Lesson video

Hello, geographers.

My name is Mrs. Griffiths.

Welcome to today's lesson.

Today's lesson is all about water resources, the demand for them and also the supply.

So we're gonna be thinking about what are the key reasons why some parts of the world are seeing a growing demand for water resources.

And we're also gonna think about what are the factors that affect water supply.

So that balance of demand and supply, that's what it's all about today.

Our outcome for today is I can explain reasons for the increasing demand for water and factors that affect water supply.

So that's what I hope you can say by the end of today's lesson.

We have some keywords for you today.

The first is abstraction.

Abstraction is the extraction of water from a water source, such as a river, on the surface, or an aquifer, underground.

Over-abstraction.

Over-abstraction occurs when the extraction exceeds recharge by precipitation.

So that's the rate of extraction exceeding the rate of recharge.

And then poverty.

The definition is more than a lack of income, it includes hunger and malnutrition, limited access to education and other basic services.

And of course today's basic services we're gonna be touching on are all relating to water.

So let's make a start on today's lesson, but look out for those keywords.

So water resources' demand and supply, we have two key questions.

Firstly, why is the global demand for water rising? And secondly, what factors affect water supply? But let's start with that first one.

Why is the global demand for water rising? Abstraction of fresh water from rivers, lakes, and reservoirs, or groundwater sources, supplies agriculture, industry, and households with what they need.

Well, with what we need.

Let's have a look at this graph we've got here.

The title is Global Freshwater Use Over Time.

What does this graph show? Well, it shows that globally the use of freshwater has increased over time since 1900, rapidly increasing from the 1950s, and you can see that where the blue area rises steeply.

And then from the 2000s, the growth in the use has flattened off somewhat, we might add there.

It's not increasing quite so rapidly.

Now what does this graph reveal? It's slightly different to the last one because here we have broken down freshwater use over time by region.

We've got three categories of country there.

This is what's called a stacked line graph, where the area under the top of the colour there is showing us the amount.

In the OECD, a group of HICs that includes most of Europe, North America, and Oceania, freshwater use has plateaued since 1980.

That's a good geographical word isn't it, plateau, like a high, flat area.

In contrast, the combined consumption of NEEs, in this case Brazil, Russia, India, China, and South Africa, they combine to form that BRICS acronym, appear to have rapidly increased since 1980.

Now can you think about why it is that any use of water or demand for water has increased over time, particularly rapidly since 1980? The global demand for water is rising, and this is due in part to economic development.

And this is really relevant, isn't it, to our newly emerging economies.

Laura asks, "Why? Do rich people have more baths than showers?" Well, that's a good question.

And Izzy says, "My mum said it's AI using all the water these days.

Like how?" Well, that's another good point, but perhaps we'll have to come back to that one.

Let's deal with the first one.

Why does economic development link to a rising demand for water? Well, the increasing commercialisation of agriculture leads to more intensive food production and therefore more irrigation.

So the demand of water supply for farmers has gone up particularly in newly emerging economies.

Also, manufacturing industries consume water, for example, in food processing and the production of consumer goods.

So as countries develop, and manufacture more, and have more industry going on, they've got a greater demand for water.

People around the world have different experiences of everyday chores.

I'm gonna show you two videos from the website Dollar Street that compare the experience of families with different incomes washing their clothes.

Take a look at these.

Here's the first one.

A lady is washing clothes in Myanmar.

And here, we have a family in India with a much higher monthly income.

And this gentleman is putting on the wash.

Which of these chores looks easier to you? And which do you think is using more water? Rising affluence has created a new class of consumers in middle income countries, a new middle class that can afford to buy expensive appliances for the home that use large volumes of water.

So the global demand for washing machines is growing.

And of course this has an environmental impact.

It increases the demand for water not only because washing machines use a lot of water, unless you're picking the eco cycle perhaps, but also it's so much more convenient, isn't it? So you're more likely to put the washing on.

Artificial intelligence, AI, requires large volumes of water to cool data centres and is placing new demands on the world's water resources.

