Informing BC Stakeholders

You are here

Glossary beginning with A



Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities. Various types of adaptation can be distinguished, including anticipatory, autonomous and planned adaptation:

  • Anticipatory adaptation – Adaptation that takes place before impacts of climate change are observed. Also referred to as proactive adaptation.
  • Autonomous adaptation – Adaptation that does not constitute a conscious response to climatic stimuli but is triggered by ecological changes in natural systems and by market or welfare changes in human systems. Also referred to as spontaneous adaptation.
  • Planned adaptation – Adaptation that is the result of a deliberate decision, based on an awareness that conditions have changed or are about to change and that action is required to return to, maintain, or achieve a desired state.

[IPCC Fourth Assessment, Working Group II, Appendix I Glossary, p. 869]


A collection of airborne solid or liquid particles, with a typical size between 0.01 and 10 µm that reside in the atmosphere for at least several hours. Aerosols may be of either natural or anthropogenic origin. Aerosols may influence climate in several ways: directly through scattering and absorbing radiation, and indirectly by acting as cloud condensation nuclei or modifying the optical properties and lifetime of clouds.

[IPCC Fourth Assessment, Working Group I, Annex I Glossary, p. 942]


The fraction of solar radiation reflected by a surface or object, often expressed as a percentage. Snow-covered surfaces have a high albedo, the surface albedo of soils ranges from high to low, and vegetation-covered surfaces and oceans have a low albedo. The Earth’s planetary albedo varies mainly through varying cloudiness, snow, ice, leaf area and land cover changes.

[IPCC Fourth Assessment, Working Group I, Appendix I Glossary, p. 942]


Resulting from or produced by human beings.

[IPCC Fourth Assessment, Working Group II, Appendix I Glossary, p. 869]


The gaseous envelope surrounding the Earth. The dry atmosphere consists almost entirely of nitrogen and oxygen, together with trace gases including carbon dioxide and ozone.

[IPCC Fourth Assessment, Working Group II, Appendix I Glossary, p. 869]