Health after Extreme Cold, Heat, Storms and Floods - Professor Sir Chris Whitty

Weather and climate-related events can cause significant mortality and disability.

Sudden cold, heat, storms and floods all present risks to health, especially to the most vulnerable. Even in countries with temperate climates like the UK, weather-related deaths can be in the thousands, for example cold snaps causing cardiovascular deaths. In countries with more extreme weather this can be much greater. Some can cause major social disruption.

This lecture considers how weather events cause harm to health, and our countermeasures.

This lecture was recorded by Professor Sir Chris Whitty on 14th May 2024 at Barnard's Inn Hall, London

The transcript of the lecture is available from the Gresham College website:
https://www.gresham.ac.uk/watch-now/storms-floods

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Transcript

0:04

It's so great to see you all. Thank you very much for coming. Um, I thought, uh, as this was my last talk, I should talk about the quintessentially English and more widely British subject, and that's the weather. Uh, but this is the kind of weather it is genuinely reasonable to grumble about. This is serious weather extremes. We live in one of the most temperate countries in the world, uh, with relatively small, uh, variations of cold and heat. Uh, and as I'll come on to, uh, other forms of storms even here, uh, thousands of people in some years die due to weather related issues. So this is a major issue in every country in the world, including this one. Will we ever be able to see beyond the current observable universe? Oh, It's much worse than that. The observable universe is shrinking. If you want to know, what are my odds of winning the lottery, you come straight to probability. Yeah, because probability is all about how likely or not events are to happen. I think the chance of there being an undiscovered second species, very like humans out there in the world today is pretty slender. However, And these are the pictures, if you haven't seen them. I mean, New York was orange. The air was orange. They said one day out in that air was like smoking a pack of cigarettes. It had the same effect on the lungs as smoking a number of cigarettes. So people who'd never smoked in their life were suddenly going to suffer some of the same health effects. Any further questions is a brand new podcast from Gresham College, a place where we ask our speakers all of your questions that went unanswered following their lecture, guests have included Ronald Hutton, Robin May, Chris Lin tot, Sarah Hart and Maggie snowing. Any further questions? All episodes are available wherever you listen to your podcasts. Um, extremes of cold heat, hurricanes, uh, massive floods, severe droughts are rare here, but of course, common elsewhere. And additionally, as a relatively wealthy country, we have the ability to reduce the effects of these very significantly. But we do see as I'll come on to thousands of people dying, uh, in, uh, very many years. In fact, most of these deaths occur at the extremes of life, the very young. But above all those, uh, who are old or very old by, uh, by historical standards, uh, and for the, for these people, um, streams of temperature in particular are extremely dangerous. Now, as humans, we have a really phenomenal capacity to keep our temperature in a very narrow range. Everyone will have learn about this at school, or all of us experience this as the seasons go through. Uh, in the cold. Our temperature, our temperature, uh, is kept stable by, um, reducing the amount of blood flow to the periphery, uh, by, uh, having our hair stand on end. Sometimes by shivering, by reflex approach to exercise. In the heat, we sweat and the amount of heat that is gone goes out to the periphery with peripheral dilatation of the blood vessels, uh, allows heat to be taken from the core out to the, uh, periphery of the body. So our body is extremely good in the variety of other mechanisms, uh, at doing this. Uh, and, um, if we over time, are exposed to long periods of cold or long periods of heat, we have further adaptations. So, for example, if we were, if you were to move or any of us were to move to very hot climate, you'd start over time to sweat more, but the amount of salt in your sweat would go down significantly so you retained the same amount of sodium in your body, and your body will therefore adapt to this new temperature. Nonetheless, at the extremes of temperature, we need help. And, uh, we have a lot of ways of doing them, uh, to keep temperature in the comfortable and almost invariably the same safe range. But all of these cost money, some of 'em cost a lot of money, some of 'em cost less money. Let's take central heating, which is there to help us stay warm when it's colder, which is the bigger risk at the moment in the uk. Uh, people will have to put a lot of energy and in due course, therefore a lot of money into central heating or other ways of staying warm capital investment in insulation, warm clothes. In hotter climates, people tend to be, um, uh, putting their energy and their money into keeping the temperature cool to things like, uh, central heating building design, uh, and again, changes to the way in which people are closed. Now, the mechanisms we do this in engineering terms have varied over history. So I've put at the top, um, the hyper course in, uh, Ted Worth villa, uh, which is one approach to keeping a building warm and at the bottom, uh, a, uh, heat pump, uh, which is a much, uh, more contemporary methods of keeping it warm. Nevertheless, the principle has remained the same, and this means that, um, money reduces the risk from temperature to a fair degree, but not completely, and its absence is an additional risk factor. Now, in addition to that, there are practical cultural responses that are made in countries which are, uh, high temperature or low temperature. And I've just given some illustrations here. Uh, high a, a cultural response and a, uh, uh, to a, uh, very hot dry climate on the left tour eggs who live around the Sahara, uh, to, um, uh, uh, the very cold environments in which, uh, and to hot and moist climates, uh, here in Southeast Asia. But there are a variety of other ones. There are cultural adaptations to heat, uh, wherever, uh, humans live Eating cold. Now, moving on to the, um, health impacts of these, uh, major changes in weather and in due course in climate. Let's start with cold, which is