It was with deep sadness that the Interdisciplinary Observatory on Climate Change received the news of the passing of Professor Ignacy Sachs on 2 August 2023. Ignacy Sachs was one of the main founders of the concept of eco-development and, since the 1970s, helped to spread, at the United Nations and in the academic debate, the need for profound transformations in development models, considering social justice, ecological prudence and economic development.

Director of studies at the École des hautes études en sciences sociales (EHESS) in Paris, he has taught generations of Brazilian PhDs, awakening interest in South-South relations, with an emphasis on relations between Brazil and India. At the École, he directed the International Centre for Research on Environment and Development (CIRED) and later founded the Centre for Research on Contemporary Brazil (CRBC). All OIMC researchers, in particular our current coordinator, who developed and defended his thesis under the supervision of Prof Sachs, pay tribute to this unique economist and thinker, forerunner of many contemporary agendas, and express their solidarity with his family and loved ones.