Science and Engineering

How to Build a Liveable Mega-city?

It is inevitable that the city will be the dominant space for the future of humanity. In particular the rise of the mega-city has been a particular transition in recent decades.

Many mega-cities have grown organically. They sprawl into the countryside and grapple with environmental problems such as air and water pollution and cope with enormous volumes of domestic and industrial waste. The countryside becomes valued for its unpolluted naturalness, while the city is portrayed as a source of pollution and waste.

However, a positive view of cities develops from contemporary notions of New Urbanism and the sustainable or eco-city. These eco-cities aim to minimize their contribution to climate change, and produce little pollution; they compost and recycle materials, encourage urban agriculture and convert waste to energy. They take advantage of the high population density to have a small ecological footprint.

In Hong Kong, we need clean air. We need a sustainable and secure supply of energy, water and food. The city produces large quantities of sewage and solid waste, but it is unclear how to make the best policy decisions to ensure that their impact on the environment is minimized.

Scientific analysis can help us understand the constraints under which a city operates and minimise the use of resources and the creation of pollution, while maximising efficiency. Science can also provide the basis of new technologies that improve the energy efficiency of buildings, enhance the yield of urban agriculture, and increase the attractiveness of renewable and carbon-neutral sources of energy and of recycled water.

Science has not always played a big part in Hong Kong's policy development, yet the complexity of sustainability issues makes its role more important in the future. Science can also provide an improved understanding of the urban environment and the accompanying technology allow cities to be more liveable.