Extreme weather special

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1:27I'm here at the BBC Weather Studio in London with weather reporter and meteorologist Chris Fawkes. Chris, hello. Hello. Tell me about what you do. So here at the BBC Weather Centre, we produce well over 100 forecasts each day. We broadcast to a couple of hundred million people on TV and radio at the BBC. We're quite a small team, actually. We've got 12 presenters that work here around the clock here at the Weather Centre. And you've got some incredible equipment which we'll tour a little bit later on. We'll come back to you later in this podcast. We're also going to be joined by our tech editor Zoe Kleinman, Greya Jackson from The Climate Question, Marco Silva from BBC Verify and Myra Anubi from People Fixing the World.

2:13We'll be finding out why extreme weather events are on the increase, what role climate change plays, and how we can better predict, contain, and even prevent some of the most devastating results. But first, let's start with a reminder of why all this matters. The National Weather Service is predicting close to hurricane-force level winds. The anticipated winds, combined with low humidities and low fuel moistures, will keep the fire threat in all of Los Angeles County critical. Please be patient with those people who are saying, I just want to go look at my house and I want to see what's left. We know that, but we have people literally looking for the remains of your neighbours.

2:57In some areas, more than a year's worth of rain fell in just a few hours. It is a catastrophe. The floods we had in 1982, when I was 10 years old, were a joke compared to what happened here yesterday. Thousands of hectares of farmland have been destroyed, and the UN is mourning more than half a million people are in urgent need of food and drinking water. We already displaced people from war zones, and after the floods, we don't have anything left. It's the worst drought I've ever seen in my entire life. Joao and others are carrying huge, heavy bottles of water on their backs. The ground is very, very dry, covered in huge cracks.

3:42There's absolutely no water to be seen here. This is the third storm in a year. Even before the officer got to me, the water was all the way up to my chest. This town is devastated and we need help.

4:00Chris and I have decamped from the BBC Weather Centre and come up to the Global News Podcast studio. Chris, we heard there from the US in the aftermath of Hurricane Helene, from the drought in the Amazon in Brazil, from the wildfires in Los Angeles and Portugal, and then the devastating flooding in Valencia in Spain. Where do you want to start? well we should start i suppose in la that's the most recent of our stories and you know here we do get a lot of variability in our weather from one year to the next and actually the last couple of years 2022 and 2023 were wet years in california what this did is actually created pretty good conditions for vegetation to grow now normally in los angeles county we get most of the rain falling between October and April in a typical year.

4:53This year in Los Angeles, well between May 2024 and now, they've had just four millimetres of rain. So they've had barely anything and that's led to severe drought conditions. That's dried out all of the vegetation that's grown rapidly over the last couple of years from those good growing years if you like and it's resulted in these tinderbox dry conditions. Added to that we've had something called a Santa Ana wind. this is where we get air descending down through the atmosphere it becomes very dry and warm as it descends we get high pressure to the east of the mountains low pressure in the pacific that causes the winds to blow and over the tops of the mountains we've seen gusts up to about 99 miles an hour and so once these fires started they spread very very quickly not just across the vegetated areas but throughout whole communities as we've seen yeah and we've had a question from a listener on this.

5:43Just take a listen. I am Sachin Rana from India. How did the fire pick up its intensity? And how did it spread over a wide area, destroying everything in its path and reducing everything to ashes? Yeah, how did it happen so quickly? I mean, there's still question marks about what instigated the fire. You know, was it natural? Was it arson? Was it power lines clicking together in those strong winds. I think there are questions still to be asked about that. But once you start these fires, because those winds are so strong, so dry, so warm, and we've got all of that vegetation that's just there available to burn, we'll add in that persistent wind for day upon day upon day.

6:24It makes battling these wildfires extremely difficult and dangerous because you've got embers just flying up into the air. They can leap over firefighters setting off new blazes and you can get all kinds of severe phenomena, even fire tornadoes we've seen mixed in with these, which create some particular hazards. Now, according to the California Department of Forestry and Fire Protection, 19 out of 20 of the largest wildfires in California have occurred since 2003 and seven of the 10 biggest fires in California have occurred since 2020. Now, one of the central predictions about climate change is that we expect droughts to become more frequent.

7:06And so the conditions for these wildfires become more frequent in a warming world. So more of them to come. And of course, it's not just fires, is it? We heard about another extreme weather event that hit the US last year. And of course, that was Helene. Yeah, Hurricane Helene was a really interesting storm. It underwent rapid intensification. That's where the winds pick up by 35 miles an hour in 24 hours. Now, this one was even stronger than that. It hits the Big Bend region of Florida as a powerful Category 4 hurricane. 140 mile an hour winds, the strongest ever to hit this part of the United States.

