Former U.S. President Barack Obama called on Monday for rich nations to end years of deadlock with developing countries over cash for climate change, and criticised China and Russia for their "lack of urgency" in curbing emissions.

"We have to act now to help with adaptation and resilience," Obama told a meeting of island nations at the summit, adding that his views on the immediacy of the threat had been shaped by his experience growing up in Hawaii.

Obama said too little progress had been made since the 2015 Paris Agreement to try to curb warming at 1.5 degrees Celsius above pre-industrial levels and lambasted China and Russia for a lack of commitment in making the Glasgow talks a success.