In a strange setting reminiscent of a Fellini film, Mayor Bloomberg and United Nations Secretary-General Ban Ki-moon launched a new climate change campaign yesterday from inside a temporary park in the middle of Times Square, complete with fresh natural grass, a white picket fence, and an array of flowers.

Mr. Bloomberg announced a new consumer awareness campaign in the city, Together, which first began in the United Kingdom last year. The initiative, funded and organized by a group of corporations and nonprofit charities, is intended to encourage people to adopt more environmentally friendly habits.

At the event, Mr. Ban emphasized cooperation in tackling climate change. “Climate change is too big a challenge for any country, corporation, or community to address alone, instead it requires a broad coalition acting together for the greater good,” he said.

Organizers said that the patches of grass uprooted to create the Times Square park, which was open to the public for the day once the press conference ended, would be replanted in their original setting afterward.