Born in 1967 in Madrid (Spain), she is a lawyer and a founding member of a Spanish non-profit organization, the Instituto Internacional de Derecho y Medio Ambiente (International Institute for Law and the Environment). She has worked in the environmental department of the solicitors firm Allen & Overy in London, was part of the drafting team of the 1995 Spanish Environmental Framework Bill and has provided legal advice to the Spanish Ministry of Environment from September 2001 to June 2000 for the EU Spanish Presidency, mainly for the preparatory process of the World Summit on Sustainable Development (WSSD).

A. Barreira teaches environmental law and policy in several centres in Spain. She has made presentations in numerous international and national conferences and seminars and has published several articles on diverse environmental law topics, particularly on water issues. She has attended the following international conferences: VI UN Commission on Sustainable Development, R�o +5 (1997), COP-5 UN Climate Change Convention (Bonn,1999), Workshop on article 8 (j) of the UN Convention on Biological Diversity (Madrid, 1997), the Geneva Social Summit (2000), Asia Europe Meeting(ASEM)- Environment (Beijing, 2002), WSSD PrepCom 2 (New York, 2002), UNEP Global Ministerial Environment Forum (Cartagena de Indias, 2002) and the WSSD (Johannesburg, 2002).

She is a law graduate ( Complutense University, 1985-1990), holds two LL.Ms degrees: in environmental law from London University (1993) and in international legal studies from New York University (1996). In August 2002, A. Barreira was selected by the United Nations University Leadership Academy (UNULA) to participate in the course on 'Leadership on Environment and Human Security' hold in Amman and in Johannesburg. In 1993, she received the British Council European Young Lawyer Award in 1993. She is member of the BoD of the IWRA-Spanish Committee and of the IUCN Environmental Law Commission and Alumna of the Salzburg Seminar.