﻿Hello. My name is Miss Adamson, and welcome to lesson six in the climate change scheme of work. Today's lesson is all about why future predictions about climate change are uncertain. For today's lesson, you will need a pen, a pencil, and an exercise book, or at least a piece of paper to write on. If you're missing any of these pieces of equipment, you can pause the video quickly now to go and get them and play it again when you are back. Before we make a start on this day's lesson, I would like you to write down the title at the top of your page, which is "Why a future predictions about climate change uncertain?" And underline it nice and neatly. So the big question for today is all about future predictions of climate change. And you may be thinking, well, how on earth can we predict future climate changes, if it can't even get tomorrow's weather completely right? The important thing to remember is that climate, is a much longer term effect than weather, and it changes on a slower timescale. To predict the weather, you need to know exactly what's happening in the atmosphere at each moment in time, down to the smallest scale Climate on the other hand, is simply the average weather pattern of a region, over many years. And this is usually around about 30 years. It shows a much more general overview of patterns and changes. And this means it can be predicted through range of methods. Now, climate models use complex equations to calculate process and changes. They use some of the world's largest super computers, and often tens of millions of lines of computer code as well. They rely on scientists, inputting data on possible changes to greenhouse gases or to changes solar output and volcanic commissions as well. Scientists can then recreate past climates using these models and using what they know about past climates, and then compare them against evidence that we have for all changes in climate in the past. For example, from tree rings or ice cores. And these have been shown to be relatively accurate. So this gives us some good confidence in them for any future predictions that we can make too Now the body, the organisation, if you like, who are responsible for looking at all of this data and modelling future climate changes, some people call it the IPCC. This is the Intergovernmental Panel on Climate Change. And they're responsible for gathering all of the data and modelling possible climatic changes in the future. They then use this data and these models to advise governments based on the scientific evidence as to what the governments and their countries can do to maybe prevent or possibly adapt to any climate change that could happen in the future. Now, even though the IPCC can model all of this data and what could possibly happen, because the temperature projections that they work out depend on the choices people, countries make in the future, they can't fully say, which of the scenarios, is more likely to come to pass by the end of the century. And on this graph, we can see three possible scenarios. The three lines, red, green, and blue, show these three possible outcomes that could happen. However, all of these scenarios are simply estimates, and greenhouse gas concentrations might actually grow at rates that are higher, or maybe lower than scenarios shown in the graph, and therefore impacts in climate change in different ways. If a future carbon dioxide emissions and greenhouse gas emissions, follow the same increase though that they have over the last decade, increasing it more than 3% per year carbon dioxide levels in the atmosphere, and therefore the temperatures, would actually exceed the scenario represented by the red line on the graph by the end of the century if not before. And you can see the red line on the graph is showing the largest estimated change in temperature compared to the other two. The important thing though,..... to think about is all three of these lines represent some kind of a future where humans cut down greenhouse gas emissions to some extent. It's not simply life carrying on as we know it, it's making some changes now to what we do. We're now going to have a look at describing the graph that we just looked at. Use the graph to answer the three questions on your screen. Number one says, how much has the worst case scenario, the red line changed? Number two says how much has the medium case scenario, the green line change? And number three says how much is the best case scenario, the blue line changed? To work out what the predicted change by 2100 days, simply read the right hand side of the graph. Make sure you include the units in degrees C. Remember though you can go back to the previous slide, to see a larger version of the graph, if you need to. When you happy to have a go, make sure you pause the video to complete your task, and then resume again when you finished. Well done. Let's go through what your answer should look like. Number one, says the worst case scenario is an increase of around 4.2 degrees C by 2100. Number two, says the medium case scenario is an increase of around 3.2 degrees C by 2100. And number three says the best case scenario is an increase of around 1.8 degrees C by 2100. If you need to create your answers, make sure you do from this slide before you move on, it's really important you've got this data correct on your notes. So from the graph that we've just looked at, the three scenarios that the IPCC suggests a possible start with a worst case scenario. This means that emissions are medium to high rates. Although even this would need some kind of reduction compared to present day emissions. This worst case scenario as we've seen, would see an increased global surface warming of around 4.2 degrees C by 2100. And that's a