Global Warming Glossary *
Stalinization - The accumulation of salts in soils.
Salt-water intrusion / encroachment - Displacement of fresh surface water or groundwater by the advance of salt water due to its greater density. This usually occurs in coastal and estuarine areas due to reducing land-based influence (e.g., either from reduced runoff and associated groundwater recharge, or from excessive water withdrawals from aquifers) or increasing marine influence (e.g., relative sea-level rise).
Savanna - Tropical or sub-tropical grassland or woodland biomes with scattered shrubs, individual trees or a very open canopy of trees, all characterized by a dry (arid, semi-arid or semi-humid) climate.
Scenario - A plausible and often simplified description of how the future may develop, based on a coherent and internally consistent set of assumptions about driving forces and key relationships. Scenarios may be derived from projections, but are often based on additional information from other sources, sometimes combined with a "narrative storyline." See also climate (change) scenario, emissions scenario and SRES.
Sea ice - Any form of ice found at sea that has originated from the freezing of seawater. Sea ice may be discontinuous pieces (ice floes) moved on the ocean surface by wind and currents (pack ice), or a motionless sheet attached to the coast (land-fast ice). Sea ice less than one year old is called first-year ice. Multi-year ice is sea ice that has survived at least one summer melt season.
Sea-ice biome - The biome formed by all marine organisms living within or on the floating sea ice (frozen sea water) of the polar oceans.
Sea level change - Sea level can change, both globally and locally, due to (i) changes in the shape of the ocean basins, (ii) changes in the total mass of water and (iii) changes in water density. sea level changes induced by changes in water density are called steric. Density changes induced by temperature changes only are called thermosteric, while density changes induced by salinity changes are called halosteric. See also Relative Sea Level; Thermal expansion.
Sea level equivalent (SLE) - The change in global average sea level that would occur if a given amount of water or ice were added to or removed from the oceans.
Sea-level rise - An increase in the mean level of the ocean. ► Eustatic sea-level rise is a change in global average sea level brought about by an increase in the volume of the world ocean. ► Relative sea-level rise occurs where there is a local increase in the level of the ocean relative to the land, which might be due to ocean rise and/or land level subsidence. In areas subject to rapid land-level uplift, relative sea level can fall.
Sea surface temperature (SST) - The sea surface temperature is the temperature of the subsurface bulk temperature in the top few meters of the ocean, measured by ships, buoys and drifters. From ships, measurements of water samples in buckets were mostly switched in the 1940s to samples from engine intake water. Satellite measurements of skin temperature (uppermost layer; a fraction of a millimeter thick) in the infrared or the top centimeter or so in the microwave are also used, but must be adjusted to be compatible with the bulk temperature.
Sea wall - A human-made wall or embankment along a shore to prevent wave erosion.
Semi-arid regions - Regions of moderately low rainfall, which are not highly productive and are usually classified as rangelands. "Moderately low" is widely accepted as between 100 and 250 millimeters (~4 and ~10 inches) precipitation per year. See also arid region.
Sensible heat flux - The flux of heat from the Earth's surface to the atmosphere that is not associated with phase changes of water; a component of the surface energy budget.
Sensitivity - Sensitivity is the degree to which a system is affected, either adversely or beneficially, by climate variability or change. The effect may be direct (e.g., a change in crop yield in response to a change in the mean, range or variability of temperature) or indirect (e.g., damages caused by an increase in the frequency of coastal flooding due to sea-level rise).
Sequestration - Carbon storage in terrestrial or marine reservoir. Biological sequestration includes direct removal of CO2 from the atmosphere through land-use change, afforestation, reforestation, carbon storage in landfills and practices that enhance soil carbon in agriculture. See Uptake.
Silviculture - Cultivation, development and care of forests.
Smart metering - The application of information technology in buildings to control heating, ventilation, air conditioning, and electricity use effectively. It requires effective monitoring of parameters such as temperature, convection, moisture, etc., with appropriate control measurements.
Snow line - The lower limit of permanent snow cover, below which snow does not accumulate.
Snow water equivalent - The equivalent volume/mass of water that would be produced if a particular body of snow or ice was melted.
Snowpack - A seasonal accumulation of slow-melting snow.
Social cost of carbon - The value of the climate change impacts from 1 metric ton (~2,205 pounds) of carbon emitted today as CO2, aggregated over time and discounted back to the present day; sometimes also expressed as value per metric ton of carbon dioxide.
Social unit costs of mitigation - Carbon prices in US$ per metric ton (~2,205 pounds) of CO2 and US$ per metric ton (~2,205 pounds) C-eq (as affected by mitigation policies and using social discount rates) required to achieve a particular level of mitigation (economic potential) in the form of a reduction below a baseline for heat-trapping gas (greenhouse gas) emissions. The reduction is usually associated with a policy target, such as a cap in an emissions trading scheme or a given level of stabilization of heat-trapping gas greenhouse gas) concentrations in the atmosphere.
Socio-economic scenarios - Scenarios concerning future conditions in terms of population, Gross Domestic Product and other socio-economic factors relevant to understanding the implications of climate change. See SRES.
