Lesson video

Hello there, and thank you for joining me.

My name is Dr.

Robinson, and I'll be guiding you through this lesson.

So let's get started.

Welcome to today's lesson from the unit of, "Maths and the Environment." This lesson is called, "Making Cities Greener." And by the end of today's lesson, we will understand various approaches to improve local environments.

Here are some previous keywords that will be useful during today's lesson and a new keyword.

We'll unpack the new keyword later in the lesson, but you may want to pause the video now, if you want to read through these definitions, and then press play when you're ready to continue.

This lesson is broken into two learning cycles.

We're going to start by looking at the importance of urban greening.

Here we have Jun who says, "Apparently, making towns and cities greener is really important!" And here we have Andeep who says, "Okay, but what does making somewhere greener actually mean?" Well, there are many elements to making towns and cities green, and this is also called urban greening.

Let's unpack the word urban a little.

Typically, an urban environment has the following features.

It has a high density of buildings, many roads, and with the roads comes traffic, and also carbon emissions from the vehicles and factories within that area.

Urban greening aims to incorporate more green spaces, such as parks and trees into an urban environment and promote sustainability for its citizens, its infrastructure, and it's transportation.

So let's check what we've learned.

Which of these are urban greening strategies? Pause while you choose from A, B, C, D, or E, and it may be more than one, and then press play when you're ready for answers.

The answers are A, which is adding parks or cities, C, which is adding trees to the streets in a city, and D, which is promoting sustainable and public transport options in a city.

Let's go back to Jun.

He says, "So, urban greening is about making a city more natural and sustainable, but why is that important?" Well, urban greening has many benefits to both the environment and the population of that town or city.

Increasing the amount of green spaces may result in an increase in the diversity of wildlife in the city, improving the air quality of the city, offsetting carbon emissions due to the oxygen released by plants and trees and improving well-being.

Also, promoting sustainability may result in improving the air quality of the city, reducing carbon emissions due to there being fewer vehicles being used in the city, reducing noise pollution, and reducing wastage of resources.

So let's check what we've learned there.

Over time, the population in urban areas has increased a lot.

What possible problems might result from an increase in urban population? You've got six options to choose from, and there may be more than one.

So pause while you do it and press play for an answer.

There are four answers here.

A, more vehicles on the road resulting in more frequent traffic.

B, more vehicles on the road resulting in higher carbon emissions.

E, which is increasing the pressure on local facilities such as hospitals.

And F, more buildings being built in a limited restricted space.

One strategy for urban greening is to build more cycle lanes around a city.

Which of the options you can see in the screen here, are benefits of cycle lanes? Pause while you choose, and there may be more than one, and then press play for answers.

Here they are.

B, which is reduces carbon emissions.

C, it improves the health and well-being of commuters.

And D, it reduces noise pollution.

Bicycles tend to be quieter than cars, so if there are fewer cars because more people are cycling, it's gonna reduce the noise pollution.

Which of these options are ways an urban living environment can become more sustainable? Pause, while you choose, and there may be more than one, and press play for answers.

Here be these ones.

A, which is the solar panels on top of buildings can make an environment more sustainable.

C, insulating buildings that will reduce the need for heating in the winter.

And D, rooftop gardens or allotments can promote independent agriculture or help with growing food in that environment as well.

Okay, it's over to you for Task A.

This task has two questions, and here is question one.

Pause while you do it and press play for question two.

And here is question two.

Pause while do this and press play to look at some answers.

Okay, let's look at some answers.

With question one, you have to imagine you are the mayor of a medium-sized city, and you were given the task of adding two different urban greening strategies of your choice to that city.

In part A, you have to decide which two strategies you think will be most effective to implement and explain why.

Well, there's no definite right or wrong answer here.

Any answer may be valid, so long as you have a correct justification.

So let's take a look at just a few examples.

One example could be you might suggest cycle lanes for that city.

In some cases, a road may become one way only, which allows for the other half of the road to be turned into a cycle lane.

That means no new cycle lanes need to be built in that case.

In other cases, you may have to build the cycle lanes by building into the pavement or doing some roadworks and so on.

But that way one suggestion for how to build a cycle lane.

Another suggestion could be to have trees in the streets.

Now that, I don't mean have trees in the middle of the road, at the sides of the roads, but still in the streets and the tree saplings can be planted along different streets.

Then in part B, you have to decide which two strategies you think will be most effective at improving the well-being of the population in the city.

Again, there's no right or wrong answers, so let's just take a look at a couple examples.

One could be to have green parks in the city.

People in the city will then have easy access to green spaces where they can enjoy walking, relaxing, or having their lunch or maybe jogging around them or doing exercise or whatever.

It could help.

Another suggestion could be to improve the public transport options.

People may worry less about travelling to work on time, on public transport if it's, there's more options and it's more reliable.

Then in part C, you have to write down which two strategies you think will be most effective at improving sustainability within the city.

Again, there's no definite right or wrong answers here.

Let's take a look at a couple of examples.

One example could be, again, to be improving the public transport options.

Fewer people using cars on the road means a reduction in carbon emissions.

