The climate impact of travel behavior: A German case study with illustrative mitigation options

Global greenhouse gas mitigation should include the growing share of emissions from transportation. To help understand the mitigation potential of changing travel behavior requires disaggregating the climate impacts of transportation by transport mode, distance, and travel behavior. Here we use disaggregated data on travel behavior to calculate the climate impact of Germans traveling nationally and internationally in 2008 and develop some illustrative mitigation options. We include all relevant long-lived greenhouse gases and short-lived climate forcers and use global temperature change for 50 years of sustained emissions as the emission metric. The total climate impact is determined almost entirely by car (similar to 46%) and air travel (similar to 45%), with smaller contributions from public transportation. The climate impact from the highest income group is 250% larger than from the lowest income group. However, the middle classes account for more than two thirds of the total impact. The relatively few trips beyond 100 km contribute more than half of the total impact because of the trip distance and use of aircraft. Individual behavioral changes, like shifting transport modes or reducing distance and frequency, can lead to useful emission reductions. However, a comprehensive package of mitigation options is necessary for deep and sustained emission reductions. (C) 2013 Elsevier Ltd. All rights reserved.