In late 2005, Montreal hosted the United Nations Climate Change Conference. Government ministers, scientists, leaders of nongovernmental organizations and journalists gathered for this annual meeting of countries participating in the Kyoto Protocol, a policy aimed at reducing the emission of greenhouse gases.

American photographer Joel Sternfeld gained access to the conference using newspaper credentials. He hoped to answer a question for himself: “I wanted to know if climate change was real”. What he found was worse than what he expected. “In the opinion of nearly all the participants, not only was climate change occurring, it was also about to reach a tipping point and become irreversible”. Using a telephoto lens, Sternfeld trained his camera on a range of participants to create an “archive of humanity” amid what was then a largely invisible ecological crisis. “I tried to take photographs of delegates at the moment when the horror of what they were hearing was visible on their faces. At stake, after all, is the continuation of Earth as a planet fit for us to live on”.

Sternfeld published When it changed, a book of these images, in 2007. It outlines alarming scientific discoveries, the actions and inactions of governments and corporations and increasingly extreme weather events. This exhibition presents the photographs from that book. At this watershed moment in global environmental history, and in the face of an ever-unfurling stream of evidence, Sternfeld is emphatic: we cannot say that we did not know that our world had changed.

(Curator: Kathryn Hill, associate curator of contemporary art, and Jeffrey Richmond-Moll, George Putnam Curator of American Art, Peabody Essex Museum)