Robinson became the first female president of Ireland in 1990 and then acted as the U.N. High Commissioner for Human Rights from 1997 to 2002. She's currently a member of The Elders, a peace advocacy group formed in part by Nelson Mandela.
Joan Burton, deputy prime minister of Ireland, said Robinson will inject a much needed sense of urgency into the climate debate.
"It is a sign of the esteem in which former President Robinson is held that she has been asked to undertake this very difficult but crucial task, and a sign of her longstanding commitment to climate justice that she has accepted it," she said in a statement.
Robinson herself said she had "mixed emotions" about leaving her position at a peace council for the Great Lakes region of Africa, but felt it was appropriate to respond to the request from the U.N. secretary-general.