addressing climate change adaptation in regional transportation plans

Addressing Climate Change Adaptation in Regional Transportation PlansA Guide for California MPOs and RTPAs3.0 Climate Change Scienceand Impacts3.1 A BRIEF OVERVIEW OF CLIMATE CHANGEThe greenhouse effect is the warming of the Earth’s surface and loweratmosphere due to the presence of GHG, such as carbon dioxide, methane, andwater vapor. These GHG let the sun’s energy through to the ground, but impedethe passage of energy from the Earth back into space (Le Treut, 2007).Most of the energy emitted from the sun, solar radiation, travels down throughthe Earth’s atmosphere and is absorbed by the Earth’s surface; a smallproportion is reflected straight back into space by clouds and by the Earth’ssurface. The absorption of solar radiation causes the Earth’s surface and loweratmosphere to warm up.Figure 3.1The Greenhouse Gas EffectSource: IPCC, 2007.Cambridge Systematics, Inc. 3-1