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Climate change: global impacts

Key questions

What is climate change?

Climate change may impact on world population distribution in a variety of ways

How can geographers and scientists work together to reduce these impacts?

What is climate change?

Climate change refers to changes in the earth's temperature over the last 100 years. Since 1900, the average temperature on the planet has increased by 0.75 degrees Celsius and the UK's sea level has risen by about 10cm. There is strong evidence that the increases in temperatures experienced over the last 100 years cannot be explained by natural causes alone. Humans are changing the climate by their actions, particularly by emitting greenhouse gases.

The global impact of climate change on world population distribution

There are various theories as to the potential global impacts that climate change may have on people in the future. These impacts may include sea level rise causing flooding, more extreme weather events such as hurricanes, impacts on food, water and energy supplies and changes in animal species and the distribution of diseases.

It is uncertain how populations will respond to changes in climate due to global warming. However, theories suggest that there may be large population movements from low lying areas where climate change has affected sea level to areas where it has not. For example, areas in Southern India and Bangladesh which happen to have some of the highest populations and population densities may see flooding if the temperatures were to increase by four degrees Celsius. This may cause mass migrations of people to areas which have not been affected by flooding. This lesson is theoretical as these actions are based on a series of assumptions:

  • Climate change will continue to cause temperatures to increase

  • Humans will continue emitting greenhouse gases at the same rate or an increased rate as they are doing currently

  • People/governments have not stepped in long before an impending crisis to work together to reduce the impacts of climate change on areas that will be seriously affected by climate change

If climate change was to impact people in this way, there are likely to be areas of gain and areas of loss in population. Not all areas of the world are likely to be affected equally.

  • Areas which may gain in population due to stable or improved conditions for human habitation: Canada, Patagonia in Argentina, Antarctica and New Zealand

  • Areas which may loose population due to being submerged by water or due to desert conditions making human habitation very difficult or impossible: South-west USA, parts of southern Europe, large parts of Australia, Amazon Rainforest, Polynesia, Peru, Southern India, most of African continent

It is important to stress that this is theory and we do not know for sure how populations may change and move. Most theorists believe there is likely to be some kind of mass migration of people. For further discussion of this idea read the climate change to force mass migration article in The Guardian. However, some commentators have suggested that the idea of mass population movement is unlikely, see ‘climate migration fears misplaced' at the BBC News Website.

How can geographers and scientists work together to reduce the impacts of climate change?

Whatever the outcome, climate change is impacting on people now and geographers and scientists have a role to play in reducing the impact that climate change is having on people all around the globe. Food, water and space shortages are just three problems that may cause problems in the future due to climate change. Geographers and scientists can work together to reduce these impacts.

Food shortages: Geographers can use GIS technology to map changes in farming and food production due to climate change. Scientists help farmers by developing new varieties of crops that are more fuel and water efficient as well as being able to survive in difficult environments.

Water shortages: Geographers can graph and map water use to detect where the hot spots of water use exist and who is using the most. Scientists can develop new more efficient technologies to reduce water use, for example more efficient washing machines or small scale technologies such as water harvesting. Scientists can develop novel ways of transporting water from areas of surplus to areas of deficit.

Space shortages: Geographers can study and record the distribution of populations and what people need in terms of living space. Scientists can develop novel ways of using space in building construction and ways of making unsuitable areas inhabitable.


What is climate change?

Using the interactive resources on the BBC News website, write a paragraph about the main ideas associated with climate change including the Greenhouse Effect and the impacts of changing climate. To help you get started do this quiz as a class.

Main Activity

How might climate change impact on world population density?

This activity is based on theory. We are not sure exactly what might happen in the future, if the world was to heat up by 4°C. However, for geographers and scientists theories are useful to help us prepare and minimise the impacts, should large scale changes take place.

The activity consists of four tasks:

  • Task one - Annotating a population density map

  • Task two - Colour coding the possible impacts of climate change

  • Task three - What will our planet look like in the future?

  • Task four - How can scientists and Geographers work together to minimise the impacts of climate change?

Download the How will climate change impact on world population density? worksheet and follow the instructions as given to complete each task. You will also need to download the Impacts of climate change worksheet to annotate your population density map.


Write three short paragraphs in response to the questions below, then discuss you answers as a class.

How might the world's population distribution change if the climate was to change by 4°C?
What positive opportunities might climate change bring? For example, to Canada and Patagonia?
What problems might scientists and geographers have in working together on climate change?

Extension activity

Use the resources and information gained in the lesson to create your own population choropleth map showing the possible population density if the climate was to increase by 4°C.

Discuss the following questions as a class:

  • What do you think the impacts of climate change will be for people in London?

  • Do you think we are prepared for flooding, large movements of people or rapid changes in weather? Why/why not?

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The Geography of Science Lesson 4 Teacher's Notes


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The Geography of Science Lesson 4 Teacher's Notes (1)


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The Geography of Science Lesson 4 How will climate change affect world population density


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The Geography of Science Lesson 4 How will climate change affect world population density (1)


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The Geography of Science Lesson 4 Impacts of Climate Change


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The Geography of Science Lesson 4 Impacts of Climate Change (1)


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