Lesson video

This lesson is called Climate Change and Human Health and is from the Unit Health and Disease.

Hi there, my name's Mrs. McCready and I'm here to guide you through today's lesson.

So thank you very much for joining me today.

In our lesson today, we're going to explain how climate change affects human health and how diseases get spread around the world.

Now in our lesson today, we're gonna come across a good number of keywords and they're listed up here on the screen for you now.

You may wish to pause the video to make a note of them, but I will introduce them to you as we come across them.

So in our lesson today, we're going to have a look at the factors that influence human health before we take a look at the effects of climate change on human health.

So are you ready to go? I certainly am, let's get started.

So what is human health? Well, we can define human health as how well we can cope with life both physically and mentally.

And the healthier we are, the more able we are able to cope with life.

Now, in order to maintain good physical and mental health, we need to look after our body and mind.

And we need to make sure that we therefore have a good source of diet, we have lots of exercise, and we do things that make us feel happy and healthy.

Now, human health is influenced by many different factors.

These include the food that we eat, the pathogens that we are exposed to, so the sorts of illnesses that we might get, the availability of fresh water, whether that's easy to come by or not, and the environmental conditions that we are surrounded by, and how these change the climate is included in that.

So these factors impact how healthy we are likely to be.

So let's take a look at these in a bit more detail.

Well, nutrition is about having a balanced and broad healthy diet, which contains, essentially, a little bit of everything.

Lots of fruit and vegetables, some starch based products such as bread, rice and pasta, milk and dairy products, meat, fish, eggs, beans, so a source of protein.

And then other nutritional foods which provide us with minerals and vitamins that we need to have in a small but steady quantity.

And this is represented by the eatwell plate, which I expect you have come across in previous science lessons.

Now, the eatwell plate is just one way of picturing how our balanced diet may look like, and it's a good way of imagining whether our meal that we're eating at the time is itself well balanced and nutritious.

And we can take from the eatwell plate, that if we have anything in excess or anything missing from our diet, then it's likely to impact our health, especially if that happens over a sustained period of time.

And if we are missing any essential nutrients or have anything in great excess at the detriment of other things, then we are likely to suffer from malnutrition, which is a type of poor health.

Now there are lots of different types of malnutrition and one example is a disease called kwashiorkor.

And kwashiorkor is caused by a lack of protein.

And it is relatively prevalent in countries where malnutrition is present, where availability of nutritious food and a broad balanced diet is difficult to come by.

So kwashiorkor, which is caused by a lack of protein over a long period of time, not just for a couple of days or so, but for many, many months.

And by lacking protein, what it means is that the body cannot repair itself effectively.

And so organ dysfunction, loss of hair, skin and teeth all become an issue for people who are suffering with kwashiorkor.

And they also experience water retention, especially around their abdomen and around their feet, which is why, as you can see in the picture, the little boy looks like he's actually very well fed because his tummy is swollen.

But that's not an indication in this case of being overfed.

This is a typical symptom of kwashiorkor, which is a form of malnutrition, which has been sustained over many, many months, if not longer than that.

So kwashiorkor is a disease caused by a lack of carbohydrate, protein, calcium, or fat.

What do you think? I'll give you five seconds to decide.

Well, well done if you chose protein such as meat, fish and beans because that is what causes kwashiorkor.

Well done.

Let's have a look at pathogens now and how they affect our health.

So we that our health is impacted by pathogens.

So this is germs that we can pick up from around our environment and these cause disease.

And anytime we've had a cold or the flu, a sickness bug, that sort of thing that's caused by a pathogen that we've picked from our surroundings.

So pathogens include bacteria, viruses, fungi, and protists.

And these are all able to invade our body and cause us disease.

And the sorts of diseases that these organisms are causing are called communicable diseases because they can be passed on from one organism to another and therefore very easily spread.

And the easier they are to spread, the more contagious they are.

Now, malaria is an example of a contagious disease, a communicable disease which is spread from person to person using mosquitoes.

So mosquitoes transmit the protists which causes malaria from one human to another because it pierces the skin, feeds on the blood of the human.

