Lesson video

Hello, I am Mrs. Adcock, and welcome to today's lesson on global climate change and the effects.

Climate change is the result of an increase in global temperatures.

We are going to look at what are the effects of climate change and how can we reduce global warming to limit the effects of climate change.

Today's lesson outcome is I can describe some of the major effects of climate change and suggest ways humans can limit the effects.

Some of the key words we will be using in today's lesson include global warming, sea ice, convection currents, climate and climate engineers.

Here you can see those keywords written in a sentence.

It would be a good idea to pause the video here and read through those sentences, and you might even like to make some notes so that you can refer back to them later in the lesson.

Today's lesson on global climate change and the effects is split into three main parts.

First of all, we are going to look at rising sea levels and what is causing those sea levels to rise.

Then we are going to have a look at climate change.

And then we will finish the lesson by having a look at ways that we could reduce global warming.

Let's get started on the first part of our lesson on rising sea levels.

An increase in greenhouse gases leads to more lower frequency infrared radiation being absorbed and radiated.

You can see in the diagram there that we've got the sun, and the sun emits infrared radiation.

This passes through our atmosphere and is absorbed at Earth's surface.

The Earth then radiates out infrared radiation of a lower frequency, and it's this lower frequency infrared radiation that is absorbed by greenhouse gases.

And there's greenhouse gases in our atmosphere.

When they absorb and then radiate out this lower frequency infrared radiation, they are stopping that radiation from escaping into space, and therefore this warms the lower atmosphere and causes global warming.

Global warming is one of our keywords for today's lesson, and that means an increase in global temperatures.

What are some of the impacts of global warming? Hopefully, you are able to think of some of the ways that global warming impacts life on Earth.

We are going to look at these more closely throughout the lesson.

First of all, global warming increases ocean temperatures.

And when the ocean temperature increase, this causes water to expand.

And when the water expands, it then takes up a greater volume, and this increased ocean volume causes sea levels to rise.

So what is the difference between the oceans and the seas? Here, we've got an image showing water levels being measured, and over time, scientists have seen that there has been an increase in sea levels.

Research from NASA suggests that about 50% of measured global sea level rise on Earth is from increasing ocean temperatures causing expansion of water.

So as the ocean temperatures increase, the water expands, and this is causing a rise in sea levels.

Time for a check.

What are the effects of rising ocean temperatures? Is it A, increased ocean volume, B, ocean water expanding, C, sea levels rise? Choose any answers that you think are correct.

The correct answers are A, B and C.

Increased ocean volume, ocean water expanding and sea levels rising are all effects of rising ocean temperatures.

So great job if you chose all three of those.

Not only are rising temperatures causing ocean temperatures to rise, which causes expansion of water, but global warming is also causing glacial ice to melt at an increasing rate.

Glacial ice is found in both the Arctic and Antarctica, and glacial ice forms on land, although bits of glacial ice can break off and float on the oceans, and these are known as icebergs.

In Greenland, devastatingly, the glaciers are disappearing four times faster than they were in 2003.

And this melting of the glacial ice is contributing to rising sea levels.

Sea ice is different to glacial ice because sea ice floats on the surface of the oceans, so it forms not on land, but on the surface of the oceans, and it is also melting as a result of global warming.

When sea ice melts, it has a small effect on raising the sea levels.

Some of you might be surprised that melting sea ice has an impact on sea levels, and this is because it is like ice cubes sat in a glass of water.

When they melt, they will not cause the volume of the water to expand as they will just fill the volume of the water that they displaced.

However, sea ice contains fresh water, and this increases the sea levels when it melts because fresh water is less dense, so when it melts, it will take up a larger volume of water than it displaced as ice.

However, the impact on sea levels is not as significant as when glacial ice melts.

If Earth's temperature continues to rise and all glacial and sea ice worldwide melted, sea levels may rise by more than 60 metres.

This will have a big impact on coastal areas.

An increase in sea levels leads to more flooding of coastal areas, and an increased sea level also leads to increased coastal erosion.

Time for a question.

Which of the following cause a rise in sea levels? Is it A, melting glacial ice, B, flooding, C, melting sea ice, D, increasing ocean temperatures? Now choose any of those answers that you think cause sea levels to rise.

The correct answers are A, melting glacial ice, C, melting sea ice, and D, increasing ocean temperatures all cause rising sea levels.

Well done if you chose all three of those answers.

