Interview with flood scientist Hannah Cloke on extreme weather: transcript

Key points

• Cloke says she was fascinated by water from childhood and now works on flood forecasting and warnings.
• Climate change does not cause every flood or fire but makes them more likely, more frequent or more intense.
• Computer models can sometimes forecast floods, heat waves and fires two or three weeks ahead.
• The same models can map dangerous zones to guide where to build and where to adapt homes.
• Vulnerable countries such as Mozambique and Bangladesh need better flood warning systems, and getting warnings to local people is the hardest part.
• Cloke describes heat as a silent killer, citing the thousands of deaths in the UK during last summer's heat.

Chapters

1. 0:00Cloke's early fascination with water
2. 1:02Flood forecasting and linking events to climate change
3. 2:51How well floods and heat waves can be predicted
4. 4:09Using models for planning and flash floods
5. 6:03Global flood warning systems
6. 6:44Arts and science in communicating flood risk
7. 9:27Climate change as a health crisis

Full transcript

0:00Now, last year, the UK recorded its highest ever temperature of 40.3 degrees Celsius. And on the news recently, we've seen devastating floods, droughts and wildfires worldwide. My next guest is Hannah Cloak, a specialist in extreme weather and professor of hydrology at the University of Reading. She has appeared on TV, including in the panorama episode Wild Weather, Our World Under Threat. and she was the subject of the Life Scientific on Radio 4 in 2021. Welcome Hannah. It's lovely to be here. When did you first discover your fascination with water and geography? I wonder if I was actually just born into water because you know when I was a little girl I was just fascinated by it and we used to go on holiday to Devon to see my grandparents every summer and I just used to throw myself into the sea, you know, go paddling in Dartmoor rivers and just spent hours and hours in the water. So I think it was there from when I was very, very small. I'm

1:02sure that my mum and dad influenced me as well. That's amazing. I love that. But then water can also be quite a devastating force on the world. So could you talk a little bit about that and you know, the research that you do now? So I do love water. I love the sound of rain. I love flinging myself into rivers, but I'm very aware that, you know, these things can turn into monsters. Heavy rainfall, rivers can turn floody, and they will absolutely devastate communities. So it's really interesting being very fascinated by water and how it moves around the planet, but yet being very aware of how dangerous it can be. And that's really why I do what I do. So I'm interested in flood forecasting.

1:45and warning people, making sure people can get out of the way of dangerous floods. Now it seems like some scientists perhaps are a bit reluctant to kind of pinpoint the cause of some of these extreme weather events as being because of the climate crisis. What's your response to that? Yeah, it's an interesting question because it's always flooded. So it's flooded since before humans existed and we've always had heat waves and there's always been forest fires so it would be wrong to say that every forest fire is caused by climate change what it does is it makes it more likely so we see more of them sometimes they're more frequent sometimes they're more intense so our floods can cover more land they can be more violent because of the fingerprints of climate change so it's really important to distinguish that because we can't just go around saying oh this flood is definitely because of climate change but we can can say That it's more likely because of climate change. And the fingerprints of climate change are there, which means that we need to take it seriously.

2:51So it's almost like there's the effect that we're having on the planet is to make things a little bit more riskier in this sort of natural disaster regard. Yeah, that's exactly it. The risk changes that that factor of it's going to happen more often, it's going to be worse. Yeah. And how good are we at predicting, you know, the next flood or the next extreme event like that? We've got some really good models now. So we have huge computer models of the Earth system that can put together how the atmosphere moves around, what's happening on the land surface and in our rivers.

3:26And we're actually pretty good now at saying whether a natural hazard like a fire or a heat wave or a flood is going to happen, even sometimes two or three weeks ahead. So is that enough? Is two or three weeks ahead, I guess, enough to respond to that adequately? So it depends what you're trying to do. So if you're trying to get people out of the way, then you need at least a week sometimes to prepare all of that stuff in advance. We only tend to hear about things a day in advance. Somebody says, you know, actually, tomorrow it's going to rain really hard. You need to, you know, get out of your house. But But behind the scenes, people are moving around, putting equipment in the right place, going on alert.

4:09And with this kind of, I guess, in the longer term, if I'm, you know, from my perspective as a structural engineer, I've been involved in, you know, urban planning and looking at cities and so on. How can we use the kind of modelling that you do to maybe better design where human beings decide to settle down? Yeah, humans have a tendency to live in very dangerous places. We like water, right? We want to live next to rivers. It's really pretty living next to the river. And, you know, it's really functional. In In London, it's a really nice place to live, people want to live there, it's really expensive, but it can be very, very dangerous indeed.