Interesting comment here.

By 2027, the predictive global demand for AI could consume a volume equivalent to the water demand of the population of Canada.

Wow.

A check for you here.

Which region of the world consumed most fresh water in 1980 and in 2010? Was it the BRICS, the MINT countries, OECD, or rest of the world? Take a look at the graph and then restart the video when you know the answer.

And if you said BRICS, you'd be absolutely right.

Well done.

The global demand for water is rising not only due to economic development but also due to population increase.

And here we've got a graph of global population over time.

Note the, like, purple area is a prediction.

The United Nations has predicted that the global population will continue to grow until the 2080s.

It says that the population will peak at about 10.

29 billion in the mid-2080s.

Until then, a growing population will place growing demands on the natural world to supply it with resources, such as water.

A check for you here.

True or false? The UN predicts the global population will continue to increase between now and the year 2100.

Is that true or false? And remember, I'm gonna need an explanation in a moment.

And if you said false, what was your explanation? We had this.

The current prediction is that population growth will slow towards the end of the 21st century and total population will peak in the mid-2080s.

So here we've got population change by region over time.

So we've broken down that overall graph of change over time into, and it's colour coded.

Again, it's a stacked line graph looking at the area relating to different regions of the world.

Oceania is really hard to see 'cause it's that tiny orange line on the top.

The growth in the size of populations around the world has been uneven over time.

And this is also true for the UN's predictions if we look at the graph about the way population might change up to 2100.

A check for you here.

This is our graph of population change by region over time.

Which continent has the largest population today? And if you said Asia, you'd be absolutely right.

Second question then.

Which two continents are predicted to see the largest growth in population during the 21st century? And if you said Asia and Africa, you'd be absolutely right.

Well done.

Now thinking about that graph of population change by region over time, we can see that Africa's population is still accelerating.

So the rate of increase is high and it's accelerating.

However, Asia's population has doubled since 1975, but the rate of increase has begun to slow.

The supply of water clearly must keep pace with the growth in these populations or we need to conserve water resources more effectively, particularly in those regions where population's growing so quickly.

A check for you here.

True or false? The rate of consumption of water is rising globally due to economic development and population growth.

Remember, I'm going to need you to explain your answer in a moment.

And if you said true, why is that? Well, the global population is growing and predicted to continue to do so for decades.

In addition, with economic development, people tend to consume greater volumes of water per head or family due to being able to afford modern appliances such as dishwashers and washing machines, which we've seen use lots of water and also are very convenient to use.

Task A then.

We need to grab a pen or a pencil here.

So I've got three tasks for you.

The first one is state the UN's prediction for the global population up to 2100.

Secondly, suggest how the trend you've described will affect water consumption.

Thirdly, let's have a look at Izzy's comment here.

"If AI is so smart, it will definitely be able to work out how to consume less water in future." Do you agree or disagree with Izzy's argument? Discuss it with a partner.

So we've got two things to write an answer for.

And then thirdly, I'd like you to discuss that with a partner or have a good think about whether you agree with her.

So pause the video now here.

And you've got some work to do.

Best of luck with that.

And I'll see you in a moment when you want to check your answers.

How did you get on? Stating the UN's prediction for the global population of 2100, this was our answer.

The UN predicts that the global population will continue to grow up until the 2080s.

It will peak at about 10.

3 billion in the mid-2080s.

Did you get that from the graph? Then, second one, we needed you to suggest how the trend you described will affect water consumption.

Your answer might include something like this.

With a larger global population, demand for water resources will increase.

An increase to number of mouths to feed will mean more intensive farming techniques are required, most likely to involve irrigation.

The amount by which the water consumption will increase will depend on how wealthy growing populations are.

Typically, richer nations consume more water per person, using greater volumes in the home, for example, using power showers and washing machines.

How'd you get on with that? So what I like about that answer is we've got an idea of a growing population impacting not only household use but industrial use.

So we're looking at the primary industries there of agriculture.