the much bigger risk in the UK at this point in time. Cold causes a number of severe illnesses of its own, just cold. There's nothing else that causes them, but it also makes many other diseases that all of us may have significantly more likely. And what I put here is the excess deaths, the additional deaths in winter compared to the other months here in the uk. Remembering we are a relatively temperate country. Now, there's some good news and some bad news. The first, let's start off with the bad news. There is still a significant winter excess in terms of deaths in this country of probably on an average year around about 20,000 deaths. Some years it's more, some it's less, uh, for reasons we'll come on to. The good news is that if we compare that to the 1950s, this has got substantially better. And this, some of this is due to improvements in medicine, but a lot of it in fact is due to improvements in housing and heating, uh, over time. So this winter excess has steadily decreased and aberration, of course, around covid. Now, the reasons for this are, are multiple, but there are broadly three, uh, cold makes, uh, various conditions worse or more likely, it significantly increases the risk of quite a number of infections. The reasons for this are complex, and I'm happy to answer questions on it. Uh, but at all of us will know that the time you are likely to get influenza pneumonia, uh, covid, although not quite so clearly seasonal, uh, is in the winter months. The second, and probably the most important in terms of the numbers after that is cardiovascular disease. And this is in part because of this physiological response. The body has to cold that it's shutting down the peripheral blood system. The blood gets stickier, a variety of other changes, but there's a significant increase in the number of heart attacks and strokes, uh, which, uh, you get, and I'll go through these in slightly more detail in the next few slides. And then, of course, the obvious things like slips and trips on ice. And you think, well, breaking a bone is a, a an unfortunate thing to happen if you're a child or a young adult. That's broadly true. If you break a bone as an elderly adult, that has a high mortality. So these kind of things are actually non-trivial. Now, here's the, uh, impact, um, on cardiovascular disease, and I think it's quite striking, uh, on this graph. What we see is the risk of myocardial infarction, heart attack by temperature. So the further left, uh, the temperature down to zero degrees, uh, um, uh, the more, uh, the lower the temperature. And on further right, uh, the higher the temperature down to about 15 degrees, there isn't a huge, uh, gradient in terms of temperature. After that, it starts to change significantly. If you are a young person, the impact on cardiovascular disease is almost unmeasurable. If you're an older person over 50, uh, and I'm in, I'm over 50. So to be clear, I might bit older. I'm including people in what I would sort a middle age. Uh, there is an increase in the tar chances of heart disease. But if you've gotta blameless cardiovascular disease, otherwise you'll hit fit and healthy, that impact is relatively modest. If on the other hand, you have significant health problems already, uh, and the example here is hypertension, you at all points more likely to have it. But if you get cold, your chances of having a stroke or heart disease are substantially increased. So the more risk factors you have going into a cold snap, the more likely you are to have problems with cold when you reach that. Now, this is a complex interaction. Some of it's just straight temperature, some of it is air pollution, so people burn more fuel. You act, air pollution's a very significant risk factor for cardiovascular disease. It's stroke and heart attack. Uh, and, um, some of it, uh, is that, uh, infections also increase the risk of cardiovascular disease. So it's not a straightforward, uh, just temperature relationship. Nevertheless, this combination is actually a very powerful driver of cardiovascular axi in the winter, and it can be lagged. So you, meaning you can have the cold day or the cold week in the beginning of January, uh, and you're still seeing an excess of cardiovascular mortality in late January and, uh, February. Then there are some diseases or conditions which are very specific to cold weather. The first one I want to talk about is frostbite, uh, and early frostbites. The early stages, uh, are relatively, uh, benign in the long term, although unpleasant at the time. People get pins and needles. They, their extremities, uh, their extremities go white, sometimes called frost nip. But if you go back into the warmth relatively quickly, you'll will make a full recovery. This is, has no long-term, uh, implications. Intermediate, uh, frostbite is rather like having a moderate level of burn on the outside of the body. The skin go, skin goes cold goes red. It blisters, particularly when people go back into the warmth. And then, uh, it'll lop off. And usually the skin underneath that is relatively viable. So it's unpleasant, but it's temporary. If, however, someone is out in severe cold for a long period, they can get severe frostbite. And this is where the skin below the, uh, the, so the tissues below the skin get extremely cold and they die. And the this tissue is now unrecoverable. Uh, and we can have significant damage to muscles, tendons, nerves, bones. If you leave this untreated, well, people will get gangrene and other major problems. This tissue cannot be, uh, resolved. Um, and, uh, this therefore will need quite radical surgery. And very specialist care, usually in this country, done in burns units, so can lead to people losing, uh, limbs, uh, toes and fingers. Uh, certainly. So frostbite is one of the very specific things you can get with extremes of cold. And it usually happens at the periphery, hands and feet. Uh, in particular If someone has frostbite. And it's usually relatively straightforward to see, uh, most of the first aid for it is relatively obvious, but a couple of things are worth stressing. Uh, first one obvious, move someone to a warmer place, but try and minimize them. Putting pressure on the affected error. So if they've got a frostbite in their foot, try and make sure they don't use that. Remove, uh, areas of random replace wet things by dry ones. All of these, I think if you were asked from first principles, what would you do? People would, would agree, warm someone up, uh, by wrapping