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Today, climate scientist and lead author on the IPCC’s most recent climate assessment, Joëlle Gergis, on our never-ending stretch of rainy summers and what they mean for the climate disaster.

Why a third wet summer could be the most dangerous yet

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We could be in for another wet, cloudy summer. 

The chances of another La Niña weather event are growing, and it’s now very likely the east coast of Australia will be drenched once again.

That could make it the riskiest summer yet for flooding, with catchments still full and communities still regrouping.

Today, climate scientist and lead author on the IPCC’s most recent climate assessment, Joëlle Gergis, on our never-ending stretch of rainy summers and what they mean for the climate disaster.

 

Socials: Stay in touch with us on Twitter and Instagram

Guest: Author of Humanity’s Moment: A Climate Scientist’s Case for Hope, Joëlle Gergis.

Read Transcript

[Theme music starts]

##RUBY:

From Schwartz Media, I’m Ruby Jones. This is *7am*.

We could be in for another wet, cloudy summer. 

The chances of another La Nina weather event are growing, and it’s now very likely the east coast of Australia will be drenched once again.

That could make it the riskiest summer yet for flooding, with catchments still full and communities still regrouping.

Today, climate scientist and lead author on the IPCC’s most recent climate assessment, Joelle Gergis - on our never ending stretch of rainy summers and what they mean for the climate disaster.

It’s Tuesday, September 13. 

[Theme music ends]

##RUBY:

Joelle, we’ve just seen two years of rain and flooding - two La Nina years in a row. And there are signs that we could be about to see the same again - a third year of heavy rainfall. How likely is that looking?  

##JOELLE: 

At this stage it's looking very likely. So the US and Japan have actually already declared a third La Nina event is currently underway in the Pacific and their Bureau of Meteorology use slightly different definitions. But it's very likely that in coming weeks we'll also see a La Nina officially declared here in Australia. 

##RUBY:

And I want to come back to what that might mean. But before we do, could we talk for a moment about what we've just seen on the east coast of Australia only a couple of months ago? I know that that's close to where you are. What did you observe when the flooding happened?

##JOELLE: 

So really we've seen this interesting set of conditions where we've got a La Nina event which tends to bring above average rainfall to the eastern part of Australia, locking in with conditions in the Indian Ocean where it's also experiencing warmer than average ocean temperatures. And when you see the Indian and Pacific Oceans locking in, you start to get very, very wet conditions indeed.

##Archival Tape -- 10 News (Host): 

“Residents in the north of the state who are again facing devastation only weeks after record breaking flooding inundated communities and washed away livelihoods.”

##Archival Tape -- 9 News (Resident):

“I have some neighbours next to us who are stuck in their roof cavity and they really need help desperately.”

 ##Archival Tape -- 10 News (Reporter):

“It's the next wave of this seemingly never ending flood disaster.”

##Archival Tape -- 10 News (Resident):

“I mean, sometimes I feel like quitting, but, you know, I just got to get back on my feet.”

##JOELLE: 

And so we've seen this now for two years in a row. 

And what we're experiencing right now is potentially the third round of this.  

And for instance, in parts of northern New South Wales, we've seen extraordinary levels of rainfall and associated flooding. So for example, just north of Lismore in the town of Dunoon, they experienced 775 millimetres of rainfall in a 24 hour period. So that's effectively the entire rainfall of cities like Melbourne or London in a 24 hour rainfall period. 

And of course it's also caused catastrophic levels of flooding that have seen places like the Lismore CBD completely devastated. 

##Archival Tape -- 7 News Lismore:

“We're currently at 14 metres high. This is the first we've seen at this high since the fifties. This is a storm. It's unprecedented. 

And if you have a look at the damage, this is it. This is a main street, or part of the main shops in Lismore, in the CBD. You have a hair salon over there completely underwater. You've got a car there, shops, homes, everyone. It's all, all completely underwater here.”