This is especially true if public transport uses electric vehicles.

Another option could be to insulate buildings, and that's because the cost and energy consumption when heating a house or office or whatever sort of building in the winter, can be very, very high.

Then question two, you are told that several old cities in the UK have tried to implement urban greening strategies, but they struggle to do so.

In an answer give one possible reason why that might be the case.

Well, once again, there are lots of different things you could write here.

So let's just take a look at an example.

Old cities that have grown larger over time may not have grown with urban greening in mind.

This means that these cities may not have the space for urban greening parks or the roads may not be wide enough to accommodate cycle lanes, routes for large buses, trains, or trams and so on.

There are many other reasons as why.

Okay, great work so far.

Let's now look at the maths behind urban greening.

Here we have a photograph of Leeds.

In 2020, the city of Leeds had the highest level of transport emissions of any local authority in the UK, at 1471.

6 kilotons of CO2 that year, oh dear.

An effective urban greening initiative may result in the following carbon emission reductions over a five year period.

Let's take a look at those initiatives.

One could be a residential initiative, which would reduce carbon emissions by 5%.

Another could be an industry initiative, which would reduce carbon emissions by 12.

5%.

And I know there could be a transport initiative, which could reduce carbon emissions by 15%.

What might have been the carbon emissions from transport in Leeds in 2025, if an urban greening initiative was implemented in 2020? Well, let's take this bottom one as an example here, a transport initiative.

That will result in a 15% reduction.

A 15% reduction means the carbon emissions would be 85% of what it was before.

Now 85% has come from doing 100% subtract the 15% reduction.

85% is 0.

85 as a decimal.

So we could calculate 85% of what the carbon emissions were in 2020, and that would tell us that the transport carbon emissions from Leeds could have been 1250.

86 kilotons in 2025.

And that's what we get when we multiply 0.

85 by 1471.

6.

Where 0.

85 is the 85%, which would be left over after a 15% reduction.

And the 1471.

6 is what the carbon emission levels were in 2020.

So let's check what we've learned.

According to the Office of National Statistics, that's the ONS, in 2021, Leeds has the second largest population of any local authority in the UK.

A lot of people seem to want to live there.

Therefore, it makes sense that the larger population would produce a large quantity of transport car emissions.

Funding for urban green initiatives may prefer to target local authorities that have the highest average carbon emissions per person in the population.

So we have some information now, about the transport emissions and the populations of three locations in the UK.

Which of these three local authorities might be preferred in an urban greening funding? Pause while you choose and press play when you're ready for an answer.

Well, what we're looking for here is the highest average transport carbon emissions per person in the population.

So what we wanna do is calculate what is the emissions per person for each of these local authorities.

And you can do that by dividing the amount of emissions by the population for each of those locations, and you'll get these numbers here.

And that will show you that North Warwickshire would be the preferred choice of urban greening funding in this case because it has the highest emissions per person.

So what will the average transport carbon emissions per person be in North Warwickshire in 2025 after an estimated 15% reduction in emissions due to urban greening? Could you please work that out and give your answer accurate to three significant figures? Pause while you do it and press play for an answer? Well, the answer is 0.

00635 kilotons of CO2 per person.

The way we work that out is by first taking the transport emissions for North Warwickshire, multiplying it by 0.

85, which is 85% of the decimal, and 85% is because there's a 15% reduction from 100% percent.

And if you do that, you get 414.

97 kilotons of CO2, and that would be the total amount of transport emissions for North Warwickshire after a 15% reduction.

So what we need to do next is work out the emissions per person by dividing it by the population.

So we done 414.

97 divided by 65,340, and that is where the 0.

00635 has come from.

So could you please now give one possible reason why the estimation of future CO2 emissions per person may not be accurate? Pause while you think about this and write something down and press play when you're ready to see an answer.

Well, there could be different reasons why, but one reason could be that the population of North Warwickshire may change before the year 2025.

Now, some urban greening initiatives require large spaces.

For example, urban green parks require a large area that can be converted or renewed, to made it into a green park.

Now this means that there have to be large empty spaces that can be renewed into parks.

For older cities though, this is quite rare to find.

Or, it could mean that there are large areas of derelict buildings, which derelict means they are old and unused, there could be large areas of derelict buildings that must be knocked down before the space can be renewed.

And this is incredibly costly and it adds time to the project.

Another urban greening initiative that requires large spaces is cycle lanes.

They require roads and connecting routes to be safe.

That means inner city roads have to be wide enough to split parts off into cycle lanes with the minimum width of a cycle lane being 1.

5 metres, and the recommended width being two metres.

Now, sometimes you find cycle lanes which are not on roads, but go between roads.

They connect through different parts of towns in different ways.

But off-road routes between parts of city need to be unobstructed for that to be the case.

So let's check what we've learned.

According to the Office of National Statistics, the ONS, Doncaster borough has a total area of approximately 569 square kilometres.

Approximately 0.

75% of land in Doncaster borough is classified as brownfield areas, which are disused areas that can be repurposed.

A medium-sized urban green park can be around three square kilometres in area.

