The Group of 20 (G20) leaders except U.S. President Donald Trump on Saturday reaffirmed their commitment to the Paris Agreement, saying it is "irreversible", read a declaration after the conclusion of the G20 summit in Hamburg.

The G20 leaders said in the declaration that they remain "collectively committed" to mitigate greenhouse gas emissions through increased innovation on sustainable and clean energies and energy efficiency, but "take note of" the decision of the United States to withdraw from the agreement.

"The United States of America announced it will immediately cease the implementation of its current nationally-determined contribution and affirms its strong commitment to an approach that lowers emissions while supporting economic growth and improving energy security needs," it added.

Nevertheless, leaders of the other 19 members reaffirmed in the declaration their "strong commitment to the Paris Agreement, moving swiftly towards its full implementation in accordance with the principle of common but differentiated responsibilities and respective capabilities, in the light of different national circumstances."

The Paris Agreement aims to tackle climate change by cutting greenhouse gas emissions and sets a global target of keeping the rise in the average temperature no higher than 2 degrees Celsius above pre-industrial levels.

Themed "Shaping an Interconnected World," the Hamburg summit kicked off Friday.

Argentina will take over the G20 presidency from Germany in December, and host the 2018 summit.