Lesson video

Hello, geographers.

My name is Mrs. Griffiths.

Welcome to today's lesson.

Today we're going to be thinking about food resources at a global scale and thinking about factors that affect demand and also supply of food.

So we've got a number of different factors to consider and I think we probably should get started.

The outcome of today's lesson is as follows.

I can explain the reasons for increasing demand for food and the factors that affect food supply.

So two parts to that, the reasons for increasing demand for food and the factors that affect food supply.

We have some keywords here for today.

They are drought, which is a long period of time with little or no rainfall, leading to a shortage of water.

Irrigation, the applying water to land in order to supply crops and other plants.

Water stress, which occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use.

And poverty, we're going for a wider definition here.

So it's more than lack of income, it includes hunger and malnutrition, limited access to education and other basic services.

Okay, so those words will come up across today's lesson.

How does our lesson break down? Well, as I say, we're looking at demand and then supply.

So why is the global demand for food rising and what factors affect food supply? So let's start on that first part.

Why is the global demand for food rising? Okay, so to kick us off, we have a divided bar chart, which appears to be about per capita sources of protein.

So what does this divided bar chart show? Let's have a look at what the colours mean.

Have a look at the different axes.

What is this graph about? Well, I'm sure you spotted that here at the top of the graph or those top bars on our diagram are all newly emerging economies.

Where as further down the graph, we have a long list of high income countries.

So they're grouped together because what we can see is that with increasing wealth, we have increasing consumption of animal protein, increasing consumption of animal protein.

Now it's true to say our diet changes with rising affluence.

So as we get richer, typically our diet changes.

Richer countries consume a larger amount of animal protein, meat and dairy, per person.

And that's born out by this data here, isn't it? The global demand for food is rising and one of the reasons for that, remember we're looking for two reasons, is economic development.

So producing meat and dairy for wealthier populations means using a lot more land for food production.

Laura asks, "Why is that? Do cows need more room than crops?" Well, that's a fair question.

So why is it that producing meat and dairy means using a lot more land for food production? Meat and dairy production is less efficient than growing crops as food for people to eat.

Let's have a think about why that might be.

80% of land farmed today is used for livestock, both grazing and also growing crops for feed.

The meat and dairy only provides, well less than a fifth of our calories, and less than half of our protein needs globally.

So we can see it's quite inefficient.

So the increasing wealth of populations around the world and they're typically eating more meat and dairy, is placing a bigger load on the planet, on the environment.

Now you might say to me, is there another way? Well, people who are proponents of a plant-based diet or switching to less meat and dairy say we could reduce the land used for farming and conserve by diversity.

If we only chose to eat a little bit less meat and dairy or go plant-based.

Different data resource for you here.

What does this graph tell us about economic development and demand for food? Have a little look at that and then I'll give you an answer.

Now I'm sure you spotted the title is Daily per Capita Supply of Calories versus Gross Domestic Product per Capita.

So along the x-axis we have GDP in dollars per capita, and then on the Y axis we have kilocalories per day.

So what this is, it's a scatter graph or a scatter plot and it's colour coded according to different areas or different countries of the world, but we haven't just used Xs or dots for our plots, we've actually got proportional circles.

So there's a whole other dimension of the data here, but let's try and keep it simple and look at what this tells us about economic development and demand for food.

As I say, with two sets of data for the same countries, we can use a scatterplot to see if there's a general relationship between those data sets.

So are those data sets in some way linked? A line of best fit can be added to show the general trend.

And the way you go about drawing this line of best fit is it must go through as many plots as you can manage with an equal number of plots either side.

Now obviously you've got to try and ignore the outliers or the anomalies.

We'll come onto those in a second.

This scatterplot of GDP against calories shows that there's a strong positive correlation between calorie consumed, or supplied in this case, per day and average income.

When I say it's calories supply, we have to be a bit careful about looking at this data as exactly equal to food consumed as some food supplied is wasted.

But it's a good guide of average consumption.

As I mentioned, there are some outliers or anomalies within this dataset and we can see for example that Japan appears to have average calories that are much lower than expected for this income level and perhaps that's culturally specific to their diet.

The largest increase in calories supplied per capita and consumed takes place within this dataset in the transition from being a low income country to a newly emerging economy.

So what we see globally is a real ramping up of calories consumed per day with economic development.

Check for you here.

Which of these are high income countries consuming more than 3,500 calories per day? And we've got four options for you.

So it might be that one or more are correct.

Pause the video now and restart it to check your answer.

