UN Secretary Antonio Guterres. (Photo: Reuters)

The summit aims to accelerate actions to implement the Paris Agreement on Climate Change and hold average global temperature increase below 2°C.

In his opening speech, UN Secretary General Antonio Guterres warned that the world is facing at least three degrees Celsius of global heating by the end of the century. He asked leaders to come to the summit with pledges consistent with reducing greenhouse gas emissions by 45 percent by 2030 and then to net zero by 2050.

All 60 countries committed to net-zero carbon dioxide emissions by 2050.