addressing climate change adaptation in regional transportation plans

Addressing Climate Change Adaptation in Regional Transportation PlansA Guide for California MPOs and RTPAsA2This emission scenario represents a differentiated world in which economicgrowth is uneven and the income gap remains large between now-industrializedand developing parts of the world; and people, ideas, and capital are less mobileso that technology diffuses more slowly. The underlying theme is self-relianceand preservation of local identities. Fertility patterns across regions convergevery slowly, which results in continuously increasing population. Economicdevelopment is primarily regionally oriented and per capita economic growthand technological change more fragmented and slower than other scenarios. Theemissions lie near the high end of the range of GHG emissions scenarios.B1This emissions scenario presents a future with a high level of environmental andsocial consciousness, combined with a globally coherent approach to moresustainable development. The B1 scenario assumes global population growthpeaks by mid-century and then declines, a rapid economic shift towards serviceand information economies, and the introduction of clean and resource-efficienttechnologies. The emissions at the low end of the range of GHG emissionsscenarios.General Circulation ModelsGeneral circulation models (GCMs) are used for predicting climate change. Theymodel how the atmosphere, oceans, land surface, and ice interact to createweather and climate over long periods of time (decades and centuries) over thewhole globe. GCMs subdivide the Earth’s surface, atmosphere, and oceans intoa 3D grid of thousands of cells. Standard physical equations for the transfer ofheat, water, and momentum are solved for each grid cell to predict temperature,precipitation, and winds. Many relevant processes are well represented at thescale of these grid cells, such as the large-scale westerly flow of moisture fromthe Pacific Ocean. Many GCMs have been developed around the world; themost recent IPCC assessment report made use of projections from 24 differentGCMs.Cambridge Systematics, Inc. 3-9