Environmental problems, such as pollution or the destruction of forests, are among the most serious challenges of today’s society. In recent years, increasing emphasis has been given to global phenomena, such as ozone layer depletion and climate change (e.g., Rayner and Malone, 1998a). These phenomena constitute global environmental risks, and it is one of the major problems for scientists as well as for policy makers how to assess, communicate, and manage these risks. Many of these environmental problems are anthropogenic, that is, they originate from human activities. Hence, the ultimate causes of global risks can be found in decision making processes -- on individual, organisational, and societal levels -- that lead to environmentally relevant behavior. Environmental problems arise from the fact that many individual choices are detrimental for the environment in the long run, such as car driving or overfishing, but are hard to change.