What are the impacts of rising sea levels? Is it A, melting glacial ice, B, flooding, C, coastal erosion, or D, increasing ocean temperatures? The impacts of rising sea levels are flooding and coastal erosion.

So well done if you identified those two answers.

Other impacts of sea ice melting, so apart from flooding and coastal erosion, the other impacts are more extreme seasonal temperatures, because sea ice is important in reflecting heat back into space.

If we have less sea ice, then there will be less heat reflected back into space, and this will impact seasonal temperatures.

And as a result, this will impact crop production, and therefore this could lead to higher food prices.

Another impact of sea ice melting is a loss of habitat, and this will affect certain species, such as polar bears and walruses.

Here's another question for you to have a go at.

Global warming is causing sea ice to melt.

What are the effects of melting sea ice? A, higher sea levels.

B, more extreme seasonal temperatures.

C, less coastal flooding.

D, loss of habitats.

The correct answers are A, higher sea levels, B, more extreme seasonal temperatures, and D, loss of habitats.

The answer is not C because as sea ice melts, it may cause sea levels to rise, and that would result in more coastal flooding, not less coastal flooding.

Time for our first practise task of today's lesson.

Explain how global warming leads to rising sea levels.

Now, there's lots to think about here.

Make sure you include the following key terms in your answer.

Temperature, expansion of water, glacial ice and sea ice.

Pause the video, have a go at answering this question, remembering to include those key terms, and then come back when you're ready to go over the answers.

Welcome back.

I hope you were able to include those key terms in your answer.

Explain how global warming leads to rising sea levels.

Higher ocean temperatures cause expansion of water.

This results in higher sea levels.

Higher surface temperatures cause glacial ice and freshwater sea ice to melt, which can also lead to rising sea levels.

It is unlikely that you will have the exact wording in your answer, but make sure that you have covered all of the key points in your answer.

We've had a look at how increasing global temperatures may cause rising sea levels.

We're now going to move on to have a look at climate change.

Global warming will result in climate change.

It can cause more powerful convection currents, increasing the number and severity of storms. Convection currents on Earth are a result of uneven heating from the sun.

The cooler, more dense air sinks, and less dense, warmer air rises, and this creates areas of lower pressure.

And it's these convection currents that cause wind and influence weather conditions.

Stronger convection currents may result in thunderstorms. And if they are forming over the oceans, we could get an increased number of hurricanes.

We could see an increased number of hurricanes and lightning storms as a result of climate change.

Increasing average temperatures can affect atmospheric airstreams and change weather patterns.

Some areas will experience increased rainfall, which could cause flooding and have negative impacts on crop production.

Here, we've got an image showing increased rainfall, and if we have increased rainfall in areas, then this could lead to more flooding.

More flooding can then impact crop production, and as we saw earlier, impact on crop production can result in increases in food prices.

Changing rainfall patterns don't always mean more rain and more risk of floods.

They can lead to some areas becoming even drier.

This can lead to prolonged periods of droughts, which again affects crop production and increases the risk of wildfires.

We've got an image there showing an area suffering from drought, and also an image of a wildfire.

So changing rainfall patterns don't only lead to increased risk of flooding, but they can lead to an increased risk of droughts and wildfires.

Time for a check on understanding.

Increases to Earth's temperature can affect, A, the number and severity of storms, B, the solar strength, C, convection currents, D, weather patterns.

The correct answers are A, the number and severity of storms, B, convection currents, D, weather patterns.

So increases in the Earth's global temperatures, so global warming, can affect the number and severity of storms, convection currents and weather patterns.

Well done if you chose those three options.

Another question here, changes to weather patterns such as rainfall can cause flooding, more sea ice, wildfires, droughts.

Choose any options that you think are correct.

Changes to weather patterns such as rainfall can cause flooding, wildfires and droughts.

So well done if you chose all three options, A, C and D.

Changing climate affects biodiversity.

Living organisms are under pressure to quickly adapt to increased temperatures, changing weather patterns and extreme weather events.

Biodiversity is the variety of all living organisms, which includes plants, animals and bacteria.

It's really important that we have biodiversity.

What are some of the changes we've seen in plants and animals due to changing climates? Some plants may flower earlier.

Migration and hibernation patterns may change.

And all of these are important because they impact the entire food web.

Some organisms have their habitats destroyed.

Again, the loss or reduction of numbers of any organism is really important because it affects other organisms within the food web.

Biodiversity is really important to maintain healthy ecosystems and provide humans with essential items, such as food and medicines.

Time for another question.

