Achieving the goals of the Paris Agreement requires increased global climate action, especially towards the production and use of synthetic e-fuels. This paper 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.