7:43Now that caused problems, but I think the biggest problems from Hurricane Helene actually came as it moved inland. It weakened significantly into a normal area of low pressure. And you might think, well, that's it, that's the problem's gone away. But it wasn't. If you consider that water hazards are responsible for 86 % of fatalities in such tropical systems, well, it's the water that's the far bigger hazard. And this area of low pressure became slow moving in Tennessee and it brought enormous falls of rain. In the mountains of North Carolina, we recorded 30.78 inches of rain, 780 millimetres of rain.

8:21And that led to catastrophic flooding and Hurricane Helene became the deadliest hurricane to reach the mainland United States since Hurricane Katrina way back in 2005. And then there was that terrible drought in the Amazon. What was going on there? Yeah, well, this one's interesting because it's partly driven by climate change, partly driven by natural events. So as we heard a moment ago, droughts become more frequent in a warming world. And that's the background that we're in in our current climate. Temperatures globally are about 1.3 degrees Celsius higher than they were during the pre-industrial period.

8:59So that makes droughts more likely. Coupled with that, we've got a natural phenomenon going on, El Nino. Now, in 2003, 2004, we had an El Nino pattern that also reduces rainfall. So it was the combined effect here that caused the severe drought. with quite a few rivers in the Amazon basin actually reaching their lowest level on record last year. I have to say things are slowly improving now because we are going into the rainy season and we're starting to see the droughts ease in parts of Brazil, which I suppose is good news. But yeah, climate change does increase the risk of such droughts. Yeah, talking of rainy seasons, everyone will remember the images of the flooding in Spain.

9:40cars literally being tossed around like toys, more than 220 people dead. And there were complaints about the way officials handled it, weren't there? Yeah, there are questions, I suppose, that still remain about the floods that hit Valencia. I mean, there was a huge amount of rainfall in just eight hours, about a year's worth of rainfall, 491 millimetres of rain, and that led to some catastrophic flooding. I've been looking back, though, at the performance of the local weather authorities, is AMET. They're the Spanish forecasting authorities. And in the days ahead, they actually predicted this area of low pressure.

10:16They called it a Dana weather event. And they do get these several times during the year, but they highlighted this one was going to be particularly bad. In the morning of the floods, they had a top level red weather warning that was in force. So they were expecting some severe flooding. But what came was enormous amounts of rain. And I if we look at this area of Spain we've had deadly floods that happened back in 1957 and 1982 so they don't come along too often but when they do they can be absolutely devastating and I think what we see with this weather event is an enormous amount of rain coming in a short space of time the rivers in this part of Spain run off the land very very quickly so you don't necessarily get a lot of warning before a wave of water hits your properties and your communities so I think the main questions that still are to be asked really about this are about when the public received warnings from the government both the national governments and the regional governments the way that the water levels were monitored in these river catchments given that the history of flooding and how quickly the flooding comes on in this part of the world and of course like a lot of places around the world we've seen quite a bit of construction in what are known to be flood prone areas so there are questions that remain about this flooding i can look back here in the uk back in 2007 following the catastrophic floods we had here in the uk there was a pit review that was done by lord pitt and he recommended a much closer collaboration between the met office which is the uk forecasting authority and the environments agency which is responsible for issuing flood warnings and that resulted in the setting up of the flood forecast center which is manned by hydrometeorologists what they do is they can take weather data forecast data and model what the response of the rainfall is likely to be on individual river catchments and so that's led to a much more joined up approach and we're much better at forecasting floods these days so there could be questions about how we go about forecasting floods in other parts of the world in the future yeah that's fascinating because definitely the complaint at the time i just remember the stories that we were running was that people, even if the information had been there, they didn't feel they'd been warned.

12:30Yeah, that's right. I've read reports of people actually getting notified on their mobile phones about the flooding when it was happening, when the rain was already coming down. But from a meteorological point of view, at least there were red level weather warnings, top level weather warnings that were issued the morning that day. So actually hours before the flooding event hit. So being able to provide people with enough warning that an extreme weather event is coming is a key part of limiting their impact. But how does weather prediction actually work? So I'm back in the BBC Weather Centre with Chris Fawkes.

13:07And Chris, how does this work? How does weather prediction work? Show me your machines. A lot of the stuff that we do starts off with the computer models that model the atmosphere and the numbers involved in these computers are truly staggering the uk met office supercomputer that crunches all the numbers can do 14 000 trillion sums a second taking in 215 billion weather observations every day that's enough for two million sums for every man woman and child on the planet so the numbers are immense there are a million lines of code that go into these computer programs and what comes out is a simulation of what we think the weather's going to look like.

