Recently, experts of the National Climate Center under the China Meteorological Administration (CMA) comprehensively analyzed the meteorological data of past 31 years and found that the top 10 hottest provincial capitals and municipalities of China are Chongqing, Fuzhou, Hangzhou, Nanchang, Changsha, Wuhan, Xi’an, Nanjing, Hefei and Nanning.

The director and an analyzer of the Climate and Climate Change Assessment Office under the CMA Zhang Cunjie told the reporter that the “furnace” city is just a common phrase and there is no scientific standard to define it.

The traditional “furnace” cities mean the large-scale cities of the Yangtze River valley. In summer, these cities are controlled by the subtropical anticyclone and have high-temperature and high-humidity weather for long periods, making people feel unbearably hot like being in a “furnace.” Therefore, people try to define the “furnace” city but use different standards. For example, some use the extreme maximum temperature and some use the number of days with high-temperature weather (In the meteorology, weather with a daily maximum temperature above 35 degrees Celsius is usually regarded as high-temperature weather).

“To judge whether a city is hot or not, many factors should be taken into account,” Zhang said, “For example, the places with an extreme maximum temperature higher than 35 degrees Celsius in summer are increasing in the north of China. But compared to southern regions, northern regions have shorter high-temperature periods, lower humidity and large temperature differences between day and night, and people of northern regions do not feel that uncomfortable in summer. Therefore, we should not use a single index to judge whether a city is hot or not.”

Global warming and “urban heat island effect” are increasing number of the “ovens”

Why is the list of “oven” cities becoming longer in recent years?

Zhang believes that it is mainly due to the global warming and the “urban heat island effect.” In addition, the increasing urban population, urban buildings, traffic pressure and man-made heat sources are strengthening the “urban heat island effect.” According to satellite remote sensing and land observation data, the underlying surface temperatures of urban areas are obviously higher than those of their surrounding areas.

Zhang said that northern China has seen a larger temperature increase than southern China in the past few decades, and the increase is particularly marked in northern cities. Xi’an, Zhengzhou, Shijiazhuang, Jinan, Beijing, Tianjin, and other northern cities are undergoing increasingly hot summer days. Southern cities are suffering an equally hot summer, though they have seen a smaller temperature increase.

The key is to actively cope with global warming

Climate experts noted that extreme high temperature events are expanding in scope of activity and increasing in frequency due to global climate change and human activities. Heat waves have become one of the most severe meteorological disasters, and caused more deaths worldwide than floods, tornadoes, and severe storms combined.

“The Intergovernmental Panel on Climate Change (IPCC) predicts that global warming will continue, and the urban heat island effect will become increasingly evident due to urbanization,” Zhang stressed. “Cities will get hotter and hotter, resulting in more hot cities. People from all walks of life should take active and effective measures to reduce the damage heat waves may cause to human health and production activities, and make efforts to reduce greenhouse gas emissions, in order to slow global warming.”

Editor:Zheng Limin |Source: People’s Daily

CCTV.com – China