One factor behind the high public support may be knowledge of the costs of non-action, w hich DIW (2008) estimates to reach around EUR 800 billion by 2050 (more than 30% of GDP). The conviction that climate change policies generate new sources of growth also plays a major role in public acceptance. While climate change mitigation policies contributed to reducing GHG emissions, a significant share of past abatement was due to specific events and structural changes.