them, uh, in blankets. A few things not to do in particular. Don't rub it in the affected area, which is a natural thing to think you should do.'cause we tend to do that in other areas. Uh, and don't apply direct heat. These can cause further damage in this already damaged skin. Uh, smoking as with so many other things will make it worse because smoking tends to lead to the blood, the blood vessels contracting almost immediately. So smoking will be an exacerbating factor. Please don't, uh, get people to smoke. And rewarming is generally best done on medical supervision because done un, uh, if you're not doing care carefully, there'll be further, um, damage than you need. It will be painful. A very different kind of direct effects of, uh, heat. Um, and one which is much more dangerous, but less dramatic is hypothermia. Much more common in elderly and babies. Uh, and this is usually caused by prolonged exposure to cold or immersion in water. So people who've fallen in water, who have been in cold water for a long period are at risk of this. But a range of conditions, I'm not gonna read them out there, can make this more likely. So it's not just people who are older in low temperatures, anyone can have it, and it's made more likely by some medical conditions. It is in practical terms, but you're not usually wa walking around with a thermometer in your pocket to test this, where the body temperature drops below 30 degrees, 35 degrees, uh, centigrade. Now, suggestive symptoms of this. So how you spot it in someone, and this is something that is really worth being able to spot. Uh, shivering, pale, cold, dry skin. That's probably not particularly surprising. But here's the key ones. Confusion, slurred speech, uh, and, uh, people doing what's called paradoxical undressing, where they're cold, it's cold outside, but they start taking their clothes off. Any of these should indicate to you that hypothermia is probably setting in slow breathing. And in babies, they're floppy. Uh, they're unwilling to feed. Hypothermia is a medical emergency, and it may well lead to cardiac arrest where the body, where the heart just stops. Important point to realize is compared to something like frostbite, the patient themselves does not know they have it. So they have lost the ability to understand that they are cold. And this is causing, causing damage if someone does have for hypothermia. Um, the first aid, again, some of it is common sense, some of it is things, uh, we need to learn common sense, move people indoors to a sheltered and dry environment, get off wet clothes, dry clothes cover their head, not their mouth and nose. But, uh, everything else, Uh, warm drinks are a very sensible thing to do. If they can keep them down and sugary food, if they can eat it so that they're, uh, they can continue to sort of burn, uh, energy, uh, internally, you must keep them awake because temptation will be to drift off. But do get help if someone's got hypothermia, much better to over call it, get them to hospital and they find they don't have it than to under call it and realize you're in trouble too late. Then a few don'ts, and these are things, some of these are not obvious. Don't use a heart bath. That can be extremely dangerous, caused to very rapid, uh, changes, uh, or heat them to warm them up too quickly. The warming is gonna have to be very gradual. That's one of the key things about hypothermia, despite what it shows in all the films with, uh, some Bernard dogs bounding over the snow with, uh, uh, brandy barrels do not give them alcohol, uh, which will definitely make things worse and don't rub their arms or feet, arms, legs or feet. People do need to be warmed, but it needs to be in a gradual and controlled way.'cause otherwise you get big changes of the, of the salts within the blood, the body, and these can be extremely dangerous. Deaths from hypothermia are unsurprisingly age related. The older you are, the more likely these are to occur. But there are also important external factors, and I'm just using us data here, uh, showing that, uh, for every age, the risk in a rural area, uh, is greater than the risk in an urban area. And that's imp practical terms, because generally people live in better heated houses, flats and other things in urban settings. It's a, it's a purely practical effect. If we look at cold related excess mortality in England and Wales, um, uh, and we compare it to the index in multiple deprivations. So for want of another term, uh, the best measure we really have of poverty, relative poverty in the uk, if you compare those two maps, they very closely correspond. They correspond in the country as a whole. And indeed, if you take London, the city we're in at the moment, they correspond within London. Poorer areas of the city have higher relate rates of, uh, cold related deaths. And that's largely because people, because they can't afford heating, uh, will run heating at a lower level. There are other reasons. The impact of this on the NHS is substantial. Every year with utter predictability, there will be an NHS crisis. This has gone on over multiple, uh, previous governments. I, I regret to say it will probably happen over some future governments. And that is because the, all these cold effects come together in a period of the year in an extremely tightly engineered system, which there therefore is, uh, under much greater pressure predictably over the winter period. And therefore weights in a and e and a variety of indirect effects, uh, get worse. So how do we reduce the deaths, uh, from cold related, uh, diseases? Some of this is common sense. You'll all know it. Layers of clothes, heating spaces where vulnerable people, particularly the oldest and the youngest, uh, live. And then the risk is really about reducing the systematically, the various risk factors that make this a problem. Reduce the risk of respiratory infections and vaccination is certainly one of the tools. There are others reduce the risk of cardiovascular disease.'cause if the risk is lower, then, uh, you, you carry that through to the winter months. Reduce the risks of chip trips and slips. Uh, we tend to do it the old-fashioned way of we do it at all. Uh, in the uk in countries that have a lot of cold, for example, that will have heated paves in areas around where elderly people live as a way of reducing these risks. Uh, and we must reduce fuel poverty.'cause fuel poverty drives a lot of, uh, what, uh, causes this. Just going through a few of those, I mean, here