significant amount, even if we make some changes to how we live. The medium case scenario, is that middle one on the graph remember, relies on us adopting more energy efficient technology and ways of living. And this is on top of reducing greenhouse gas emissions from transport and factories for example. Again, this would still see some kind of an increase in global surface temperatures, however, by 3.2 degrees C by 2100 this time. So slightly less than the worst case scenario. The best case scenario that we saw in that graph suggested by the IPCC is if greenhouse gas emissions are cut dramatically. And this means that we'll need to move towards a more ecologically friendly way of living, right across the globe, including widespread use of renewable energy amongst other things as well. Even if we manage this however, there would still be a slight increase in global surface temperatures, this time by roundabout 1.8 degrees C by 2100. Although, as we've seen, this is much, much lower than the other two scenarios. Let's now go in a bit more detail about what the graph and the IPCC are suggesting, let's quickly check our knowledge. The first thing I'd like you to do is write down the three possible temperature changes by 2100. So those are the ones in the coloured boxes just here. Make sure you leave a bit of a space in between each one. Have a look at a three scenarios then, on the right hand side of your screen, and match each one up to the correct temperature change. When you're happy to have a go, make sure you pause the video to have it go, and then play it again once you finished. Well done. Let's go through the correct answers there. So 1.8 degrees C, this' the low emission scenario. 3.6 degrees C, is the high emission scenario. And then 2.8 degrees C, is the medium to low emission scenario. Again, make sure you correct any answers you need to before you move on. So you've got a full set of notes from today's lesson. So why exactly is the future of climate change so uncertain? There are three main reasons why it's so tricky to predict ahead. The first one, is all about population growth. We don't know exactly what's going to to happen with population growth in the future. The second one is all about emissions rates. They're very, very difficult to measure, but also how to change them as well and make any changes for the future. The third one is about technology. Technology is becoming better, and more cost effective all the time. But we still don't know exactly how this might change in the future. So we'll have a look at each one, in a little bit more detail. The growth of the human population over the last 70 years, has exploded from about 2 billion to nearly 8 billion. And this is a growth of over 30,000 people per day. We all breathe out carbon dioxide with every breath. Adds that to the greenhouse gas emissions from energy sources and transport, which increases with every additional human on the planet. However, we just don't know how the population would change in the future. More people could, mean an increase in greenhouse gas emissions, as more people, need that more energy and more fuel production. If the population remains stable, so stays as it is at the moment, there's not be as large an increase in greenhouse gas emissions, or if the population decreases which is a possibility, there may actually be a reduction in greenhouse gas emissions. So climate scientists have got to model, based on a range of different scenarios here, because we just don't know which one is going to happen. The second thing that we're thinking about is the fact that emission rates are very difficult to measure and also change. It's pretty much impossible to accurately measure all emissions from everywhere in the world. The best way is to model and then estimate based on factors that scientists definitely know. For example, the number of factories, the number of car journeys, aeroplane journeys, and other things too. This of course means that the actual emissions might be higher or possibly lower than predicted, which could have a huge impact on the enhanced greenhouse rate. Either by increasing it more than expected, if greenhouse gas emissions are higher than predicted, or maybe less than expected, if greenhouse gas emissions are actually lower than expected, which obviously would be better. Again though, we just don't know exactly what's going to happen, and exactly what is happening with greenhouse gas emissions at the moment. The third reason, was all about technology and the fact that all the time, technology is becoming better and becoming more cost effective. This means, that we can use less fossil fuels, for example, to produce energy. We've improved access to renewable source of energy, for example, with wind farms and solar panels, which again are becoming cheaper and more accessible all the time. So we don't have to burn fossil fuels to produce electricity or energy, which of course is releasing carbon dioxide into the atmosphere. We can use these renewable sources, which won't release any greenhouse gases. Although these improvements are big and happening all the time, we still just don't know what the future holds for this technology. Will it continue to improve, or we've actually reached the peak now of what's possible. Again, scientists have got to model based on all the different scenarios and all the different possibilities to get close to maybe one that could be right. That then brings us to the main task for today's lesson. There's an extract from a newspaper article on your screen. First of all, let's read through it together. Why can't the scientists get it right? We just don't know what is going to happen with climate change in the future. Scientists tell us it isn't their fault