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00:00Hi, everybody. I wanted to make a special update video this week on El Nino because it was declared by
00:09Noah earlier on this week, and the media has picked up on it and just gone real strong.
00:18I've seen things like Super El Nino, Godzilla El Nino plastered in a lot of places, and I wanted to
00:25have a chat with you, a discussion that's based in scientific evidence and scientific language, as well as uncertainty, because
00:36El Nino is a very concerning issue for farmers because of its correlation with drought and bushfire.
00:45I know, you know, the declaration of El Nino in 2023, a lot of people decided to destock, and then
00:53we got rainfalls later, and it's a very controversial thing because we don't always communicate the science in a way
01:04that is understandable, and because it informs a lot of really heavy decisions.
01:11So that's what we're going to do today. We're going to have a discussion about El Nino, about what we
01:16do and what we don't know, as well as how we come to that information, so that you feel informed
01:23and equipped to make decisions as we go ahead, but also so that you have a better critical thinking lens
01:31when you're looking at the media and how they're covering the El Nino declaration.
01:36Cool, so let's get started. Just, by the way, if you don't know who I am, my name is Alex
01:42Dunn. I'm a PhD student of atmospheric science at Monash University, and with the ARC Centre of Excellence for 21st
01:49Century Weather, so I research and I study weather.
01:52Now, I'm not an expert in El Nino myself. I'm very lucky to be surrounded by Australia's leading experts on
02:02ENSO, on El Nino in Australia, and so we've had a lot of discussions this week about what it means
02:09and from those experts, how they'd even like me to communicate with the general public so that that information is
02:16really clear.
02:16So that's just a bit of a background of where I'm coming to you from.
02:21So ENSO, the El Nino Southern Oscillation, is a climate mode of variability, which means it is a natural form
02:29of change in our climate, and it oscillates between a positive state called El Nino and a negative state called
02:39La Nina.
02:40And for us in Australia, we typically think of El Nino as dry and La Nina as wet.
02:48But really what it is, is changes in the Pacific Ocean's temperatures.
02:53So we can see here in this in this schematic that El Nino has warmer than average waters in the
03:01Pacific Ocean.
03:02And for Australia, this causes dry, sinking air to occur over the continent, whereas La Nina is cooler than average
03:14temperatures for the Pacific Ocean.
03:16And this basically has a lot of rising moist air, which brings a lot of rainfall for Australia.
03:22So that's just a quick summary of what ENSO actually is.
03:27In terms of climate change and ENSO, unfortunately, climate change and El Nino, the El Nino stage of ENSO, tend
03:39to amplify each other.
03:40They both for Australia, increase temperatures, they decrease rainfall, they decrease snow, they can increase frost risk because we get
03:53more sunny, clear days.
03:55So really cool night times.
03:56So they're quite hand in hand.
03:59And what has occurred as global average temperatures have risen is that the El Nino state has also changed slightly,
04:09but they are two separate things.
04:12Climate change is this long term trend of increased global temperatures, whereas El Nino or ENSO, the El Nino Southern
04:21Oscillation oscillates between two different phases.
04:24So that's just something to think about.
04:27So let's start now by seeing what's actually happening in the Pacific Ocean.
04:33This red patch here shows that we have warmer than average temperatures in the Pacific Ocean, and that is the
04:43first indicator of El Nino.
04:46There are four indicators that when the Bureau used to declare El Nino, that would need to be checked.
04:53If we got three out of four, we would declare El Nino.
04:58Currently, we hit four out of four of those criteria.
05:03So the Bureau doesn't declare El Nino anymore.
05:08NOAA, which is a North American Institute, they declared El Nino because El Nino is a global issue.
05:17They typically have a lower tolerance for calling El Nino than the Australian checklist does, but we currently hit all
05:25four of those marks on the Australian checklist.
05:27So we have officially entered an El Nino phase.
05:32And what we mean by that is that not only do we have these warmer than average temperatures,
05:39but across our models and we look at multiple ensembles of multiple different runs of models, they are all showing
05:49that this section of the Pacific Ocean is continuing to warm and stay warm.
05:57So let's quickly chat about that sort of model spread.
06:02So the first thing to know about models is that there are different providers of them, actually.
06:10So we'll start with this.
06:11So this is from James Weather and you can see we have the Australian model.
