Scenario families Scenario families contain individual scenarios with common themes. The six families of scenarios discussed in the IPCC's Third Assessment Report (TAR) and Fourth Assessment Report (AR4) are A1FI, A1B, A1T, A2, B1, and B2. Scenario descriptions are based on those in AR4, which are identical to those in TAR.[4] [edit] A1 The A1 scenarios are of a more integrated world. The A1 family of scenarios is characterized by: * Rapid economic growth. * A global population that reaches 9 billion in 2050 and then gradually declines. * The quick spread of new and efficient technologies. * A convergent world - income and way of life converge between regions. Extensive social and cultural interactions worldwide. There are subsets to the A1 family based on their technological emphasis: * A1FI - An emphasis on fossil-fuels (Fossil Intensive). * A1B - A balanced emphasis on all energy sources. * A1T - Emphasis on non-fossil energy sources. [edit] A2 The A2 scenarios are of a more divided world. The A2 family of scenarios is characterized by: * A world of independently operating, self-reliant nations. * Continuously increasing population. * Regionally oriented economic development. * Slower and more fragmented technological changes and improvements to per capita income. [edit] B1 The B1 scenarios are of a world more integrated, and more ecologically friendly. The B1 scenarios are characterized by: * Rapid economic growth as in A1, but with rapid changes towards a service and information economy. * Population rising to 9 billion in 2050 and then declining as in A1. * Reductions in material intensity and the introduction of clean and resource efficient technologies. * An emphasis on global solutions to economic, social and environmental stability. [edit] B2 The B2 scenarios are of a world more divided, but more ecologically friendly. The B2 scenarios are characterized by: * Continuously increasing population, but at a slower rate than in A2. * Emphasis on local rather than global solutions to economic, social and environmental stability. * Intermediate levels of economic development. * Less rapid and more fragmented technological change than in A1 and B1 --------------------------------------------------------------------------------------------------------------------- http://www.greenfacts.org/en/climate-change-ar4/toolboxes/ipcc-emission-scenarios.htm The Emission Scenarios of the IPCC Special Report on Emission Scenarios (SRES) A1. The A1 storyline and scenario family describes a future world of very rapid economic growth, global population that peaks in mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies. Major underlying themes are convergence among regions, capacity building and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income. The A1 scenario family develops into three groups that describe alternative directions of technological change in the energy system. The three A1 groups are distinguished by their technological emphasis: fossil intensive (A1FI), non-fossil energy sources (A1T), or a balance across all sources (A1B) (where balanced is defined as not relying too heavily on one particular energy source, on the assumption that similar improvement rates apply to all energy supply and end use technologies). A2. The A2 storyline and scenario family describes a very heterogeneous world. The underlying theme is self reliance and preservation of local identities. Fertility patterns across regions converge very slowly, which results in continuously increasing population. Economic development is primarily regionally oriented and per capita economic growth and technological change more fragmented and slower than other storylines. B1. The B1 storyline and scenario family describes a convergent world with the same global population, that peaks in mid-century and declines thereafter, as in the A1 storyline, but with rapid change in economic structures toward a service and information economy, with reductions in material intensity and the introduction of clean and resource efficient technologies. The emphasis is on global solutions to economic, social and environmental sustainability, including improved equity, but without additional climate initiatives. B2. The B2 storyline and scenario family describes a world in which the emphasis is on local solutions to economic, social and environmental sustainability. It is a world with continuously increasing global population, at a rate lower than A2, intermediate levels of economic development, and less rapid and more diverse technological change than in the B1 and A1 storylines. While the scenario is also oriented towards environmental protection and social equity, it focuses on local and regional levels. An illustrative scenario was chosen for each of the six scenario groups A1B, A1FI, A1T, A2, B1 and B2. All should be considered equally sound. The SRES scenarios do not include additional climate initiatives, which means that no scenarios are included that explicitly assume implementation of the United Nations Framework Convention on Climate Change or the emissions targets of the Kyoto Protocol. Emission scenarios are not assessed in this Working Group One report of the IPCC. This box summarizing the SRES scenarios is taken fromthe TAR and has been subject to prior line by line approval by the Panel. http://www.mapcruzin.com/climate-change-shapefiles/ccm/gisclimatechange-scenarios.htm B1 Scenario The B1 storyline and scenario family describes a convergent world with low population growth, but with rapid changes in economic structures toward a service and information