Lesson video

This lesson is called Eating Sustainably and is from the unit climate change and living sustainably.

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 compare the impacts that different types of foods have on climate change and suggest ways that we might be able to eat more sustainably.

So in our lesson today, we're going to consider a number of key words, and they're listed up here on the screen for you now.

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

In our lesson today, we're going to first of all look at foods and the greenhouse gas emissions that they have before we consider how we might be able to eat sustainably.

So are you ready to go? I certainly am.

So let's get started.

Now we all need to eat food to survive.

You probably know that already, and you'll certainly know that when you are feeling hungry.

But have you ever thought about the food that you are eating and wondered the processes that were involved in producing that food or the effects that those processes have on climate change or how we might be able to eat more responsibly? So let's have a look at this burger and have a look at these questions in relation to that.

So with this burger, the vegetables were grown with fertilisers on land that was probably once forest, but was deforested and converted for farming.

The bun is made of grain and the grain was grown on farmland with fertiliser, and then it's been processed to make bread.

And cows were raised on farmland, fed with crops, and then their meat and their milk was processed to make the burger and the cheese.

And it's possible that the farmland that these cows grew on was originally forest land and therefore the trees have been cut down and the land converted to farmland as well.

In addition to the food, of course, there's the packaging.

All of these items will have been packaged and they will have all been transported from where they were made to where they are served and then sold in a shop.

Now, if we consider this whole process of producing food and all the stages that that involves, we can see that all of those stages cause greenhouse gas emissions.

So greenhouse gases include carbon dioxide and methane.

And when they are released into the atmosphere, we call them emissions.

So what are these stages then? Well, firstly, a land use change.

If the land was forestry and is converted to farmland, then carbon dioxide is released during the deforestation process used to clear the land for farming.

Then when plants and animals are being farmed, they release greenhouse gases, in particular, methane from cows and carbon dioxide from fertilisers, and also from farm machinery.

So if plants are being grown, they may not themselves release greenhouse gases, but some of the processes surrounding managing them will release greenhouse gases.

Then of course, there's the food that farm animals require in order to sustain them and allow them to grow.

And making those foods requires fertiliser and farm machinery.

And both of those things cause greenhouse gas emissions, particularly of carbon dioxide.

The processing involved in turning the raw food products into the food that we can buy and eat requires a lot of electricity.

And by generating electricity, often that produces greenhouse gases including carbon dioxide because most of the time, that electricity is generated by burning fossil fuels which release carbon dioxide into the atmosphere as part of the burning process.

There are also the other aspects of food production, including transporting food around from one place to another in the process.

And by transporting food either in its raw form or in its final processed form, requires usually fossil fuels to be burnt and therefore, carbon dioxide to be released into the atmosphere.

Also, the process of selling food, be that take away food which is ready to eat, or food that we're buying in the supermarket that then has to be cooked at home, all of those things require electricity for things like refrigeration and for the other processes that are going on in the shops like running their tills and their lights and the heating of the buildings.

All those sorts of things require electricity and most of the time that electricity will have been made by burning fossil fuels, releasing carbon dioxide into the atmosphere.

And then of course, producing the packaging that that food has come in, unless it's completely packaging free, that will also have required electricity to make and perhaps release greenhouse gases as part of the materials and how they've been processed.

And so greenhouse gases have been emitted in that part, but also will be emitted when that packaging decomposes because it's either been thrown away or because it is being recycled into something else.

So there are many, many stages in the food production process and all of those stages release greenhouse gas emissions into the atmosphere and therefore all of these stages contribute to the greenhouse effect.

And the greenhouse effect leads to global warming and global warming causes climate change.

So all food production will have some element of greenhouse gas emission contributions.

So which stages of food production involve emissions of greenhouse gases? Your options include land use change, farming, feeding, animals, processing, transport, retail and packaging.

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

Okay, so you should have chosen all of those stages because all of those stages involve emissions of greenhouse gases.

Well done if you did choose all of those stages.

So let's look at this in slightly more detail, because different foods have different greenhouse gas emissions because of the different processes involved in making the foods and the different ways in which they're transported and the different types of land that they might have been created with in the first place.

So you can see in this detailed chart a number of different types of foods listed on the left and then the amount of greenhouse gas emissions per kilogramme of food represented in the bars going across.

And the total number of greenhouse gas emissions per kilogramme listed as the number on the end of the bar.

That total greenhouse gas emissions number is known as the carbon footprint of that food.

So the carbon footprint includes all the aspects of generating that food from land use change to farming, processing, transport and packaging as well, and everything in between.

And so this is the carbon footprint, the amount of carbon that is being released into the atmosphere in the form of carbon dioxide or methane and therefore contributing to climate change.

So different stages of the production process contribute different amounts of emissions to the carbon footprint.

And you can see that for beef, as indicated on the diagram, the amount of carbon dioxide which is emitted into the atmosphere during the farming process of cows is really quite substantial.

