IPCC Report.pdf - Adam Curry

Glossary of TermsAnnex IIAbrupt climate changeThe nonlinearity of the climate system may lead to abrupt climatechange, sometimes called rapid climate change, abrupt events, or evensurprises. The term abrupt often refers to time scales faster than thetypical time scale of the responsible forcing. However, not all abruptclimate changes need be externally forced. Some changes may be trulyunexpected, resulting from a strong, rapidly changing forcing of anonlinear system.AdaptationIn human systems, the process of adjustment to actual or expectedclimate and its effects, in order to moderate harm or exploit beneficialopportunities. In natural systems, the process of adjustment to actualclimate and its effects; human intervention may facilitate adjustment toexpected climate.Adaptation assessmentThe practice of identifying options to adapt to climate change andevaluating them in terms of criteria such as availability, benefits, costs,effectiveness, efficiency, and feasibility.Adaptive capacityThe combination of the strengths, attributes, and resources available toan individual, community, society, or organization that can be used toprepare for and undertake actions to reduce adverse impacts, moderateharm, or exploit beneficial opportunities.AerosolsA collection of airborne solid or liquid particles, with a typical sizebetween 0.01 and 10 μm, that reside in the atmosphere for at leastseveral hours. Aerosols may be of either natural or anthropogenicorigin. Aerosols may influence climate in several ways: directly throughscattering and absorbing radiation, and indirectly by acting as cloudcondensation nuclei or modifying the optical properties and lifetime ofclouds.AlbedoThe fraction of solar radiation reflected by a surface or object, oftenexpressed as a percentage. Snow-covered surfaces have a high albedo,the surface albedo of soils ranges from high to low, and vegetationcoveredsurfaces and oceans have a low albedo. The Earth’s planetaryalbedo varies mainly through varying cloudiness, snow, ice, leaf area,and land cover changes.AnthropogenicResulting from or produced by human beings.Anthropogenic emissionsEmissions of greenhouse gases, greenhouse gas precursors, and aerosolsassociated with human activities. These activities include the burning offossil fuels, deforestation, land use changes, livestock, fertilization, etc.,that result in a net increase in emissions.Atlantic Multi-decadal Oscillation (AMO)A multi-decadal (65- to 75-year) fluctuation in the North Atlantic, inwhich sea surface temperatures showed warm phases during roughly1860 to 1880 and 1930 to 1960 and cool phases during 1905 to 1925and 1970 to 1990 with a range of the order of 0.4°C.AtmosphereThe gaseous envelope surrounding the Earth. The dry atmosphereconsists almost entirely of nitrogen (78.1% volume mixing ratio) andoxygen (20.9% volume mixing ratio), together with a number of tracegases, such as argon (0.93% volume mixing ratio), helium, and radiativelyactive greenhouse gases such as carbon dioxide (0.035% volume mixingratio) and ozone. In addition, the atmosphere contains the greenhousegas water vapor, whose amounts are highly variable but typicallyaround 1% volume mixing ratio. The atmosphere also contains cloudsand aerosols.Available potential energyThat portion of the total potential energy that may be converted tokinetic energy in an adiabatically enclosed system.Baseline/referenceThe baseline (or reference) is the state against which change is measured.It might be a ‘current baseline,’ in which case it represents observable,present-day conditions. It might also be a ‘future baseline,’ which is aprojected future set of conditions excluding the driving factor of interest.Alternative interpretations of the reference conditions can give rise tomultiple baselines.CapacityThe combination of all the strengths, attributes, and resources availableto an individual, community, society, or organization, which can be usedto achieve established goals.Carbon cycleThe term used to describe the flow of carbon (in various forms, e.g., ascarbon dioxide) through the atmosphere, ocean, terrestrial biosphere,and lithosphere.Carbon dioxide (CO 2 )A naturally occurring gas fixed by photosynthesis into organic matter.A byproduct of fossil fuel combustion and biomass burning, it is alsoemitted from land use changes and other industrial processes. It is theprincipal anthropogenic greenhouse gas that affects the Earth’s radiativebalance. It is the reference gas against which other greenhouse gasesare measured, thus having a Global Warming Potential of 1.CatchmentAn area that collects and drains precipitation.Clausius-Clapeyron relationship (or equation)The differential equation relating the pressure of a substance (usually556