A super El Nino is on the way. What should we expect?

0:11Teresa Zakaria:Hello,

0:17Teresa Zakaria:welcome to the Naked Scientist podcast, the show that brings you the biggest breakthroughs and talks to the major movers and shakers in the worlds of science, technology and medicine. I'm Chris Smith and today we're considering the phenomenon called El Nino and how this can affect the weather, the economy and our health and why this year is predicted to be one of the worst on record.

0:49Teresa Zakaria:El Nino is a natural climate pattern that begins with unusually warm ocean temperatures in the tropical pacific and its effects are felt worldwide. Experts warn that floods, droughts and extreme heat could worsen this year with some tabloids using a bit of journalese to describe what they're calling a Godzilla or a supersized event. But what's the science that underpins El Nino? How is it predicted and what could this year's iteration mean for both the economy and global health? We begin with a very brief introduction to El Nino and a conversation between our reporter Rachel Ralph and Aidan McGiven, a meteorologist and weather presenter at the Met Office.

1:32Rachel Tolhurst:Well El Nino is a naturally occurring climate phenomenon usually involving warm water across parts of the tropical pacific ocean in a typical year easterly trade winds across the tropical pacific push warm waters all the way towards indonesia where those warm waters pile up and cause a lot of thunderstorms and heavy rain through indonesia and northern australia in an el nino year those easterly trade winds weaken so much that warm water sloshes back towards central and eastern parts of the Pacific and spread out. This is a vast amount of seawater. It's a huge ocean covering a third of the planet.

2:16Rachel Tolhurst:So it's an incredible redistribution of heat and thunderstorms from western parts of the Pacific towards central and eastern parts of the Pacific. And that massive redistribution of heat causes big consequences, especially across the Pacific area and countries bordering the Pacific, but elsewhere across the world as well, we see weather impacts from El Nino and ocean impacts as well. El Nino was discovered centuries ago by Peruvian fishermen because they noticed that the usual upwelling of cold waters off the coast of South America occasionally weakened, the waters warmed, and the fishing deteriorated in certain years.

2:59Rachel Tolhurst:It typically peaked around Christmas, which is why it was named El Nino de Navidad, the Christ child. So that's why it was named El Nino, because of its timing and its impact on fishermen off the coast of South America.

3:12Vicky Pryce:But we're seeing something quite different to normal right now, aren't we? So what is happening with El Nino at the moment?

3:18Rachel Tolhurst:The way that scientists monitor El Nino is through a region called the Nino 3.4 region, which is basically a rectangular area of the tropical and central pacific about twice the area of india and when sea surface temperatures there are half a degree above average for the time of year and that heat is sustained for several consecutive months el nino is declared that happened earlier this summer and those sea surface temperatures are now well above average we're talking about the latest three-month average May, June, July being 1.39 Celsius above average. And the most recent weekly reading gave a 2.6 Celsius anomaly.

4:07Rachel Tolhurst:Now, to put that into context, a strong El Nino would be considered one to two degrees above average. And the strongest on record, 2015-2016 El Nino, dubbed Super El Nino, that peaked at 2.6 Celsius above average. And this El Nino hasn't peaked yet. It's likely to peak later this year, late autumn, early winter. So there's more warming to come. And what the Met Office are predicting is that it will peak at three degrees above average. That would make it the strongest in living memory. But other organisations around the world are predicting even warmer than that, four degrees or more of warming.

4:48Rachel Tolhurst:So this is being dubbed the strongest El Nino ever recorded and perhaps even further back than that for centuries.

4:55Teresa Zakaria:Aidan McGiven. During an El Nino, the movement to the west of that patch of high pressure that would normally sit over the Pacific adjacent to the coasts of the US and Peru has the effect of pulling wetter weather southwards, which boosts rainfall over the southern US states and countries in South America like Peru, which can be subject to torrential rains and floods. On the other side of the Pacific. Australia typically experiences the reverse with rising temperatures, droughts and bushfires. The changing wind patterns overall though also reduce the likelihood of hurricanes in the Atlantic, so those clouds do have some silver linings.

5:35Teresa Zakaria:Nevertheless, now we understand what El Nino is and the consequences it can carry, how do we know when it's intensifying and how do meteorologists and climate scientists monitor and forecast it. With a bit more meat on the bones, here is the former BBC weather forecaster, Peter Gibbs.

