Beijing, Aug 24 (IANS): US President Barack Obama's senior climate change advisor Brian Deese is in Beijing to assess key climate change issues ahead of Obama's upcoming visit to the country for the G20 summit in early September, the US Embassy here said on Wednesday.

Deese will meet Vice Premier Zhang Gaoli, and the special representative for climate change in China, Xie Zhenhua, to discuss imperative climate change issues, including the implementation of the agreement reached in 2015 in Paris during the COP21 climate summit, Efe news reported citing a statement by the US Embassy.

They will also discuss mutual efforts to amend the Montreal Protocol, adopted in 1987 to protect the Ozone Layer, to include more measures to check hydro fluorocarbons, or HFCs, a greenhouse gas used in refrigerators and air conditioners.

They will also discuss a global market-based measure to check greenhouse emissions from international aviation, following up on previous agreements between Obama and Chinese President Xi Jinping.

China and the US, the two most polluting countries in the world, have reached landmark agreements in the last three years to tackle climate change.

During Obama's visit to China in November 2014 to attend the APEC (Asia Pacific Economic Cooperation) forum, the two countries signed a historic agreement to reduce their greenhouse emissions over the next two decades.

Obama's upcoming visit to China for the G20 Summit, to be held in the eastern Chinese city of Hangzhou on September 4 and 5, is also expected to focus on the fight against climate change.