Considering a worst-case scenario is sometimes too much to bear, but that's exactly what Greenpeace is doing with their new billboard ad campaign that features aged politicians apologizing for failure to act on the opportunity to stop a climate change catastrophe.

Among the politicians on the billboards are U.S. President Barack Obama, Prime Minister of Canada Stephen Harper, President of Russia Dmitry Medvedev, President of the Government of Spain José Luis Rodríguez Zapatero, and Chancellor of Germany Angela Merkel.

Says Greenpeace: "We're hoping these ads predict the wrong future."

To see images of these billboards, go here.