previous chairs of the steering committee include: interim chairs brad herbert and ebele okeke in 2017-2018, amina j. mohammed, deputy secretary-general of the united nations and former minister of environment of nigeria in 2016, andrew cotton in 2014 to 2015, anna tibaijuka in 2011 to 2013; roberto lenton in 2005 to 2010, sir richard jolly in 1997 to 2004 and margaret catley-carlson in 1990 to 1996.