13:49But even after all of those calculations, we all know that sometimes the weather doesn't quite go to plan. And so one of my jobs as a forecaster is to look at the computer model outputs, take a look at things like satellites or weather observations, and have these available to be right the way around the world, and actually go and have a look. So, Chris, obviously I am not an expert in this like you. What I see on the screen is a huge map of Europe. I can see, I imagine those are the clouds just off the coast of Spain. But what I can't really tell, as someone who isn't an expert, is what all this means.

14:28Show me what I should be looking at. OK, so what we're looking at here is the Mediterranean basin. So we can see the satellite picture. The white is the cloud here. And this particular area of cloud is actually a named storm. It's been named by the Italian meteorological authorities. And if I zoom in, I can see the structure of the cloud, not just that, but I can actually see these weather observations. Now, these come to us from right the way around the world. The ones we're looking at here are actually on the north coast of Algeria. And the numbers here tell me that we've got some very, very heavy rain at the moment across northern Algeria.

15:04And this is one area we're watching to see if there might be some flooding over the next few days. It just looks like a fluffy cloud on the screen, but it's when you click on there, and then I guess you're right-clicking, aren't you? And then the numbers come up, which give you that backstory. Yes, so I'm zooming in, and all of these circles you can see are around the world, actually. I can zoom right out and show you right the way around the planet. Wow, what power! Go to Singapore, they've got some thunderstorms there at the moment. So these are the actual observations that people are recording.

15:36So, Chris, that's what we have currently. I'm going to go and see Zoe Kleinman. Can you come with me, our technology editor? Let's see where she thinks the technology might be evolving. So, Zoe, you're on the line. How are you doing? I'm good, thank you. This is such a good topic, I think, because as someone who lives in a particularly cold and wet part of the world, weather prediction is very important to me in terms of where I go, what I wear and what I take with me when I go out. Well, Chris and I have just been looking at the finest state-of-the-art current weather prediction technology, but you're the expert on what's going to come, aren't you?

16:14How is it going to change? I think weather prediction is getting more accurate and it's going to increasingly get easier. And the reason for that, it might not surprise you to hear, is artificial intelligence. I want to tell you about a really interesting tool that we've just had some new research on published last month. It's called Gencast and it was made by Google DeepMind in the UK. And it's basically an AI programme that does weather predictions and it performed 20 % better in tests than the current world leader. And what's really interesting about it, not only was it better and more accurate on day-to-day forecasts, it was also more accurate on extreme event prediction up to 15 days in advance.

17:03And it was better at predicting the paths of hurricanes, which, as we know, can change quite dramatically at very short notice. It was trained on 40 years of weather data, which is an awful lot of data and also contained an awful lot of variables. and it used that data to make its own predictions. It does the same as traditional predictions, by the way, which is called ensemble forecasting, where you get a range of them, but it was calculating which one was the most probable and it was very good at it. Traditionally, forecaster tools involve basically solving enormous amounts of equations and they use supercomputers to do it because they have to, but it still takes a long time.

17:44And Gencast managed to process its forecasts in eight minutes, which is considerably faster isn't it but of course the data it was using had been gathered and processed in all of our old school ways that we've been doing for for the last 40 plus years and so what we don't know is whether going forward if we if we were to just rely on ai generated data because that would become wouldn't it our data set whether it would be as reliable we don't know so we talk a lot about the impact of artificial intelligence on everything from from medical diagnoses to even lyric writing. Is AI making a difference in predicting the weather too?

18:23I think it's certainly got the potential to do that and we're going to see more and more companies focusing on that. I guess one of the ironies is that it might end up being matters related to climate change that could hold it back because we know that AI is a very power-hungry tech, it's very energy-hungry, it needs banks of computers in massive data centres to run it and a lot of those at the moment require large quantities of water to keep them cool. And so although there is hope that perhaps it will come up with solutions to the climate change problem that we haven't yet thought of, there is an environmental price tag attached that is currently quite high and some experts question whether we can actually afford it in terms of the Earth's resources.

19:10Chris, do you find this exciting? Do you see your job changing? I'm sure it will change in the future. You know, every time there's been available extra computing power, we've seen a step change in the forecasting capabilities. And I don't suppose AI is going to be any different from that. However, I have looked at some AI models from time to time when the forecasts have been difficult. And I've gone back and looked what had been predicted by these AI models on previous days. And, you know, sometimes it's good. Sometimes it's not so good. I don't see anything groundbreaking at the moment in terms of difference in the day-to-day forecasting whenever I've looked at these models but I'm sure it will come.