And if you said, well, the USA and Germany are both high income countries consuming more than 3,500 calories per day, you'd be absolutely right.

I've just added a line there so we're absolutely clear what we're looking at here.

Brazil is not above that line, is it? And Japan, despite being a high income country, quite a long way below that line in terms of those number of calories consumed on average per person.

Okay, so we've looked at one reason why the global demand for food is rising, but we have a second one here which is population increase.

So here we have a graph showing the global population change over time.

And from 2025 we have a prediction by the United Nations.

So the United Nation predicts that the global population will continue to grow until the 2080s.

How old will you be then? So the UN says that the population will peak at about 10.

29 billion in the mid 2080s.

So at this point, we can see that the population starts to flatten off in terms of that global population.

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

Check for you here then, true or false? The UN predicts the global population will continue to increase between now and the year 2100.

Is that true or false? So pause the video to have a think about that one.

Restart it when you want to check your answer.

But remember I want you to explain why.

And if you said false, could you give a bit more detail on that? Well, the answer we had was 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.

Well done if you had that.

So we've looked at overall population change globally, but if we break it down by region, we can see it on this sort of stacked line graph here.

We've got the number of people in each continent and how that changes over time.

The growth in the size of populations around the world has been uneven over time and that is also true for the UN's predictions.

Check for you then, which continent has the largest population today? And if you said Asia, well done.

Now I might have another question for you here.

Here we go.

Which two continents are predicted to see the largest growth in population during the 21st century? And if you said Asia and Africa, well done.

So if we look at population change by region, we can see that at this point Africa's population is still accelerating.

Now obviously that's an average across many countries within this continent, but there are particular countries like new emerging economies like Algeria where the population is still booming.

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

Food production, as we've said, must keep pace with the growth in these populations.

So we've got that second factor having an impact on global demand for food, explaining why global demand for food is rising.

True or false for you then, the global demand for food is rising due to economic development and population growth.

Is that true or false? And why? And if you said true, what was your explanation? Ours was as follows, richer nations consume more calories and their diet is comprised of more meat and dairy products.

Meat and dairy takes a lot of land to produce, plus more people means more mouths to feed.

That links to that idea of population growth, doesn't it? Okay, so practise tasks.

Number one, let's state the UN's prediction for the global population up to 2100.

So can you use those graphs to do that? Secondly, suggest how the trend you have described will affect demand for food.

So suggestion to be made.

And then thirdly, do you agree or disagree with Laura's argument? Her argument is, "Eating a more plant-based diet is a natural outcome of studying geography GCSE." Discuss that with a partner.

Okay, so the first two you're going to need a pen for.

So grab a pen now, pause the video and then restart it when you want to check your answers.

Okay, how do we get on? Our answer to question one was as follows, the UN predicts that the global population will continue to grow until the 2080s.

It will peak at about 10.

3 billion in the mid 2080s.

Then we had to suggest how that trend will affect demand for food.

So we've got, with more people to feed, food demand will increase.

The amount by which food demand increases will depend on how wealthy growing populations are.

Typically richer nations consume more meat and dairy.

And meat and dairy production is less efficient than growing crops as food for people to eat.

Well done if you had something like that.

Now how did you get on with this discussion? What did you think of Laura's argument? I've got to guess what you thought, but let's think about what we came up with.

We thought, well, some people would say true with an understanding greater impact of farming livestock on land use and biodiversity.

So you understand what the impact is of consuming meat and dairy.

Geographers are likely to choose a lifestyle that conserves the environment.

So perhaps having a more of a plant-based diet.

Whereas other people thought, well it's all down to personal preference and perhaps you don't see a link between your studies and what you do at home.

Other people might have thought, well, finding out about how development affects diet does make you wonder if your own choices make a difference or not.

So we think about our own personal choices versus the choices on average across a nation.

So gets you thinking about some of these real issues.

So that was the first part of the lesson, but now we need to move on to the second part.

What factors affect food supply? What factors affect food supply? So if we think about the factors that we need to consider when we're thinking about what affects food supply, there are a number.

So we have climate, water stress, technology or access to technology, pests and disease, conflict, and poverty.

So these are the different factors we're going to consider briefly across the second half of this lesson.

Let's start with climate.

So climate is a physical factor that affects the global pattern of food supply.

And here we can see we've got a choropleth map of precipitation, precipitation for 2023 across the world and we've got total annual rainfall there.

I've also added the equator so we can see where that is.

Rainfall and temperature range are key factors in plant health, drought and flooding are key threats.

