In October 2014, Müller co-chaired the Berlin Conference on the Syrian Refugee Situation along with Foreign Minister Frank-Walter Steinmeier and the UN High Commissioner for Refugees, António Guterres. In November 2014, he and German Environment Minister Barbara Hendricks hosted a conference which raised $10 billion for the Green Climate Fund’s projects to fight global warming. During his term, the German government pledged €800 million (2016) and €1 billion (2019) in contributions to the Global Fund to Fight AIDS, Tuberculosis and Malaria.