Lesson video

This lesson is called Climate change and food production and is from the unit Climate Change and biodiversity.

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 food production is affected by and contributes to climate change, and how changes in our diet can help to limit climate change.

But this is quite complicated, so we're going to unpick that in a bit more detail.

Now, in our lesson today, we're going to come across a 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 first of all look at food production and greenhouse gas emissions.

So where do greenhouse gas emissions get produced through this process of making food? And then we're going to have a look at how we might change our diet to reduce climate change.

So are you ready to go? I certainly am.

So let's get started.

The total population of humans on Earth has increased above eight billion people.

In fact, it reached that mark in 2022.

And that means there is an awful lot of people who need feeding across the planet.

And feeding all of those people is already a challenge.

Now, if we add into the mix the increasing average surface temperature of the Earth caused by global warming, we can start to appreciate how global warming and an increasing population of humans will make it ever more difficult to feed all of the people on Earth well.

So this is a very real problem that we are trying to get to grips with and it is challenging because it has many different things impacting on it, and we're gonna explore some of those in our lesson today.

So let's first of all take a look at what the greenhouse effect is and the role of greenhouse gases in that process.

So greenhouse gases include carbon dioxide, methane, and water vapour.

And these are present within our atmosphere.

And what they do is help to keep the atmosphere and the Earth warmer than they would be if those gases were not present.

And this process of keeping the Earth warmer than it would be otherwise is called the greenhouse effect.

So it's where sunlight is radiated to Earth through the atmosphere and the greenhouse gases help to trap more of the heat in the atmosphere than would otherwise be kept.

And that helps to keep the atmosphere and the Earth warmer than it would be.

Now, 99.

9% of scientists believe that the emissions that we are releasing of greenhouse gases from all of the different types of activities that we are undertaking whilst living on the planet are enhancing the greenhouse effect because we are putting more greenhouse gases into the atmosphere.

And so there are more of these gases able to trap heat in the atmosphere and this is causing global warming.

And global warming is where the Earth is heating up beyond where it ought to be.

So the Earth is now hotter by at least one and a half degrees more than it should be.

And global warming drives climate change because it is driving changes in our long-term weather patterns because of this extra energy, this extra heat that is trapped within the atmosphere by the greenhouse gases that we are emitting.

Now, as climate change continues, which it will do as global warming continues to increase, which will continue to happen because we are continuing to add greenhouse gases into the atmosphere.

So these are all linked to one another.

So as climate change continues to increase, extreme weather events will become more frequent.

And producing food is difficult enough on a good day.

But when we have extreme weather events occurring more frequently, then it becomes even harder to produce the amount of food that is required to feed all of the humans on Earth.

Now these weather events, these extreme weather events include extreme heat in some places.

So not everywhere will become hotter, but some places will experience extreme heat.

So this is hotter than normal temperatures lasting for longer than normal lengths of time.

And this will lead to drought and it will also lead to wildfires.

And we are already seeing this happen across the planet.

In other areas, other types of extreme weather will happen.

So in other areas, extreme rainfall will happen and extreme storms, so high winds and high rain, and this will cause flooding, and growing crops in flooded areas, as you might also have seen on the news over the last few years, is also extremely difficult.

So these extreme weather events are already happening and they are already making it very difficult to grow crops enough to feed all the humans on Earth.

So climate change means that everywhere we grow food will get hotter and drier.

True or false? Okay, so that is false.

Can you explain why though? So you should have explained that by saying that climate change is the long-term shift in weather patterns.

And some places will get hotter and drier, but not everywhere because other places will have more frequent storms, rain and flooding.

Well done if you got that.

So human activity is contributing to climate change, and producing food is one of the activities that is contributing to climate change because many of the different stages involved in the production of food, from growing it to getting it to our homes ready to eat it, many of the different stages involved in that long process cause emissions of greenhouse gases to be released.

So what are these stages? Well, they include land use change, so changing land from forest land to farmland for instance.

So the deforestation of land releases lots of carbon dioxide into the atmosphere as the land is cleared.

Also, farming itself releases emissions of greenhouse gases into the atmosphere, partly through animals.

Cows in particular, because of the way they digest food, release enormous quantities of methane into the atmosphere.