And by doing so, the protists is able to enter the human's body and so it spreads from person to person.

And you can see in the photo there that that lady is sleeping underneath a mosquito net in order to prevent her from being bitten by mosquitoes and therefore getting the malaria protists which will lead to malaria.

I also said that the availability of fresh water is important for maintaining our health health, and this is because we can't drink sea water.

It's too salty, there's too much salt in sea water for that to be healthy for us.

And so we need to drink fresh water, which is not salty.

Now dirty water carries pathogens and pathogens as we've just seen cause diseases and the sorts of diseases that get that get spread by dirty water include typhoid, cholera and hepatitis A to name a few.

And these are nasty diseases that develop very quickly and lead often to death if not treated rapidly.

And so a lack of clean fresh water leads to diseases spreading very quickly.

And you can only just imagine how many diseases may well be present in the water that those women are spooning into their buckets.

So insufficient fresh water causes health problems, and this includes dehydration, various diseases as already shown, which are essentially down to poor hygiene, but not necessarily because the people themselves are being deliberately unclean, but maybe because they have no choice other than to be unclean because of the water availability around them.

And it also leads to malnutrition because there is often a lack of water with which to grow food and therefore not sufficient quantities of food as well as insufficient quantities of fresh water.

So a lack of clean fresh water causes which of the following problems, malnutrition, rehydration, or the spread of diseases? I'll give you five seconds to decide.

Okay, so you should have said that a lack of clean fresh water leads to malnutrition and the spread of diseases.

Well done if you spotted both of those.

So what I'd like you to do now is just to summarise the factors which influence human health by considering these two examples.

So in the first example, water wells are installed in poor communities, in developing countries, and often with life-changing results.

So what I'd like you to do is to suggest what these life-changing results might be.

Then I'd like you to consider what Jacob is saying.

So he says that his friend eats only cheddar cheese and plain crisps.

So what I'd like you to do is to suggest what problems this might cause for Jacob's friend over time if he sustains this type of diet for a long period of time.

So pause the video and come back to me when you are ready.

Okay, let's check our work.

So with the water wells, what types of changes might be seen? Well, you might have said that providing a supply of fresh water will improve the health of the community.

It will reduce the spread of diseases and it will provide water for farming, cooking, and cleaning.

And then with Jacob's friend, what problems might he experience over time? Well, you might have said that this will lead to an imbalance of nutrients which will cause ill health and he may end up with malnutrition and diseases such as kwashiorkor.

Well done if you've got both of those answers, do add to your work if you need to, well done.

Okay, let's move on to have a look at the effects of climate change and how this impacts human health.

Now, climate change is the long-term shift in weather patterns caused by global warming.

And climate change is happening because humans are releasing vast quantities of greenhouse gases including carbon dioxide and methane into the atmosphere.

And we have been accelerating this release of greenhouse gases over the last couple of hundred years or so.

Now greenhouse gases cause the atmosphere to reflect more radiation, which has been reflected from the earth's surface and bounce it around the atmosphere.

And this causes the atmosphere to warm up.

And whilst we want the atmosphere to warm up to some extent because it keeps the earth at a nice ambient temperature of about 15 degrees on average, we do not want it to heat up more than it should be.

But by putting more and more greenhouse gases into the atmosphere, what we are doing is causing the atmosphere to be able to heat up more than it should.

And this is causing climate change.

Now, climate change leads to more extreme weather conditions and these extreme weather conditions whilst previously happening once in a hundred years or once in 400 years are becoming more and more frequent.

We only have to look back over the UK weather records for the last 20 years or so to see that that is the case that's actually happening.

So extreme weather conditions include extreme drought, extreme heat, and extremely windy, wet weather, essentially cyclones and hurricanes and all of these are really dangerous extreme weather conditions.

They are very damaging.

They can damage buildings, they can damage crop, they can cause ill health.

They are very destructive indeed, and they are becoming more frequent because of climate change.

So long periods of drought reduce the availability of fresh water.

