U.S. President Barack Obama speaks Thursday at the end of the G20 Summit at the Excel Centre in London.

London ? President Barack Obama leaves London today for a NATO conference in Europe after a global summit here that he said helped the world turn the corner and chart a course out of the worst economic crisis since the 1930s.

“Earlier today, we finished a very productive summit that will be, I believe, a turning point in our pursuit of global economic recovery,” Obama said at the end of the daylong conference Thursday evening.

“The whole world has been touched by this devastating downturn. And today the world’s leaders have responded with an unprecedented set of comprehensive and coordinated actions.”

The G-20, a group of 19 countries plus the European Union, reached an agreement to pump an additional $1.1 trillion into the International Monetary Fund and related institutions to help struggling countries restore growth and create jobs; to expand regulation of all “systemically important” financial institutions such as hedge funds; and to pressure tax-haven nations that let the wealthy hide their riches from taxation.

British Prime Minister Gordon Brown proclaimed the summit’s consensus the start of a new financial architecture for a changing world, one in which the U.S. cannot and will not set the course alone.

“The old Washington consensus is over,” Brown said. Now, he said, there is “a new consensus” based on “taking global action together. … A new world order is emerging.”

Obama didn’t dispute Brown’s assertion, although he maintained that the U.S. still plays a pivotal global leadership role. He at first defined the fading “Washington consensus” as pro-globalization and deregulation that took a “cookie cutter” approach to all countries.

Later, he expanded to say that the world is no longer the same as when dominant leaders such as Franklin D. Roosevelt and Winston Churchill could sit down together “in a room with a brandy” and remake the world’s financial system at the end of World War II.

“That’s not the world we live in. And it shouldn’t be the world that we live in. And so, you know, that’s not a loss for America … Europe is now rebuilt and a powerhouse. Japan is rebuilt, is a powerhouse. China, India — these are all countries on the move. And that’s good. That means there are millions of people, billions of people who are working their way out of poverty.”

As if to underscore the changing global economic personally in the summit’s final hours to mediate a dispute between France and China landscape — not to mention his own emergence on the world stage — Obama intervened.

French President Nicolas Sarkozy was pushing to have the G-20 spotlight offending tax havens based on a list published Thursday by the Organization for Economic Cooperation and Development.

China objected, however. White House aides said it was because China doesn’t belong to the OECD. China also has resisted a crackdown that might hit its own tax shelters in Hong Kong and nearby Macau.