ABU DHABI, May 4 -- United Nations Secretary-General Ban Ki-moon on Sunday commended efforts by the BRICS bloc of emerging economies in fighting global warming but urged them to increase their contribution.

Ban said contributions of Brazil, Russia, India, China and South Africa to combating global warming was most important as they are on the way to transforming themselves into developed countries.

"But we expect the BRICS to increase their efforts and do more as time is against us," Ban said.

The UN chief made the remarks here at a press conference following the opening of the two-day Abu Dhabi Ascent, a pre- summit for the UN climate summit in New York in September.

More than 1,000 participants, including government ministers and energy experts have gathered in Abu Dhabi for the event.

Ban said China has been spearheading the promotion of green energy within the BRICS, especially in megacities.

He also praised South Africa for a "good step forward" in establishing the Southern African Power Pool, a cooperation among national electricity grids of 12 countries in the southern hemisphere.

Ban stressed that efforts to stop global climate warming must be supported by all states.

"I am inviting heads of state and government, along with mayors and senior representatives from business, finance and civil society, to join a 'race to the top,'" Ban said in opening remarks to the Abu Dhabi Ascent. "Solutions exist. The race is on. It's time to lead."

BRICS countries champion the principle of "common but differentiated responsibilities and respective capabilities" in the fight against climate change.

"Responsibility for climate change ... rests on all countries, differentiated according to the extent to which they have contributed historically to the urgent problem which we now face, taking into account national circumstances, capabilities, population, development needs, in the context of equitable access to sustainable development," BRICS ministers said in a joint statement issued last September in Rio De Janeiro.