And then other aspects of farming also release carbon dioxide into the atmosphere.

For instance, fertilisers, both the production of fertilisers and the use of them on the land, plus also the use of farm machinery like tractors and combine harvesters.

These all burn fuel which releases carbon dioxide and other greenhouse gases into the atmosphere.

Then the process of feeding animals.

This involves producing crops or fertilisers for crops and using farm machinery that all release carbon dioxide and other greenhouse gases into the atmosphere, just like it does when those foods are being made for us.

There are other aspects to food production as well.

The processing of the raw food, the raw, fresh harvested food, be that meats or plant or fungi-based produce.

All of these require processing and processing that food into the things that we buy off the shelf.

And the packaged goods of food all require electricity to be generated in order to run those production processes.

And often that electricity has been generated using fossil fuels and therefore creating greenhouse gas emissions.

And then there are other processes involved in production of food, such as moving it from farm to processing centre, from processing centre to the shops and from the shops to our homes.

And most of these processes will release carbon dioxide and other greenhouse gases into the atmosphere as fossil fuels are burnt in petrol and diesel engines of cars and lorries to transport food from one place to another, for instance.

And then the process of selling that food to us in supermarkets.

Well, the shops have to have lighting and heating and also refrigeration.

All of these things require energy and often it is generated using fossil fuels which produce greenhouse gases.

Finally, we also need to consider the packaging that our food comes in.

All of the packaging requires some level of processing, whether it is paper or plastic or some other type of packaging.

All of it needs to be made and therefore is very likely to have been made by processes that release greenhouse gases into the atmosphere.

So producing food is a complex process and it is also one that releases great quantities of greenhouse gases into the atmosphere.

So if we have a look at a variety of different food types, we can see the total number of emissions that are released for that type of food, and that is known as its carbon footprint.

So on the graph there, the carbon footprint for a kilogramme of beef is 60 kilogrammes of greenhouse gases.

So for every kilogramme of beef that is produced, 60 kilogrammes of carbon dioxide and other greenhouse gases are released.

Each bar is made up of the various different stages involved in producing food.

And each of those different stages contribute different quantities of greenhouse gas emissions to the total carbon footprint for each type of food.

So you can see the size of each of those different coloured sections of the bars varies depending on which type of food it is.

And you can see that for beef, the farming section is by far the largest section.

Now this is a complex picture because there are lots of different stages to food production and they each have different values depending on what type of food it is that we are talking about.

But understanding those emissions will help us to make better food choices.

It's complex, but it is doable.

So let's have a look at tomatoes.

So this is the greenhouse gas emissions from producing one kilogramme of tomatoes.

Land use change produces 0.

37 kilogrammes.

Farming produces 0.

71 kilogrammes.

The processing of tomatoes is very minor of only 0.

01 kilogrammes.

Transporting tomatoes involves 0.

18 kilogrammes, and retail 0.

02 and packaging 0.

15 kilogrammes.

And that in total is 1.

4 kilogrammes of greenhouse gas emissions.

So for every kilo of tomatoes, 1.

4 kilos of greenhouse gases are emitted.

Now tomatoes can be grown outside in hot countries like in Spain and Italy.

But if we are buying in the UK tomatoes that have been grown in Spain or Italy, we have to transport them to the UK.

However, if we look at the emissions from transport for the tomato, we can see that the carbon footprint for transport is a fairly small proportion of the overall carbon footprint.

However, if we were to review this graph extract for tomatoes that have been grown in the UK, we would see that the total greenhouse gas emissions would be greater because those tomatoes would have to be grown within a heated greenhouse and that would increase the emissions from the farming part of the graph enormously.

So there's a payoff here.

If we grow tomatoes in the UK, we will need to heat the greenhouses that they are being grown in and that will increase the farming emissions total.

But if we eat tomatoes that have been grown in Spain and Italy, they don't need heated greenhouses.

In fact, they can be grown outside, not even in greenhouses.

And so that section from farming will be much less, but transport will be increased.

However, increasing transport for tomatoes grown abroad will still be less than the emissions made by growing tomatoes here in the UK in a heated greenhouse.

So which stages of food production involve emissions of greenhouse gases? Land use change, farming, feeding animals, processing, transport, retail or packaging? I'll give you five seconds to decide.

