Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- Part I The Earth System
- 2 Components of the Earth system
- 3 Global cycles
- Part II Global Physical Climatology
- Part III Soil Processes
- Part IV Hydrometeorology
- Part V Biometeorology
- Part VI Terrestrial Plant Ecology
- Part VII Terrestrial Forcings and Feedbacks
- Index
- Plate section
- References
2 - Components of the Earth system
from Part I - The Earth System
- Frontmatter
- Contents
- Preface
- 1 Introduction
- Part I The Earth System
- 2 Components of the Earth system
- 3 Global cycles
- Part II Global Physical Climatology
- Part III Soil Processes
- Part IV Hydrometeorology
- Part V Biometeorology
- Part VI Terrestrial Plant Ecology
- Part VII Terrestrial Forcings and Feedbacks
- Index
- Plate section
- References
Summary
Chapter summary
Earth's climate must be understood in terms of a system of several interacting spheres and the energy, water, and biogeochemical cycles that link these spheres. The main components of the Earth system are: atmosphere, air; hydrosphere, water; cryosphere, frozen portion of Earth; biosphere, living things; pedosphere, soil; and humans. People are important agents of environmental change through land use and land cover change and co-option of the hydrologic cycle and biogeochemical cycles. Greater understanding of Earth and its climate requires that all components of the Earth system – physical, chemical, biological, socioeconomic – be considered.
Atmosphere
The atmosphere is the air that surrounds Earth. It is comprised primarily of nitrogen (N2) and oxygen (O2), which together account for 99% of the volume of the atmosphere (Table 2.1). Many other gases occur in trace amounts that when combined comprise less than 1% of the volume of the atmosphere. Although they occur in minor quantities, some of these gases play an important role in Earth's radiation balance through the greenhouse effect.
Greenhouses gases are poor absorbers of solar radiation, but are strong absorbers of longwave radiation. As a result, the Sun's radiation passes through the atmosphere and heats the surface, but the longwave radiation emitted by the surface is absorbed by greenhouse gases in the atmosphere. The majority of this longwave radiation is emitted back to the surface, warming the surface. This re-emission of longwave radiation back to the surface is the greenhouse effect that warms the surface.
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- Ecological ClimatologyConcepts and Applications, pp. 15 - 27Publisher: Cambridge University PressPrint publication year: 2008