19:49It is early days as they say. Chris and Zoe thank you. We'll be back shortly.

19:58Still to come in this podcast. These large heavy cows are like habitat engineers so their role here is to eat and move in a way that help us to prevent another wildfire. We find out about some of the possible solutions to these extreme weather events.

20:22This advertisement feature is paid and presented by Poland's Ministry of Foreign Affairs. Looking for the perfect place to grow your business? For over 30 years, Poland has been a launchpad for innovation at the heart of Europe, powered by world-class research and ambitious young talent. From bold startups to established powerhouses, Poland offers the momentum, resources and reliability you need to take your business further. Poland, where businesses don't just grow, they're built to last. Find out more at polandyourplacetogrow.com. This advertisement feature is paid and presented by Poland's Ministry of Foreign Affairs.

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22:47If journalism is the first draft of history, what happens if that draft is flawed? In 1999, four Russian apartment buildings were bombed, hundreds killed. But even now, we still don't know for sure who did it. It's a mystery that sparked chilling theories. I'm Helena Merriman, and in a new BBC series, I'm talking to the reporters who first covered this story. What did they miss the first time? The History Bureau, Putin and the apartment bombs. Listen on BBC.com or wherever you get your podcasts.

23:25OK, so we've been talking about extreme weather events and forecasting the weather and hovering over it, climate change. So to explain the links and differences, Greya Jackson of The Climate Question is here. Hello, Greya. What's the difference between weather and climate? Yeah, it's a great question. So the main difference is we're looking at timescales. scale. So when we're talking about the weather, we're talking about short term events, maybe days, maybe weeks at most. When we're talking about climate change, we're talking about really long term studies. We're looking at averages over a year, maybe even a decade.

24:05And the other key difference is that climate change is solely driven by humans behaviour. When we drive around our petrol cars or burn our coal fires or cook on gas, these are all emitting planet warming gases, which are causing our planet to warm. 1.6 degrees warmer, in fact, than pre-industrial times. That's new data from Copernicus, EU's climate service, just recently. So two real differences, sort of the length of time we're looking at, but also climate change is solely driven by our actions. If it's not a stupid question, why does climate change cause extreme weather? It's not a stupid question at all, Alex.

24:45It's a great question, I think. And, you know, we can look at it in lots of different ways depending on what extreme weather we're talking about but if you take heat as an example as the daily temperature shifts to warmer levels hotter days become more likely and more intense what does that mean for things like fires well longer lasting heat waves draw more moisture out of the soils and vegetation that creates very dry conditions you know perfect fuel and tinder for fire that can spread at incredible speed i mean particularly if the winds are really strong just like we've been seeing in LA but with all that moisture being drawn out of the ground out of lakes rivers the vegetation we get more moisture in the atmosphere for every one degree of rise in average temperature we see about seven percent more moisture in the atmosphere and with more vapor in the air that means rainfall can become even heavier so there's lots of different ways in which climate change is making weather more extreme.

25:44So how much extreme weather is caused by climate change? So we can say broadly that extreme weather is becoming more likely and more extreme in a warmer world. That's according to the Intergovernmental Panel on Climate Change is where the world's scientists get together and produce gold standard research and publication. But we did have this major scientific breakthrough two decades ago where scientists began to attribute climate change to a specific weather event. And when you look at it today, they roll out these studies within a few days of a hurricane. I remember Hurricane Beryl, you know, results came out, I think it was just five days after it made landfall about how much rainfall was made worse by climate change.

26:31And it's really interesting how scientists do this work. There's one particularly prominent group called the World Weather Attribution. They're based at Imperial College London and I caught up with their lead scientist, she's one of the pioneers of this kind of work, Dr Freddie Otto, on exactly how they do this and that was recently on the Climate Question podcast. We have very good observations and very good records of how many greenhouse gases have been put into the atmosphere in addition to the natural ones since the beginning of the Industrial Revolution. And then we can take these out of the atmosphere of climate models and find out what's possible weather in the world that might have been without climate change.

27:16And if we, for example, find that a heat wave in today's climate is about a one in 10 year event, but find that without human induced climate change, it would only be a one and a thousand year event, then we can attribute the difference. So this change in likelihood that this event has been made 100 times more likely to climate change, because that's the only difference between these two climates that we've looked at. So Greya, what is the impact of extreme weather? I mean, it's huge. And typically, it's felt by the poorest among us. And that's because often poor people don't have the means to evacuate or rebuild after a disaster.