WASHINGTON (AP) - The United States and China will sign the global climate agreement reached in Paris on April 22. That's the first day it opens for signatures.

WASHINGTON (AP) The United States and China will sign the global climate agreement reached in Paris on April 22. That's the first day it opens for signatures.

The White House says the two countries want swift implementation and spur other countries to sign on.

The deal was reached in December, but doesn't go into effect until at least 55 countries comprising at least 55 percent of global greenhouse gas emissions sign on.

The U.S. has run into a major roadblock. In February, the Supreme Court put on hold the president's sweeping emissions limits for power plants. President Barack Obama was counting on those cuts to meet the U.S. commitment under the deal.

Obama senior adviser Brian Deese says the White House is confident the limits will be upheld in plenty of time.