Lesson video

This lesson is called "Impacts of Transport on the Greenhouse Effect," and is from the unit "Climate Change and Greenhouse Gases." 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 impact of different types of transport on the greenhouse effect, and we're gonna come across a number of keywords in our lesson today.

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, consider the types of emissions that come from the types of transport that we use to get around.

Then we're going to consider the emissions from making transport, before we consider, and compare, different types of transport with each other.

So are you ready to go? I certainly am.

Let's get started.

Now, when we move around the country, around the world, we use transport, and most of the transport that we use burns fuel.

And when we burn fuel, we produce greenhouse gases, and release them into the atmosphere.

We also release other polluting gases and particulates.

So particulates are solid particles, or liquid droplets, that are released into the atmosphere, and we'll look at them in a little bit.

So most types of transport burn fuel in engines in order to enable them to move, through the sky, on the sea, or on our roads, or rails.

We are increasingly transferring to electric motors, but we are a long way from transferring all of our transport to that type of engine.

So if we have a look at all the greenhouse gas emissions that are produced by the UK, we can see that about a quarter of all of those greenhouse gas emissions are produced by transport, as you can see in that blue segment of the pie chart.

And if we zoom in to that blue segment, and have a look at all the different types of transport that we use in the UK, we can see that about two thirds of those greenhouse gas emissions from transport are being released by traffic on the roads.

About a sixth is released from flying, and the rest is from shipping, rail, and other non-road use.

So you can see where the bulk of our greenhouse gas emissions from transport are being emitted from, from road traffic, and from flying.

Now, particulates are tiny little pieces of solid particles, or liquid droplets, that are suspended in the air.

And often include water droplets, which is what makes exhaust fumes visible.

So often they are invisible.

Most particulates actually are invisible.

We just can't see them.

But some are.

And most particulates are harmful to our health, particularly people who already have a lung condition, such as asthma, or emphysema, COPD, or bronchitis, something like that.

If you already have a lung condition, then particulates can make it worse.

So true or false? Burning fuel in engines produces invisible particles of solids that pollute the air.

Okay, so you should have said that that is true.

And that is true because burning fossil fuels produces particulates.

These are tiny, solid particles, and liquid droplets, and many of them are far too small to be seen, and many of them are invisible.

Well done.

Now, diesel, and petrol, engines produce particulates, greenhouse gases, and other pollutants.

So a pretty potent mix of all of these things.

But the amount of each of these things varies with the vehicle.

Now, electric vehicles, such as electric cars, vans, and trains, don't produce particulates or greenhouse gases, because they are using electricity to move around, rather than burning fuels.

However, if the electricity was generated by burning fuels, then the particulates will have been released just slightly upstream of the vehicle.

And unfortunately, just over a third of UK electricity generation does do exactly that.

It is generated by burning fossil fuels, and therefore particulates, greenhouse gases, and other pollutants will have been released into the atmosphere, just not necessarily by the vehicle at the time that it is moving.

Now, since 2022, we have made a great move to using electricity generated by renewable energy resources, and more than 40% of the electricity generated in the UK is now from renewable energy resources as standard.

And in 2024, that increased to more than half of the electricity generated, for the first time ever.

And this value is increasing rapidly.

So if we can use renewable energy to generate electricity to power our vehicles, then we can reduce the amount of greenhouse gases that are being emitted by transport, and that is certainly a good thing.

However, there are pros and cons to using electric vehicles, and if you have an electric vehicle at home, you may well have heard discussions, by the adults in your family who have bought that vehicle, as to the pros and cons of them.

So usually electric cars are more expensive to purchase than petrol cars.

However, they are usually cheaper to run than petrol cars, because the cost of electricity is usually much less than the cost of petrol for every mile that the car is driving.

Charging the car can be quite a trouble too, because nearly half of all UK households do not have a driveway, and therefore it's very difficult to charge an electric car.

Now, electric car charging stations are becoming increasingly available, in both residential areas, and housing estates, and also in other places, like shopping centres, in their car parks, and in service stations along the motorway.

But nevertheless, it can still be much harder to find a charging station than it can be to find a petrol station.

The infrastructure is still being developed.

So which of the following is an advantage of using an electric car compared to a petrol car? Is it A, it produces more greenhouse gas emissions, or B, it is usually cheaper to buy, or C, it is usually cheaper to run, or D, it is easier to charge overnight on a driveway compared to refuelling a petrol car.

I'll give you five seconds to decide.

Okay, so you should have chosen that the advantage of using an electric car, compared to a petrol car, is it is usually cheaper to run.

Well done if you chose that option.

So what I'd like you to do is to list some of the advantages of an electric car, or a petrol car, or both of them, compared to other types of transport.

So how are they better than other types of transport? Consider electric cars separately from petrol cars, and them both, in the column, in the middle.

So pause the video, and come back to me when you're ready.

Okay, let's check your work.

So advantages of electric cars include that they are typically cheaper to run.

