单选题 Humanity has passed a milestone: more people live in cities than in rural areas. The current rate of urbanization is unprecedented in our history. In 1950, only 29% of people lived in cities, by 2050, 70% are projected to do so — most of them in poorer countries. Among many other issues, this rapid concentration makes cities a front line in the battles against climate change and pollution. Confronting the challenges of rampant urbanization demands integration multidisciplinary approaches, and new thinking. Take the building boom associated with the increased wealth of urban areas, and its impact on greenhouse-gas emissions as example. In China alone, the United Nations Environmental Program estimates the energy demand for heating homes build over the next decade could increase by some 430 terawatt-hours, or 4% of China's total energy use in 2003. Worldwide, the energy consumed by buildings already accounts for around 45% of greenhouse-gas emissions. Fortunately, researchers in Germany and elsewhere have already shown that they can reduce that energy consumption by 80%-90%, just by overhauling obsolete building designs and using existing technologies. These ultra-efficient buildings demand that planners, architects, engineers and building scientists work together from the outset, and require higher levels of expertise the conventional buildings. But such buildings are often cheaper than those built using conventions methods. Research is also needed to develop technologies, materials and energyconcepts; the green building research today is fragmented and poorly funded. Expanding cities must embrace such technologies and strategies — and not just in the developed nations. Many poorer countries have a rich tradition of adapting buildings to look at practices, environments and climates—a home-grown approach to integrated design that has been all but been lost in the West. They now have an opportunity to combine these traditional approaches with modern technologies. Integrated thinking is also needed to mitigate urban air pollution, which is becoming serious health and environmental risk in many regions—as shown by China's struggle to clean up Beijing's air for the Olympics. Understanding air pollution will require researchers from multiple disciplines, from atmospheric chemistry to meteorology, working over scales from street level to global. And reducing it will require integrated policies for urban planning, transport and housing — not least to reduce the use of cars.

单选题 The passage begins with______.

单选题 From the illustration of China, the author is trying to tell us that______.

单选题 Which of the following can meet the demand by the rampant urbanization?

单选题 The author thinks highly of those poorer countries______.

单选题 China's struggle to clean up Beijing's air for the Olympics, according to the passage, is a convincing example of______.