Over more than two decades, Hassan has been a global leader in advancing science and science capacity in the developing world. He was the founding executive director of TWAS, and served in that position from 1983-2011; he continues to serve as the Academy's treasurer. He also is past president of the African Academy of Sciences.

From 1980-1986, Hassan served as professor and dean of the School of Mathematical Sciences at  Khartoum University in Sudan. In 1974, he was awarded a PhD in plasma physics from the University of Oxford.

His re-election to the IAP post came at the meeting of the IAP General Assembly on Wednesday, 27 February 2013, in Rio de Janeiro, Brazil. Hassan's second term in the post runs for three years.

Also elected as co-chairman was Volker ter Meulen, a virologist who has held top academic and science policy posts in Germany and Europe. From 2003-2010, ter Meulen was president of the German Academy of Sciences Leopoldina, and from 2007-2010, he served as president of the European Academies of Science Advisory Council. He was dean of the faculty of medicine at the University of Würzburg from 1998-2002.

Ter Meulen replaces Howard Alper, chairman of Canada's Science, Technology, and Innovation Council and distinguished professor in the Department of Chemistry at the University of Ottawa. Alper served two three-year terms.

TWAS and IAP are partner organizations based in Trieste, Italy. IAP is a global network of the world's science academies, launched in 1993; today, it is comprised of 106 academies and receives its core funding from the Italian government.

IAP's primary goal is to help member academies work together to advise citizens and public officials on the scientific aspects of critical global issues. IAP is particularly interested in assisting young and small academies achieve these goals and, through networks and communication links created by IAP activities.