are just, uh, three of the, uh, diseases of older age in particular, which are temperature related and which can be prevented to some or a large degree by vaccination, uh, covid influenza, pneumococcal disease already used. And hopefully we will shortly have another important infection that affects older people, RSV, uh, added to that list so we can reduce the risks. We've been extremely effective, in fact, at reducing the risks of coronary heart disease and stroke. Uh, this is looking at the mortality rates over time since the 1970s. I consider this as one of the great triumphs of contemporary medicine. And as a combination of broadly three groups of things, primary prevention, things the government does, reductions in smoking, reductions in air pollution, reducing, providing exercise facilities for people. Secondary prevention. What doctors, nurses, pharmacists do, they find someone with a high risk factor, put them on treatment for things like hypertension, high cholesterol and treatment in which indeed the provost is a particular, uh, expert. Combination of these has led to year on year, steadily, massively improved risks, uh, for these diseases. And then engineering, engineering is actually at the basis of reducing a large number of public health risks. I've talked about that many times, uh, over the, uh, years. I've had the privilege of being a professor at, uh, Gresham College. Um, warehouses are warmer in winter and you can at the same time maintain ventilation that will significantly reduce the risk. Those two are in some degree of tension. It's important that we insulate homes. This is one of the best ways we can do to reduce the risk of cold related disease, actually also heat related disease, uh, without, um, leading to ongoing, uh, expenditure. But the UK housing stock whilst improving. And on the right, which I've shown is the relative EFF efficiency, uh, of our housing stock is one of the, the oldest and coldest, uh, in Northern Europe. Um, as the population ages, in my view, this should be a major priority. But when doing this, we need to be aware that there is a trade off between a making a, uh, building better ventilation. So reducing things, the risk of things like flu and covid and keeping it warm. Those two, uh, if your main means of ventilation is opening the windows, uh, are obviously in, um, uh, some form of tension. Just to back up my point, um, that the average, uh, home heat loss over five hours, which is just a measure of how efficient things are. The UK scores particularly badly and in particular, particularly badly for Northern Europe, which is where cold dominates. So improving our housing stock, I think is one of the most important things we could usefully do here. Now, moving on to heat. Um, heat can cause, again, multiple forms of illness ranging from dehydration, heat syncope where people just faint in the heat, heat cramps. Many of you'll have had these at various points when doing sports in hot climates. Uh, heat exhaustion, which I'll talk about, uh, and the most dangerous heat stroke, which I'll talk about at, uh, slightly greater length, Very hot days lead to increased mortality. And the number of hot days is steadily increasing as we go through climate change. That's just a, a statement of fact. Um, LA in 2022, so two years ago, the UK for the first time recorded temperatures over 40 degrees centigrade. And that is going to increase now, not every year, but taken dec uh, for the rest of the lives of everybody in this, uh, in this building. And indeed, beyond that, in that year, there were about 2,800 deaths due to, um, to heat, uh, in those over 65. So these are not trivial numbers. So heat is potentially very dangerous. I, uh, sometimes find it slightly unhelpful that people say, oh, what people worried about is just a hot summer. Like everyone had heat, extreme heat kills people, and particularly it kills older people. Um, the specific effects of heat are heat, stroke and heat exhaustion, which I'll talk about. But indirect effects include dehydration, which in the elderly is very dangerous and can lead to a, a whole range of other diseases, uh, uh, and cardiovascular disease. So just to, again, back that up. This, I'm gonna show it two different ways to make two slightly different points. These are the number of daily death occurrences compared to the five year average. So these actual numbers, they're not, uh, extrapolations. And on the, the green line we've got to here is the daily temperature. And the bars, the gray bars are the hot periods during the summer months. And as you can see with a very degree, high degree of predictability, in the very hot days, the more number of people who died went up. That's just a statement of fact and went up in a big enough way that you can really see it with a naked eye. You don't need to do complex statistical tests to see that effect is happening. If, however, you then split that out by people who are over 70 and under 70. In fact, the impact on people under 70 was minimal. So almost all of this effect is in fact in older people, people in their seventies, eighties, nineties, or indeed above. So being older and having very high temperatures is a very high risk situation. Now, in terms of specifics, um, there are two broad things which are, again, specific to heat, uh, heat exhaustion and heat stroke. And people can move from heat exhaustion into heat stroke, but they are, as I'll come on to quite different, uh, physiological states. Heat exhaustion is really an exaggeration of the ordinary response to heat. The body is responded normally to heat, but it's very hot heat. So it's actually, uh, doing it in a very severe way. People will be sweating profusely, they'll be tired and maybe dizzy because they've lost, um, uh, fluid, but they've also got all their blood out in the periphery, they'll be very thirsty. These are all normal responses to a hot situation. They'll have some, probably some headache, nausea and may have vomiting, which is problematic 'cause it makes rehydration more difficult. They may well have cramps. And again, many of you may have had these when playing sport in heat. Um, clammy, they may have heat rash. They'll often feel weak. And if you feel that pulse, it'll be fast and they'll be breathing fast. All of these are actually normal responses to heat, but just taken to an extreme event, there were early warning signs of what might happen. But if you treat people rapidly, uh, the recovery can be very good. And the first