And by doing so it means that crops that we are growing to feed ourselves with, are unable to grow and therefore fail.

And this means that crops that we might have been growing either to feed animals which we're growing to feed ourselves or to feed ourselves fail, and therefore that chain breaks down.

So low crop yield can lead to famine and that causes malnutrition and therefore poor human health.

Periods of extreme heat are also becoming more common due to climate change.

And extreme heat is particularly difficult to deal with, if you are elderly or very young, because sustaining a high temperature and trying to function and live within temperatures are body temperature or above 37 degrees or above makes it very difficult to cool our body down despite drinking lots, staying in the shade, those sorts of things, it still makes it very difficult to cool down.

And this is particularly difficult for people who are very old or very young because their body's systems may not be able to cope so efficiently and effectively with this sustained heat and it can ultimately lead to hypothermia and eventually to death if it's not treated properly.

So this is a particular problem.

Extreme heat and sustained high temperatures are becoming more frequent as climate change worsens.

I also mentioned cyclones and extreme weather events such as high winds and high rainfall and cyclones bring these sorts of conditions which cause damage to buildings and infrastructure, causes flooding, it disrupts water supplies because the area is flooded and therefore dirty water is being mixed in with clean water.

Sewage is contaminating clean water as well.

And so the availability of fresh water significantly reduces and that leads to the spread of disease and also to poorer human health, especially if those conditions are sustained for long periods of time.

So cyclones, heavy rainfall and heavy wind cause significant damage especially to infrastructure, which then leads to impacts on human health.

So climate change is making it harder to grow crops in some parts of the world, true or false? So you should have said that that is true, but can you explain why? Well, you should have said that that is because periods of drought make it harder to grow crops due to the lack of water and extreme rainfall and high winds can damage crops as well.

Well done if you said both of those points.

Now I said that climate change can impact the availability of fresh water and therefore climate change can also cause the spread of pathogens.

But it's not just waterborne pathogens that climate change causes to spread.

Other pathogens which are spread by organisms for instance, such as malaria spread by the mosquito can spread to different areas because of climate change.

So we know that mosquitoes carry malaria amongst other diseases and malaria carrying mosquitoes are mainly found in the tropical regions of Central Africa.

However, the changing climate is causing the prevalence of those mosquitoes to change.

So countries such as Ethiopia, which you can see is on the east side of Africa, are becoming hotter and more humid.

And because of these changing climate conditions, malaria is becoming more common as well.

And that's because the conditions now in Ethiopia are much more favourable to the mosquito for the mosquito to reproduce.

And if the mosquito can reproduce more easily because the climate conditions are more favourable for it to survive, then it is more able to spread the malaria protists from organism to organism, from human to human.

And so there has been an increase in the spread of malaria through countries like Ethiopia, which had a low incident rate of malaria before, but that incident rate is increasing as climate change worsens.

Now this has a number of significant impacts.

Obviously firstly, it's impacting the health of the people who are living in that country, but also this is exacerbated, this is worsened because the people who are living in that country have a low natural level of immunity to malaria.

And that means that more humans are succumbing to the disease and that means, that it is able to be passed on even quicker, more easily by the mosquitoes, because the protists isn't being killed by those humans, by their innate immunity, but is being allowed to establish itself within those humans and therefore more readily able to be passed from one human to another via the mosquito.

There are other diseases which are being spread into new geographical areas as well, and they also affect other animals and plants as well.

So for instance, dengue fever and cholera are spreading relatively quickly through parts of Africa and Bangladesh and Nepal as the climate changes.

And this just like malaria is because these diseases are better able to survive in the new climate conditions within these countries than they were before and are therefore spreading quickly through the country because the population also doesn't have an innate immunity within it.

And the countries are less well prepared to deal with these diseases having not had them as an issue until now.

Another disease is ash dieback.

Now this affects ash trees and has spread rapidly through northern Europe and into the UK.

Now ash dieback is causing the substantial loss of ash trees across Europe and into the UK.

And this is causing destruction to habitats and food chains because of course ash trees are a producer and therefore have significant implications for the organisms which depend upon those trees for survival in one way, shape, or form, either habitat or as food source for instance.

