Book contents
- Frontmatter
- Contents
- List of figures
- List of SI unit prefixes
- List of chemical symbols
- Preface to the First Edition
- Preface to the Second Edition
- Preface to the Third Edition
- 1 Global warming and climate change
- 2 The greenhouse effect
- 3 The greenhouse gases
- 4 Climates of the past
- 5 Modelling the climate
- 6 Climate change in the twenty-first century and beyond
- 7 The impacts of climate change
- 8 Why should we be concerned?
- 9 Weighing the uncertainty
- 10 A strategy for action to slow and stabilise climate change
- 11 Energy and transport for the future
- 12 The global village
- Glossary
- Index
3 - The greenhouse gases
- Frontmatter
- Contents
- List of figures
- List of SI unit prefixes
- List of chemical symbols
- Preface to the First Edition
- Preface to the Second Edition
- Preface to the Third Edition
- 1 Global warming and climate change
- 2 The greenhouse effect
- 3 The greenhouse gases
- 4 Climates of the past
- 5 Modelling the climate
- 6 Climate change in the twenty-first century and beyond
- 7 The impacts of climate change
- 8 Why should we be concerned?
- 9 Weighing the uncertainty
- 10 A strategy for action to slow and stabilise climate change
- 11 Energy and transport for the future
- 12 The global village
- Glossary
- Index
Summary
The greenhouse gases are those gases in the Atmosphere which, by absorbing Thermal radiation emitted by the Earth's surface, have a blanketing effect upon it. The most important of the Greenhouse gases is water vapour, but its amount in the Atmosphere is not changing directly because of human activities. The important Greenhouse gases that are directly influenced by human activities are Carbon dioxide, methane, nitrous oxide, the chlorofluorocarbons (CFCs) and ozone. This chapter will describe what is known about the origin of these gases, how their concentration in the Atmosphere is changing and how it is controlled. Also considered will be particles in the Atmosphere of anthropogenic origin that can act to cool the surface.
Which are the most important greenhouse gases?
Figure 2.4 illustrated the regions of the infrared spectrum where the Greenhouse gases absorb. Their importance as Greenhouse gases depends both on their concentration in the Atmosphere (Table 2.1) and on the strength of their absorption of infrared radiation. Both these quantities differ greatly for various gases.
Carbon dioxide is the most important of the Greenhouse gases that are increasing in atmospheric concentration because of human activities. If, for the moment, we ignore the effects of the CFCs and of changes in ozone, which vary considerably over the globe and which are therefore more difficult to quantify, the increase in Carbon dioxide (CO2) has contributed about seventy per cent of the enhanced Greenhouse effect to date, methane (CH4) about twenty-four per cent, and nitrous oxide (N2O) about six per cent (Figure 3.8).
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- Information
- Global WarmingThe Complete Briefing, pp. 28 - 55Publisher: Cambridge University PressPrint publication year: 2004