COPENHAGEN (AP) - President Barack Obama says that the world's will to address climate change "hangs in the balance" and insists any deal must include transparency among nations.

The U.S. leader said on Friday that a changing environment is an unacceptable risk to nations' security, their economies and the planet.

He says countries must work together on national actions and keep checks on those commitments. Obama says a deal that does including sharing information would be a "hollow victory."
He also says industrialized nations must help developing nations adapt.

Obama called the emerging agreement imperfect but adds that no country would get everything it wants. He says time is running short and it is time to take a "substantial step forward."