Staying within the limit of the Paris Agreement of 1.5 °C global warming requires closing the global 2030 ambition and action gap arising from insufficient current policies and contributions. G20 countries have a crucial role to play in realising increased climate policy ambition, given their strong economic and political influence as well as their high share in global greenhouse gas emissions. This background paper provides an overview of mitigation options from recent literature and analyses the role of the G20 for their implementation. It provides the basis to identify key policy areas and promising options for intergovernmental cooperation between the G20 nations or other relevant actors.