Okay, so you should have said that all of these stages of food production involve emissions of greenhouse gases.

Well done if you did.

Okay, let's consider this again.

So Izzy's aunt is in the supermarket and she can choose tomatoes grown in Spain or in the UK.

And she says, "I've heard that buying local food is best, so I'll buy the tomatoes grown in the UK, they'll have lower emissions than the ones shipped over from sunny Spain." So can you explain to Izzy's aunt why the total emissions could be higher for the tomatoes grown in the UK? So pause the video and come back to me when you are ready.

Okay, let's review your work.

So your explanation to Izzy's aunt might have included that it is hot enough in Spain to grow tomatoes outdoors and that transporting them to the UK is a small proportion of all of the emissions that are released when tomatoes are being grown.

However, tomatoes grown in the UK might have been grown in a heated greenhouse and this will result in a large increase in the emissions during the farming stage.

So it's important to think about emissions from all of the stages of food production and not just from transport when considering which foods to purchase and from where.

Well done if you've got all of those points.

Do add to your work if you need to.

Okay, let's move on to having a look at how changing diets could reduce climate change.

So there are more than eight billion people living on planet Earth now, and providing food for all of those people is very difficult and becoming harder because of climate change.

So in order to be able to produce all the food that will be required to feed all the people living on planet Earth, we must limit climate change.

And in order to do that, we must reduce the emissions of greenhouse gases.

And many of these emissions come from food production itself.

And we've seen that that is a complex process with many different stages.

All of those stages contribute to emitting greenhouse gases.

And so changes to all of those stages could benefit climate change.

Now, if we are able to reduce the amount of carbon being released from a process, it is called decarbonization.

So what we need to do is decarbonize the food industry and all of those processes within it.

Now that's a really big task, but perhaps we can chip away at that in lots of different ways.

The problem is though, that most of us are not responsible for the production of the food that we eat.

So what can we do as individuals to impact positively on climate change through our food choices? Well, let's go back to that graph and we can see the footprint, the carbon footprint for all of these different types of food.

So the best way that we can reduce greenhouse gas emissions is to eat less meat and eat more fruit and vegetables instead.

And some of those meats are highlighted in blue on the graph and some of those vegetables and fruits are highlighted in green on the graph.

And you can see that, overall, meats tend to have a higher carbon footprint than fruit and vegetables.

That's not true for all of them, but it is true overall.

So one change that we could immediately make is to buy and eat less meat and buy and eat more fruit and vegetables.

And if we do that, food producers will rear fewer animals and make fewer meat-based products.

And all of that will contribute to reducing emissions.

So let's just summarise that.

You can only choose the words fruit, meat, and vegetables.

So how will you fill it in the gaps of this sentence? I'll give you five seconds to decide.

Okay, so the best way to reduce greenhouse gas emissions from what you eat is to replace meat with fruit and vegetables.

Well done if you got all three words in the correct locations.

So let's go back to this graph again.

If we choose to eat meat, then we need to make some very smart choices about which types of meat we eat in order to be able to reduce emissions.

So if we eat beef and lamb, the cows and the sheep that we have reared in order to produce that meat have released an enormous amount of greenhouse gases whilst they were growing.

And that's because cows and sheep are ruminant animals.

They eat grass and they have to use microorganisms in their gut to digest that food in order for them to be able to turn it into useful nutrients for their body to use.

And that process of rumination, the processing of the grass within their digestive system, produces an enormous amount of methane.

And the problem with methane is that methane is an even more powerful greenhouse gas than carbon dioxide is.

So having more methane in the atmosphere is even worse for climate change than having more carbon dioxide.

However, pigs and poultry are not ruminant animals and therefore they have a lower number of emissions from the farming section of their total greenhouse gas emissions.

And you can see that in the graph there.

The brown section in the bars for pig and poultry meats are much smaller than they are for beef and lamb because of the way they digest food.

So that's one way, that's one change that we could make.

Another change is by eating fish.

Now the emissions for fish are lower than those for meat.

Wild fish has the lowest of all of the emissions for animals, and that's because the greatest number of emissions comes from the boat vessels, the fishing vessels themselves, which went out into the sea to catch the wild fish in the first place.

