Clean energy and the reform of the international financial system will top the agenda of the upcoming meeting of the Group of 20 (G20) in the US city of Pittsburgh, which is scheduled for September 24-25, a Mexican expert told Xinhua in an interview on Monday.

Tomas Milton, an expert on international relations at the National Autonomous University of Mexico, said that the use of clean energy, as a way to address climate change, has been a leading topic for the G20 nations at several international fora this year, alongside other burning topics including the economic crisis and how to prevent a repeat of 2008's world-battering recession.

"In the last weeks, we have seen meetings of G20 ministers on green energy ending without agreements," Milton said, adding "People are now looking to Pittsburgh to make concrete plans and discussions on the topic."

A green fund plan initiated by Mexican President Felipe Calderon will be a key idea to be discussed at the meeting, Milton said.

The fund, proposed during the Mexico round of the Major Economies Forum on Energy and Climate in June, would share out $10 billion by the World Bank to nations that reduce greenhouse gas emissions, allowing emerging nation governments to invest more in such industries and projects.

"The fund could be a great opportunity for nations to get resources to invest in clean energy technologies. Pittsburgh could be a great opportunity to carry out the plan," Milton said.

Emerging market nations and businesses can and do go to international markets to borrow money for clean energy projects, but the fund, if approved, could dramatically accelerate the progress that is being made, Milton said.

Observers will also be keen to see new concrete measures for tackling the world's financial architecture that include regulations to check future crises, he added.

"The only idea that has been generally agreed is the disappearance of tax havens," Milton said. "Six months have passed debating other measures within the G20 mechanism, but what are we doing?"

International financial institutions (IFIs) including the World Bank, the International Monetary Fund and development banks remain governed by financial structures set up by the 1944 Bretton Woods agreements, which were driven by a need to prevent a further world war and fears about the expected Cold War.

Now that 55 years have passed, the world has changed more profoundly and more quickly than the IFIs, he said.

"It has been recognized that there are structural errors in the international financial system," Milton said. "We have overcome the worst effects of the world financial crisis, but now the sense of urgency has gone."

Initiatives like South America's Bank of the South (BotS) might prove to be a viable alternative to the systems grounded in the Bretton Woods agreements, unless those institutions move swiftly to update themselves, Milton went on to say.

The BotS is a Venezuela-led initiative that has found support in nearby Brazil, Argentina, Ecuador and Bolivia.

"Venezuela's President Hugo Chavez has been trying to create a region-wide financial institution because of the obsolesce of the Bretton Woods institutions," Milton said.

"This attempt is worthwhile and could work," he said, adding that it remains to be seen if Pittsburgh can generate realistic ideas to update the IFIs.