5:53Aidan McGivern:When things are starting to happen, you'd be looking for those easterly trade winds, and that means winds blowing from the east, to start weakening, or even to reverse and start blowing from the west instead. And that's an early sign that there's something afoot. And then pressure difference. So those trade winds are actually driven by the atmospheric pressure difference across the Pacific. So they blow normally from a region of high pressure in the east above upwelling cold water to low pressure in the west. Now that difference used to be measured and still is to some extent as a simple difference in pressure between two stations, Darwin in Australia and Tahiti.

6:37Aidan McGivern:And that was known as the Southern Oscillation Index. The oscillation bit coming from the fact that we go from El Nino to its opposite, La Nina, and then back again with some normal bits in between, if you like. If that index went negative, it meant the pressure difference was reduced, which weakened the winds which makes El Niño more likely as that warm water in the west all starts washing back eastwards again. It's positive during La Niña. Unfortunately that's not as reliable as it could be because those locations are well to the south of the equator where the main action happens. So now we tend to use something a bit more representative called the Equatorial Southern Oscillation Index, which looks at the pressure difference between two large regions along the equator.

7:27Aidan McGivern:There's one just lying across Indonesia, the other one over the Pacific, extending out from the South American coast. But the concept is still the same. If the pressure changes from one to the other, then you can say that something is starting to happen. And then thirdly, we talked about sea surface temperature. That's done in a similar way to pressure. So geographically defined boxes over the central and eastern pacific called nino 3 and nino 4 where sea surface temperatures are monitored by satellite plus ships buoys very smart things called gliders which actually glide under the surface of the sea measuring temperature as well but then it gets a little bit complicated because different countries use different thresholds and average periods to decide whether an El Nino is actually underway.

8:17Aidan McGivern:But broadly, if you're seeing a half a degree Celsius rise in average sea surface temperature in the monitoring regions sustained over several months, that is defined as an El Nino. And we saw that happen in June. It was declared in June and is gradually building now.

8:36Teresa Zakaria:What sort of lead time do we get? As in when we begin to see these changes, they might just be something that's going to fizzle out so how do we we know that it's the real deal and how far in advance do we kind of get that instinctive feel that we're dealing with

8:52Aidan McGivern:a quite a major weather phenomenon fortunately i suppose compared to things like storms coming through el nino is a bit of a slow burner so once you start to see these things happening you know you've got a period of months before it's going to build to its peak. So then you can project it out several months ahead because they are quite predictable in the way they evolve. They're not predictable in when they're going to happen, how frequently they're going to happen. It's a very irregular cycle. It can be a couple of years between El Ninos. It can be five, six, seven years between El Ninos. but once things do start to get going you know you've got several months of this thing building before it hits a peak towards the end of the year and then gradually tails off the following year and the predictions as to how intense it's going to be are actually done using essentially the same models that produce the weather forecasts because they take into account not just atmospheric motion but what's happening in the sea with sea temperatures and sea currents as well so you can actually make some pretty useful forecasts in terms of the intensity and therefore how big the likely impacts are going to be several months in advance so obviously that's the benefit because you can get planning in place nice and early why are they describing this one as a particularly

10:17Teresa Zakaria:super i don't think that means special i mean as in i think they mean very big don't they but what what singles it out as this is a bigger one than average the forecast model started flagging

10:28Aidan McGivern:up the potential for something out of the ordinary pretty early on in the development process and those forecasts are still on track it's developing faster than the historic super el ninos of 97 98 and 2015 16 it's already a degree ahead of those at this stage i mentioned half a degree celsius warming is enough to declare an el nino a two degree celsius rise overall is regarded as a big event. The current Met Office forecasts show this one peaking later this year at above three degrees and other models are similar. So there's a very high probability it's going to be the strongest El Nino ever observed.

11:14Aidan McGivern:And those records go back to 1950. The World Meteorological Organization is really ramping up the warnings. They put out a warning with nearly 100 % confidence, which is unprecedented, that this thing is going to persist right into February of next year.

11:31Teresa Zakaria:And what will we expect to see? How will things change for us as this unfolds?

