A total of 138 heads of state and government so far will attend a climate summit due to kick off in terror-hit Paris on November 30, the French government said Friday.

Panama's President Juan Carlos Varela was the latest to confirm his attendance at the opening by world leaders including US President Barack Obama, China's Xi Jinping, Narendra Modi of India and Russia's Vladimir Putin, a French presidency official said.

The summit will open in the French capital just two weeks after last Friday's jihadist massacre of 130 people out for dinner, drinks and a concert.

The Paris Conference of Parties (COP21) is tasked with producing the first-ever deal committing all the world's nations to climate action starting in 2020.

About 160 countries have already filed voluntary carbon-curbing pledges to underpin the future pact, but scientists say the aggregate effect falls far short, and Earth is on course for warming of about 3 C, or more.

Scientists say 2 C is the threshold beyond which humankind will struggle to adapt to massive crop failures, water shortages, killer storms, disease spread and wars over dwindling resources.