How is climate change affecting biodiversity? Is it, A, altering migration patterns, B, improving habitats, C, plants are flowering earlier, or D, altering hibernation periods.

How is climate change affecting biodiversity? As with the other questions, choose any options that you think are correct here.

Climate change is affecting biodiversity by altering migration patterns, plants are flowering earlier, and altering hibernation periods, and these can all lead to a decrease in biodiversity.

Well done if you chose option A, C and D.

You're doing really well.

Time for our second practise task of today's lesson.

You need to answer these two questions.

Question one, describe changes to the climate caused by increasing temperatures on Earth.

And question two, describe how climate change affects biodiversity.

Pause the video now.

Have a go at answering those two questions.

Give it your best shot, and then come back when you're ready to go over the answers.

Question one, describe changes to the climate caused by increasing temperatures on Earth.

Your answer may include increasing temperatures on Earth can affect convection currents, and this increases the number and severity of storms, such as hurricanes and lightning storms. Global warming can also alter weather patterns, causing increased levels of rainfall in some areas, and this will result in more flooding.

You may have gone on to mention how this could impact crop production and food prices, and other areas will experience less rainfall and that would result in droughts and increased risks of wildfires.

You might want to pause the video now and add any details that you missed to your answer.

Question two, describe how climate change affects biodiversity.

Your answer may include climate change can reduce biodiversity by altering migration patterns, altering hibernation periods, destroying habitats, causing flowers to flower earlier, or you may have gone on to mention how birds may lay their eggs earlier.

And all of these may impact the entire food web.

Well done if you included many of those points in your answer.

It's time for us to move on to the final part of our lesson.

Having looked at rising sea levels and climate change and some of the impacts these have on life on Earth, we're now going to look at how we can reduce global warming.

Changes in human behaviour can reduce the release of greenhouse gases, such as carbon dioxide and methane.

CH4 is the molecular formula for methane into the atmosphere.

This could lead to smaller increases in global temperatures.

One change humans could make is to walk or cycle where possible, rather than driving.

And if we can walk or cycle, then this will reduce carbon dioxide emissions from vehicles.

Can you think of any other ways humans could reduce their carbon dioxide emissions? There are lots of things that we could do as individuals to try and reduce our carbon dioxide emissions.

You may have thought of things such as reducing the amount of electricity that we use by perhaps turning electrical appliances off when they're not in use, switching our light bulbs to energy saving light bulbs, or perhaps you thought of insulating our houses.

Some additional changes that humans could make to reduce their carbon dioxide emissions include planting more trees because when trees photosynthesize, they take in carbon dioxide out of the atmosphere.

And also, we could switch to using more renewable energy sources.

At the moment, a lot of our electricity is generated in fossil fuel power stations, but perhaps we could switch to using renewable energy sources such as wind, solar or geothermal.

Methane, CH4, is another greenhouse gas.

How could humans reduce the levels of methane emissions? Some changes that humans could make to reduce their methane emissions include reducing waste sent to landfill.

So there are methane emitting bacteria at landfill sites that contribute to global methane emissions.

So if we reused items or recycled items rather than sending them to landfill, then this would reduce methane emissions.

Eating less rice.

Paddy fields also contain methane emitting bacteria, and therefore if we ate less rice, there would be less need for so many paddy fields.

And finally, eating less meat from cows, we could reduce our methane emissions.

Just to recap, we could reduce our methane emissions by reducing waste sent to landfill, eating less rice, and also eating less meat from cows.

Let's have a check for understanding, how could humans alter their behaviour to reduce methane emissions? A, plant more trees, B, reduce waste sent to landfill, C, use renewable energy sources, D, eat less meat from cows.

The correct answers are reduce waste sent to landfill and eat less meat from cows.

So well done if you chose options B and D.

Planting more trees would not reduce methane emissions, but that would absorb some of the carbon dioxide from the atmosphere.

And also using renewable energy sources would reduce carbon dioxide emissions, but not reduce methane emissions.

Climate engineers are doing lots to reduce global warming.

They are working to reduce the levels of greenhouse gases released into the atmosphere.

Not only that, but also remove greenhouse gases from the atmosphere to lower the current levels, and also lower global temperatures.

You may have heard climate engineers referred to as geo engineers.

Climate engineers hope to achieve these goals through the application of technology.

This process we're gonna look at now is called carbon capture and storage.

And carbon capture and storage is a process involving collecting carbon dioxide from power station emissions before it is released into the atmosphere.