11:37Aidan McGivern:It's a tricky one. We're a long way away, of course, from the epicentre of this event. And because our weather is so changeable anyway, it's quite hard to pick out the signal from the noise in terms of what impacts across northwest Europe, in fact across Europe generally, you will get from an El Nino. It looks like there's a reasonable correlation overall between El Nino, particularly a strong El Nino, and warmer and wetter autumn weather across southwest Europe. That tends to happen. The Met Office certainly are suggesting an increased risk of wetter, stormier weather for northwest europe including the uk through this autumn and early winter but interesting the effects in europe often lag behind the actual el nino event so it might actually be into next winter that we actually see the impacts so it's really complicated and it also depends on interactions with other climate oscillations which operate over months years some of them decades others so similar sort of flip-flops we have one in the north atlantic for example called the north atlantic oscillation where the atlantic flips between very active weather coming in from the west over long periods of time that can give us very wet winters to much more leisurely movement of the jet stream which opens the door to more easterly outbreaks so it depends how the impacts from el nino phase in with things like the north atlantic isolation as to whether they reinforce each other or cancel each other out that's why it gets more and more complex the further away from the center of things that you get are we looking at another heat wave next summer it's it's virtually impossible to say i mean all you can say is that all that heat going into the atmosphere is going to raise global temperatures overall i mean it always does with an el nino 2024 is the warmest year on record because it was an el nino year this is a godzilla el nino So 2027 is highly likely to be the warmest year on record to surpass 2024.

14:08Aidan McGivern:Whether we get a heat wave or not is down to other factors, like we've had this summer with the weather getting stuck, having high pressure persisting for week after week after week after week, just allowing temperatures to build up. Now, that isn't necessarily dependent on El Nino. So you've got the background, higher temperatures globally, but you need other factors to kick in and come into play for us to end up with another prolonged heatwave. With a man, Peter Gibbs.

15:00Teresa Zakaria:You're listening to the Naked Scientist podcast with me, Chris Smith, and today we are taking a closer look at the El Nino phenomenon and its impacts around the world. So far, we've discussed the climate effects of the phenomenon, but what about its impacts on our wallets? In a normal year, it can cost the global economy trillions of pounds because the economic shockwaves felt in one part of the world through productivity changes, reduced trade activity and even stockpiling can actually reverberate globally and eventually give everyone a shake-up to some extent. A lack of rainfall in Central America is currently hampering shipping through the Panama Canal for instance which relies on fresh water to fill its locks for passing ships.

15:44Teresa Zakaria:Meanwhile the waters off the coast of Peru usually yield millions of tons of anchovies for fertiliser and food but the warm water welling up along the coastline as this El Nino gathers momentum have driven the fish away, ruining the catch. Heavy rain and snow in Chile and Peru, meanwhile, of course flooding, disrupting copper mining. The economic impacts of these effects won't be confined just to those directly affected industries and geographies. The ripples will propagate over long distances. Vicky Price is former Joint Head of the United Kingdom's Government Economic Service.

16:20Peter Gibbs:anything like that affects agricultural production more generally, trade flows, supply chains, and even movement of people. And of course, it can create a lot of food poverty in particular across the world, which does require a lot more spending to relieve some of the pressures. And that spending, of course, is something that through various international agencies, countries like the UK contribute to as well. So it's not at all cost free. And it can, of course, also lead to higher food prices in particular. And given that we're already in an inflationary resurgence period, it could then mean lower household incomes in real terms and higher interest rates because one is trying to control that somehow.

17:05Peter Gibbs:So altogether, not good news.

17:08Teresa Zakaria:In essence, then, is the sort of globalisation era that we've moved into where we get stuff just in time from all over the planet does that mean we are actually paradoxically more vulnerable

17:19Peter Gibbs:to shocks like this coming along yes i think there is a lot of emphasis now on food security but that of course means more sort of let's produce our own products and let's not import from others that of course has huge repercussions if it were to be at all effective on what happens in the rest of the world we all know that trade is good we've seen what happens when the supply routes are affected, whether it happened during COVID, when everything stopped, or with the war in Ukraine, and of course, now with the war in Iran, the implications for the world economy is quite significant. So what people have in fact done through this, if you like, on-shoring and near-shoring, which is happening, basically produce things yourself, not just on food, but in other areas too, in order to avoid the supply chains.

