It’s not just his own travel, but the carbon footprint of the arts internationally, which preoccupies Mr. Bel. “If you won’t buy tomatoes that don’t come from France, or wherever you live, why do we watch culture that is flown in from other countries?” he said.

Courtney Geraghty, the artistic director of the Crossing the Line festival, said that it was important to awaken peoples’s consciences about environmental issues, but also important to show work from abroad. “In countries where there is nationalism and protectionism,” she said, audiences need “cross-cultural dialogue and international voices.”

Mr. Bel acknowledged that his decision was radical, and that his choice was not available to all. “Everyone intelligent and sensitive to this cause must invent their own solutions,” he said. “But our work in contemporary art is to change things.” (Huge swirl of arms.) “We must change this.”

Julia Jacobs contributed reporting from New York.