Urban Kidney 都市腎臟

When I take a sip of coffee and a piece of bread, I wouldn’t speculate the aftermath of them - well, at least not every time. The same would happen when I flush the toilet or dump the food leftover in trash can. 當我啜飲咖啡、啃食麵包的時候,我不會去思索它們的去向──至少不會每次都想。同樣的情況發生在我沖馬桶和倒垃圾的時候。 Dr. Hall (I mean Charlie) lectured on the natural nature of cities, which resembled communities in ecosystems or organisms in species. Cities are like human bodies too, taking energy and material from outside and producing waste after consuming them. The only one difference that I can think of now is that cities are partly autotrophic because of the existence of urban forest, but we don’t have algae on our skin to undergo photosynthesis. In fact, this difference doesn’t make a difference. The biomass production in urban neighborhoods is only a tiny fraction (1/200~1/700) of the energy consumed by residence and transportation in the same area, according to a paper in press by Prof. Hall (2011), which means the cities...