Soil moisture - Water stored in or at the land surface and available for evaporation.
Solar radiation - Electromagnetic radiation emitted by the Sun. It is also referred to as shortwave radiation. Solar radiation has a distinctive range of wavelengths (spectrum) determined by the temperature of the Sun, peaking in visible wavelengths. See also: Thermal infrared radiation, Insolation.
Soot - Particles formed during the quenching of gases at the outer edge of flames of organic vapors, consisting predominantly of carbon, with lesser amounts of oxygen and hydrogen present as carboxyl and phenolic groups and exhibiting an imperfect graphitic structure. See Black carbon.
Southern Annular Mode (SAM) - The fluctuation of a pattern like the Northern Annular Mode, but in the Southern Hemisphere.
Spatial and temporal scales - Climate may vary on a large range of spatial and temporal scales. Spatial scales may range from local (less than 100,000 square kilometers), through regional (100,000 to 10 million square kilometers) to continental (10 to 100 million square kilometers). Temporal scales may range from seasonal to geological (up to hundreds of millions of years).
Specific energy use - The energy used in the production of a unit material, product or service.
Spill-over effect - The effects of domestic or sector mitigation measures on other countries or sectors. Spill-over effects can be positive or negative and include effects on trade, carbon leakage, transfer of innovations, and diffusion of environmentally sound technology and other issues.
SRES - The storylines and associated population, GDP and emissions scenarios associated with the Special Report on Emissions Scenarios (SRES) (Nakićenović et al., 2000), and the resulting climate change and sea-level rise scenarios. Four families of socio-economic scenario (A1, A2, B1 and B2) represent different world futures in two distinct dimensions: a focus on economic versus environmental concerns, and global versus regional development patterns.
Stabilization - Keeping constant the atmospheric concentrations of one or more heat-trapping gas (greenhouse gas) or of a CO2-equivalent basket of heat-trapping gases. Stabilization analyses or scenarios address the stabilization of the concentration of heat-trapping gases in the atmosphere.
Stakeholder - A person or an organization that has a legitimate interest in a project or entity, or would be affected by a particular action or policy.
Standards - Set of rules or codes mandating or defining product performance (e.g., grades, dimensions, characteristics, test methods, and rules for use). Product, technology or performance standards establish minimum requirements for affected products or technologies. Standards impose reductions in heat-trapping gas (greenhouse gas) emissions associated with the manufacture or use of the products and/or application of the technology.
Storm surge - The temporary increase, at a particular locality, in the height of the sea due to extreme meteorological conditions (low atmospheric pressure and/or strong winds). The storm surge is defined as being the excess above the level expected from the tidal variation alone at that time and place.
Storm tracks - Originally, a term referring to the tracks of individual cyclonic weather systems, but now often generalized to refer to the regions where the main tracks of extra-tropical disturbances occur as sequences of low (cyclonic) and high (anti-cyclonic) pressure systems.
Stratosphere - The highly stratified region of the atmosphere above the troposphere extending from about 10 kilometers (~ 6 miles), ranging from 9 kilometers (~5.6 miles) at high latitudes to 16 kilometers (~10 miles) in the tropics on average, to about 50 kilometers (~31 miles) altitude.
Stream flow - Water flow within a river channel, for example, expressed in cubic meters per second (cubic feet per second). A synonym for river discharge.
Subducted - A geological process in which one edge of a crustal plate is forced sideways and downward into the mantle below another plate.
Subsidy - Direct payment from the government or a tax reduction to a private party for implementing a practice the government wishes to encourage. The reduction of heat-trapping gas (greenhouse gas) emissions is stimulated by lowering existing subsidies that have the effect of raising emissions (such as subsidies to fossil fuel use) or by providing subsidies for practices that reduce emissions or enhance sinks (e.g. for insulation of buildings or for planting trees).
Succulent - Succulent plants, e.g., cactuses, possessing organs that store water, thus facilitating survival during drought conditions.
Sulfur hexafluoride (SF6) - One of the six greenhouse gases to be curbed under the Kyoto Protocol. It is largely used in heavy industry to insulate high-voltage equipment and to assist in the manufacturing of cable-cooling systems and semi-conductors. Its Global Warming Potential is 23,900.
Sustainable development - Development that meets the cultural, social, political and economic needs of the present generation without compromising the ability of future generations to meet their needs.
Glossaries of the contributions of Working Groups I, II and III to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report 2007.
Nakićenović, N., J. Alcamo, G. Davis, B. de Vries, J. Fenhann, S. Gaffin, K. Gregory, A. Grübler, T.Y. Jung, T. Kram, E.L. La Rovere, L. Michaelis, S. Mori, T. Morita, W. Pepper, H. Pitcher, L. Price, K. Raihi, A. Roehrl, H.-H. Rogner, A. Sankovski, M. Schlesinger, P. Shukla, S. Smith, R. Swart, S. van Rooijen, N. Victor and Z. Dadi, 2000: Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, and New York, 599 pp.