Is there enough brownfield areas in Doncaster that can be renewed into a medium-size urban green park? Pause while you write something down and press play when you're ready for an answer.

Well, what you need to do here is find 0.

75% of the area of Doncaster, which is 569 square kilometres.

We can do that by first converting the percentage into a decimal, which would be 0.

0075.

And then if you multiply that by the area of Doncaster, you'd get 4.

2675 square kilometres.

And that number is bigger than three square kilometres.

Therefore, our conclusion could be yes, there is 4.

2675 square kilometres of brownfield area that can be renewed into urban green parks.

But wait a minute, what assumption is being made when saying that 4.

2675 square kilometres of the area can be renewed into urban green parks? Pause while you write something down there and press play when you're ready for an answer.

Well, the assumption is that this area is in one location and not several smaller brownfield areas scattered all around Doncaster.

If the brownfield areas are scattered, then it cannot be renewed into one medium-sized park.

Okay, it's over to now for Task B.

This task has two questions, and here is question one.

The urban city of Oakfield has been given 10 million pounds of funding to start an urban greening initiative.

And what you are going to do is recommend a set of effective urban greening strategies to spend that money.

You've got some information to help you.

The information tells you some things about the city itself and tells you some things about the cost of each initiative and also the stipulations of when that initiative can be implemented.

What you need to do is use a table of information about Oakfield and the cost of each urban strategy, to recommend a set of effective urban greening strategies and write down details such as, how much of the city they will apply to and the cost of them.

And just double check that Oakfield can afford to implement all the strategies you want to use.

You will need to check whether or not those strategies can actually be implemented, by looking at any requirements, and also the figures given to you about Oakfield.

So double check what can be implemented first, and see how much it will cost, and then come up with your plan.

There's no definite right or wrong answer here.

The important part is that you check all the details along the way and you include those details in your plan and justify what you wanna do and why and how much it'll cost and so on.

A nice clear plan is the way to go forward with this.

So pause the video while you do this and press play when you're ready for question two.

And here is question two.

Could you please discuss any possible limitations of your proposed urban greening initiative in question one? Write down a couple of sentences to answer this question, pause while you do it, and press play for some answers.

Okay, let's go through some answers.

In question one, a good starting point with this is to work out which initiatives can actually be implemented.

So we could work out, for example, the quantity of transport carbon emissions per person by dividing the amount of carbon emissions in total by the population.

And that will give you 0.

0045 kilotons when you round to two significant figures.

You may want to work out the percentage area of the city that is available for renewal, and that will be 23%, which you get by dividing the 23 square kilometres by the 98 square kilometres, and then multiply it by 100 to convert it into a percentage, which will be 23% when rounded to two significant figures.

And you may have also worked out the average daily amount of sunshine, which is 3.

7 hours per day when rounded to two significant figures.

And you get that by dividing the 1,356 hours of sunshine in the year by the number of days in the year.

Once you work that out, you can look at which initiatives can actually be implemented.

Now, planting trees along the streets requires an average of 3.

5 hours of daily sunshine.

Well, we have 3.

7 hours of sunshine per day, so that means that strategy is available.

The cycle lanes is suggested only if the transport carbon emissions per person is over 0.

004 kilotons.

Well, it is, it's at 0.

0045 kilotons per person, so that means that strategy is also available.

The urban park renewal requires 25% of the city area to be available.

Well, there's only 23% of the area available, so that means that strategy is not available.

The bottom one, the electric zero-emission buses needs to have an area of 200 square metres required per bus.

Well, there is a maximum of 37 buses that can fit in the depot, so that means that one is available.

There are three strategies available, but we cannot afford to implement all three of the strategies because the total cost is 17,606,000 pounds.

However, we might reduce costs by having just less of some of these.

For example, we could have cycle lanes and all the street trees, plus 13 electric buses, and that would cost 4,160,000, or the cycle path, some street trees, and a greater number of electric buses, but just not quite enough to get us over 10 million pounds in total.

When looking at your own plan, please check that you've justified which strategies can be used and why they can be used.

And then you've costed how much they would cost to implement.

And then question two, you have to discuss the possible limitations of your proposal in question one.

There are plenty of different things you can write here, but let's take a look at an example.

A large assumption here is that the entire area of Oakfield is street that can have trees planted on them.

In reality, the area of Oakfield that is streets might be a lot less than the 98 square kilometres, since a lot of the land will either be buildings or roads.

Another assumption is that all the roads are wide enough and off road locations are safe and unobstructed enough to have cycle lanes built on them.

And there are other assumptions you may make as well.

Fantastic work today.

Let's now summarise what we've learned.

Urban greening is the process of adding green parks, trees, cycle lanes, and other initiatives that improve sustainability of a town or city, improve the mental wellbeing of its population and offset or reduce its carbon footprint.

The impact of urban greening on reducing carbon emissions can be quantified.

And there are careers that do precisely that.

Different urban greening initiatives will cost different amounts of money.

Each initiative will either be viable or unviable, depending on the specific properties of each area.

Well done today.

Have a great day.