Climate Change

Introduction

Climate change is not going to happen alone. As our climate changes other global environmental problems are going to carry on occurring, such as habitat destruction, pollution, soil erosion and species extinctions. What we currently have very little understanding of is how all these things will interact in the future. Climate change may make some of these problems much worse and some of them may themselves contribute to climate change creating a feedback loop. This unit identifies several global change problems that may interact with climate change.

Unit authored by Carly Stevens

Learning outcomes

By the end of this unit you should be able to:

• know the impacts that climate change is having on the natural environment;

• understand how climate change can lead to habitat destruction and how habitat destruction can interact with other aspects of climate change to threaten the survival of some animal species;

• understand how climate change has the potential to exacerbate air pollution with potentially life threatening consequences;

• understand how soil erosion may be made worse by climate change and could in turn lead to further climate change;

• recognise how systems work by seeing the relationships between climate and other forms of environmental change.

1 Global environmental change

Global environmental change is a relatively new discipline of environmental science. It is concerned with the impacts of large-scale phenomena on our environment. This includes plants, animals, soils and the atmosphere. We already know that climate change is having a severe impact on the natural environment. For example, the European Environment Agency shows that water temperatures in selected European rivers and lakes are increasing. This has important implications for the animals and plants that live in them.

Climate change is obviously one of the key changes that our planet is currently facing, but climate change affects the whole planet and will take many years to progress, so it will not happen in isolation; there are many other changes, at small and large scales, that will happen at the same time. Other global change phenomena that may interact with climate change include habitat destruction and pollution of the air and of water.

It is hard enough to predict what will happen under climate change alone, but it becomes even more complicated when we begin to consider what might happen when other things are changing in parallel.

2 Habitat destruction

The way that scientists predict the response of plant and animal species to climate change is by using ‘climate envelope models’. These models map where a species should be able to survive in the future if it is to live in the same range of climatic conditions that it does now. The concern with some species is that this range of suitable conditions may be reduced dramatically in the future and the species become extinct.

Polar bears are an example of where climate change may lead to habitat loss: as temperatures rise, the sea ice on which they live are beginning to melt. How climate change may affect polar bears is addressed by the ‘Climate change threatens polar bears’ article in New Scientist.

Climate change alone may not be a threat to a particular species. However, it may become a threat when it combines with other man-made changes. Chapter 5 of the UNEP report ‘Migratory species and climate change’ considers marine turtles as an example of how this might be the case. It is quite a complex report; if you find it difficult to understand then focus on the conclusions.

This example shows that although the turtle could probably adapt to climate change it will struggle to adapt to it in light of habitat destruction and pollution. For example, if sea levels rise and some turtles lose their nesting beaches then they will have to find new ones, but if alternative sites are heavily impacted by man they will not be suitable.

3 Air pollution (ozone)

Climate change can interact with other environmental problems with potential consequences for humans as well as animals. Air pollution is one factor that could interact with climate change. This could be both in the levels of pollutant and the effect it has on humans and the environment. Ground-level ozone is a form of air pollution. Although in the upper atmosphere ozone is important to protect us from UV radiation, at ground level it can be a harmful pollutant.

Because sunlight is involved in ozone formation and because high temperatures are needed for high ozone concentrations at ground level, global warming has the potential to increase the formation of ground-level ozone. As ozone is potentially threatening to human health, this could have very serious consequences. In the UK this is less of a concern than, say, in the USA, where warmer summer temperatures mean ozone is already a serious problem. It is estimated that a 4°C rise in temperature could result in a 20 per cent increase in maximum ozone concentration in San Francisco Bay, breaching US air quality standards. This would increase the health risk for sensitive individuals in the population.

4 Soil erosion

Soils are really important to us for many reasons – food production, biodiversity and water quality to name a few. However, climate change threatens soils in several ways and has the potential to interact with the existing global problem of soil erosion. Soil erosion is the removal of soil, usually by water or wind. Soil erosion can have a devastating impact on agriculture; the US dustbowl of the 1930s is one of the most famous examples.

You can learn more about soil erosion by reading the ‘What is soil erosion?’ article at the Soil Erosion Site.

As climate changes, the implications for soil erosion may be serious. A higher frequency or higher intensity of rain may increase soil erosion by water; and in dry areas, prolonged drought periods may increase soil erosion by wind.

Increased soil erosion may also increase water pollution. This is not only because the sediment and soil particles eroded are pollutants themselves, but also because they can often carry other pollutants with them.

5 Peat erosion

Peat erosion may be particularly significant in terms of climate change. If, as predicted, the UK summers become warmer and drier, then there is an increased risk of peat erosion occurring. Peat soils store large amounts of carbon, locking it away and preventing it from becoming available for conversion to greenhouse gases. However, as peat is eroded, that carbon is no longer locked up and can potentially be released. This could make the problem of climate change worse, creating what is known as a positive feedback; that is, it makes itself worse.

Acknowledgements

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Text

Unit authored by Carly Stevens

Unit image

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Links

All links accessed 26 November 2009.