L'AQUILA, Italy — Targeting global warming, President Barack Obama and other leaders of the world's richest industrial countries pledged Wednesday to seek dramatic cuts in greenhouse gas emissions by 2050 to slow dangerous climate change. Setting a marker for success, they agreed for the first time that worldwide temperatures must not rise more than a few degrees.
However, their goals are nonbinding, and it's far from clear they will be met. The wealthy nations failed to persuade the leaders of big developing countries to promise to cut their own fast-spreading pollution, unable to overcome arguments that the well-established industrial giants aren't doing enough in the short term.
Obama and his counterparts from the other wealthy Group of Eight nations agreed that global temperatures should be kept from rising by more than 2 degrees Celsius, or 3.6 degrees Fahrenheit, in the fight against weather changes caused by mankind.
The results left some Western leaders cheering. British Prime Minister Gordon Brown called the group's statement a "historic agreement." German Chancellor Angela Merkel said it was "a clear step forward."
Environmental groups said the effort fell far short in its bid to cut carbon emissions that come mainly from energy production and that trap heat in the atmosphere. Still, climate change experts said the measure on trying to limit temperature increases _ with agreement by both the G-8 and a 17-member group of industrialized and developing nations meeting here this week _ was an important step.
An increase up to the limit the leaders set wouldn't eliminate the risk of runaway climate change but would reduce it, experts said. Even a slight increase in average temperatures could wreak havoc on farmers around the globe, as seasons shift, crops fail and storms and droughts ravage fields.
"After a long struggle, all of the G-8 nations have finally accepted the 2-degree goal," said Merkel.
The United States and other G-8 nations set a goal of reducing their greenhouse gas emissions by 80 percent or more by 2050. That's part of a plan to have all such gases, from rich and poor nations alike, fall by 50 percent globally by that year.
But developing countries feel the better-established nations aren't doing enough in the shorter term. They also worry that major reduction commitments on their parts, even if below the 80 percent target of rich nations, would hamper economic growth in China, India, Mexico, Brazil and many other non G-8 countries.
As for the target for limiting global temperatures, a summit statement said it reflected a "broad scientific view."
Until now, however, the U.S. had resisted embracing the target because it implied a commitment to dramatically change the way the world generates electricity, fuels its cars and builds its houses. U.S. businesses and the broader national economy could suffer badly under strict pollution limits, many argue.
Environmentalists welcomed the shift in U.S. policy but criticized the G-8's failure to agree on more immediate goals for the industrial countries. The long-term ambition "is too far off to matter _ poor people are being hit today," said Antonio Hill, of the nonprofit Oxfam International.
The G-8 leaders also addressed the global recession and agreed economic conditions are still too shaky to begin rolling back massive fiscal stimulus plans.
A statement said leaders "note some signs of stabilization," but it stressed the difficult outlook instead of counter-concerns over debt and high spending.
The leaders did commit to preparing exit strategies from the "unprecedented and concerted action" that has been taken to boost growth through government spending, low interest rates and expansive monetary policy. Germany, worried about running up crippling debt, has pressed for spending restraint, but other major economies including Britain, Japan and the United States won't rule out the need to pump in more money.
The leaders gathered Wednesday in the earthquake-devastated central Italian city of L'Aquila, many arriving in electric cars and all welcomed by Italian host Premier Silvio Berlusconi. Over a long working dinner, they discussed world security issues ranging from Iran to North Korea.
They emerged with a joint statement deploring government-backed violence and media restrictions in the aftermath of Iran's disputed election last month. The condemnation and concern were a far cry from the calls by some for something tougher, such as sanctions against Tehran or other action. In the face of Russian opposition, the Iran issue didn't even rate a statement separate from the other security issues, as had been expected.
Nonetheless, the Obama team and other leaders portrayed the statement as a victory in its unanimity. "I think it's a strong statement and it reflects a real sense of urgency," said Williams Burns, Obama's undersecretary of state for political affairs.
Obama also announced at the dinner that he will host a nuclear security summit early next March in Washington. Around two dozen nations are expected to attend, to focus on nuclear terrorism, the black markets trade in nuclear materials and the detection and interception of materials in transit, said Obama adviser Mark Lippert.
The abrupt return home from Italy of Chinese President Hu Jintao after ethnic tensions soared in China's western Xingjiang territory could weaken trust-building discussions on making further progress on climate change. He did leave a national delegation behind.
China is among five developing market economies _ along with Brazil, India, Mexico and South Africa _ that are participating in the summit for the fifth straight year, joining the talks on Thursday to discuss aid and development. Also joining are nine African nations.
The summit is also including a discussion of ways to expand the G-8 even further amid growing sentiment that the world's most-industrialized nations can no longer claim leadership on the global political and economic agenda.
The G-8 document also calls for a rapid conclusion to the stalled Doha round of trade talks, but it doesn't set a deadline. That will be up for discussion on Thursday.
The group's statement on the world economy calls for an "enhanced global framework for financial regulation" to help prevent future economic crises, but it fails to make any concrete proposals. Leaders say they will address issues such as executive pay, definition of capital, risk management and the regulation of hedge funds and credit rating agencies.
Associated Press writers Alessandra Rizzo, Ben Feller, Colleen Barry and Emma Vandore in L'Aquila, and Dina Cappiello in Washington contributed to this report.