Karsten Sach served for over three decades in the German Federal Ministry for the Environment, Nature Conservation, and Nuclear Safety. From 2016 to 2022, Dr. Sach was Director General of the department “International and European Policies, Climate Protection.” He also served as the German chief negotiator on Climate Change at the UNFCCC Conference of the Parties from 1999 to 2021 and was closely involved in the negotiation of the Paris Agreement. In addition, Dr. Sach represented the German government in numerous international organizations and initiatives and worked closely with leading think tanks in the fields of climate, energy, environment, and international governance. After his retirement in 2022, he works as a freelance consultant on climate protection.

Dr. Sach was strongly involved in the establishment of the International Renewable Energy Agency (IRENA). For decades, he worked on the development of EU legislation on environmental and climate protection, including the European Green Deal. Between 2008 and 2014, he served as Chairman of the Management Board of the European Environment Agency (EEA).