Enviropedia
Climate Change
Global Warming
Ozone
Air Pollution
Weather & Climate
Sustainability
Kids
INFORMATION
Climate System
Climate Change
Empirical Study
Climate Models
Palaeoclimates
Global Warming
Introduction
Greenhouse Effect
Enhanced G-Effect
Greenhouse Gases
 - Carbon Dioxide
   - Sources
   - Sinks
   - Carbon Cycle
   - Concentrations
   - Equilibrium
 - Methane
   - Sources
   - Sinks
   - Concentrations
 - Nitrous Oxide
   - Sources
   - Sinks
   - Concentrations
 - Halocarbons
   - Sources
   - Sinks
   - Concentrations
 - Ozone
 - Other Trace Gases
 - Adjustment Time
 - Summary
Greenhouse Forcing
 - Forcing Factors
 - GWPs
 - ΔF-ΔC Relationships
 - 1765 to 1990
 - Ozone
Aerosols
 - Aerosols
 - Radiative Forcing
   - Direct
   - Indirect
 - Total Forcing
Climate Variations
 - Surface Temperature
 - Precipitation
 - Other Variations
   - Stratosphere
   - Cryosphere
   - Circulation
   - Cloudiness
Detection
 - Modelling
 - Attribution
   - Latitudes
   - Stratosphere
   - Precipitation
   - Sea Level Rise
   - Fingerprints
 - When?
Future Climate
 - GCM Simulations
 - Feedbacks
   - Water Vapour
   - Clouds
   - Ice Albedo
   - Greenhouse Gases
 - 21st Century
Impacts
 - Agriculture
 - Forestry
 - Ecosystems
 - Water Resources
 - Oceans & Coasts
 - Humans & Health
Responses
 - Stabilising
 - FCCC
 - Kyoto Protocol
 - UK Programme
   - Energy Demand
   - Energy Supply
 - Evaluation
Conclusion
LINKS
Navigate

1.2.1.6. Other Trace Gases

In addition to these gases, water vapour (H2O) is a vital atmospheric constituent, averaging about 1% by volume, with significant variations across spatial and temporal scales. Its presence in the atmosphere forms part of the global hydrological cycle. Water vapour, being the most important natural greenhouse gas on account of its abundance, plays a crucial role in the regulation of the atmosphere's energy budget. Despite this, the total volume of water in the atmosphere is relatively small, and, if precipitated completely and evenly over the whole Earth, would yield only about 25mm or 1 inch of rainfall (Kemp, 1994). In reality, of course, rainfall distribution is highly uneven, due to the internal dynamic processes within the global climate system.

In addition to the gases in Table 1.1, there are other reactive gas species produced by cycles of sulphur (S), nitrogen (N2) and chlorine (Cl) halogens. For a further discussion of these species, Wayne (1991) offers a useful text.