Nobel Laureate Steven Chu on Tuesday called for greater international cooperation in coping with climate change and wider-scale application of clean energy.

While delivering a speech entitled "Energy, Climate Change and the Transition to a Sustainable World" at the Hong Kong University of Science and Technology, Chu warned of the risks of climate change.

"The World Meteorological Organization has ranked 2014 as the hottest year on record, as part of a continuing trend. Fourteen of the 15 hottest years have been in 21st Century," he said, adding that global warming is likely to continue, given that rising levels of greenhouse gases in the atmosphere and the increasing heat content of the oceans.

"The damage already done to our environment may not be known for a century," Chu warned.

He stressed international cooperation in dealing with climate change and suggested that countries should not be too obsessed with economic growth.

During his speech, Chu also shared his observations on the rapidly-changing energy landscape, and how clean energy sources are becoming the low cost option to people's energy needs.

An established physicist and a champion in clean energy, Chu co- won the Nobel Prize in Physics in 1997 for a method to cool and trap atoms along with his colleagues Claude Cohen-Tannoudji and William Daniel Philips.