Compare that to farmed fish, like farmed salmon, for instance, and you can see that the farming section of their emissions is greater, and that's because of the fact that they are bred and reared within fish farms, which themselves have a higher carbon footprint than the fish out in the wilds of the ocean.

But together, fish have lower emissions in total, a smaller carbon footprint, therefore, than all of those other farmed animals, beef, lamb, pigs, and poultry.

So raising cows, sheep, pigs and chickens and turkey all comes with a larger carbon footprint than fish does.

There are other changes that we could also make.

So for instance, some plant-based products have high emissions and this is because of the land use change that has happened in order to be able to grow those crops in the first place.

So chocolate, coffee and palm oil all have high land use change emissions because forest land has been destroyed so that these crops can be grown instead.

And this significantly impacts on the carbon footprint for those crops.

And you can see that in the graph, the green sections are significant for these three crops.

However, some crops that grow on trees have negative land use change emissions.

So olive oil, citrus fruits and nuts all have negative emissions for land use change.

And you can see that the green sections of those parts of the graph are sticking out on the other side of the zero line.

That's because they are negative in value and that's because these crops are growing on trees and the trees have been planted on land that was previously used for a different type of agriculture like growing wheat, for instance.

And therefore, by replacing crops such as wheat and barley with trees, we are enabling more carbon dioxide to be taken outta the atmosphere because we are growing trees, and trees are removing large quantities of carbon dioxide during photosynthesis in order to grow and put down the amount of material needed to grow the actual tree, the tree bark and the wood and so on.

And so olive oils, citrus fruits and nuts all have negative land use change values because of the impact of changing land from farmland back into a form of forest land.

So starting with the lowest, can you put these diets in order from the lowest to the highest carbon footprint? So the options include: a diet of farmed fish and vegetables, a diet of lots of beef and lamb, a diet of poultry and vegetables, a diet of vegetables, fruit and nuts, and a diet of wild fish and vegetables.

I'll give you five seconds to think about it.

Okay, let's put these in order from lowest to highest carbon footprint.

So you should have started off with the diet of vegetables, fruit and nuts being the lowest and then chosen the wild fish and vegetables, then the farmed fish and vegetables before the poultry and vegetables, then the beef and lamb diet.

Well done if you've got them in the correct order.

So let's summarise how changing diets could reduce climate change.

That's quite complicated, but these students have said "We don't have any choice in the food we eat at home.

We just have to eat what we're given.

So what can we do to help reduce the carbon footprint of our diets?" So can you help Lucas, Jun, and Aisha to write a letter to their parents to explain changes in their diet and why this could help to limit climate change? So pause the video and come back to me when you are ready.

Okay, let's review your work.

So in your letter you might have said that the emissions of greenhouse gases from food production are contributing to climate change and this will make food harder to produce.

So that's setting the scene.

You might also have said that changes in diet can help to reduce emissions.

So that's the reason to do it.

You could have also included some data, such as beef having the highest emissions, followed by lamb, then poultry, then fish.

And so if we replace meat with vegetables, fruits, and nuts, this will help to reduce the emissions from our food and to reduce the impact on climate change.

And you could have put all of these ideas and maybe some other examples into your letter.

So well done.

If you've included any other points and if you've missed any of those key points out and haven't got alternatives which are equivalent, then you might want to add them into your letter in the appropriate place.

But well done.

Okay, we've reached the end of our lesson now and what we've seen is that food production is at risk because of global warming leading to climate change.

And this is causing extreme weather events to become more common, which is making it more challenging to produce food.

Now the emissions of greenhouse gases come from lots of different activities that humans undertake across the globe, but many of them come from the variety of different activities involved in food production.

And these include land use change, farming, feeding animals, transport, retail, and packaging.

And all of these contribute to the carbon footprint of foods.

And if we change our diet, we can help to reduce the emissions from food production and therefore limit climate change.

And if we compare different foods and the different parts of the food production process when we are considering which foods to include within our diet, this will help us to understand the impact of our food choices.

It's a complex picture, but it's worth investigating because it could really make quite a significant change to climate change.

So I hope that's given you lots of things to think about and plenty to discuss with the people that you live with around the dinner table.

So thank you very much for joining me today and I hope to see you again soon.

Bye.