So the effects of climate change are being felt in many parts of the world and across many different organisms. And we can therefore say that the effects of climate change on health are complex and they are interconnected.

And unfortunately the people who have contributed the least to causing climate change are often the ones who are suffering the most.

We only need to reference those who are being affected by malaria and dengue fever to see that that is true.

However, we know what we need to do in order to reduce emissions that are causing and driving climate change.

And therefore it is imperative, it is up to us to make those changes because every fraction of a degree of warming that we don't experience that we prevent will protect human health and save lives.

So anything that we can do to reduce the impact of climate change will help.

No matter how small it might seem.

If we all did little things, they would add up to being really big things.

So which of these factors impact the availability of fresh water? Mosquitoes, drought, or greenhouse gas emissions? I'll give you five seconds to decide.

Okay, so you should have said that drought and greenhouse gas emissions, which are driving climate change are factors that impact the availability of fresh water.

Well done if you said both of those.

And which of these cause diseases to spread more quickly into new geographical areas? An increase in global temperatures, the presence of fresh water, low natural immunity in the local population, or hypothermia, what do you think? Okay, so you should have said that, increased global temperatures and low natural immunity in the local population all cause diseases to spread more quickly into new geographical areas.

Well done if you spotted both of those.

So I've said that human health and climate change are complex issues which are highly interconnected in many different ways.

And what I'd like you to do is to summarise those impacts by creating a flow chart.

So start with human activities and finish with poorer human health.

And what I'd like you to do is to arrange the word boxes as you can see on the screen, into a series of flow charts that show how causes lead to effects.

Now there will be several branches and several cards may lead to one card, and one card may lead to several cards.

So you'll need to connect the cards with arrows to show how one cause leads to various different effects and so on in several stages, moving from human activities through to poorer human health.

So pause the video.

This is quite a challenging task to do.

Take your time and really give it good consideration and come back to me when you are ready.

Okay, now that was a hard task, so I hope you've spent quite a long time really thinking about it.

Well done for your efforts so far.

Now this is how I've organised my cards.

So starting with human activities, I've led to climate change.

And from climate change I've led to the fact that there are more extreme weather events, which include high winds and high rainfall.

And there are also more extreme weather events including, droughts.

From these two extreme weather events.

I've suggested that this leads to fresh water supplies being disrupted, and as a result this will lead to reduced crop yield and this leads to malnutrition and famine, which leads to poorer human health.

So that's one branch.

Going back up to fresh water supplies being disrupted.

I've then also said that this causes pathogens to spread and this is exacerbated by low natural immunity in the population which is causing pathogens to spread faster.

So I've piped that one into the top of pathogens spreading, and from that I've said that this causes disease and this leads to poorer human health.

So that's the second branch within our pathway.

Then going back up to the top following climate change, I've also said that this leads to an increase in average temperatures, and this means that mosquitoes are able to reproduce faster, which causes pathogens to spread, and then the knock on problem of disease causing poorer human health.

I've also said that an increase in average temperatures leads to hypothermia, and this leads to disease, which in turn leads to poor human health.

So that's another branch through this maze.

So just review your work.

Have you divided your answers up into these flows and have you connected them in a similar way to me? You can certainly see how this is a very complex picture and a highly interconnected one.

So well done if you've made some, most or all of these connections.

Okay, we've come to the end of our lesson today.

So thank you very much for joining me.

I hope you found it interesting, as we've learned how human health is influenced by a number of different factors, including nutrition, pathogens, the availability of fresh water, and environmental conditions.

We've also seen how climate change affects the availability of fresh water, and this affects also how crops grow and how diseases spread and their prevalence.

We've seen how communicable diseases which are caused by pathogens can spread more easily and into new geographical areas due to climate change.

And we've also seen how other health impacts, including from heat and from malnutrition, are also becoming more common as a result of climate change.

So there's plenty to think about there, and plenty of action that we can take.

Thank you very much for joining me today, and I hope to see you again soon.

Bye.