They do not emit greenhouse gases, or particulates, and they can be easy to charge on a driveway.

The advantages of petrol cars is that they are typically cheaper to buy.

It's very easy to find a petrol station, and they are very quick to refuel.

And the advantages of both types of transport are that they are reliable, convenient, and provide the freedom to travel whenever you like.

So, well done if you've listed all of those points, do add to your work if you've missed anything out, though.

And well done.

Okay, let's move on to consider how vehicles are made.

So building a vehicle needs energy and resources, and maybe you've seen inside a vehicle factory.

They're absolutely fascinating places.

Now, energy, and resources, usually, or at least often, means greenhouse gas emissions.

So when might greenhouse gases be emitted? Well, greenhouse gases may be emitted when building a vehicle when the resources are extracted from the ground in the first place.

So when we're mining metals, and removing plastics from the ground, then greenhouse gases are likely to be being used in order to extract those resources in the first place.

And then cleaning those materials up, and turning them into actual materials that can be used within the vehicle itself.

So producing those materials before they are assembled, also requires energy.

Making various different parts, of which there are thousands for any vehicle, all requires energy.

And then putting them all together, in the right order, at the right time, is an incredibly complicated process, and requires an awful lot of energy in order to be completed properly.

So that's when a vehicle is being put together.

But what about at the end of the vehicle's life? So when a vehicle has run its useful purpose, maybe it's just worn out, or perhaps it's been involved in an accident on the road for instance, and it's now no longer able to be used, then some of the parts of the vehicle are likely to become waste, and other parts are likely to be used as spares.

Now, if the vehicle is well and carefully designed, it can be much easier to recycle it at the end of its life, but that does require quite a lot of very careful planning.

Now in the UK, it is a requirement that at least 85% of the mass of a vehicle must be recycled.

The rest can go to waste, to landfill, but at least 85% of it has to be recycled.

So how might it be recycled? Well, the metal can be remelted, and reused to make new steel, to make a new car, for instance, or maybe something else out of metal.

The interior fabric can be shredded, and used to make home furnishings, the stuffing in sofas, and cushions, and things like that.

Some of the plastics in the car can be recycled, and turned into new products, of a variety of different types, depending on what type of plastic it is.

The tyres can be used to make surfaces for artificial sports pitches and children's playgrounds.

You've probably been to a playground, or maybe your school has a playground, which is a little bit bouncy underneath itself, and that will be made of recycled car tyres.

There are many, many different precious metals contained within a vehicle, in particular within the catalytic converters, which are used to clean the exhaust fumes before they're released into the atmosphere.

And those precious metals can be reclaimed, re-harvested, and then reused in new catalytic converters, for instance.

And the glass in the windows can be reused to make new glass products.

In fact, glass is quite easy to recycle.

So lots of the car can be recycled into many different new things.

So what proportion of a car is not recycled in the UK? Exactly 15%? Exactly 85%? Less than 15% or less than 85%? I'll give you five seconds to remember.

Okay, so you should have said that the proportion of a car that is not recycled in the UK is less than 15%.

Well done.

So what I'd like you to do now is to match the material in an end of life vehicle, listed on the left, with a product that it can be recycled into, listed on the right.

So how are you going to match those up? Pause the video, and come back to me when you are ready.

Okay, let's see what matches you made.

So, you should have matched: the window glass to a new glass product, the interior fabric to fillings for furniture, tyres for playground surfaces, body work for new steel products, and the metal in batteries for new car batteries.

Well done, if you've got all of those joins correct, but do correct your work carefully, and neatly, if you've made any mistakes.

Well done.

Okay, let's move on to the last part of our lesson comparing different types of transport.

Now we know that we need to reduce greenhouse gas emissions from transport, because by doing so, we can slow global warming.

And you can see that if we manage to do that, the increase in average surface temperature on earth will start to slow eventually.

If we manage to reduce other greenhouse gas emissions, then we could possibly even reverse global warming, which would be an absolutely incredible achievement.

Now, different types of transport emit different amounts of greenhouse gases.

And you can see there in the graph how much greenhouse gases are emitted, per person, per kilometre of travel, for planes, different types of cars, rail, and coach travel.

And you can see that the largest emitter is planes.

So travelling by plane emits the greatest quantity of greenhouse gases.

And travelling by coach emits the least.

Now interestingly, the equivalent figure for travelling on the Eurostar, which is in an electric train, is only 5.

5 grammes.

So that's by far the least polluting type of transport in our list.

Now, there are things that we can do to reduce the emissions that are being made when we travel, and one of the things that we could do is to car share.

Now, if we car share with two people, we can reduce our emissions, from 139 grammes per kilometre of travel down to 114 grammes per kilometre.

And if we have four people in the car, then it goes down to 60 grammes per person, per kilometre.

However, we don't do a lot of car sharing in the UK, because on average, each car contains 1.

6 people.

Now obviously you can't have 0.

