HANGZHOU -- Presidents of China and the United States handed over their countries' instruments of joining the Paris Agreement separately to Secretary-General of the United Nations Ban Ki-moon on Saturday in Hangzhou.

Chinese President Xi Jinping said that climate change concerns the well-being and future of humanity. The Paris Agreement has charted the course for post-2020 global cooperation against climate change, and it indicates that a cooperative, win-win, equitable and fair climate governance mechanism is being shaped.

The handover of the legal document is a new and solemn commitment of the Chinese government, he said.

Depositing the documents together, China and the United States have displayed their ambition and determination to jointly tackle a global challenge, Xi said.

Taking advantage of implementing the Paris Agreement, the international community should make greater efforts to improve global governance mechanism and innovate on relevant actions, so as to facilitate the full operation of the agreement, the president said.

Developed countries should honor their commitments and provide financial and technological support to developing countries and enhance their capability in climate actions, Xi said.

China, a responsible developing country and an active player in global climate governance, will implement its development concepts of innovative, coordinated, green, open and shared growth, fully advance energy conservation, emission reduction and low-carbon development, and embrace the new era of ecological civilization, he said.