4:44So we have this legacy of people living in really, really dangerous places, but we can use the same types of models that we use when we're forecasting whether a flood is coming next week. We can use that to work out what the risk is of any types of floods coming along. We can say, you know, these zones are dangerous zones, do not build here, perhaps even move people out of the way. and then these places you know there is still some risk so you need to adapt your homes or your businesses and what kind of time skills are you able to make these predictions on now so when we're thinking about an upcoming flood so it's going to flood tomorrow or next week we can say with some confidence whether that flood is going to happen But when we look long term and we think about our changing climate, we can see how likely those types of floods are to happen in the future.

5:31And some of the things we're most worried about actually are flash floods, those ones that are really difficult to predict in the short term. And, you know, sometimes they come along in an hour or something, a big thunderstorm happens and it sweeps through the streets or along a river. But we know that they are getting more likely in the future. And a warming climate means we're holding more water in the atmosphere, heavier rainfall, more intense rainfall, more flash floods. What about the scene kind of more globally? I guess we've talked a little bit more specifically at the UK perhaps.

6:03What's happening on the worldwide basis with flood prediction? Some of the most vulnerable places in the world are desperately in need of much better flood forecasting and warning systems. a lot of those places you know they don't have enough funding to really get to grips with some of these global models so it's about working together with partners perhaps in Mozambique and Bangladesh places that are very filled with floods often and a lot of people die every year from these types of floods so the more that we can support those countries and provide kind of the infrastructure and work together with them to help them get their warnings to the people so they can get out of the way of those floods the better.

6:44Yeah, it seems like it's one of those things where, you know, the more we come together, the better our responses can be and so on. So quite a big challenge. It's a big job. It is a big job. The world is a very big place. Yeah. And we do have global models and they do provide flood forecasts and heatwave forecasts. But actually getting that message to the people on the ground, that's really, really tough. So you can only really do that at the local level. So, you know, you're moving from global, you know, environmental models to actually psychology at the local level and that's a big chain of chain of events completely so now I'm going to ask you a completely different question which is poetry apparently I've heard that you've written some poetry there's something about the brain isn't there doing arts and science together I mean is that something you quite enjoy yeah I think as a scientist I was a bit wary about it thinking that's that that's a bit unscientific let's not do that you know people will laugh at me but actually opening up that different way thinking actually generates new ideas and you actually start to think in a

7:46different way as well and communicate in a different way. So I work now with artists, musicians across the board, do a lot of work with museums and it's brought a lot, a much richer way of communicating things like flood risk. Yeah, I mean, it sounds like, I mean, I know this, but, you know, arts and sciences, if we need to talk to each other, then we can learn new things from each other, which is brilliant. Yeah, and not be frightened, not be frightened to do so. I know, 100 percent. So that's really great. And is there something that you would be devastated to lose if it got swept away in a flood?

8:21It's really important, actually, to focus on that when you're trying to communicate to people whether they're at flood risk and what's actually going to happen to them. because if they just think about like how much rain is falling or how high the river is it means nothing to them but if you pick something that's really precious to someone so for me that's my grandmother's music box you know she gave it to me sadly she's passed away it means a lot from my childhood and it sits on my shelf and I always imagine you know how would I feel if that got swept away in a flood and to me that's the real meaning of being at flood risk Yeah. And I guess it's a way to explain the risk to other people, like you said, that it might feel like a very distant thing. Yeah. And they have to imagine it. So they have to be able to imagine those floodwaters in the house and putting their possessions at risk, perhaps putting their family at risk. And you need to help that imagination along. So those types of precious objects are really helpful to do that. Just to change scales a little bit again, but the Wellcome Trust, which some of our viewers may be familiar with has recently started talking about how climate change is a health crisis.

9:27You know, what are your thoughts on that? There are so many links between climate and health. I don't think I could cover them all now. I'll pick a couple. I mean, last summer we saw absolutely intense heat in the city. We went over that 40 degree barrier and it was terrifying. And it meant, you know, thousands of people died. And that, you know, that's pretty severe. And that's in the UK. We're not even thinking about places on the planet where it's absolutely inhospitable to live. So heat is a giant killer. It's a silent killer.

9:59as well so we don't it's not like a roaring flood water coming through your house it you know it really picks the vulnerable people as well um so that that's an obvious example of where climate and health are so intricately linked thank you so much for chatting to me it's been fascinating to hear about really what's a major problem worldwide but also you know like you said the psychology of the family or the person of the community that then has to respond to that on a local level So I really appreciate your time.

Source and licence

Recording: File:Interview on extreme weather with physical geographer Hannah Cloke – The Royal Society.webm by The Royal Society (2023-09-01), via Wikimedia Commons. Licence: CC BY 3.0.

The transcript is machine speech-to-text by the TidyTools Audio & video transcriber; the summary, key points and chapters were written by Claude from that transcript. Both may contain errors: check the recording before quoting it.