aid for someone with heat exhaustion is something which most people should be able to just sort out, uh, peripherally you don't need necessarily. In fact, normally you do not need, uh, any help from trained professionals. A good first aider, indeed, someone with, uh, some basic training will usually be able to do this, uh, much of it common sense, move them to a cool place. Uh, remove outer clothing, keeping people's dignity. Um, cool water and rehydration with water or sports strengths, cooler, the better generally, um, spray them or sponge them with cool water so that you are cooling them down peripherally. Uh, if you've got a fan, use the fan to help, um, uh, reduce their temperature. And if you've got cold packs, which you may have if you are in a, in an urban environment, uh, wrap them in cloth so they don't freeze to people and then put them particularly in the armpits and the groin where there's a lot of blood flow. And therefore you can cool people down relatively quickly. If people have got heat exhaustion, they should improve within about 30 minutes. You still want to get 'em home, you want to get 'em calm, you keep want to get 'em rehydrated, but actually the recovery will be rapid by contrast. Heat stroke is a medical emergency, and the broadly two forms is something called exertional heat stroke. This happens when young fit people are exposed to usually a combination of high temperature and extreme, uh, uh, extreme, uh, activity. So, for example, special forces soldiers yoing over the brecken in the summer, carrying heavy packs could get this, their healthy people. But, uh, the risk of their, their body has been highly stressed. Uh, mortality for this is low, uh, but it's still very dangerous. Non exertional heat stroke though, when people just get it, despite ordinary daily living, has a very high mortality, particularly in the elderly. So in older people and people with severe heat, stroke mortality can be 50% or more. So this is very dangerous here. The body is not just doing an extreme reaction, that's the normal reaction to heat. It is behaving irrationally in, in the sense to heat, or it's behaving in a way that is very dangerous. The body has lost what's called thermo regulation. It's lost the ability to realize it is too hot. Multiple parts of the body now start to malfunction. This will include inflammation clotting. The kidneys will start to go heart, uh, brain and muscles, and eventually people will fit. Uh, and cardiac arrest, if you don't treat them, uh, is likely to occur. So this is very dangerous, uh, indeed. Now, how do you recognize someone's got heat stroke? Uh, if you've got a thermometer, that's the most, uh, telling thing. If they've got a core temperature over 40 degrees, that's a very strong reason to worry about them. Particularly if there's no reason to think they got an infection. They will often rather, like, uh, with cold related problems, hypothermia have altered mental state. So con confusion, slurred speech, seizures, and in severe cases are gone. Coma, their skin will be hot because they are hot but dry. They, they are no longer sweating. Their body is not, is no longer recognizing what the correct response to the body should be. It's, it's basically given up, uh, the correct response. Uh, and, um, they'll have, uh, a number of other symptoms In contrast to, um, first aid for heat exhaustion. This is something where you're gonna need professional help, but the first things you can do yourself, same, same starting point, take 'em to a cool place. But in this case, put them in the recovery position on their side because there's a high chance they may vomit or might go into have a fit. Uh, and that makes that easier to, uh, manage. Then call 9 9 9 or one one two. Uh, remove the outer clothing, cool them down. This is similar to heat exhaustion. And then ideally put a cold wet sheet over the body and keep on doing so until their temperature comes down, uh, within the normal range. Then put it onto a, a dry, um, sheet. But hopefully help will have come before then in exact contrast to high colds related mortality. High temperature excess is concentrated in, in urban centers. Places like London are on average, hotter than the rest of the country. And therefore if there's gonna be heat exhaustion, it's more likely to be in these areas and is much less likely to be so economically driven. That's largely actually because here we don't tend to use air conditioning and other things, at least in domestic settings. So the benefits of being wealthier are much less. As with cold, we, we as the UK, can learn a lot from countries which have historically had hotter temperatures 'cause that's the way we're going to head. Uh, and just to reiterate, even this incredibly hot period in the uk there were many places in southern Europe which were a lot hotter, uh, at that point in time. And they've learned to, uh, adapt society to these hot temperatures. And you'll see a very different form of architecture. Much smaller windows, uh, white coloring windows tend to be, um, uh, covered if there's very hot, uh, time coming. Do draw the curtains of roti. Ways you can do that to avoid a literal, uh, greenhouse effect. Moving on to wind. Um, there are multiple causes of wind at different times of the year. And I'm not gonna go into the meteorology of this in detail, but I will, uh, just talk about a few of them. Uh, the uk um, as a seafaring nation has always worried about the wind.'cause those in peril on the sea are at very high risk of even relatively moderate storms. Uh, but on land the risks are generally lower. So on land, the direct risks to life and limb from wind usually are caused by flying debris and falling objects, at least in the immediate period. But in the longer period, there may be loss of power, there may be loss of water, there may be loss of shelter, and particularly in winter or in very hot time periods, those can be tricky. We tend to think of variations of the befor scale. Here is the Francis Beaufort, uh, really designed for, um, mariners, uh, originally, uh, and based on on sea conditions, um, damage, uh, sufficient to cause injury to humans is very rare on land. Uh, below Force eight, which is, uh, a wind speed of between six to two and 74 kilometers. Now, that's the kind of, uh, level we're talking about. Um, going all the way up to a hurricane Force 12, which in the UK is an astonishing, uh, thing. We very rarely would see this. Uh, and, um, here, there can be significant damage. But