Even before the Climate Summit gets under way next Tuesday inside the United Nations Headquarters in New York, the Summit’s message will be hard to miss.

That’s because, beginning at 7:30 p.m. Saturday and continuing until 11 p.m., the north facade of the Secretariat building and part of the General Assembly Building will be transformed into canvases for images – some of them 30 stories high — related to the topic of climate change.

“There’s no bigger billboard on the planet,” said Fisher Stevens, who produced the work and said he hoped the film would motivate world leaders, corporate executives and New Yorkers to act decisively to limit climate change.

He takes the issue personally.  “I have an 11-month-old son; I’m terrified at what he is going to be breathing, what he is going to be eating in 20 years.”

“I think it’s the biggest story on the planet,” said Louis Psihoyos, who founded the Oceanic Preservation Society and directed the 12-minute piece, which will be shown — in a loop — on Saturday night, then be dismantled. A video of the event will be posted on YouTube next week.

“This event is all about inspiring people,” said Psihoyos.

The content of the film was to remain under wraps until Saturday night, but included work from some of the best photographers and cinematographers in the world, he promised.

The effort required the collaboration of many. In addition to working with UN officials, the three men worked with the NYC Police Department and the Mayor’s Office of Film, Theatre & Broadcasting to plan and create the project over the course of a month.  (As of Friday night, they were still tweaking the audio).

This is not your father’s drive-in movie. It will use 24 IMAX projectors to paint the white marble walls of the Secretariat Building and the General Assembly with a message they hope will inspire the world to save itself, said Travis Threlkel, the creative technologist behind the project.

“It’s really going to touch people,” he predicted.