So we can see there on the diagram, we've got a power station.

And rather than releasing those carbon dioxide emissions into the atmosphere, they are captured before they are released.

This carbon dioxide is then piped deep underground, and here, the carbon dioxide is stored in old oil and gas fields or coal mines.

So the carbon dioxide was trapped and stored deep underground, rather than being emitted into the atmosphere.

This process is called carbon capture and storage, and it's thought to reduce emissions from power stations by up to 90%.

Which of the following is not part of the carbon capture and storage process? Is it A, collect carbon dioxide from emissions, B, pipe the carbon dioxide underground, C, dissolve the carbon dioxide in the oceans, D, the carbon dioxide is stored in old oil and gas fields? The correct answer is D, dissolving the carbon dioxide in the oceans is not part of the carbon capture and storage process.

Another technology that has been developed by climate engineers is called direct air capture, and this is a new technology with facilities being developed worldwide.

What are the stages of direct air capture? So let's see what happens.

First of all, large fans draw in air.

The air passes through filters, which binds the carbon dioxide molecules.

The filters are then heated to release the carbon dioxide molecules.

So we've brought in the air, and then we've captured those carbon dioxide molecules from the air.

And then the carbon dioxide is either stored underground like in carbon capture and storage, or it's collected to be used in products.

And we use carbon dioxide in products such as carbonated drinks or fire extinguishers.

The clean air which has had the carbon dioxide removed is then passed back out into the atmosphere.

Here are some other technologies which climate engineers are currently working on.

More efficient renewable technology, more energy efficient industrial processes, fertilising the oceans to increase phytoplankton levels.

And if we increase phytoplankton levels, then more photosynthesis will take place and this will reduce the amount of carbon dioxide in the atmosphere.

Designing a catalyst to mimic photosynthesis, attempting to turn carbon dioxide into edible protein, that's an interesting one, and also solar radiation modification.

So trying to reflect radiation back to space.

Which of the following is not a technique used by climate engineers to reduce the levels of greenhouse gases? Direct air capture, deforestation or carbon capture and storage? The correct answer is deforestation, B.

So direct air capture and carbon capture and storage are two techniques used by climate engineers, and deforestation involves cutting down trees, which would actually lead to increased levels of carbon dioxide, a greenhouse gas, in the atmosphere.

For our final practise task of today's lesson, there's three questions for you to have a go at.

Question one, give two ways that individuals can reduce carbon dioxide emissions.

Two, give two ways that individuals can reduce methane emissions.

And finally, question three, describe how carbon capture and storage reduces atmospheric carbon dioxide levels.

Pause the video now.

Have a go at answering those three questions.

And then come back when you're ready to go over the answers.

Welcome back.

Let's start with question one.

Two ways that individuals can reduce their carbon dioxide emissions.

Your answer may include walk or cycle rather than drive.

Use public transport.

Use energy from renewable sources.

Plant more trees.

Switch to energy saving bulbs.

Turn off devices when not in use.

And you may have thought of some other correct answers as well.

Question two, give two ways that individuals can reduce methane emissions.

You may have mentioned eating less rice or eating less meat from cows, or recycling or reusing items so that we reduce waste that's sent to landfill.

Finally, describe how carbon capture and storage reduces atmospheric carbon dioxide levels.

CO2 emissions are captured before they enter the atmosphere.

They're then piped deep underground, where the carbon dioxide is stored in old oil and gas fields or coal mines.

Well done if you correctly answered all three of those questions.

We have reached the end of today's lesson on global climate change and the effects.

We'll just summarise some of the key points that we've covered in today's lesson.

Increasing average temperatures lead to an increase in sea levels.

So we saw how the increasing temperatures led to glacial ice and sea ice melting, and the expansion of water as the ocean temperatures increased, and how all these led to an increase in sea levels.

Increasing average temperatures may cause more powerful convection currents, increasing the number and severity of storms, such as lightning storms and hurricanes.

Increasing average temperatures can affect atmospheric air streams and change weather patterns, leading to some areas experiencing more rainfall and other areas experiencing less rainfall.

Changes of human behaviour can lead to smaller increases in global temperatures, and we looked at some of the ways we could reduce our carbon dioxide and methane emissions.

Climate engineering may enable humans to reduce global temperatures through the application of technologies, such as carbon capture and storage and direct air capture.

Well done, you've worked really hard in today's lesson.

I've enjoyed it.

I hope you have to, and that you are able to join me for another lesson soon.