German Chancellor Angela Merkel (3rd R) and U.S. President Barack Obama (2nd R) talk during the G7 summit at the Elmau Castle near Garmisch-Partenkirchen, southern Germany, on June 8, 2015. G7 summit concluded here on June 8. [Photo/Xinhua]

The Group of Seven (G7) leaders reaffirmed their commitment on Monday to fill a gap of financial support to developing countries for addressing climate change, and declared to seek a phaseout of fossil energy globally within this century.

Although the "club of rich countries" described their commitment as "ambitious", analysts doubted that considering their past real actions, what G7 made here could be another empty promise.

In a communiqué issued after the two-day G7 summit in luxurious Palace Elmau at the foot of Alps in Germany's southern Bavaria, leaders from the United States, Germany, France, the United Kingdom, Italy, Canada and Japan said they would continue their efforts to meet their previous commitment of providing 100 billion U.S. dollars a year by 2020 from both public and private sectors to developing countries to help them battle against climate change.

Other targets include: to seek a global decarbonization over the course of this century, to reduce global carbon emissions by 40 to 70 percent by 2050 compared to 2010 levels and to transform their own energy sectors by 2050.

"Urgent and concrete action is needed to address climate change," said the G7 leaders in the communiqué, asking "all parties" to share the task of emission cutting.

French President Francois Hollande, whose country will host the United Nations climate conference where a new global climate deal was set to be reached at the end of this year, was quoted by AFP as saying that the commitments was "ambitious and realistic".

Environmental activists, however, said the seven leading industrialized countries need more actions than words.

"G7 leaders still aren't spelling out how they will keep their promise to deliver 100 billion U.S. dollars in climate finance by 2020 and failed to commit to provide more of this money from public funds -- a vital foundation for success in Paris at the end of the year," commented Oxfam, an international nongovernment organization on development issues, "Developing countries need a credible financial roadmap, not a set of accounting tricks."

"Developing countries are ready to move fast and far on renewables, but they need finance and technology from rich countries to do it. We need to see more of these concrete commitments for immediate action," said Samantha Smith, leader of WWF's Global Climate and Energy Initiative.

The developed countries, including the G7, which held historical responsibilities to the climate change, promised in 2009 to increase their climate financial support to developing countries to 100 billion U.S. dollars a year by 2020. A clear roadmap to meet this commitment, however, was never provided.