Opponents of runway plan should look beyond the dolphins to see the wider harm

The debate over a third runway at Hong Kong's airport is heating up again, but it is a debate in name only. In reality, the outcome is a foregone conclusion with only minor tweaks, such as the date to begin construction, yet to be worked out.

The "debate" has mostly been between the pro-business forces and the dolphin lovers. While experts argue about whether local dolphins can withstand yet another encroachment on their habitat, somehow the affordability of a third runway, said to cost HK$136 billion, has been shuffled aside. Nevertheless, when figures in the hundreds of billions are thrown around, it will take more than a few dozen dolphins to stop the new runway juggernaut.

Lost in this debate, however, is another environmental matter that gets little attention, namely, the assumption that unbridled economic growth is unassailable. A few numbers will help in understanding the broader implications.

At the present rate of growth - about 20,000 more take-offs and landings with each passing year - current projections show the airport under its two-runway system reaching capacity in about five years.

Assuming it takes about 10 years to build the third runway, full operations will not start much before 2025. However, at that stage, given the present rate of growth, plans for a fourth runway would need to be quickly put in place because public discussion coupled with construction need about 15 years. That would take us well into the 2030s, by which time the major debate would not be about dolphins - which, by this time, will be long gone - but about the lack of sea space for landfill, and noise levels in Tuen Mun. In essence, it is not unrealistic to foresee the waters between Chek Lap Kok and Tuen Mun being fully converted to runways half a century from now.

The absurdity of this projection should be clear. Unrestrained growth is not sustainable.