Well done if you've got an answer like that.

Thirdly, do you agree with Izzy's argument? Discuss it with a partner.

Well, you might have said something like this.

True, artificial intelligence can be put to good use by instructing it to come up with ways to reduce our environmental footprint, and no doubt its environmental footprint.

So we might look at something like water use or power use.

You might have said, well, AI's use of water is placing an unnecessary additional demand on overstretched resources.

So it's a bit of a worry, and it probably will need that water.

Or you might have said, well, in the future, we'll have to think carefully about our use of energy and water-hungry technology, perhaps thinking about it in the context of climate change.

Okay, so we've had a go at answering that first question, why is the global demand for water rising, thinking about those two reasons, but what about what factors affect water supply? How are we gonna supply those people? Well, factors in water supply are various.

Let's have a look at the ones that we have here.

So we've got climate and climate change, geology, pollution, over-abstraction, limited infrastructure, and poverty.

So we're gonna have a look at each of those six factors in turn.

Let's start with climate then.

Climate is a physical factor that affects the global pattern, sorry, of water availability.

And here we've got a map that's showing us information about annual precipitation by political boundaries.

So we've got the countries there.

And we can see we've got a colour scale at the bottom.

The darker the colour, the wetter the climate.

Rainfall clearly is a key input into local drainage basins.

Temperature affects the rate of evaporation from the land surface, so another aspect of climate to bear in mind.

Total annual precipitation and temperature range across the year determine areas of what's termed physical water scarcity.

So there just isn't very much a very great volume of water available.

Scientists can model a likely impact of climate change on the pattern of temperature.

And these models are improving over time.

But the impact on future precipitation patterns is currently less clear.

However, we do have some evidence that more intense tropical storms are likely because of the way that we've seen tropical storms change.

And of course if they're more intense, we see more rainfall.

Flood events are a threat to water supply in affected locations.

A question here.

Why is more rain a threat to the water supply? Well, that's a good question.

Let's have a think about that one.

This photo was taken after Hurricane Maria devastated the island of Puerto Rico in 2017.

And we can see that standing water on what looks like the carpark and the roads.

Think about what impact that's having on people's health, on the environment, but also water supply.

The sudden addition of storm water to drains can overwhelm treatment facilities, affecting water quality.

Climate events which threaten water availability also occur more gradually.

It doesn't have to be this sort of dramatic kind of one, two, three-day event.

These things can occur more gradually, such as the process of desertification.

So that's where the climate is changing.

And that may well affect water supply.

Second factor then, geology.

It's the type of bedrock, and it affects the permeability of the land and therefore influences the pattern of surface water storage, because if it's highly permeable, you might have fewer rivers running across the surface of the ground.

They might all be underground.

So it also affects the pattern of water storage underground.

While surface water may be limited at ground level during dry months, water-bearing rocks, or aquifers, provide the base flow of rivers and maintain the availability of this key resource.

In some parts of the world with an arid or a semi-arid climate, aquifers hold non-renewable reserves for water (indistinct).

These are natural stores that were charged at a time when the region experienced a different, much wetter climate.

Now one example of this is seen in Saudi Arabia, which has, for some decades, exploited non-renewable reserves or ancient water stores as it developed.

But of course its approach has more recently changed, which we'll touch on in a moment.

A check for you here.

Which of the following statements are true? I'd like you to read those through and then restart the video when you have an answer.

And if you said, well, physical water scarcity is typical of arid and semi-arid areas, that's true.

And geology influences the pattern of water storage above and below the ground, that's also true.

Well done.

Pollution is another factor that affects water supply.

So quality of water is important, as well as quantity.

Sources of pollutants include agriculture, industry, and human settlement, where sanitation services are limited and watercourses become open sewers.

And here we've got a bar graph showing the percentage of domestic wastewater that's sewage that is safely treated by region.

We've got really different percentages here.

So Oceania, so that's Australia and New Zealand, 79.