And we'll come back to that in a moment.

But for now, who correctly explains what is meant by the carbon footprint of producing a particular food? Is it Alex who says it's the total amount of carbon used to produce the food, or is it Aisha who says it's the total emissions of greenhouse gases while producing the food? Or is it Lucas who says it's the total amount of carbon present in the food after it has been produced? I'll give you five seconds to decide.

Okay, so you should have chosen Aisha, that the carbon footprint is the total emissions of greenhouse gases while producing the food.

Well done if you did choose her.

So going back to this graph, what do you notice about the carbon footprints of meats compared to fruit and vegetables? So look down the list on the left and see how they compare.

Okay, so you should have noticed that meats tend to have a higher carbon footprint than fruit and vegetables.

Now, that's not true for all of them, but it is true for the large majority of them.

So beef, lamb, pigs and poultry and fish, all have greater carbon footprints than wheat, tomatoes, peas, bananas, apples and nuts for instance.

If we go back to beef, we can see that it has by far the highest carbon footprint of all of the different types of food listed on this graph by an enormous amount, by more than twice that of lamb for instance.

And this is because of the emissions which are generated as the cow is farmed.

So you can see on that bar against beef, the really big round section of the bar, which is about the farming part of the process of making beef.

And that is because cows emit quite a lot of methane as they are digesting their grass food and turning it into nutrients that they can use to build their body.

So the meat that we eat or their milk that we can then either drink or turn into other products like yoghourts and cheese.

And if we look at this graph again and have a look at the other end of the graph, we can see that some crops that grow on trees have a negative value for land use change.

So you can see, if you're looking at the green section of the bar that olive oil, citrus fruits and nuts and in particular, nuts have a negative value for land use change.

And this is because these crops are growing on trees.

And so when we're converting land from one use to the use of farming olive oil, citrus fruits and nuts for instance, what we're doing is planting trees to enable that process to happen.

And trees, as they grow, take in carbon dioxide rather than emit it.

And so they're actually removing carbon dioxide from the atmosphere rather than releasing it back into the atmosphere, which is why the land use change value is negative.

So have a quick look again at the graph.

Which non meat product has the highest emissions from land use change? So you are looking at the green bar as part of this and for non-meat products.

I'll give you five seconds to examine the graph and decide.

Okay, so you should have identified that rather sadly, at least in my case, chocolate is the non-meat product with the highest emissions from land use change.

Very sad news indeed for all those chocolate lovers out there, including me.

So let's summarise this first part of the lesson, looking at food and greenhouse gas emissions by considering Izzy's father.

So Izzy's father drinks coffee with cow's milk.

And what I'd like you to do is to firstly tot up the total carbon footprint per kilogramme of coffee with cow's milk that is being produced, and then explain why switching to coffee with soy milk rather than cow's milk would reduce emissions.

So pause a video, look at the graph in good detail and come back to me when you are ready with your answers.

Okay, so what did you put? Well, for the total carbon footprint per kilogramme of coffee with cow's milk, you should have spotted that coffee has a carbon footprint of 17 and cow's milk has a footprint of three and therefore the total carbon footprint is 20 kilogrammes of carbon dioxide equivalences.

And then why would switching to coffee with soy milk reduce emissions? So soy milk has a carbon dioxide equivalent emissions of 0.

9 compared to three kilogrammes for cow's milk.

So it's less than one third of that of cow's milk and therefore we'll be reducing the amount of carbon dioxide and related gases into the atmosphere.

Well done if you were able to both calculate that and add that response to your work.

Good job.

Okay, let's move on to the second part of our lesson about eating sustainably.

So we've just seen how if we change from using cows milk to soy milk for instance, we can reduce the emissions of greenhouse gases.

So remember, the greenhouse gas emissions are the amount of greenhouse gases that are released into the atmosphere and this is driving climate change.

So if we can reduce this by some fairly simple changes, then we will reduce the amount of climate change that will be happening on earth.

And this means that we will also be able to eat sustainably.

So a sustainable activity is one that can be carried out over a long period of time with little or no negative impact on the environment.

And if the product that we are eating more of has a lower carbon footprint than one which we had eaten previously, then we can say we are making a more sustainable option in our food choice, for instance.

Now living sustainably is a really important long-term goal for the human race.

We all need to live more sustainably and support all of the other things that we do in sustainable ways as well.

So if we can live and eat sustainably, it will help us to limit the amount of climate change that is happening and it will also help us to meet our own needs without damaging the planet and compromising the ability of future generations such as our children and our grandchildren and those of other parts of the world, those children and grandchildren of other people around the world to meet their needs.

So it's not just about us and our life, but it's about the life of our future children and grandchildren and generations beyond that as well across the entire planet.

And anything that we can do to make our lives more sustainable and reduce our carbon footprint will help us to achieve this goal.

So what is a sustainable activity? Is it A, an activity that has to be carried out over a long period of time? B, an activity that causes greenhouse gas emissions.

