He is the Chairman of the Greek Initiative at UN level on protecting cultural and natural heritage from climate change impacts. He is a member of the Board of the European Public Law Organisation and the Director of its climate and circular economy Institute. He is as well the Ambassador of the EPLO to Bulgaria. He was until 2023 a member of the environmental and social advisory council of the EBRD and is also currently the Chair of the Bureau of the Espoo Convention and of the SEA Protocol, Chair of the MoPs in 2019, elected Chair for the MoPs in December 2020 and re-elected Chair for the period 2021-2023 and the period up to 2027. He is the Chairman of the AmCham circular economy committee. George Kremlis is Honorary Director of the European Commission, where he has spent the major part of his career as Advisor in the Legal Service and Head of various legal and policy Units in DGENV. 

He was until 2023 special Advisor to the Greek Prime Minister on energy, climate, environment and circular economy issues. He is doctor honoris causa of the Varna Free University, member of the Advisory Board of the Balkan Economic Forum, and the founder and president of the Circular Gaia Symposium.