Since the IPCC Fourth Assessment Report in 2007, there has been a marked increase in national policies and legislation on climate change, however, these policies, taken together, have not yet achieved a substantial deviation in emissions from the past trend. Many baseline scenarios (those without additional policies to reduce emissions) show GHG concentrations that exceed 1000 ppm CO2eq by 2100, which is far from a concentration with a likely probability of maintaining temperature increases below 2°C this century.

Mitigation scenarios suggest that a wide range of environmentally effective policies could be enacted that would be consistent with such goals. This chapter (part of the IPCC Climate Change 2014 - Climate Change Mitigation report) assesses national and sub‐national policies and institutions to mitigate climate change in this context. It assesses the strengths and weaknesses of various mitigation policy instruments and policy packages and how they may interact either positively or negatively. Sector‐specific policies are assessed in greater detail in individual sector chapters.