Or C, an activity that can be carried out over a long period of time with little or no damage to the environment? I'll give you five seconds to decide.

Okay, so you should have chosen that definition C is correct for a sustainable activity, which is an activity that can be carried out over a long period of time with little or no damage to the environment.

Well done if you chose that.

So going back again to this graph, we can see that there are lots of different elements to how food is produced.

So let's focus in on transport.

This is the red bar.

What do you notice about the emissions from transport of food? So look at the red in all of those different food types.

Well, you can see that it's a small proportion of the total emissions for most foods.

And even the most heavily carbon footprinted foods have a very small proportion of their carbon footprint given over to transport.

So what does this mean then? It means that eating locally produced food is a good thing, but it will only provide a very minimal impact on the total carbon footprint of our food.

So whilst eating locally produced food is definitely a good idea, it is not going to make a substantial difference to your personal carbon footprint.

What will have the biggest impact, however, is eating less meat and more fruit and vegetables because you can see that the vast majority of fruit and vegetables have very low carbon footprints compared to the vast majority of meat products meat.

And if we do continue to eat meat, we can have the biggest impact on reducing our carbon footprint by avoiding eating beef because this has by far the greatest carbon footprint of all of the different food types listed in this graph.

And if we do carry on eating meat, the best options are fish and poultry such as chicken and turkey because you can see that poultry has a 10th of the carbon footprint of beef and fish, which is caught from the wild, has a 20th of the carbon footprint of beef.

So making small changes like reducing the amount of beef that we eat and swapping it for poultry or fish will make quite a substantial change to your carbon footprint.

Another thing that we can do to eat more sustainably is to reduce the amount of food waste that we create.

Because if we throw away edible food, what we are doing is replacing it with new food and that edible food still remains.

And that means that our carbon footprint becomes both the emissions from the food that we are throwing away plus the emissions for all the new food that we are eating in its place.

So you can see how reducing food waste is a really important thing to try and do to reduce the carbon footprint of our food and eat more sustainably.

Now, I know from experience that this is a really hard thing to do and sometimes it's easier to reduce food waste than others, especially if you are really busy or have other commitments and constraints on your time.

But if we can eat up more of our leftovers, turning them into new meals or perhaps freezing them until we are ready to eat them, if that's possible, we will be able to improve the sustainability of our food and therefore reduce our carbon footprint of our food as well.

It's quite tricky to do, but it's certainly something to try for.

So starting with the action that has the most impact, could you put these actions in order of their impact upon reducing emissions? Your options include using plant-based milk instead of cow's milk, eating chicken instead of beef, eating a vegetarian diet, and eating locally produced foods.

I'll give you five seconds to decide.

Okay, so in order of impact with starting with the action that will have the most impact, you should have chosen letter C, eating a vegetarian diet as your first option, then eating chicken instead of beef, followed by using plant-based milk instead of cow's milk, and then eating locally produced foods as your fourth option.

Well done if you got them in the correct order.

So what I'd like you to do in the last part of our lesson to finish this part up is to write a letter to the head teacher of our school and suggest ways that the school could help everybody to eat more sustainably.

And I'd like you to include ideas about the carbon footprint and the emissions of different types of food in your response.

So make it nice and firm, but polite and include some facts and figures if you can as well.

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

Okay, let's see what you've written.

So you might have included suggestions such as putting up posters or using assemblies to help people understand how choosing different foods can reduce greenhouse gas emissions, changing the types of foods available and reducing waste in the cafeteria, recommending eating less meat and more vegetables and choosing fish or chicken instead of beef.

And maybe you've included other ideas which might impact particularly the school canteen or parents at home and how they are feeding their children.

I'm sure you've come up with lots of ideas, including the ones on the screen.

Just make sure that your ideas are talking about the carbon footprint, carbon dioxide emissions from different types of foods and how we can eat more sustainably.

Well done.

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

And in our lesson today, we have seen how producing food for humans and for other animals to use includes lots of resources.

And these resources include land and fertilisers and fuels, and all of these release greenhouse gases that lead to climate change.

Things like land use change, farming, processing, transport, retail and packaging, all add to the carbon footprint, but are not necessarily very easy to identify when we're considering food because of the way that we don't really see our food being made a lot of the time.

Now, meats have generally a higher carbon footprint than vegetables and fruit, and we've seen that with a lot of data.

And we've seen that food production is more sustainable when it has a small and negative impact on the environment, for example, by reducing emissions of greenhouse gases.

We've also seen how changing what we eat and reducing food waste can help us eat more sustainably and also reduce greenhouse gases emissions.

So there's plenty of things to think about from this lesson and maybe you can go home and have a conversation with the people that you live with about the types of food that you eat and what you might be able to do to eat more sustainably.

So good luck with any conversations that you have and any attempts to change your diet as well.

Make sure you are sensible when you are doing that.

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

Bye.