During his three-day visit to China, UN Secretary General Ban Ki-moon joined an event aimed at promoting sustainable development on Wednesday, after a series of meetings with China's top officials in Beijing.

The UN-hosted event, dubbed "The Future We Want," is a global campaign that was initiated by Ban in November 2011 to call on people around the world to share their visions and hopes for the future. Three million Chinese people participated in the campaign through social media conversations, especially Weibo, where they shared hopes and expectations for a future world.

An impressive 232 Chinese residents from around the nation participated in the production of a public-service film, in which they stated their expectations for the world 20 years in the future. The film was presented at the Rio+20 summit held in Brazil last month.

"We already know a great deal about 2032. We know that we will need 50 per cent more food, 45 per cent more energy and 30 per cent more water - just to continue to live as we do today," Ban said at the event.

"The world needs a new course that truly balances economic growth, social development and environmental stewardship," he said. "Rio+20 was not an end but a new beginning - a milestone on an essential journey toward 2032 and beyond."

It is Ban's fifth visit to China since 2007, when he took office as UN Secretary General. He arrived in Beijing on Tuesday and held an online conversation in the evening with Chinese Weibo followers, who asked more than 16,000 questions covering various issues such as the role of UN, the Syrian crisis, youth unemployment and human rights.

Ban met with Chinese President Hu Jintao and Foreign Minister Yang Jiechi in Beijing Wednesday, when he expressed his deep appreciation for China's leadership and active participation in the United Nations, and exchanged ideas with them on global issues, including developments on the Korean Peninsula and in Syria.