that they can't predict with accuracy. They say that because the future of the population of the globe is uncertain, we just don't know how much we will contribute to climate change. Also, carbon emissions are constantly changing, and we don't know how this will continue into the future. The question, the main task for today's lesson says, using evidence from this article, explain to reasons why climate change predictions are uncertain. You also have some success criteria on your screen to make sure you have everything you need in your answer. The first thing you need to make sure you do, is identify. So find two points from this article about why climate change predictions are uncertain. You then need to explain each point. So basically say why it makes climate change had to predict. Everything that we've just gone through, all through today's lesson. And then the final thing is to use connectives in your writing. Now, before you have a go at your answer, we'll have a look at an example paragraph using another reason why climate change predictions are uncertain. So the examples answer says or the example paragraph says, humans are getting better at adapting to and reducing climate change as it happens. And that's the main point for this paragraph. This means that as we develop new technologies, such as carbon capture and removal, there are likely to be less carbon emissions. And that's one part of the explanation there. It then goes on to use a connective. As a result of this, climate change is hard to predict because we don't know how technology could develop and get better in the future, for example, to reduce greenhouse gas emissions. And that's the second part of the explanation to fully link it back to why that makes climate change so hard to predict. Now, remember, this is only an example. This doesn't have the two reasons used the newspaper article that you're going to have to explain for your answer. So it's now your time to have a go. Read the article carefully, to find the two reasons why climate change predictions are uncertain. Make sure you follow through the success criteria and the example answer structure. You can go back in the video to see it again if you need to. When you are happy to have a go at this then, you can pause the video to complete your task, and resume again when you're finished. Well done. Let us go through what your two paragraphs should look something like. So the first paragraph, was all about the population. It says one reason predictions of climate change are uncertain is because we don't know what the population will go up or down in the future. And that's the first point that you should be making. The first reason that you should have identified. Then a connective, because of this, future emissions are hard to predict, because more people on earth would have been likely to cause higher emissions. However, a lower population on earth could cause lower emissions. So again, nice bit of explanation as to exactly why that makes climate change hard to predict. The second point or the second paragraph, should look something like this one. The point in this one is all about greenhouse gas emission rates being hard to measure and change. So it says, another reason that predictions of climate change are uncertain, is that greenhouse gas emission rates are hard to measure and change. This means that the actual emissions might be higher or lower than predicted, which could have a large impact on the enhanced greenhouse effect, either by increasing it more than expected, if greenhouse gas emissions are higher than predicted, or less than expected, if greenhouse gas emissions are lower than expected. Make sure your answers look something like that. They've got that level of detail and to fully explain why they make climate change predictions so hard. If you haven't got any of those bits of detail, you can add them into your answer to make sure you've got full set of notes from today's lesson. That then brings us to the end of today's lesson. A really big Well done on all the fantastic learning you've achieved today. It's not easy sometimes to think that the future is so uncertain. But we need to understand exactly why that is and what the possible scenarios are. Before we finish today, I would like you to take some time and write down just three key bullet points, three things that you're going to remember from today's lesson as a bit of a summary underneath your lesson notes. Before you close this lesson, make sure you complete the quiz. If there's anything in the quiz that you don't, not too sure about, remember you can come back to this video if you need to. Today's lesson that we've been looking at why the future predictions of climate change are uncertain. Next lesson though, we're going to have a look, at how we can adapt to climate change, what we can do to try and cope with any changes. I'll see you next time.

This lesson will focus on how climate change can be predicted, and also why these predictions are uncertain due to population growth and other changes.

Geography

Y9 Geography

Key Stage 3

Year 9

Miss

Why are future predictions about climate change uncertain?

Climate change

UNIT

What evidence do we have to show that the climate is changing?

What are the natural causes of climate change?

What is the greenhouse effect?

What are the possible effects of climate change?

How could climate change affect Bangladesh?

How can humans adapt to climate change?

How has Bangladesh adapted to the threat of climate change?

How can humans mitigate the effects of climate change?

Lesson overview: Why are future predictions about climate change uncertain?

Intro Quiz

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9 lessons in Climate change: