Thanks to fellow physicist Jason Pun Chun-shing and his quantitative assessment, we now know that Hong Kong is not just a world-class light polluter, but the world leader ("Light pollution in HK 'worst on the planet'", March 20).
Ironically, the epicentre is near the Space Museum. This is just confirmation of what I have already known qualitatively for the past 15 years teaching astronomy just up the road at the Polytechnic University.
At the beginning of the semester, I implore students to "imagine" a deep dark night sky, something few have ever in their lifetimes experienced. Only once was I ever successful in showing the Milky Way and that was to 120 students on a trip to Inner Mongolia.
I also teach human ecology, the study of ecosystems with human beings in them. It isn't just the upset of circadian rhythms and hormonal imbalances which are unhealthy. Our light pollution problem is simply indicative of a much larger one.
Biologists point out that we are in the midst of an anthropogenic mass extinction event, that for the first time in four billion years of geological history, one species, us, is undoing the very substrate of the natural world that all creatures are dependent upon.
A major part of the problem is that overwhelmingly our kind live a life of deep urban bias and are ignorant of the dictates of nature.
Dangerously ill-equipped, how can we possibly make sustainable decisions? During an entire 24-hour period, how many of us have travelled anything other than a man-made path?
This is the true challenge of the 21st century, to turn this around, to learn to embrace what the American poet Gary Snyder calls the "real work" that all of us, regardless of profession or preoccupation, need to learn to take on.
I am fortunate. Raised in part in upstate New York, I have had direct visceral experiences of nature.
The Iroquois have a bicameral legislature, a longhouse of the men and another of the women.
Identity is not narrowly human for there are various clans, such as the wolf, bear, and turtle. These are "councils of all beings". And policy issues must address a single question, "How will this affect us for seven generations into the future?", not just the next fiscal quarter. That "us" is not exclusively human.
When will we start the conversation in Hong Kong?
Dr John Freeman Babson, Department of Applied Physics,Hong Kong Polytechnic University