2% share of safely treated domestic wastewater, compared to Sub-Saharan Africa, we've got 20%, and Central and Southern Asia, 24%.

So shockingly low access to safe treatment or safe sanitation.

In lower income countries and newly emerging economies, manufacturing industries are subject to less regulation.

So industry could be a source of pollutants.

Where companies face fewer penalties, harmful industrial wastewater is more likely to be released into rivers and streams. Improved water sources deliver water that has the potential to be safe to drink.

So these are piped supplies or boreholes, protected wells or springs, rainwater and bottled water.

Note, actual contamination is not tested for this kind of broader definition of improved water sources.

But we've got a choropleth map here showing people that are not using improved water sources.

And you can see there's some quite big numbers.

Millions of people live without this basic resource in countries in South America, Africa, and Asia.

The largest populations are in East, South, and Southeast Asia, and West, Central, and East Africa.

And I'll just draw a ring around those so that you're absolutely clear where we're talking about.

So it's those purple and particularly the darker purple countries where we've got the largest populations, we've got millions of people living without an improved water source that has that potential to deliver safe water.

Now water stress is when demand exceeds supply.

In this map, there are five categories, from no stress to critical stress.

And the countries that are in red, how are they using fresh water that's more than a hundred percent of internal resources? Well, internal resources here relates to renewable resources.

So these countries are using what's called non-renewable resources.

Do you remember I mentioned that earlier? So fresh water withdrawals can exceed a hundred percent of total renewable resources where extraction from non-renewable aquifers takes place or use of desalination plants is significant.

And I want to focus in on Saudi Arabia.

A mini case study for you here.

Over-abstraction, this is what it's about.

So this occurs when the withdrawals exceed recharge by precipitation.

Using satellite imagery, we can zoom in to the northwest of Saudi Arabia, where the desert has been farmed.

I'm using The Geography Visualiser here.

If we look at Tayma, which is a desert oasis, it receives just 65 millimetres of rainfall a year but benefits from a natural spring, which is why we have this settlement in the desert.

Now can you spot the fields of crops around Tayma? Well, let's zoom in a little bit.

It might make it a bit easier.

West of Tayma, gigantic circular fields are visible, irrigated using groundwater pumped from deep underground.

This irrigation relies on the use of water from ancient aquifers, what I was talking about, non-renewable resources.

Such underground stores of water are classed as non-renewable, having been created by historic rather than current climatic conditions.

And if we look closely at the image, we can see the traces of fields no longer irrigated.

In the 2010s, Tayma's oasis was drying up due to over-abstraction.

Saudi Arabia's farmers stopped producing wheat a decade ago due to water stress countrywide.

So those historic traces of fields are, if you like, evidence in the landscape of that period of water stress and the retrenching of the kind of scale of farming within Saudi Arabia.

Concern over over-abstraction of the country's non-renewable groundwater resources has prompted Saudi Arabia to invest in new technologies in recent years, such as desalination of sea water.

So they're looking to different supplies of water to supply their growing population.

Limited infrastructure, so this is another factor that affects water supply.

Water infrastructure delivering clean water to people's homes is often underdeveloped in rural areas of lower income countries.

Now we've got a scatter graph here of the share of the urban population versus the share of the rural population using safely managed drinking water.

So we've got rural population on the x-axis and urban population on the y-axis.

What do you notice about that? In this scatter graph, it's clear that in most countries the share of the population with access to safely managed drinking water is greater in urban areas, save a few outliers or anomalies.

The cost of developing water networks in rural areas is usually much higher per family or per property than in urban areas, given the lower density living.

And so that's the reason why the development of rural infrastructure is simply not prioritised.

Poverty is another factor.

So poverty in many lower income countries and newly emerging economies means that there's unequal access to this essential resource within the population, with the poorest more likely to share a supply.

And we can see that example of the gentleman heading out from his house to find water.

Whereas the other two families here, these photographs are taken from Dollar Street, we've got their monthly income underneath, so we can see these are much, much wealthier families, they have a tap in their home.

