G7 leaders called at a summit Monday for a "decarbonisation of the global economy" and said deep cuts in greenhouse gas emissions are needed over the course of this century.

Ahead of a UN climate summit in Paris late this year, the Group of Seven major industrialised nations urged global emissions cuts at "the upper end of" the 40-70 percent range by mid-century compared to 2010 levels.

The G7 also reaffirmed the goal of limiting global warming in the 21st century to two degrees Celsius (3.6 degrees Fahrenheit) from pre-industrial levels, first agreed at a 2009 UN climate summit in Copenhagen.

Scientists warn that on current trends, Earth is on track for double that target.

The goal in cutting heat-trapping greenhouse gases is to slow global warming which is blamed for melting the planet's ice caps and glaciers, raising sea levels and causing more violent storms, floods and droughts.

"Urgent and concrete action is needed to address climate change," the G7 leaders said in a final statement after a two-day summit in Germany.

"We emphasise that deep cuts in global greenhouse gas emissions are required with a decarbonisation of the global economy over the course of this century."

US President Barack Obama said "we continued to make progress toward a strong climate agreement in Paris".

And French President Francois Hollande welcomed the "ambitious and realistic commitments", adding: "We do not have the right to fail".

- 'Fossil fuel days numbered' -

The Group of Seven leading industrialised countries -- Britain, Canada, France, Germany, Italy, Japan and the United States -- make up about 10 percent of the world population but one quarter of global emissions.

Not at the G7 summit were China, the world's number one polluter, and other big emerging economies such as India, Russia and Brazil.

The G7 nations also said they were committed to jointly mobilise financing from public and private sources for a previously agreed $100-billion fund to finance climate efforts in poor countries from 2020.

They also committed "to doing our part to achieve a low-carbon global economy in the long-term including developing and deploying innovative technologies striving for a transformation of the energy sectors by 2050".

G7 countries agreed to support a set of initiatives to expand renewable energy in developing countries, particularly in Africa.

Environmental groups broadly welcomed the fact that the G7 meeting at Germany's Elmau Castle resort had acknowledge that "the days of fossil fuels and carbon pollution are numbered", but criticised members for being vague on the details.

"Elmau delivered," said Greenpeace climate expert Martin Kaiser, adding that at the summit "the vision of a 100 percent renewable energy future is starting to take shape while spelling out the end of coal".

He added however that "some G7 leaders have left the door open for high risk technologies, like nuclear energy and carbon capture and storage".

Oxfam's Jorn Kalinski said that "G7 leaders have indicated that fossil fuels are on their way out" but added that "they must now live up to their own rhetoric and kick their dirty coal habit".

"They must also reassure developing countries that they will keep their promise to deliver $100 billion by 2020 for climate action in developing countries, and provide the additional predictable funding needed in the longer term."

WWF said the G7 had sent "important political signals but few concrete commitments from the countries themselves ... The course is right, but more speed, ambition and specific actions are needed".

Its climate expert Samantha Smith said that on the $100-billion fund so far "we have seen just over $10 billion committed. We would have liked the G7 to have provided certainty on finance".

She stressed that although G7 leaders "left out the details... it is clear after this meeting that the days of fossil fuels and carbon pollution are numbered".