Achieving the goals of the Paris Agreement requires increased global climate action, especially towards the production and use of synthetic e-fuels. This paper, produced for the German Federal Environmental Authority (Umweltbundesamt UBA), focuses on aviation and maritime transport and the role of green hydrogen for indirect electrification of industry sectors. Based on a sound analysis of existing multilateral cooperation the paper proposes four potential initiatives to increase climate ambition of the G20 countries in the respective policy field: a Sustainable e-Kerosene Alliance, a Sustainable e-fuel Alliance for Maritime Shipping, a Hard-to-Abate Sector Partnership and a Global Supply-demand-partnership.