18:08Peter Gibbs:And reshoring also extended to near-shoring, which basically means get your stuff from countries that are very close to you, because that, of course, affects quite significantly your cost of moving things around and reduces your various threats that might exist there, the probability of everything going terribly, terribly wrong. That may give you a little bit of security, but it generally means you don't produce as well as would have been the case before, and it affects the world economy as well, which is dependent on trade growth continuing.

18:39Teresa Zakaria:Have economists like you got ways of modelling this? Have you got a big kind of planetary economic model where you can see all the trade flows and who's selling what to where and therefore you're in a position to say, well, if there is a paucity of productivity from this geography because of this impact, these are going to be the knock-on effects?

18:59Peter Gibbs:You can look at, of course, people involved in particular sectors in terms of employment. You can look at prices. the extent to which trade has reduced prices in a number of areas, because obviously if there is greater supply, that helps. But there is no doubt that trade is good for you. There is a lot of proof of that in the models that shows you that if you reduce the growth of world trade, you also reduce growth in the economies as well. So anything that disrupts that, like a really serious El Dino is going to have an impact across the board.

19:38Teresa Zakaria:Is there evidence that government's jurisdictions are flinching and they're stockpiling, panic buying almost, or at least securing their patch of economic turf, agricultural turf, to make sure that they are future-proofing things? Or are people tending to sleepwalk into this thinking, well, it'll probably be okay, things might go up in price a bit, but we'll see how it goes? I mean, what's the reaction been so far?

20:04Peter Gibbs:There have been some lessons learned, particularly from previous El Niño's, if you like, but also from COVID, which is an interesting one to look at because there were severe shortages of various products during COVID, which of course is one of the reasons why everyone started thinking about the whole supply chain situation. Should we change it in order to ensure that we are insulated from those shocks? But there's also been quite a move to stockpile a bit. The data as of early summer, 2026 suggests that wheat and grain, if you look at global stockpiles, were actually quite high, and therefore they could withstand one of the shocks.

20:44Peter Gibbs:Now, what's happened afterwards with the drought and the wildfires, I don't know where we've ended up. But yes, there seems to have been a move to be slightly better prepared for shocks. And the good thing about the way in which AI and other advances in meteorological forecasts have all improved is giving us a little bit more warning of what may happen and therefore allows one to be a little bit better prepared. So from that point of view, maybe we have indeed learned the lessons of stockpiling. But then you get to the ridiculousness, which is actually also possibly learn from COVID period, which is we've just been told in the UK to make sure that we have enough supplies for about four days for emergencies or very bad weather, because, of course, the worry in the UK is flooding in the next few months and not being able to go out and do any shopping or even goods, not, of course, arriving at the supermarkets or even at your corn shop is going to be a problem.

21:51Peter Gibbs:So we're encouraged to have at least four days of stocks to survive. Now, is that good or is it counterproductive? There is some evidence that suggesting during COVID not to stockpile actually led to panic buying instead. So, yes, there are lessons to be learned and people perhaps will be better prepared. But whether one has the ability to do that across the world and also, you know, thinking of relatively poor areas, then that's a question mark.

22:19Teresa Zakaria:What about situations like the drive to put in lots of solar installations in countries like the UK? People say we've got some of the best land for growing stuff here and we've got some of the worst land for growing electricity so we shouldn't be issuing something that we're really good at to do something that we're much less good at and we ought to be rethinking that. Is this going to give policymakers pause for thought the fact that taking out of production very very fertile land relatively speaking is probably not making good sense economically when we are confronting possible food shortages in the future it can it could change

23:00Peter Gibbs:the way that the whole thing is looked at but of course the farmers have been worried about this in some cases of course some have benefited from turning the farmland into solar panel territories But, of course, there has been this worry about the environment more generally and rewilding and so on. And what we have seen is that actually it hasn't helped hugely in terms of even doing something about stopping fires from spreading faster. So farmers would like to go back to what they were doing best before. And of course, this food security issue may well encourage people to, politicians as well, to rethink.

23:45Peter Gibbs:And as we know, there's a bit of a backlash against net zero going on. We do absolutely need to have more renewables. But how exactly you do them in a country like the UK, which now is becoming quite concerned about food security, is something that probably will need to be reexamined.