The quality of drinking water may be unreliable in these lower income countries or newly emerging economies, with richer families relying on bottled water or home purification.

And we can see that example on the right-hand side of some technology being used to purify the water in the case of the wealthiest family.

A check for you here then.

True or false? In lower income countries and newly emerging economies, there is a general lack of safe drinking water.

Pause the video, have a think, and remember, I'm gonna need you to explain why.

And if you said false, can you explain why? Our explanation was as follows.

There is unequal access to safe drinking water in lower income countries and some newly emerging economies rather than a general lack of it, unequal access.

Investment in water infrastructure often lags behind population growth.

Wealthier people buy bottled water or rely on expensive home purification technology that the poor simply can't afford.

Was your explanation a bit like that? I'm sure it was.

So practise tasks for you here.

Now I've got three.

Let's go through them one by one.

So the first one is to sort the factors that affect water supply into these categories.

So we've got categories, physical factors and human factors.

It should be straightforward.

Secondly, explain why limited infrastructure is a factor in the availability of water.

So explain the reason why limited infrastructure is a factor in the availability of water.

And thirdly, read all about it.

Can you summarise the impact of over-abstraction on Saudi Arabia's water supply in the mid-2010s in three sentences? So there's an article there that you need to read, and I'd like you to have a go at summarising it in just three sentences.

I haven't given you a word limit.

I'm gonna say three sentences, okay? So you're gonna try and boil that down for me.

So grab a pen, pause the video, best of luck, and I will see you when you want to check the answers.

How'd you get on? This first one hopefully was straightforward.

Sort the factors that affect water supply into these categories.

So we've got physical factors are climate and climate change.

Ooh, that's a bit controversial.

Perhaps we want to move that one over to human, but let's call it climate for now.

Geology.

And then human factors, we've got pollution, over-abstraction, limited infrastructure, and poverty.

Secondly, explain why limited infrastructure is a factor in the availability of water.

How'd you get on with that one? You may have written something like this.

Without piped water to the home, some people in low income countries, often in rural areas, must undertake tiring and lengthy round trips of half an hour or more to fetch water.

It's often the women, isn't it? The huge daily time commitment and significant physical effort limits the availability of water.

And of course it limits their opportunities more generally.

By contrast, in higher income countries such as the UK, water availability may be affected by the loss of large volumes of water due to leakage from older infrastructure.

While more developed in extent, such pipe work requires ongoing maintenance which may be insufficient.

So that idea that limited infrastructure might not just be limited in terms of its extent, but it might just be limited because it's not being maintained and it's leaking.

Well done if you've got an idea like that written down.

Thirdly, read all about it.

You had to summarise the impact of over-abstraction on Saudi Arabia's water supply in the mid-2010s in three sentences.

Quite a tricky task, wasn't it, to kind of keep it really concise.

Your three sentences might look something like this.

Saudi Arabia's farmers stopped producing wheat in the desert a decade ago due to water stress.

Concerned about the over-abstraction of non-renewable groundwater resources, the government cancelled the crop countrywide.

Wells were drying up in well-established oases because of the rate of water abstraction from underground aquifers for irrigation.

How'd you get on? That was a tricky one, wasn't it? Okay, in summary, what have we've been looking at? Water resources' demand and supply.

Well, the global demand for water is rising.

Water consumption is increasing due to two key reasons, isn't it? Economic development, as with increasing affluence, populations consume more water due to irrigation of crops, the increase in manufacturing, and increased household use.

But we've also got the idea of population increase.

So globally, the population is still increasing to some extent, and that is gonna have an impact on demand.

And then we worked our way through six different factors that affect water supply, including climate and climate change, geology, pollution, over-abstraction, limited infrastructure, and poverty.

Well, I did feel like we've gone through quite a lot there, didn't it? And I think we have.

Well done.

And we have three tasks to start with and then three tasks for that second learning cycle as well, so you have worked really hard today.

Well done.

And I'll see you again soon.