economy, with reductions in material intensity, and the introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social, and environmental sustainability, including improved equity, but without additional climate initiatives. Main characteristics of B1 scenario include: low population growth, high GDP growth, low energy use, high land use changes, low resource (mainly oil and gas) availability, medium pace and direction of technological change favoring efficiency and dematerialization. For more information on A2 Scenario read IPCC special report on Emissions Scenarios: Summary for policymakers or Full report. A2 Scenario A2 Scenario Run set is represented by the five ensemble members. Climate models are an imperfect representation of the earth's climate system and climate modelers employ a technique called ensembling to capture the range of possible climate states. A climate model run ensemble consists of two or more climate model runs made with the exact same climate model, using the exact same boundary forcings, where the only difference between the runs is the initial conditions. An individual simulation within a climate model run ensemble is referred to as an ensemble member. The different initial conditions result in different simulations for each of the ensemble members due to the nonlinearity of the climate model system. Essentially, the earth's climate can be considered to be a special ensemble that consists of only one member. Averaging over a multi-member ensemble of model climate runs gives a measure of the average model response to the forcings imposed on the model. For more information about ensemble members see Help. The A2 storyline and scenario family describes a very differentiated and heterogeneous world. The underlying theme is self-reliance and preservation of local identities. Emphasis on economic, social, and cultural interactions between regions is less than in other storylines. Fertility patterns across regions converge very slowly, which results in high population growth. Economic development is uneven, the income gap between now-industrialized and developing parts of the world does not narrow, and per capita economic growth and technological change are more fragmented and slower than in other storylines. Main characteristics A2 scenario include: high population growth, medium GDP growth, high energy use, medium-high land use changes, low resource (mainly oil and gas) availability, slow pace and direction of technological change favoring regional economic development. For more information on A2 Scenario read IPCC special report on Emissions Scenarios: Summary for policymakers or Full report. A2 Scenario Run set is represented by the five ensemble members. Climate models are an imperfect representation of the earth's climate system and climate modelers employ a technique called ensembling to capture the range of possible climate states. A climate model run ensemble consists of two or more climate model runs made with the exact same climate model, using the exact same boundary forcings, where the only difference between the runs is the initial conditions. An individual simulation within a climate model run ensemble is referred to as an ensemble member. The different initial conditions result in different simulations for each of the ensemble members due to the nonlinearity of the climate model system. Essentially, the earth's climate can be considered to be a special ensemble that consists of only one member. Averaging over a multi-member ensemble of model climate runs gives a measure of the average model response to the forcings imposed on the model. For more information about ensemble members see Help. http://peseta.jrc.ec.europa.eu/scenarios.html A key issue in the PESETA project is the use of the same set of socioeconomic and climatic scenarios in all the six sectoral studies. Two global scenarios have been selected from the IPCC’s Special Report on Emissions Scenarios (SRES), belonging to the A2 and B2 scenario storyline. This choice partly covers the range of uncertainty associated with the driving forces of global emissions: demographic change, economic development, and technological change. In the A2 scenario, where the storyline focus is on national enterprise, global greenhouse gas emissions are assumed to increase more significantly leading to approximately a tripling of average CO 2 concentrations by the end of this century compared to the pre-industrial concentration. The B2 storyline focuses on local stewardship and results in approximately a doubling of the atmospheric CO 2 concentration. Those concentration levels translate into the following global mean temperature increases in 2071-2100, relative to 1961-1990: under a scenario A2 an increase of 3°C, and under scenario B2 a temperature increase of 2.2°C. The scenarios and time windows are as follows: * for the 2011-2040 time span: the A2 socioeconomic SRES scenario with the RCA3 regional model and boundary conditions from the ECHAM4 global model; this database comes from the Rossby Centre (SMHI). * for the 2071-2100 time horizon: the A2 and B2 socioeconomic SRES scenarios for two regional climate models –RCMs- (HIRHAM, run by the Danish Meteorological Institute (DMI), and RCAO, run by SMHI) and two global circulation models - GCMs - (the atmospheric model ECHAM4 coupled to the ocean model OPYC3, and the high-resolution atmospheric model HadAM3H with sea surface temperature changes from the coupled model HadCM3). All this climate data come from the PRUDENCE project. The following table details the RCM, GCM and SRES scenarios for this period.