From 2011 to 2013 De Alba was Mexico's Permanent Representative to the United Nations (New York), where he introduced a new resolution on Special Political Missions of the UN, seeking greater transparency and accountability. He actively participated at the Rio+20 Conference on Sustainable Development (Rio, Brazil, 2012) and was elected Senior Vice-President of the United Nations Economic and Social Council (ECOSOC) in 2012. He served as Co-Facilitator of the High Level Event on the Rule of Law (2012), led negotiations for the General Assembly Declaration of the High-level Dialogue on International Migration and Development (2013) and, along with an indigenous representative, facilitated the preparation of the World Conference on Indigenous Peoples.