6 of a person, but on average that's how many people are in each car, on the roads, at any one time.

And so that means that actually that car average in the graph is for 1.

6 people in a car.

So if we then reduce it down to only one person being in the car, the driver, the amount of greenhouse gases, which are being emitted per person, per kilometre, increases to 222 grammes, much more than the plane.

And if we compare that to a four people in a car, electric car, that has only 11 grammes of greenhouse gas emissions.

So you can see that if we had a fully loaded electric car, compared to a single person petrol car, then we are making a significant reduction in greenhouse gas emissions.

So which mode of transport results in the fewest greenhouse gas emissions for two people making the same journey, train, plane, or petrol car? I'll give you five seconds to decide.

Okay, so you should have said that the mode of transport that will release the fewest greenhouse gas emissions for two people is the train.

Well done, if you chose that.

So let's have a look at planes now.

Now, planes release exhaust fumes, and they are warm and moist.

And because the plane is flying very high, and the air is very, very cold, when you are very high up in the atmosphere, then the warm moist exhaust fumes can produce ice crystals, and you will have seen them in the sky, and they're called contrails.

Condensation trails, that's what that's short for.

So contrails are formed when the exhaust fumes from planes, which are warm and moist, crystallise into ice crystals behind the plane.

Now, contrails do two things.

Firstly, they reflect radiation from the sun back out into space.

So they actually reduce the amount of sunlight coming down to earth.

And that's what clouds do as well, they do the same thing, they also reflect sunlight back into space.

However, they also add to the greenhouse effect, both day and night.

So whether it's sunny or not, they are adding to the greenhouse effect.

And the impact that they have on the greenhouse effect when you remove the reduction in radiation from the sun, from the contribution that they make via the greenhouse effect, means that actually contrails overrule, add to, the greenhouse effect, because the amount of sunlight that they reflect back into space does not equal the amount of energy that is being trapped by the greenhouse gases in the contrails themselves.

So if we go back to that graph, about the greenhouse gas emissions per person per kilometre, and add contrails onto the plane emissions, because they weren't included originally, we can see that, actually, travelling by plane releases 270 grammes of greenhouse gas emissions per person per kilometre, much, much greater than any of the other forms of transport, even if we do change the values for the car up to being one person in the car, rather than 1.

6 people per car.

Now interestingly, if we just adjusted 3% of the routes for the flights that have been taken around the world, we could halve the impact of the contrails on the greenhouse effect.

So it really wouldn't take an enormous amount of change.

Only 3% of all of the routes flown around the world would need to be changed for the impact of contrails to be halved.

That's really interesting.

So how do contrails affect the greenhouse effect? Do they A, reduce warming by reflecting the sun's radiation? B, reduce warming by acting as a greenhouse gas, C, increase warming by reflecting the sun's radiation, or D, increase warming by acting as a greenhouse gas.

I'll give you five seconds to decide.

Okay, so you should have said that contrails affect the greenhouse effect by both reducing warming by reflecting the sun's radiation back into space, and increasing warming by acting as a greenhouse gas.

Well done, if you got both of those options.

And overall, the contrails actually add to the greenhouse effect, because they act in a greater way as a greenhouse gas than is reduced by the reflection of the sunlight.

Well done, if you got both of those points.

Okay, let's summarise this last part of our lesson, by comparing the impact of electric cars, and planes, on the greenhouse effect.

So using the grid, can you say how electric cars impact the greenhouse effect, how planes impact the greenhouse effect, and how they both impact the greenhouse effect? So pause the video, and come back to me when you're ready.

Okay, let's check your work.

So the impact of electric cars on the greenhouse effect is that electric cars have no greenhouse gas emissions from the electric motors, but some emissions may be released when the electricity is being generated, and therefore there is a smaller addition to the greenhouse effect, whereas planes release greenhouse gases from the engines, and the contrails also add to the greenhouse effect.

So they have a larger addition to the greenhouse effect, and for both of them, they both cause some greenhouse gas emissions, which adds to the greenhouse effect.

So just review your work over, and make sure that you've got most of those salient points.

Do add anything that you might have missed.

And well done, again.

Okay, we've reached the end of our lesson, and what we have seen today is how burning fuels produces greenhouse gases, other polluting gases, and particulates.

And these particulates are tiny particles of solids, or droplets of liquids, that are suspended in the air.

We've also seen how electric cars usually cost more than petrol cars to buy, but are cheaper to run.

And we've also seen how the motors in electric cars do not emit greenhouse gases, but generating the electricity may do, if it isn't made from renewable resources.

We've also seen how greenhouse gases are emitted when resources are extracted for making the vehicle, producing the materials, making the parts, and putting them all together on the assembly line.

And we've seen how different forms of transport emit different quantities of greenhouse gases, and planes also create contrails in the atmosphere, which also contribute to the greenhouse effect.

So, I hope you found that interesting.

Certainly lots to think about about how we travel, and what impact that has on the earth.

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

Bye.