Many Cities Unprepared for Intense Heat Waves, Experts Say
2021-07-31
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1Many places in the northern half of the world are currently facing record-breaking heat.
2Several countries in the Middle East, including Iran, Kuwait, Oman and the United Arab Emirates, recorded days over 50 degrees Celsius in recent months.
3Moscow and Helsinki, Finland also reported their hottest June temperatures on record.
4Several weeks ago, there was a record-breaking heat wave in the Pacific Northwest of the United States and western Canada.
5Oregon and Washington state reported almost 200 heat-related deaths.
6Jennifer Vanos is an assistant professor at Arizona State University.
7She said: "(Heat) is different than other extremes because...it's invisible."
8She added that when "it's something people have never experienced before, then it becomes a lot more dangerous."
9A United Nations group on climate change says cities can be dangerous places during heat waves.
10City buildings and streets can make temperatures rise.
11And with more than 50 percent of the world's population living in cities, experts fear that heat-related health problems will become more common.
12Cities can be several degrees hotter than rural environments.
13This effect is known as the urban heat island.
14Hashem Akbari studies urban heat islands at Concordia University in Montreal.
15He said building materials in cities take in heat and hold it.
16Asphalt, for example, is a petroleum-based mixture used in streets and on the tops of buildings.
17Its dark surface reflects little light and absorbs heat.
18At the same time, buildings are often close together, which means there are fewer trees and plants.
19Plants provide valuable cover from the sun.
20Plants also absorb water through their roots and use surrounding heat to evaporate the water from their leaves.
21With fewer plants, this natural cooling effect is gone, Akbari said.
22To avoid the heat, people living in cities use electricity to power air cooling systems and fans.
23On a very hot day, those technologies use a lot of electricity.
24Sayanti Mukherjee is an assistant engineering professor at the University at Buffalo, New York.
25She said cities have "a higher population to serve, so the infrastructure is working at a higher capacity because of the demand."
26But sometimes the electricity system is unable to supply enough power to meet the demand.
27If that happens, the system shuts down and the power shuts off.
28Extreme weather events, however, are unusual.
29That makes it difficult for city planners and engineers to prepare for conditions that might not happen very often.
30The materials used to make urban infrastructure also are affected by high heat.
31Heat makes metal materials expand. Power lines, for example, are usually made with metal.
32Hot temperatures and high electricity demands cause the metal to expand and fall lower to the ground.
33The falling lines can touch trees or people and can cause fires or injuries.
34Concrete and asphalt expand with heat too.
35Quick changes in temperature can create cracks in concrete and can cause buildings, streets or bridges to weaken.
36Researchers are looking for ways to help urban populations live through extreme heat.
37Vanos said cities should keep better records of heat-related deaths.
38She said these kinds of deaths are often underreported.
39Vanos added that city governments can help identify populations that are at risk and improve emergency services.
40Akbari said more trees and grass are needed to cool cities.
41He added that structures should be built with new materials that are lighter in color and reflect more light.
42That would also lower temperatures and save energy.
43To supply energy demands, Mukherjee said cities need to use more wind and solar power.
44Experts say the heat-trapping carbon gasses have pushed the world's climate to an extreme.
45"The more frequent and intense heat waves are showing that we need to prepare ourselves more to address this problem in the future," Mukherjee said.
46I'm Dan Novak.
1Many places in the northern half of the world are currently facing record-breaking heat. 2Several countries in the Middle East, including Iran, Kuwait, Oman and the United Arab Emirates, recorded days over 50 degrees Celsius in recent months. Moscow and Helsinki, Finland also reported their hottest June temperatures on record. 3Several weeks ago, there was a record-breaking heat wave in the Pacific Northwest of the United States and western Canada. Oregon and Washington state reported almost 200 heat-related deaths. 4Jennifer Vanos is an assistant professor at Arizona State University. She said: "(Heat) is different than other extremes because...it's invisible." She added that when "it's something people have never experienced before, then it becomes a lot more dangerous." 5A United Nations group on climate change says cities can be dangerous places during heat waves. City buildings and streets can make temperatures rise. And with more than 50 percent of the world's population living in cities, experts fear that heat-related health problems will become more common. 6Urban heat islands 7Cities can be several degrees hotter than rural environments. This effect is known as the urban heat island. 8Hashem Akbari studies urban heat islands at Concordia University in Montreal. He said building materials in cities take in heat and hold it. Asphalt, for example, is a petroleum-based mixture used in streets and on the tops of buildings. Its dark surface reflects little light and absorbs heat. 9At the same time, buildings are often close together, which means there are fewer trees and plants. Plants provide valuable cover from the sun. Plants also absorb water through their roots and use surrounding heat to evaporate the water from their leaves. With fewer plants, this natural cooling effect is gone, Akbari said. 10Energy demands 11To avoid the heat, people living in cities use electricity to power air cooling systems and fans. On a very hot day, those technologies use a lot of electricity. 12Sayanti Mukherjee is an assistant engineering professor at the University at Buffalo, New York. She said cities have "a higher population to serve, so the infrastructure is working at a higher capacity because of the demand." 13But sometimes the electricity system is unable to supply enough power to meet the demand. If that happens, the system shuts down and the power shuts off. 14Extreme weather events, however, are unusual. That makes it difficult for city planners and engineers to prepare for conditions that might not happen very often. 15Materials in infrastructure 16The materials used to make urban infrastructure also are affected by high heat. 17Heat makes metal materials expand. Power lines, for example, are usually made with metal. Hot temperatures and high electricity demands cause the metal to expand and fall lower to the ground. The falling lines can touch trees or people and can cause fires or injuries. 18Concrete and asphalt expand with heat too. Quick changes in temperature can create cracks in concrete and can cause buildings, streets or bridges to weaken. 19Finding solutions 20Researchers are looking for ways to help urban populations live through extreme heat. 21Vanos said cities should keep better records of heat-related deaths. She said these kinds of deaths are often underreported. Vanos added that city governments can help identify populations that are at risk and improve emergency services. 22Akbari said more trees and grass are needed to cool cities. He added that structures should be built with new materials that are lighter in color and reflect more light. That would also lower temperatures and save energy. 23To supply energy demands, Mukherjee said cities need to use more wind and solar power. 24Experts say the heat-trapping carbon gasses have pushed the world's climate to an extreme. 25"The more frequent and intense heat waves are showing that we need to prepare ourselves more to address this problem in the future," Mukherjee said. 26I'm Dan Novak. 27Luyi Cheng reported this story for Voice of America. Dan Novak adapted it for VOA Learning English. Mario Ritter, Jr. was the editor. 28_____________________________________________________ 29Words in This Story 30invisible - n. impossible to see : not visible 31reflect - v. to move in one direction, hit a surface, and then quickly move in a different and usually opposite direction 32absorb - v. to draw in (heat, light, energy, etc.) 33evaporate - v. to change from a liquid into a gas 34resident - n. someone who lives in a particular place 35infrastructure - n. the basic equipment and structures (such as roads and bridges) that are needed for a country, region, or organization to function properly 36capacity - n. the ability to hold or contain people or things 37frequent -adj. happening often