as I'll come onto, uh, we are relatively, uh, protected. Uh, this is wind that's going into just, just over 70 mile miles an hour. So the top end of the illegal, uh, driving things on a motorway. However, there are several other, um, wind scales which other parts of the world have to use much more so significantly. And what I've shown here, uh, is the, um, uh, is one of the other scales is the, uh, fujita tornado scale, uh, and the hurricane wind scale. And in places which have significant really serious wind issues, these are much more relevant. And these start where Force 12 leaves off. So 12 Force 12 is really near the bottom of this. In the uk, uh, gales and storms are almost all in the Ottman winter, and they are largely related to most the West and mountain areas above Force 10 in the UK is extremely rare in land. So we have relatively few of these except in very exposed areas. A very different situation is the severe tropical cyclones. And these don't occur in winter and autumn, these in fact occur over the summer period, and they're caused by heating over water on, uh, and what you get is these tracks, and these are tracks going out, going out, out, um, since, uh, over, uh, many decades. And as you can see, the UK is not at the receiving end of these. These tend to move and they hit, in particular the Caribbean and Southern USA, uh, and, uh, the Eastern Seaboards, uh, of um, uh, so Asia and Southeast Asia. And these can be extremely strong. These pros a very serious risk to life. And the major ones are where there's a scale three or above. They're very destructive. So both at Hurricanes Force 12 start at seven at 118 kilometers an hour. Uh, the uh, scale here, scale three here is going at 178 to 208 kilometers an hour. And it keeps on going up. And the damage these can cause when they hit land can be colossal. This is obviously Hurricane Katrina. I've shown on the right a category five storm, which then, uh, went down to three by the time it got land. Uh, land four, A more localized form of, um, very fast wind is tornadoes. And they're different completely. They tend to form over land mass. And you get a very fast twisting, uh, whirlwind or twister. Uh, and the most commonly affected for severe ones are, um, the US and Canada. Uh, but they do occur quite frequently in the UK actually. But they're weak, they're elegant and weak. So they're good to look at and won't do you very much, uh, damage. The US ones can be really very severe. And just looking at that picture on the right, you can very easily see the track that the tornado took as it went through this town. Very, very clearly demarcated in terms of the damage. So those are winds, floods, uh, are the final thing I want to talk about. And, um, they are the natural hazard that affect most people worldwide. And there are a number of things which they can cause drowning. And I talked about this when we talked about tsunamis, uh, in the last, uh, lecture, uh, physical trauma, if people are caught in fast flow water, people underestimate quite how, how hard they're gonna be hit or hit other things, exposure to sewage in flood water, but importantly, and for the medium to long term, temporary or permanent, um, uh, destruction of sanitation, uh, leading to infection. And there's also gonna be destruction of the physical infrastructure, electrical hazards, carbon monoxide poisoning,'cause people who don't do it, uh, use diesel generators, destructions of homes, livelihoods, and importantly psychological trauma. Now, there are lots of reasons why flooding occurs and different reasons occur at different times of year. Uh, in general, in winter, which is the ones we tend to get most of in the uk, uh, storm surges. And these occur in winter, and they occur in coastal areas where a very high, uh, tide coincides with a storm coming in, pulling, uh, the, uh, the light, the level up. The second, uh, one which we tend to get again, manian winters, is what's called fluvial, um, flooding. And this is where the, the river breaks, it Spanx and spreads out onto its natural floodplain on which many of the great cities and towns of the UK are built. Both of these are much more common in winter, in summer, we get fluvial and flush flash flooding, particularly flash flooding, where the very high temperatures leads to sudden upswing, updraft of temperature, which then cools its very moist water, and you get very heavy what we would, we would call tropical rainfall over very short periods in, in areas that are largely difficult to predict and occur anyway. And of course, there are other causes like downbursts, tsunamis, uh, and groundwater by the, by the water literally comes from the ground. So just taking a, again, those one by one, um, I showed this before, but tsunamis, but it's worth re reinforcing because drowning is one of the, uh, first aid risks. There is a reasonable chance all of you could see at some stage. So, um, the key thing is to do CPR chest compressions, to keep the oxygen flowing around the blood, the, the body and in particular, uh, protecting, uh, the brain, uh, heart and kidneys. So you do five breaths, uh, and then 30 test compressions. And everybody in my view should learn how to do it. It's not particularly difficult. There's training done by St. John's Ambulance and other good organizations throughout the UK really strongly recommend people do this. Just do two breaths and just repeat that on a cyclical basis. If they vomit, put them on the recovery position as anyone who's done first aid, remember, and they may well have hypothermia. So just, uh, remember that. But the infectious dangers of flood water extend far beyond that. And probably the most important to these is sewage getting into water in substantial amounts. Part of this is due to storm, uh, storms, uh, outflows, which of course reach the, uh, news a lot in the last few years, but these are very big storms. So you've got a lot of outflow, uh, during these, uh, but in extreme cases, the whole sewage system will become completely flooded and cease to function. So all the sewage will go directly into the water, uh, and uh, downstream. And you may end up with the drinking water system not working and it becoming contaminated. So obvious things to do. Avoid any contact with flood water if you can. It is dangerous. Uh, and if you have to then wash your hands regularly with water, you think comes from a safer source. The psychological effects of flooding are often underestimated by those who've not experienced