What is the single most effective way to reduce greenhouse-gas emissions? Go vegetarian (素食)？ Replant the Amazon? Cycle to work? None of the above. The answer is: make air-conditioners better. On one calculation, replacing refrigerants (制冷剂) damaging the atmosphere would reduce total greenhouse gases equaling 90bn tonnes of CO2 by 2050. Making the units more energy-efficient could double that. By contrast, if half the world's population gave up meat, it would save 66bn tonnes. Replanting two-thirds of tropical forests would save 61 bn tonnes. A one-third increase in global bicycle journeys, just 2.3bn tonnes.
Air-conditioning is one of the world's great overlooked industries. Automobiles and air-conditioners were invented at roughly the same time, and both have had a huge impact on where people live and Work. Unlike cars, though， air-conditioners have drawn little criticism for their social impact, emissions or energy efficiency. Most hot countries do not have rules to govern their energy use. There is not even a common English word for “coolth” (the opposite of warmth).
Yet air-conditioning has done more than most things to benefit humankind. Lee Kuan Yew, the first prime minister of Singapore, called it “perhaps one of the signal inventions of history”. It has transformed productivity in the tropics(热带地区)and helped turn southern China into the workshop of the World. In Europe, its spread has pushed down heat-related deaths to 10% since 2003, Men 70,000 people than usual, most of them elderly, died in a heatwave. For children, air-conditioned classrooms are associated with better grades at school.
Environmentalists who call air-conditioning “a luxury we cannot afford” have half a point, however. In the next ten years, as many air-conditioners will be installed(安装)around the world as were put in between 1902(invention time)and 2005.Unless energy can be produced without carbon emissions, these extra machines will warm the world. At the moment, therefore, air-conditioners create a vicious cycle. The more the Earth warms, the more people need them. But the more there are, the warmer the world will be.
Cutting the impact of cooling requires three things. First, air-conditioners must become much more efficient. The most energy-efficient models on the market today consume only about one-third as much electricity as average ones, Minimum energy-performance standards need to be raised raised, orintroduced in countries that lack them altogether, to push the average unit's performance closer to the standard of the best.
Next, manufacturers should stop using damaging refrigerants. One type called hydrofluoro-carbons, is over 1,000 times worse than carbon dioxide when it comes to trapping heat in the atmosphere. An international agreement to knock out these pollutants will come into force in 2019.
Last, more could be done to design offices, malls and even cities so they do not need as many air-conditioners in the first place. More buildings should be built with overhanging roofs or balconies for shade, or with natural ventilation (自然通风).Simply painting roofs white can help keep temperatures down. Providing indoor air-conditioned comfort need not come at the expense of an overheating world.
a. design natural cooling buildings
b. raise standards for energy-performance
c. make laws for international cooperation
d. stop applying harmful refrigerants to production
