UN chief Ban Ki-moon maintains that the Group of Eight Industrial Nations (G8) has not done enough to find answers to the worsening global climate changes.

"The policies that they have stated so far are not enough," Reuters quoted Ban as saying in Italy on Thursday.

"This is politically and morally (an) imperative and historic responsibility ... for the future of humanity, even for the future of the planet Earth."

The G8 leaders in the second day of their meeting in L'aquila, Italy set a goal to eliminate the greenhouse gas emissions.

"They agreed to join with other countries to achieve a 50 percent reduction in global emissions by 2050 and a goal of 80 percent reduction by developed countries by 2050," Mike Froman, Deputy Assistant National Security Adviser for Economic Affairs told reporters in a briefing.

While China and India, two countries with some of the highest carbon emissions remained defiant, Russia expressed doubt that the targets are achievable.

The summit attendees remained unanimous that the overall world economy still appeared to be in trouble and warned that the current situation "submits the developing countries to an inordinate burden resulting from a crisis they did not initiate".

The G8 leaders will meet again in September in St.Pittsburgh as part of a larger G20 summit, to discuss the global economic crisis and financial downturn.

RB/HGH/AA