"This is as groundbreaking as saying that Brussels has bad weather and good chocolate," said Greenpeace climate expert Mahi Sideridou.
On his first visit to Europe since his second inauguration a month ago, Bush stuck to familiar themes in a keynote speech meant to mend fences damaged by the Iraq war and US rejection of the Kyoto environmental treaty.
Bush, who alienated allies and environmentalists by pulling out of the Kyoto pact in 2001, repeated his call to use technology to fight the effects of rising temperatures.
"All of us expressed our views on the Kyoto Protocol, and now we must work together on the way forward," Bush said in Brussels, headquarters of the 25-nation European Union.
"Emerging technologies, such as hydrogen-powered vehicles, electricity from renewable energy sources (and) clean coal technology will encourage economic growth that is environmentally responsible."
Kyoto entered into force last week without the United States, which insists the pact would hurt its economy and complains it unfairly excludes developing nations.
The European Union, considered a global leader on climate change, was instrumental in saving the agreement by securing ratification from Russia. Europeans hoped Bush's rapprochement tour this week would show more US willingness to act on climate change.
"I can't see any rapprochement. I can see the US line and the EU line. The question is will the EU leaders call him on that or pretend they're happy with what the US is doing," said Sideridou, of Greenpeace, the environmental lobbying group.
WILLING TO TALK?
US officials said Bush wanted to show he was willing to work on the problem with Europe. The issue was likely to come up in private talks with EU leaders during the week.
The European executive Commission is keen to get the United States on board in planning a post-Kyoto climate change regime. EU Environment Commissioner Stavros Dimas said on Monday technology advances were good -- but not sufficient.
"Technologies are important and the European Union has always been keen for progress in this area," he told Reuters by telephone. "However, to combat climate change, this is not enough. Action is needed now. Significant reductions in emissions worldwide must be agreed."
Dimas said he thought Bush was open to talk about the issue.
British Prime Minister Tony Blair has put climate change at the top of his country's agenda as president of the Group of Eight (G8) major industrialised nations this year and as holder of the EU presidency during the second half of 2005.
Blair, Bush's top ally, has said the US president wants to start discussing measures to combat climate change. Blair has suggested an agreement on the issue may be presented in July.
Under Kyoto, the EU has backed binding targets for carbon dioxide reduction. The United States has backed voluntary targets while putting billions of dollars into research on climate change technology.
"All of us can use the power of human ingenuity to improve the environment for generations to come," Bush said on Monday.
(Additional reporting by Steve Holland)