##JOELLE: 

And I have family who are in Lismore and visiting them has been a really confronting experience to realise that when you see repeated flooding like this, society just finds it really, really hard to bounce back. And in fact the record was broken, the flood height record was broken by a full two metres, which is, is a monstrous obliteration of a record. So to see this happen was just something that for me, I guess as a climate scientist was really shocking because it was completely unprecedented and unpredicted really by the models at the time. 

##RUBY:

Why is it that we're likely to see this happen again? This type of weather system appear for a third time.

##JOELLE: 

So when we get La Nina conditions in the Pacific Ocean, we have warmer than average ocean temperatures and that leads to an increase in evaporation and the sort of conditions that we need that are conducive to cloud formation. And then you tend to see enhanced rainfall during those times. And the thing with the conditions we experiencing right now is, as I mentioned, is that the Indian Ocean is also experiencing warm conditions. 

So it's effectively like a double whammy. And what that does is it primes the atmosphere with a lot of moisture. And so there's a lot of moisture that is there. And once you get these rain bearing systems play out, you start to see really torrential rain. And some of Australia's most iconic wet periods in our history have come about when we've had this combination.

And so for me, what's quite interesting is that we've got this really interesting sort of rare natural variability playing out on the background of a warmer climate. And what that means is that we're starting to see events that in the past would have been fairly weak, but they're being enhanced by global warming.

##RUBY:

Okay, so these are natural climate cycles interacting perhaps in a slightly unlucky way, one after the other, but it's really the warming climate that's amplifying the effect of them. 

##JOELLE: 

Yeah, absolutely. We are seeing this amplification. I mean, the science still is active in this area, which for me is quite interesting. So in terms of the science that's there to be done, people are looking at these various different interactions between the Indian and the Pacific and also the Southern Ocean. There's a lot of complexity in the system. 

And also these processes that play out more on weather timescales. So it is one of these things that I guess scientists are trying to figure out, well, how does our weather start to shift in a warmer world? 

##RUBY:

We’ll be back in a moment.

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##Archival Tape -- ABC Reporter:

“Australia's east coast may face another summer of heavy rains and devastating floods, with the US Oceanic and Atmospheric Administration (NOAA) saying the chance of a third consecutive La Nina event has increased.”

##RUBY:

Joelle, given that we've just had two years of of these La Nina weather events, is the fear that this third year will have an even worse impact when it comes to flooding, given that we are still living with the consequences of what has just happened, that the dams are still full, that the ground is is sodden from the flooding that we've just seen. So could this third year be even worse than what we've just seen?

##JOELLE: 

Absolutely. I mean, this is the great concern is that we're looking at the compounding effects of a prolonged wet period. So as you mentioned, the catchments are already primed for flooding in parts of western Sydney. We've already seen people who have been evacuated out of their homes several times, and also on the north coast of New South Wales, a town like Lismore. I don't think it can cope with another round of this. People still don't know whether to rebuild, whether or not they're able to stay in an area that is increasingly becoming flood prone. 

And so that really raises a lot of very complex decisions that we need to be making about how we are going to start to adapt to climate change. So a lot of the public conversation is around mitigation. So the reduction of emissions, which necessarily is very important because that is actually turning the tap off. But we have to stop and think about how are we going to manage this increased risk? And I think what's particularly interesting for me I guess is seeing how we went from the Black Summer bushfire conditions of really severe drought. 2019 was Australia's hottest and driest year on record and it was the first time in our records that those two events happened at the same time. So the concurrent hot and dry conditions. 

So really what is concerning is that there's not enough time between recovery time between these events. So we've just gone from severe drought and bushfires, into prolonged period of flooding and there are many communities are very vulnerable already. There are people still living in caravans at intense out the front of their houses in Lismore. When you drive through it's very confronting to think this is not the developing world, this is Australia and this is something that I think our politicians can see the seriousness of the issue, but we haven't really got a plan.