it. Any of you who know who's someone who's had a major flood in their area will be aware that this actually can take a really serious toll. They've lost their livelihoods, they've lost their houses, they may not have insurance any longer, uh, and they know it could happen again.'cause if this happened once this can occur on another occasion. Quite a lot of UK cities and towns are at significant risk of flooding. And these are the winter flooding, the fluvial and the pvi. Here in, uh, London, for example, uh, a lot of the land is quite low lying. If it wasn't for the, uh, Thames barrier, the risk of flooding, which is already non-trivial would be, uh, significantly higher. And some bits of east are put here. Boston underwater. Uh, in, in Lincolnshire, uh, flooding is a very significant risk and could occur, uh, across large areas of the country. Now with coastal and fluvial flooding, flooding from the river, um, due to, uh, winter flood, winter storms, it's very possible to predict where they will occur.'cause it's low lying areas on the coast or around the rivers. And it's usually possible with a short lead time to know when the met office will be able to say, five days out, there is a major storm heading our way. And here's when the tide tide's going to be. By contrast, the summer floods and particular flash flooding, which occurs with a sudden updraft of, of um, uh, hot, hot air leading to, uh, sudden very torrential, uh, flood are unpredictable where they're gonna occur and unpredictable when they're gonna occur so that the infrastructure isn't there, people aren't expecting it, they don't have all the flood barriers in place. It just suddenly the heavens open and you've got a major flood in your hands in a place that isn't ready for them. So they can lead to actually worse problems because of the lack of preparedness. Finally, where are we heading? And there are two really major drivers here, uh, one of which is climate change, and the other is the aging population. The aging population is probably the easier one. Just to summarize, um, the number of older people is steadily increasing. I did a report on this in the last year, uh, over in the uk and particularly in the peripheral areas, many of which are low lying and on the coastal strip and on average at the same level of temperature, whether they're high or low, uh, people who are older are going to be at greater risk of these temperatures. So that's just a physiological fact. So we are gonna see more heat and cold related, all other things being really equal disease, uh, because of the aging population. The other one, uh, is that is important is climate change. And for both of these, I've put here the IPCC report, which is a very authoritative, uh, neutrally written, uh, not, uh, shrill, uh, report of the risks, uh, of climate change and the science as it currently is understood In terms of climate change effects in the uk we are going to have effects, quite significant effects, some of which will make some of these things worse or significantly worse. But of course, many other countries will have much bigger ones. So, uh, on the right, what we put, what I put here is, um, the MET office is these aren't real measurements. This isn't a projection of warmer than average days and colder than average days. And as you can see, uh, the number of warmer than average days is steadily increasing as, and that will continue. So with high confidence, we're gonna have a lot more hot days and therefore the heat effects of, uh, uh, of health on health are going to increase. Additionally, high confidence, sea levels are gonna rise for a variety of reasons, and therefore coastal flooding, uh, is, uh, going to increase in some areas high confidence. There's also gonna be some decrease in cooler days. High confidence, there's a lot more complexity to the effect on major storms. If I could summarize really crudely, uh, the frequency of them is unlikely to go up, but the strength of many of them is likely to go up. But the impact in the UK is more complex to explain, and I think it's sent and the science of this is still in my view, uh, progressing. So I think it's not easy to say with absolute confidence, but I think the general view is, uh, some storms will get, uh, greater. Uh, but other countries will have probably bigger effects from this than we do. Uh, and we will likely get wetter winters as a result of this. But in many countries the effects will be very substantial indeed and particularly more marginal areas already many countries have much greater extremes in the UK of heat, of dry, of cold, uh, of wet. Uh, and for those areas, these changes can be catastrophic. So the impact on health and places like that. So health for example, is going to be really severe indeed. And that's before we get onto things like impact on agriculture. So my summary, uh, of where, uh, we are with, uh, cold heat, wind and flood, um, death and disability from cold, uh, and heat. And in some areas of the world, winter and wind and flood are common and I think more common than most people realize, measured in the thousands and tens of thousands, even here in the uk, uh, more, uh, significantly more elsewhere. The old and the very young are the major risk factors. But some other medical conditions make these risks also greater. High income, both as an individual and as a society can provide a lot of additional protection, largely due to good engineering solutions. They will reduce these risks, but definitely not to zero. Uh, clearly many countries have much greater extremes than the uk uh, and these are going to get more severe as climate change steadily progresses over the rest of this century and beyond. And I think the one thing I would say, and this is true for all three of the talks I gave in this, uh, series where I start off with, um, the medical emergencies come from man created, human created, uh, things radiological, nuclear chemical, moved on to the major geophysical ones, tsunamis, earthquakes, volcanoes, uh, but uh, actually the more, the most common than the weather related. And in due course climate related ones, it usually seems unlikely until it happens. And at that point, uh, people uh, really do notice and wish greater preparation, uh, had been made beforehand. Thanks very much. Happy to answer questions. Thank you very much Chris. Uh, with quite a few questions overlap that have come in online and they're essentially, um, about how you influence policy because you, um, outlined