And knowing that we can see that across the world, this must have a big impact.

Climate must have a big impact in particular rainfall, must have an impact on the success of growing crops.

Where do you think in the world is most difficult to produce food? Well, if you said arid environments such as hot deserts and cold deserts, you'd be absolutely right.

So here we have a choropleth map of cereal production.

So we're looking at total tonnage of cereal produced.

It's not one particular crop.

So this is a number of crops combined like maize, wheat, rice, barley, and other key crops.

Notice the scale on this choropleth map.

Again, we have the darker the colour, the larger amount of cereal crops produced.

But note the huge range of production total.

So the colour ranges from 1 million tonnes of cereal produced per year to 300 million tonnes of cereal produced per year and above.

Now wheat, barley and oats grow best in temperate climates and we'd expect that something like rice grows better in a tropical climate.

But what about that arid zone we looked at when we looked at the map, the world map of annual precipitation.

How is it that they're producing cereals as well? In North Africa and Southwest Asia that have arid or semi arid climates, water is pumped up from deep underground to irrigate cereal crops or it might be irrigated from river water if we think about the way that Egypt agriculture in Egypt is organised.

But remember that idea that also a key source is coming from deep underground.

Using the Geography Visualizer and satellite imagery, we can zoom into the northwest of Saudi Arabia where the desert has been farmed for crops.

Tayma is a desert oasis.

So it's a settlement in the desert based around natural springs.

It receives 65 millimetres of annual rainfall a year.

But as I say, its population benefits from that natural spring.

Can you spot the fields of crops around Tayma? Well, let's zoom in and take a look.

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.

So this is rock that can bear water and store water for many years.

And hopefully in that image you can see those giant circular fields that are irrigated using an arm that spins.

The traces of the fields that are no longer irrigated are also visible in this recent satellite image.

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

In the 2010s, Tayma's Oasis was drying up and this was true in a number of different places across Saudi Arabia.

So concern about the rate at which the country's water was being used cancelled Saudi Arabia's wheat crop countrywide.

So the government got involved.

Moving out over southwest Asia and thinking about East and South Asia, China and India are the world's largest producers of rice for home and export.

So each country produces greater than 20, sorry, 200 million tonnes a year.

In South, East and Southeast Asia, rice production has increased markedly since the 1960s with use of technology.

Well what kind of technology have they been using? Hybridization is a technique that enables scientists to create new super breeds of plants and in this case crops to produce a higher yield.

So this is a process that started the 1950s and the 1960s.

Combined with artificial fertilisers, some mechanisation, irrigation, and then more recently genetically modified crops that are pest or drought resistant, we've seen a real boon in rice production in these regions.

So true or false for you here? Cereal crops are produced in most countries, though the amount of food grown by farmers varies hugely.

Is that true or false? And I want you to give me some real world examples.

And if you said true, what did you have as an example? We had, for example, India and China produce more than 200 tonnes of rice alone each year while Egypt harvests 10 to 30 tonnes of cereal each year in total.

So we got kind of wildly different total amounts of cereal production there.

Okay, so we've looked at climate and we've looked at technology.

What about pests and disease? They are an environmental factor that is affecting food supply.

And we have an image there of fruit flies.

So in the tropics, key pests include insects such as locusts and fruit flies.

So now locusts you may have heard of, they can consume a crop in its entirety and threaten supply.

Fruit flies cause trees to drop fruits prematurely, reducing food for export and increasing waste.

So they are a menace.

Banana diseases, sorry, cassava diseases and wheat rust are the most harmful types of plant diseases globally caused by viruses, bacteria, or fungi.

In tropical regions, in addition to those diseases that affect the crops, malaria affects humans causing sickness that reduces the number of people available to farm.

And of course climate change may lead to pests and diseases in the tropics spreading beyond the tropics into higher latitudes.

So that's what scientists are trying to model at the moment.

So this is another additional factor that affects food supply.

We also have the factor of conflict.

So what impact does conflict have on food supply? Well, conflict disrupts, so it might disrupt the harvest, for example, if an area's been landmined or it might affect the distribution of food supplies once they've been collected, once they've been harvest within and between countries.

Food may be used as a weapon of war with international aid obstructed.

And I'm sure you can think of real world examples of that in the news.

So if we think about examples of recent conflicts that reduce the food supply, those include Syria from 2011, the Russia-Ukraine conflict from 2023.

And we have the Democratic Republic of a Congo from 2025 onwards where conflict affected the distribution of food supply.

