Cooling hot cities 为酷热的城市降温
 

　　地球正在升温，这个现象在人口密集的城市尤其明显。城市中的混凝土建筑和道路会吸收并锁住热量；同时，虽然人们家中安装的空调可以让室内变得凉爽，但这增加了二氧化碳的排放量。本文介绍为保持城市生活舒适度应运而生的可持续创新降温方法。

　　词汇：climate 气候

　　We're all familiar with the idea of climate change and how our planet is warming. Extremes in temperature have become more commonplace, making parts of the world difficult to live in. But one place where excessive heat is making life very uncomfortable is our cities. Luckily, innovation might be keeping a lid on it.

　　As thermometers record temperatures, sometimes above 50 degrees Celsius, solutions are being sought to cool the air in our cities. In India, for example, heatwaves and rapid urbanisation have led to a big rise in the use of air-conditioning units, adding to CO2 emissions. So, architects, looking for a sustainable cooling solution, are reviving an ancient 'lattice' design, used in old buildings like the Taj Mahal, to construct comfortable, low-carbon buildings. Yatin Pandya told the BBC: "Traditional architectural forms have proven their performance in combatting environmental conditions."In America, about 80% of the population lives in cities, and it's these cities that suffer from an urban heat island effect, caused by factors such as trapped waste heat, concrete structures and pavements absorbing the sun and tall buildings blocking the wind. Residents and developers have tried to heatproof these places by planting large trees that offer shade and putting plants and gardens on top of roofs that use vegetation to help trap heat. And in Los Angeles, there's an experiment to cover streets with light-coloured material that reflects rather than absorbs the sun and so they remain cooler than typical black roads.

　　But it's satellites in space that are really giving us the best picture of our over-heated cities. Glynn Hulley, who is leading an image-capturing project, called the Land Surface Temperature Monitoring mission, told the BBC: "The data can be used to identify hotspots, vulnerable regions, and assess the cooling impacts of heat mitigation approaches." It's already found how green spaces, white roads and water features, have helped prevent our cities from boiling over. But with excessive heat still posing a threat to our lives, more solutions are still needed.

　　词汇表

　　extreme 极端

　　excessive heat 过热，极度高温

　　innovation 创新

　　keep a lid on (something) 防止（情况）失控thermometer 温度计

　　heatwave 热浪，酷热期

　　urbanisation 城市化

　　air-conditioning unit 空调

　　sustainable 可持续的，长期有效的

　　low-carbon 低碳的

　　combat 抵御，对抗

　　urban heat island effect 城市热岛效应

　　trapped waste heat 散发不出去的废热

　　heatproof 使…隔热

　　shade 阴凉处

　　vegetation 植物，植被

　　reflect 反射

　　over-heated 过热的，气温过高的

　　hotspot 高温地区，热点

　　cooling 降温，冷却

　　mitigation 缓解

　　green spaces 绿地，绿色空间

　　water features 人工水景

　　boiling over （变得）过热