Mr. Hart was appointed as Special Adviser to the Secretary-General and Assistant Secretary-General of the Climate Action Team by United Nations Secretary-General António Guterres on 4 February 2020.

Mr. Hart is currently the Executive Director for the Caribbean region at the Inter-American Development Bank (IADB).  He was previously the Ambassador to the United States and the Organization of American States for Barbados and Director of the Secretary-General’s Climate Change Support Team, leading the team’s delivery of the 2014 Climate Summit and the Secretary-General’s engagement in the process leading to the signing of the Paris Agreement on Climate Change.
 
Throughout his career, Mr. Hart has served in several climate change leadership positions, including as a Climate Adviser for the Caribbean Development Bank, Chief Climate Change Negotiator for Barbados as well as the Coordinator and Lead Negotiator on Finance for the Alliance of Small Island Developing States (AOSIS), a coalition of 43 Islands and low-lying coastal states in the Caribbean, Pacific, Africa, Indian Ocean and South China Sea.  He was a member of the Kyoto Protocol Adaptation Fund Board from 2009 to 2010 and was elected by the United Nations General Assembly to serve as Vice-Chairman of the 2nd Committee of the United Nations General Assembly (Economic and Financial) during its 60th Session.