World's major polluters will work together to combat global warming, Obama says

L'AQUILA, Italy (CNN) - Leaders of both industrialized powers and emerging economies agreed Thursday to work together on setting a goal to limit global warming to levels recommended by scientists, President Barack Obama announced at the G8 summit.

The G8 countries - comprising the United States, Britain, France, Germany, Italy, Japan, Canada and Russia - agreed to a target of reducing their carbon dioxide emissions by 80 percent by the year 2050 to try to prevent the Earth's atmosphere from warming by more than 2 degrees Celsius (3.6 degrees Fahrenheit), Obama said.

Thursday's meeting with emerging economies including China also secured a commitment from the developing countries to work for limiting global warming to the 2 degree Celsius threshold, Obama said.

"Developing countries among us will promptly undertake actions whose projected effects on emissions represent a meaningful deviation from business as usual in the midterm, in the context of sustainable development, supported by financing, technology, and capacity-building," said the declaration from Thursday's Major Economies Forum on Energy and Climate.

The vast majority of climate change scientists warn that warming above the threshold would mean potentially catastrophic impacts on Earth.

Obama called the commitment of the emerging economies "an important stride forward" in minimizing climate change, but acknowledged that the issue he called one of the most challenging of our times would be difficult to confront.

U.N.-led negotiations on a new global climate change treaty are aiming to conclude with an agreement among 192 nations in Copenhagen, Denmark, in December. Obama said the G8 targets and work with developing countries are intended to support the international climate change treaty that will succeed the Kyoto Protocol in 2012.