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Climate Change


Climate Change


Scientists have predicted that the climate could increase by up to 6 °C in the next 150 years.

The changing climate is a natural phenomenon and

normally takes place over several centuries.

The term ‘climate change’ is used to refer to current changes in the climate. This is because recent scientific

records show that the global climate is warming up more

rapidly than usual.

The average global temperature has increased by 0.6 °C in 140 years.

The ten hottest years for the last 100 years have occurred since 1990.

What is climate change?


Temperature change


Evidence for climate change

a rise in sea levels of around 17cm.

increase in ocean temperatures

a decrease in the amount of arctic sea ice

retreating glaciers

changes in the organisation of ecosystems

As well as temperature change, other evidence for climate

change has also been collected:


How is evidence collected?

weather recordings using thermometers

Different techniques are used to collect evidence for

climate change:

ice core extractions – to measure small changes in temperature from trapped air and other molecules

rocks and fossils – to measure the Earth’s previous climate

plant analysis – changes in climate can alter plant

distribution in an ecosystem

measuring ice cover.

studying images of glaciers


How do we predict climate change?

This results in a huge amount of

information, which makes it difficult to

accurately model Earth’s climate.

We therefore use multiple simplified models to

understand changes in climate.

Climate models are used to predict how Earth’s climate is changing.

These are computer models which

represent the interactions between the

Earth’s atmosphere, land surface, oceans, and sun.


Modelling climate change

Data from previous climates is entered into the model to test its ability to reproduce known climates.

Using climate models, climate change scientists take

several steps to make predictions about Earth’s climate:

Scientists report a range of projections. For example, these can show how the climate might change if CO2production stays the same, if it decreases or if it increases.

The International Panel on Climate Change (IPCC) is a UN organisation responsible for assessing climate change

data. They use information from different computer models

and research to write reports about climate change.


Peer review

A recent study of peer

reviewed research showed

97% of climate scientists

agree that human activities

have led to climate change.

Research in science produces vast amounts of data,

sometimes conflicting. How do you know which research

to believe?

Peer review involves the independent evaluation of

scientific research by experts in the field. They decide

which results are published in science journals.


Scientists conclusions

Despite difficulties in modelling climate change, most scientists

agree that human activity is largely responsible.

There is strong evidence that

increasing fossil fuel use and cattle

farming has increased greenhouse

gas emissions.

Actions to reduce these emissions

are in place. For example, the Paris

Agreement aims to reduce increases

in global temperature to below 2˚C.

How can we decrease greenhouse gas emissions?


Climate Change


Climate change and human activity

An increase in the amount of greenhouse gases in the

Earth’s atmosphere has been seen over the last 200 years.

This coincides with the start of the industrial revolution,

when fossil fuels started to be used on a large scale.

This has overlapped

with an increase in

global temperatures.

The burning of fossil

fuels has resulted in

large amounts of carbon

dioxide being released

into the atmosphere.


Atmospheric carbon dioxide levels


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What does the data

tell you?

Are temperature and CO2 related? (1)


Does the data show that increases in atmospheric carbon

dioxide cause an increase in Earth’s temperature?

Are temperature and CO2 related? (2)

The data shows that there is a correlation between increasing

carbon dioxide levels and temperature. However, it cannot tell

us that one causes the other.

Carbon dioxide is a greenhouse gas,

which means it can trap the Sun’s radiation. This is a causal mechanism

for carbon dioxide to increase Earth’s temperature. However, we cannot say

for certain that this is the reason behind

the temperature increase, as other

factors may be involved.


How accurate are climate models?

It is difficult to accurately model aspects of the

climate, such as clouds,

which greatly influence

surface temperature.

Assumptions often have to be made. For example

about human activities and

population growth.

Limitations of climate models include:

Although climate models are useful, it is impossible for

scientists to say for certain what will happen to the climate

in the future.


Uncertainty in the evidence

Collecting more data on climate

change will decrease the

uncertainties in the data. This will

allow more accurate models and

predictions to be made.

Uncertainties, or unknowns, in evidence and climate models

lead to speculation and misinterpretation of scientific data.

Despite these unknowns, the

majority of scientists agree that the

change in climate is caused by

human activity.


Presenting data (I)

The graph below shows the change in global surface

temperature with respect to an average temperature.

How has the global surface temperature changed since 1992?

Data can be presented and interpreted differently.


Presenting data (II)

Making the y-axis start from

0.2 instead of zero gives the

appearance of a greater

increase in temperature.

Changing the maximum y-

value to 5 gives the

appearance of only a small

increase in temperature.

What assumptions can you make from the graph now?

These graphs show how our interpretation of data can be

influenced by the way it is presented.


Communicating climate change

Misrepresentation of data can lead

to inaccurate opinions presented in

the media that are only based on

part of the evidence.

It is important for data to be presented in an accurate and

accessible way, for both scientists and the public.

Think about where you hear about

current information on climate

change. How is it portrayed, and what

impact may this have on a person?

This information may be biased

to suit an individuals needs.


Opinions on climate change


Climate Change


Effects of climate change

The changing climate and increasing greenhouse gas

emissions affect not just the environment, but also

human lifestyle.

The main effects of global climate change include:

disrupted agriculture

changing sea level

decreasing ice cover

extreme weather

spreading disease.


Extreme weather

Extreme weather, such as severe storms and drought,

result in damaged crops and buildings.

In order to survive, people

may need to migrate

away from these areas.

This has already occurred

in some populations.

Increased rainfall causes excessive flooding in low-lying land

and can alter the organisation of ecosystems.

A reduction in fresh water

supplies and crops increases

the risk of starvation and

water deprivation.


Agriculture and crop yield

Animal welfare may be

compromised by the changing

climate and extreme weather

conditions. This could limit

the production of meat,

milk, and eggs.

Climate change will have both positive and negative effects

on crop yield, depending on the location.

An increase in drought and flooding would lead to a

decrease in crop production. This may increase food prices.

On the other hand, rising temperatures may increase

growing seasons in some areas.


Melting ice

The increasing temperature has resulted in the melting of

polar ice caps and glaciers.

What effect may this have on humans

and the environment?

Measurements show that many glaciers are losing more ice in

the summer than they gain in the winter.

1941 2004


Changing sea levels

If water is heated, it will expand and increase in volume.

The same can be said

for the oceans – as global temperatures rise,

sea levels rise with it.

Water from melting ice

sheets and glaciers runs

into the sea, contributing to

the increase in sea level.

Sea levels are measured using sensors in the sea and

satellite imagery.


Risks of changing sea levels

As populations increase, more people are living in

coastal cities.

The increasing sea levels

threaten the lifestyle of

coastal populations and put

stress on sea defences.

Increasing high tides result

in a greater occurrence of

flooding, which can damage

wetlands and infrastructure.

What adjustments will humans have to

make to cope with these changes?

Wetlands form the habitats of many animals and plants.


A prediction from climate models is that major cities could

become flooded in the future. How can we prevent this?

New Year 2160?


Spreading disease

The increasing temperature could lead to an increased

incidence of some diseases.

For example, an increase

in temperature could allow

mosquitoes to travel to

parts of the world they

were previously unable to

survive in.

This would result in an increased occurrence of malaria and

other mosquito-transmitted diseases.


Climate Change


Glossary


Multiple-choice quiz

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Climate Changetodhigh.com/clickandbuilds/WordPress/wp-content/uploads/... · 2018. 3. 2. · 9 of 33 © Boardworks Ltd 2016 Peer review A recent study of peer reviewed research showed