Efforts to mitigate climate change and adapt to its effects will require new types of partnerships, policies and instruments. Successfully addressing the climate change challenge will only be achieved, and sustained, through involvement and commitment at all levels of decision-making. In particular, sub-national authorities (regions, provinces, states or municipalities) have a key role to play in actively incorporating climate change considerations in day-to-day business and in introducing climate-friendly policies, regulations and investment decisions at their level, as a direct outreach to the public. Local planning decisions will be critical for tailoring almost every single adaptation action to the local conditions. Similarly, local behaviour and investment choices have a major impact on greenhouse gas emission levels. However, if local authorities are to succeed, effective partnerships must be achieved with their constituencies, the national government, international donors, technical centres of excellence, neighbouring regions/countries who share common interests and the private sector.