The dimming of Hong Kong's skyline for an hour one Saturday night late last month was a rehearsal of how it could truly be a "world city" in Asia.
If Hong Kong is to have a future that we are all proud of, sustainability must shine through darkness, not flashy neon and LED lights.
Many of us know about climate change and how it may affect human life. We know that the polar ice caps are rapidly melting, that the shoreline of some countries is sinking, and that food security is a real risk. In fact, many understand that we are risking our own well-being by not acting differently now.
The companies that took part in the Earth Hour campaign helped raise awareness, but did not save the world, of course.
What is more important is for people to make a commitment to significantly reduce the adverse environmental impact of their habits, both in their personal life and their businesses. Every company needs to look at how it can change its business model and use resources more efficiently.
Corporate responsibility could start as a business practice to save costs. For example, companies would profit from investing in power-smart facilities with energy efficiency labelling, and putting in place demand-side management that encourages less use of energy.
Over the past decade at least, Hong Kong has seen numerous campaigns that aimed to change consumer behaviour, both in the public and private sectors.
Some in Hong Kong are heeding the call. Together they have saved more than 143 million kWh so far, according to an energy-saving contest organised by Friends of the Earth. The energy saved is equal to that needed to power three million air conditioners for average-sized bedrooms for 48 hours. In monetary terms, HK$140 million was saved.
In one laudable government-backed campaign last year, some shopping malls agreed to adjust their air conditioning, which in Hong Kong tends to be set too cold and is the region's main medium for extravagant energy use.
Such efforts could lead to cultural and habitual change and teach us how to respect and value our planet and natural resources.
However, according to a report from Climate Change Business Forum, only 13 per cent of Hong Kong businesses reported demand for energy-efficient, low-carbon products and services.
This means corporate responsibility has not gone far enough to make a fundamental impact.
Indeed, we have too few role models in the private sector. Friends of the Earth has found that successful cases usually have committed leaders and responsible managers. Some of these leaders have said they want to initiate a code of conduct and even favour stringent legislation which they say can help break unconstructive competition in their own industries.
Whether a government task force set up to tackle light pollution can do so will be another test of our commitment to energy conservation.
We need to reduce our extravagant use of energy and to have a meaningful light pollution guideline to help resolve the intrusion of light in the community, which has been a harmful nuisance to individuals.
Our society now needs to go beyond planning for voluntary guidelines, which will have little effect, and initiate appropriate legislation.
A green mantra will only have the effect of a magic wand if those chanting it act wisely and decisively.
Mayling Chan is chief executive officer of Friends of the Earth (HK). firstname.lastname@example.org