the number of things we might need to do to mitigate all of these stuff. They are, in a way, the way we're gonna look after all these young people in the future. Some of us in the older generation need to be able to push somebody to make the right leavers move. How, from your absolutely central experience in this, how is that done and how easy is it to manipulate policy at scale? Well, I think that, um, the most central thing for changing policy, uh, and I think most people probably don't recognize this to be as true as it is, is a centrality of evidence. If you have really good scientific evidence, which is incontrovertible and you can provide a solution, very important, providing a problem without a solution is not a policy response. You've gotta provide a solution also based on evidence. Then most sensible politicians, whatever their political background, would eventually pay some attention to those changes. Once someone has had an immediate emergency, if there's been a major flood, if there's been a major heat wave, then people are much more alive to that problem for a period. But I think we shouldn't exaggerate the length of time people remember about these things. And I'm not talking about, it's not a disparaging point about politicians, it's true about society as a whole. People say, why, oh, why? And isn't it terrible on day one and on, you know, day 60 they say pretty terrible, but are you really gonna put up our taxes? Uh, and on year two, year two people have moved on to another issue. So the key thing is you've got to have really clear evidence. You've got to be able to say this is what's gonna happen. When it does happen. You can then say, say that was what's gonna happen. That is what has happened and here is the solution and here's what it costs because that's the final bit of it. Uh, generally government is about making hard choices between different things, all of which are good to do and all of which cost resource. What we have to do is say, here's a big problem, here's a solution and here's the cost. And if you don't do that, the implications in the long term are going to be substantial. Oh, thank you. Um, much of what you've talked about future changes is, is extending some of our understanding of climate change in terms of making the country hotter, climate hotter. But, um, I'm the victim of reading too many types of science and I often see things talking about the amor currents in the oceans and also possibly the gulf stream changing and doing quite the opposite, maybe up to 15 or even more degrees. Does that affect the advice that you feel, uh, you'd like government to listen to? So I think with all of climate and I, I, I did actually wonder, well I should do a whole talk on climate change 'cause it's a complex area. There are some things we're very confident of, some things we're less confident of and some speculative stuff. Many of these areas are plausible, but I would say at this point in science, pretty speculative. And therefore, if you were, if you were the prime minister or a political leader, given a choice of making a sense of decisions about those and a set of decisions about things which are definitely gonna happen, like there is gonna be a winter excess in mortality next year for sure, then you are gonna tend to put your concentration on these, uh, more immediate effects. As back to my previous answer, if the evidence grows that we're going to have some of these tipping point or major effects at that point, I think there is going to have to be a reevaluation. But they're quite a long way. I think from my view, from the central projection of where we're gonna be. And I tend to say, well, the IPCC has a very large number of really expert people in this area. I tend to kind of follow their central projections as the people who've actually looked at this, uh, collectively among the people who've got the right, the the right skills, What would be your priority to change how, the list of numbers of things, for instance, housing, where would you put your first policy initiative? I think the, the, the very first one would be insulation. And I think it's shocking actually that we have not got better insulation. And this goes back decade, over many decades and several governments to be clear, uh, getting our houses to the situation the norm for North Europe seems to me the, the single most simple thing we can do is a capital investment and then means we have, can use less energy to achieve better heat, uh, um, narrow ranges and reduce fuel poverty, uh, as a result of that. So that would be my number one. If I was allowed as second, uh, it would be be systematic about reducing the risks of infections in the oldest bits of the population by, uh, all the things we know work, uh, of which, um, uh, vaccination, air pollution reductions, uh, and ventilation in public buildings would probably be the group of things I would concentrate on. But there is quite a long list. They're all achievable and I want to be clear about that. None of these are in any sense, sort of pie in the sky. Yeah, it'd be lovely to have if we could do it. They're perfectly straightforward. If we wanted to invest in insulation, we certainly could do so. There was a, a cricketer on the radio this week who had been, um, playing cricket I think in um, Pakistan. And the temperature was 40 degrees, the humidity was over 90%. He was running and um, out there for eight hours in the baking heat. Should sporting authorities stop that? Um, well I think firstly, as I said right at the beginning, people who live in very hot or very cold climates are climatized to those over a period of time. And if you're a young and healthy person, very fit as all these sports people are, um, they will tolerate a degree of, uh, those issues which you wouldn't otherwise expect. But there has to be an upper level of tolerance. And I talked about, for example, special forces, uh, soldiers in the UK going over their really, uh, demanding grueling courses. There's a, even for them, there is an upper level of tolerance where the risk of someone getting heat stroke is so great that, uh, people will pull back. And I think the same would be true at the extremes of sport, but of course the kinds of temperatures we're talking about would not be tolerated by the same cricketer when he is in his nineties. So you have to realize that you are particularly the biggest worry tends to be people who are in the, uh, extremes of age. Again, professor Chris Wii, thank you so much.