Peter Thomson, president of the 71st session of United Nations General Assembly speaks during a media stakeout after the opening of the 71st session of the UN General Assembly at UN Headquarters in New York, Sept 13, 2016.[Photo/Xinhua]

The theme will be further strengthened in the annual high-level debate of the General Assembly, the week-long event which is set to begin on Sept. 20.

Also speaking at the opening ceremony, UN Secretary-General Ban Ki-moon said, "I welcome the theme you have chosen for this session."

"This first year is crucial. It is a time when all member states should align their policies, programmes and spending behind the 17 goals," the secretary-general said. "It is also a time to bring the Paris Agreement on climate change into force."

The high-level event Ban is hosting on Sept 21 will strengthen momentum for achieving that objective this year.

At the same time, the 71st session of the General Assembly is expected to appoint the next UN secretary-general upon the recommendation of the Security Council to succeed Ban, who will end his term on Dec 31.