US and China to lead climate change push at summit

China and the United States are expected to give the Paris climate change agreement a big push forward as the world's largest economies gather for the G20 Summit this weekend, experts say.

With China - which has shown growing international leadership on climate change - hosting the summit for the first time, "we can expect climate and energy to be front and center", said Joanna Lewis, a specialist at Georgetown University on energy and environmental issues in China.

The summit on Sunday and Monday is also the last for US President Barack Obama, who hopes to cement action on climate change as one of his legacy issues, experts say.