As a renowned astrophysicist and an outstanding populariser of science, the French-Canadian scientist was also a passionate advocate for the environment. He served as president of IUCN Member organisation Humanité et Biodiversité (Humanity and Biodiversity) from 2001 to 2015, and continued as honorary president until his passing.
 
Reeves saw astronomy and ecology as two facets of humanity’s existence, and wrote:

“Astronomy, by telling us the story of the universe, tells us where we came from, how we came to be here today. Ecology, by making us aware of the threats to our future, aims to tell us how to stay there.”
 
He was born in 1932 in the Canadian city of Montreal and studied at the Université de Montréal and McGill University, before receiving his doctorate from Cornell University in 1960. 
 
As a storyteller, he aimed to educate the public about the origins of the world. His book Patience dans l'azur ("Patience in the Blue"), which was first published in 1981, has sold more than a million copies and has been translated into more than 30 languages. Multiple books and television appearances followed, all in the name of science popularisation.
 
Using his platform, he championed nature conservation. For instance, during the 2012 French presidential election, Reeves wrote to mayors, members of parliament and candidates regarding biodiversity and climate change. 
 
He was the recipient of multiple awards and recognitions across a career that spanned many decades, becoming an Officer of the Order of Canada in 1991, and a Commander of France’s Légion d’honneur in 2003, in addition to receiving the Albert Einstein Award in 2001. Furthermore, in 2007 he was inducted into the Academy of Great Montrealers in the “scientific” category, and in 2016 he was named a Commander of the Ordre de Montréal.