Why brownfield sites are a greener option for housing development in Hong Kong

The Wang Chau housing saga is an excellent example to illustrate the environmental dilemma over brownfield sites versus green belt land for development. The earmarked area in Yuen Long of mostly brownfield site is not a bad choice for development, given its low ecological value. However, one thing is clear: there should be more rigourous control over the growth of such sites in Hong Kong.

In this city of 110,000 hectares, about 40 per cent is protected under the Country Parks Ordinance. As such, other land use zones, such as green belt and brownfield sites, are susceptible to rezoning for development.

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Green belts serve as a buffer for the conservation of existing features, and total about 15,200 hectares or 13 per cent of land in the city. According to the Development Bureau, there is no official definition of a brownfield site, but it generally refers to deserted agricultural or rural land already developed for use, for instance as port backup land, or workshops, recycling yards and open storage facilities. Given the lack of a clear definition, there are no official figures about the total area of brownfield sites in Hong Kong .

Nonetheless, community group the Professional Commons used Google Maps, Google Earth and Google Street View to come up with an estimated figure of 1,192 hectares for brownfield sites, or about 1 per cent of Hong Kong’s total area.

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Despite their relatively small share of total land, it would be a strategic move to prioritise development of brownfield sites, to avoid destroying green belt areas. A number of environmental problems could be triggered by clearing land of conservation value, such as loss of habitat, an impact on the microclimate, reduced ability of the land to act as a carbon sink, acidification, the disruption of the nitrogen cycle, and so on.

Therefore, the development of Wang Chau is a sound strategy purely from the perspective of land choice. Green belts are not protected; in fact, the government’s “Long Term Housing Strategy” report in 2015 said 50 potential housing sites had been identified on green belt land.

Tough questions for all those involved in Hong Kong’s Wang Chau housing saga

This is not to say developing brownfield sites is a better option; it is more of a strategic move, since the land has already gone to waste. More importantly, brownfield sites need to be managed as they appear to be growing in size and number, either legally through rezoning or illegally by dumping waste and clearing vegetation, thus destroying the land.

Greater efforts to manage the growth of brownfield sites will help avoid the environmental problems associated with clearing green belt areas.

Dr Elizabeth Lai is CEO of Reconnect Limited, a charity specialised in environmental education. To learn more about the nitrogen cycle, see: https://youtu.be/ND4caCj-clg