So Damn Wet
Because of a La Niña, extreme weather has been hitting the east coast of Australia for months.
Heavy rain and winds have caused flooding and power cuts, and experts are warning that these kinds of storms could continue for a while.
What’s happening is an inevitable impact of climate change, but why are we having severe storms this summer, when last year we had bushfires? And what can we expect from all summers in the future?
Last December torrential rain hit parts of New South Wales and Queensland, which left heaps of people in coastal areas on high alert for flooding.
Some even had to evacuate their homes, and Byron Bay’s famous beach almost fully disappeared because of erosion.
This heavy rain has continued into the new year, dampening the few celebrations that tried to go ahead under pandemic restrictions.
Dr. Ailie Gallant (Monash University): “When we see those big flooding events and storms events like we had, it’s usually a La Niña.”
What Is A La Niña?
La Niña is a periodic weather pattern that happens roughly every three to five years, and it’s when winds change the movement of the ocean and draw cooler deep water up from below.
Dr. Gallant describes it as kind of like a seesaw effect where on one side of the world the waters are really warm, while on the other side it’s cooling down.
AG: “So what happens is you have this kind of cascading effect where the ocean temperatures off the coast of South America actually end up affecting the weather over here, which sounds crazy.”
So why do the ocean temperatures mean that we’ve had a shit ton of rain?
Even though the waters are cooling down there’s obviously still a lot of warm air in Australia’s hotter months.
And when warm and wet air rises, it causes a much more unstable atmosphere that’s the perfect mixture for a stormy season like La Niña.
La Niña was kind of welcomed this season. A lot of people hoped it might bring some drought relief and minimise bushfire risk.
But if you take a step back from this year’s washout summer and last year’s devastating bushfire season, there’s a bigger picture here.
The Bigger Picture Is Climate Change
Dr. Gallant told me that we’re not just seeing more storms, we’re seeing more intense storms – there’s strong evidence that they’re bringing more intense rainfall and sticking around for longer.
AG: So basically, a warmer atmosphere can hold more water – that’s just basic physics, we know that. And if an atmosphere holds more water, chances are there’s going to be triggers for that water to be rained out. For example, for the La Nina in 2010 there was evidence that the really warm ocean waters off the coast of Queensland actually increased rainfall by up to 25% … which contributed to a huge amount of flooding.”
Which means the storms we’re experiencing right now are a consequence of global warming – that is: humans’ direct impact on climate change.
In December 2020 the CSIRO confirmed that the record high temperatures Australia lived through from September to November would have been “virtually impossible without human-caused climate change”.
Dr. Gallant pointed out that we’re getting weather on steroids now.
She told me that Australia should be prepared in the future for more natural disasters happening at the same time – which means a mixture of bad storms and deadly bushfires.
The Takeaway
Although droughts, flooding and bushfires aren’t anything new to Australians, the impacts of storms like the ones we are experiencing now, shouldn’t be overlooked.
When towns start rebuilding everything that’s been washed away, coastal erosion, higher sea levels, and a warmer atmosphere are impacts that can’t be fixed overnight, and they need to be properly addressed if we are going to continue to tackle climate change.