ACCORDING TO the British press, the Prince of Wales issued a "gentle rebuke" to President Bush last week. Speaking at a formal White House dinner, Prince Charles said that "many people throughout the world look to the U.S. for a lead on the most crucial issues that face our planet." That, apparently, was a coded challenge to the president to do more about climate change and the greenhouse gas emissions that cause it. But a less protocol-bound and more interesting challenge also emerged from Britain last week, in the form of a speech by Prime Minister Tony Blair.

Speaking at the first day of a summit of energy and environment ministers, Mr. Blair noticeably hinted at the idea that Europeans should begin moving away from reliance on the Kyoto treaty to meet the goal of curbing greenhouse emissions. Though the treaty set strict targets for cuts in greenhouse gases, it would stabilize rather than lower greenhouse gas emissions, and, even so, the targets are probably not attainable. The United States isn't going to sign it soon, and it sets no targets for fast-growing China and India. Instead of an "external force" that would impose an "internal target," Mr. Blair said that "in the world after 2012 we need to find a better, more sensitive set of mechanisms to deal with this problem."

It isn't completely clear what Mr. Blair meant by this, although he has spoken in the past of sharing new technology, of Western projects to help the Chinese develop cleaner methods of burning coal and of going back to examine whether there could be a greater role for existing technologies such as solar, wind and even nuclear power. What is clear is that Mr. Blair's initiative offers an excellent opening for Mr. Bush. The president, who has benefited from Mr. Blair's support, should say he supports the prime minister's initiative, wants to leave the Kyoto dispute behind and is ready to address climate change issues, actively and enthusiastically, in an international forum once again.

The timing is right for such a move. The diplomatic advantage is obvious, but so is the environmental importance: In the five years since Mr. Bush was first elected, climate-change science has been moving rapidly toward firmer conclusions. More scientists have observed the impact of global warming on plant and animal life, on the Arctic ice pack, and on weather patterns. More studies have concluded that human activity is a cause. The president has a chance to break the vicious cycle of European whining and American stonewalling on climate change. He should take it.