John Chan Koon-chung resumes his role as a green activist, driven by a sense of urgency against climate change.
Better known for founding City Magazine in the 1970s, Mr Chan, a newly elected board member of Greenpeace International, said global warming had evolved into a "round-the-corner disaster".
"We only talked about that in the 80s, while no one would have imagined how quickly it is happening," the Beijing-based writer and cultural critic said.
He was a member of the government's advisory committee on environmental protection before leaving Hong Kong in the early 1990s, partly because of bureaucratic frustrations.
"The agenda was set by the administration, which discussed targets and figures instead of raising incentives on environmental protection," he said.
Thanks to Nobel Peace Prize winner Al Gore, Mr. Chan said global awareness of climate change was now much higher.
While ideas and solutions were not lacking, now all that was needed were clues on implementation.
"I am optimistic on willpower, but pessimistic on reason [in the fight against global warming]," he said.
"We have to mobilise the masses and tell them their participation can make a difference."
Referring to the green measures adopted in Hong Kong, he said he was not happy with the fact that the city was not required to commit to any greenhouse gas emission limits under the Kyoto Protocol as it was part of China.
"It is a shame we hide behind the shadow of the mainland on environmental protection. Looking at the per capita GDP of the city, I do not see a reason why we should not shoulder the responsibility against global warming," he said.
Contrary to Hong Kong, Mr Chan said the mainland had advanced quickly in promoting green measures in recent years.
"Use of compact fluorescent lamps is now state policy, while the Olympics this year also offers an opportunity to introduce more green products," he said, adding that renewable energy, such as solar power, was becoming more prevalent, given the extensive market.
Officials' achievements on environmental protection on the mainland were now considered in their work assessments, he said.
Mr Chan said many green measures were not new to the public and feared people would be tired of more promotions.
"Perhaps you and your family can go and travel by riding a bus on holiday, instead of driving your own car.
"You can also switch off electrical appliances instead of leaving them on standby mode when you go out for dinner," he said. "They are concrete but simple steps."
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