Book contents
- Frontmatter
- Contents
- List of Figures and Tables
- Acknowledgments
- Introduction
- PART ONE EARTH'S CLIMATE HISTORY AND OUTLOOK
- 1 Salient Events of Climate History
- 2 Human and Climate Interactions
- 3 Greenhouse Gases
- 4 Emitting Economic Sectors
- 5 Forecasts of GHG Emissions and Global Temperatures
- 6 Potential Impacts of Climate Change
- PART TWO CLIMATE POLICY CHOICES
- Appendix: Discount Rates in Climate Analysis
- References
- Index
3 - Greenhouse Gases
Published online by Cambridge University Press: 01 June 2011
- Frontmatter
- Contents
- List of Figures and Tables
- Acknowledgments
- Introduction
- PART ONE EARTH'S CLIMATE HISTORY AND OUTLOOK
- 1 Salient Events of Climate History
- 2 Human and Climate Interactions
- 3 Greenhouse Gases
- 4 Emitting Economic Sectors
- 5 Forecasts of GHG Emissions and Global Temperatures
- 6 Potential Impacts of Climate Change
- PART TWO CLIMATE POLICY CHOICES
- Appendix: Discount Rates in Climate Analysis
- References
- Index
Summary
As noted above, the weight of evidence suggests that the current warming trend has been caused by anthropogenic emissions of greenhouse gases (GHGs). If we are going to try to manage future GHG emissions, we need to understand these gases and the human activities that are causing their buildup in the atmosphere. Those are the subjects of this chapter and the next.
THE MAIN GASES
A GHG is transparent to sunlight, similar to a physical greenhouse made of glass. However, a GHG does not physically block the rising warm air. Rather, it absorbs outgoing infrared radiation emitted from the warmed surface of the planet. The gas then reradiates its absorbed thermal energy in all directions, some of which goes back to the surface of the Earth. Each GHG differs in its ability to absorb various parts of the spectrum of infrared radiation.
GHGs represent only a small share of the atmosphere, which is mainly composed of nitrogen (78%), oxygen (almost 21%), and argon (almost 1%). The three main GHGs released by human activities are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Other GHGs include several compounds of fluorine (the “F-gases”) and ground-level ozone. In addition, chlorofluorocarbons (CFCs) play a greenhouse role and also damage the ozone layer of the stratosphere. Some anthropogenic emissions provide cooling effects. For instance, coal-burning industries release considerable CO2, but they also emit particles of sulfur dioxide (SO2).
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- Climate Policy FoundationsScience and Economics with Lessons from Monetary Regulation, pp. 55 - 63Publisher: Cambridge University PressPrint publication year: 2011