Environmentalist and former US vice president Al Gore voiced high hopes Monday for global climate talks due in Paris in December, saying "the future of the world depends" on their outcome.

The major United Nations conference, which will bring 125 countries together in the French capital, aims to reach a legally-binding global agreement on climate.

"The world is fortunate that France is hosting this important conference in December. They've spared no effort to make it a success," Nobel Prize-winner Gore said in a meeting with French President Francois Hollande.

"In the last century an American poet could have been writing about the string of conferences on climate when he wrote the words 'after the last no comes the yes'," Gore added, referring to Wallace Stevens.

"And on that yes the future of the world depends. This conference is the one where the world will say yes to an agreement to reduce global warming."

A ministerial-level meeting of UN climate negotiators in Lima last December yielded a 37-page blueprint for an agreement, which countries had in 2011 agreed to finalise by the end of this year.

The pact must enter into force by 2020 to further the UN goal of limiting global warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.

Scientists warn that on current greenhouse gas emission trends, the Earth is on track for double that -- a recipe for catastrophic droughts, storms, floods and rising seas.

Also on Monday, French Foreign Minister Laurent Fabius warned that the international community "does not have the right to fail" at the upcoming climate talks.

"We must resolutely engage because there is no other solution, for the simple reason that there is no alternative planet," Fabius said in Berlin.

Representatives of 35 countries have gathered in the German capital to prepare for the December talks, known as the 21st yearly session of the Conference of the Parties to the UN Framework Convention on Climate Change, or COP 21.