South Korea is the host for the Group of 20 leading economies' 2010 conference. World leaders are weighing in on the global financial crisis, placing a special emphasis in currency values in major markets like China and the United States.
European Commission President Jose Barroso said the G20 must not waiver on its commitments to advance a sustainable green economy.
He said in his statement before G20 leaders that he expected strong political signals for "real progress" on tackling climate change.
"Subsidies for fossil fuels must be gradually withdrawn," he added. "We also must continue our efforts to reduce the price volatility of oil and other commodities."
Market reforms, he said, wouldn't happen quickly but they were something the international community needed to address as it gears up for a major climate conference later this month in Cancun, Mexico.
"The G20 must not waiver in their efforts to come to a more sustainable management of our resources and a greener economy," said Barroso.