Which of the following are true? I want you to read these through and think about where you're gonna put a tick and then restart the video to check your answer.

And if you said, well the first two are true, wheat, rice, and barley are all cereal crops, and hybrid and genetically modified crops boost harvest, you'd be absolutely right.

Conflict is never a factor in food supply.

That's not right, is it, based on what I've just said.

And pest and disease only affect food supply in the tropics.

Well that's not true.

If you think about countries in the tropics producing food for export to us.

Okay, so we're onto the factor related to poverty now and how that affects food supply.

There's a huge inequality of access to food due to poverty, not least within India's population of more than 1.

4 billion people.

Now here we have an array of dishes, displaying the sort of food that's available to different groups of people within India where there is a huge inequality of income within that newly emerging economy.

While there may be food for the poorest, the poorest may well not be able to afford the food.

However, on a positive note, the number of people living in extreme poverty or in less than $2.

15 a day in India is in fact a third of what it once was in the year 2000.

So some progress made on poverty and how it affects the population in terms of the supply of food.

The share of the population that cannot afford a calorie sufficient diet varies from region to region.

So if we look at this map, we can see some regions that appear to be having a high share of the population that cannot afford a calorie sufficient diet.

And if we think about subsistence farmers, this is a real problem.

So the highest share is in East, West and Central Africa, in this particular data resource.

And where we have a lot of farmers that are small holders with less than two hectares of land, they're deemed subsistence farmers.

But unfortunately these families lack access to most technology.

So they have only the most basic tools and may not have access to infrastructure to irrigate their crops, which means their productivity is gonna be low.

So productivity, and for them food supply is low, but poverty is high.

So this is the impact of poverty on production.

True or false for you here? Lack of technology means many subsistence farmers are trapped in poverty without enough food.

Is that true or false? And why? If you said that was true, what did you have as your explanation? We had the following, using only basic tools and the labour of often poorly nourished family members will not be enough to boost the harvest on their small holding.

Okay, I have a task for you here, so we need to grab a pen.

Sort the factors that affect food supply into these three categories.

So we have economic, we have environmental, and we have the political categories.

Secondly, I'd like you to explain how access to technology is a factor in food supply.

Include irrigation, mechanisation, and hybrids or GM crops.

Okay, and then I have this task, read all about it.

Summarise the impact of water stress on Saudi Arabia's food supply in the mid 2010s in three sentences.

So you need to read this article we have from 2015, and I want you to summarise it in three sentences.

So we have three tasks.

As I say, grab your pen, pause the video now, and then restart it to check your answers.

Okay, how do we get on? So I asked you to sort the factors that affect food supply into three different categories.

We have the economic factors being poverty and technology or access to technology.

Our environmental factors here are climate, water stress, pests and disease, thinking about lots of pests and disease found in the tropics.

And then the political factor there being conflict and where the conflict affects food supply, disrupts distribution of food, for example.

Secondly, you were asked to explain how access to technology is a factor in food supply.

And your answer could include the following: Farmers who have access to technology can increase the size of their harvest by irrigation, which prevents the limiting effects of drought on plant growth.

High yielding varieties of crops created using biotechnology such as hybridization and genetic modification can also boost food supply.

Did you have an answer a bit like that.

We've got our key words in there, haven't we? About irrigation and drought.

And then thirdly, you were asked to summarise the impact of water stress on Saudi Arabia's food supply in the mid-2010s in three sentences.

Now the three sentences we had were as follows, Saudi Arabia's farmers stopped producing wheat in the desert a decade ago due to water stress.

Concerned about the rate at which the country's groundwater was being used up irrigating the crop, the government cancelled wheat production countrywide in the mid-2010s.

Saudi Arabia decided to buy land abroad to produce cereal crops to feed its population.

So it had a complete switch of policy there.

Did you get that into your answer? Well done for having a go at that one.

That was quite a tough one, wasn't it? Okay, so in summary, what have we been looking at? Well, we've been finding out that the global demand for food is rising and it's rising because of two key reasons.

One is economic development, as with increasing affluence, populations consume more calories and more animal protein.

But the other key reason is that population increase.

Though we saw that that doesn't continue all the way to 2100.

We've also had a whistle stop tour of six different factors affecting food supply and those are climate, technology, pests and disease, water stress, conflict, and poverty.

So well done.

I think we've reviewed a lot of information here today and I hope that some of it will be memorable for you.

I'm sure it will be.

Well done for working hard on this lesson, and I will see you again soon.