06:15It's called Access, the Japanese model, the US model, the CFS version and the PLS version.
06:21So these are all different developers of different atmospheric models, just like they'll change some of the inputs into the
06:30data or things like that.
06:33All of the different providers of ENSO forecasts are all showing us that we are staying in the El Nino
06:44phase.
06:46This only looks into December, but we are staying in it for a while.
06:50So that is different people, different computational models that are showing us, OK, we're going into ENSO.
06:59Within each of these lines individually, we have multiple ensemble members, which means we're looking here at the ECMWF forecast.
07:11This is made by the European modelers.
07:15They don't just put one bit of weather in and produce one forecast.
07:21They do this multiple times.
07:23And this creates a plume, which is what we're looking at, which is multiple different ensemble members, meaning multiple different
07:31members of the model.
07:32OK, and what we see from this plume is strong confidence that all ensemble members are showing us increasing the
07:44Nino 3.4 sea surface temperature, which is that band in the Pacific Ocean that we're seeing.
07:51So all ensemble members are showing us that we are heading in to an intensifying El Nino.
07:57OK, so that gives us confidence in the forecast that we deliver to you that we are going into El
08:03Nino.
08:04And then we talk about strength, and this is where we see the difference between an anomaly being, you know,
08:15just above two degrees to some of them showing almost four degrees.
08:18Now, this is where you can see much more spread.
08:22So we have less confidence in decisively communicating that it's going to be a moderate El Nino or a very
08:31strong El Nino.
08:32That's what we don't have the confidence because there's that spread in the models.
08:37Now, what is triggering the media to pick up on this super El Nino or Godzilla El Nino, this, you
08:44know, this language that we never use as scientists, by the way, is that we are hitting temperatures here in
08:54the anomaly degree that we've never seen before.
08:58And in a lot of the plots, so like the figures and the images and diagrams that we show you,
09:04there are multiple models and ensemble members of those models that the temperature bar doesn't fit anymore.
09:17We have to extend the temperature bar.
09:19So that is what is raising concern for scientists.
09:22And then that's being picked up on the media that there are some members that are showing really, really strong
09:30temperatures for this El Nino.
09:32That is only some of the ensemble members.
09:35OK, so that's that's why you're hearing this very superfluous language coming.
09:41OK.
09:43But I want to bring this down to earth about the impacts of this for your farm and your decisions.
09:52This is a somewhat complex complex plot, but here we're looking at rainfall anomaly.
10:00So the difference in rainfall basically when we're going into El Nino or La Nina.
10:05And what I want to communicate top line before we look at this.
10:10A strong El Nino does not mean strong drought conditions.
10:17So just because we're getting really strong forecasts for the El Nino does not mean we are definitely going into
10:27the worst drought.
10:28OK, that's that's there's no evidence for that.
10:32And I want to show you why that is.
10:34So when we have La Nina forecast, there is a much stronger correlation between a strong La Nina and a
10:45lot of extra rainfall.
10:48But the same is not for El Nino.
10:51The strongest El Ninos do not necessarily have the biggest rainfall anomalies.
11:00So, for example, we can see, you know, down here we've got two very strong El Nino events.
11:08They're really low on this oscillation index.
11:11Their rainfall anomaly is nowhere near as low as, for example, this El Nino, which has a very low rainfall
11:22produced, but it's not very strong.
11:25So don't panic is what I'm trying to say.
11:35There is cause for concern.
11:38There is strong evidence, though, that El Ninos are correlated with drought and bushfire risk.
11:44And that should be taken seriously.
11:48And that should go into your farm management planning for the next months to years.
11:58But what I'm trying to say is do not de-stock immediately.
12:02Do not, you know, throw the baby out with the bathwater.
12:08But when you're reading media articles, stay informed, but have that skepticism that the strength does not equal high impact.
12:18OK, that is just something to take forward with you that I wanted to get that message out there early
12:24because you are going to hear a lot of this.
12:27It is going to intensify how much you hear about this and by all accounts, it looks like we are
12:35going into a very strong El Nino season.
12:40I will keep you updated as best I can.
12:42If you have questions about how we call El Nino, how it's forecasted, reach out to your James Weather contact.
12:53They'll pass that on to me and I'll make sure to answer it in the next video.
12:57OK, have a great week.
13:00Yeah, reach out if you need to and we'll chat next time.
13:03Thanks.
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