##RUBY:

And these kind of oscillating severe weather events, like you say, between drought and flood happening back to back. Is this something that we're going to continue to see over the next decade?

##JOELLE: 

Absolutely. I mean, this is consistent with the science, what the science is saying. So because the planet is warming, we're seeing hotter conditions and that leads to a drying out of soil and vegetation. And so the drought, our droughts are getting hotter. And then when it does rain, because of the amount of heat that's in the system, a warmer atmosphere holds more moisture. And then you end up getting these torrential rains that break these, breaking droughts. And so it really is that oscillation between the land of drought and flooding rains, but becoming even more amplified. And that is really a concern because just natural variability in this country is already a lot to handle. And so with the amplification of extremes, I guess, is what the scientific community is trying to say is that with high levels of warming, these extremes start to become more pronounced and we really want to avoid that. 

##RUBY:

So how do we do that? Because we're obviously already a significant way down the path toward a climate crisis. But can we talk a bit about solutions, the things that we could be doing now to mitigate the situation that we're in? 

##JOELLE: 

Absolutely. So I think it is a really good step forward that the Federal Government is now legislating our 43% emissions reduction target, and that is a significant step and we have to acknowledge that. But by the same token, it's important to realise that the burning of fossil fuels is what is driving global warming. So the expansion of new fossil fuel projects, exploration, new gas fields and so on is really inconsistent with what the science says needs to happen. So on the one hand, it's really good that we're looking to reduce our emissions. But by continuing to export fossil fuels and to open up new projects is really something we can't be doing. So first and foremost, we have to stop that. And secondly, we have to realise that collectively where we are right now in terms of our pledges to the Paris Agreement is really inadequate. 
So even with COP26 last year we saw the world's leaders come together, but still our current collective pledges are still not where they need to be. So right now, currently implemented policy sees the planet warm by about 2 to 4 degrees and with all the net zero emission targets, if they are implemented in their entirety and funded in the case of developing countries, then we're looking at about two degrees. 

But the other thing I should mention, which I think is really important, is that those examples I've just talked about the Black Summer bushfires and the catastrophic flooding. This is with 1.2 degrees of global warming. So what happens at 1.5? What happens at two degrees? What happens at three and four? 

As we can see, this is just a preview of what's to come. And I think we need to really take it seriously, because this is a situation where at high levels of warming, the IPCC report basically says beyond two degrees, it becomes really difficult for humans to be able to adapt to this sort of disruption to the climate system and certainly ecosystems that we rely on as well.

We have to put the brakes on. So what we're doing right now isn't enough. And I think that needs to be understood more broadly, is that, yes, this is really good and we should be very pleased to see the progress that's been made here in Australia. But still we have a really long way to go. We're not out of the woods. 

##RUBY:

Joelle, thank you for your time.

##JOELLE: 

It's a pleasure. 

##RUBY:

Joelle Gergis’s book called: Humanity’s Moment: A Climate Scientist’s Case for Hope, is out now. 

[ADVERTISEMENT]

[Theme music starts]

##RUBY:

Also in the news today...

Queen Elizabeth’s body has left Balmoral Castle in Scotland to begin a long journey south to London, for a funeral to be held early next week.

In Australia, Prime Minister Anthony Albanese announced a public holiday in memory of the Queen for next Thursday, September 22.

And... 

Legislation to introduce a federal integrity commission has been delayed.

The legislation was supposed to be introduced to parliament this week, but because of the pause in sitting days due to the death of the Queen, it will now only make it to the floor of the house ‘by the end of the year’, according to Anthony Albanese.

There may not actually be enough time for the bill to pass before the end of the year, as had been promised by Labor.

I’m Ruby Jones, this is *7am*.

See you tomorrow.

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Background Reading

news
September 3, 2022
Flood-hit regions brace for a third La Niña event

As flood-affected communities fear the beginning of a third consecutive La Niña event, scientists are looking at the patterns of our oceans for clues on what to expect.