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By the end of this century, how many Chinese will be killed by the heat wave?

via:博客园     time:2019/8/7 18:14:49     readed:65

In the past seven months, heat waves have occurred frequently around the world, and major media outlets have reported on the topic of heat waves. China is also facing surging heat waves, so if global temperatures rise by another 2

According to a study from China published in Nature Newsletter on August 6, according to an estimate of 831 million of urban residents in China, the global temperature is 1.5% higher than the pre-industrial level, compared with the pre-industrial level, according to a study published in Nature Newsletter on August 6.This is an extra 0.5.

The study was led by researchers from Nanjing University of Information Engineering and Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences. According to the study, if the heating range can be controlled at 1.5,

Figure: From 1961 to 1999, the frequency of heat waves in big cities in China (in days per year) was predicted by two different emission scenarios, RCP 2.6 (blue) and RCP 4.5 (red). (Source: Nature Communications)

1. Crazy killing machine

Greenhouse gases accumulate in the atmosphere and heat waves become more frequent in the face of warming. As urbanization accelerates and more people pour into the city, the heat island effect makes the city hotter.

Generally speaking, high temperature weather occurs when the daily maximum temperature reaches or exceeds 35 C. The high temperature weather process lasting for more than three days is called high temperature heat wave.The long duration and high intensity of heat waves make it difficult for residents with poor economic and living conditions to escape the harm of high temperature.During the heat wave, the number of emergency vehicles, hospital visits and admissions will increase. The harm of heat wave mainly involves heatstroke, heat stroke, infectious diseases, chronic diseases (such as cardiovascular and cerebrovascular diseases, respiratory diseases) and other diseases, which results in a significant increase in mortality.

This is a study to predict the impact of high temperatures on heat-related mortality in Chinese urban residents at the end of this century on the scale of global warming.

The author selected 27 major cities in China, including Beijing, Chengdu, Chongqing, Guangzhou, Harbin, Shanghai, Shijiazhuang and Tianjin, with a population of more than 10 million. In 2010, the total population and GDP of the 27 cities were about 247.6 million and 13 trillion yuan, accounting for 18.6 percent and 29.7 percent of the country's total population, respectively. The heat-related mortality data used in the study came from the Center for the Prevention and Control of chronic non-communicable Diseases of the China Centers for Disease Control and Prevention.

Jiang Tong, president of the Institute of disaster risk Management of Nanjing University of Information Engineering, one of the authors of the study, said that the distribution of these 27 cities basically covers most of the provinces affected by high temperatures in China, including almost all the climate types in China. 27 cities are selected to carry out the impact of high temperature on the population of each million cities, which is representative to a certain extent.

The researchers rose 1.5% in global temperaturesThe overall mortality rate in China may rise, while the mortality rate in northern China is even higher.

Figure: using 1986-2005 heat-related mortality as a reference, 1.5

If there is no adaptation to warming from a socio-economic point of view, then the global temperature will rise by 1.5

From male to female, working age (15-64 years) and non-working age (Women are less heat-resistant than men, and older people and children are more heat-resistant than adults.The threshold temperature of men's tolerance to high temperature is about 0.8 higher than that of women.

However, this study did not explore the impact of heat waves on the thermal mortality of rural population. Unlike the urban and rural economic development of western developed countries, China's rural economic development lags behind the cities, which is an important factor in the high incidence of rural population heat death.

Guo Yuming, an associate professor of occupational and environmental health at Monash University in Australia, who has conducted a number of studies on population and heat-related mortality in China, said in an interview with DeepTech that most of the studies were aimed at the urban population, but in factChina's rural population is more sensitive to heat waves, and the heat-related mortality rate may be higher.. Because the rural economy is underdeveloped, the possibility of installing air conditioning is low, coupled with the lack of thermal insulation in houses and buildings, farmland work is also more vulnerable to high temperature damage, and its public cooling measures are far less than those in cities.

Previous studies on heat-related mortality of Chinese residents have been quite extensive. Published in March 2019According to a study, the non-accidental mortality rate of Chinese residents increases by 2% for every 1 C rise in daily average temperature, including a 3% increase in cardiovascular mortality, a 2% increase in respiratory mortality and a 2% increase in cerebrovascular mortality.

In February 2019, a report was published in theScience of The Total EnvironmentThe relationship between mortality and 31 major cities in China was analyzed, and it was concluded that women, the elderly and the low-educated population were more vulnerable to heat waves. It is considered that cities with higher concentration of PM 2.5, higher latitudes and fewer beds per capita have a higher risk of death during heat waves.

Guo Yuming said that in a comprehensive way,The northern urban population is more sensitive to heat waves, while the southern population is more resistant to high temperatures.

2. How to Fight the Homicidal Heat Wave

All countries in the world can not escape the heat wave. The heat wave in Europe in 2003 killed more than 70,000 people. In the summer of 2010, there were unprecedented high temperatures in Moscow and western Russia, killing nearly 55000 people.

Climate warming is the background of heat waves. In May this year, the Monaroya Observatory in Hawaii detected atmospheric carbon dioxide concentration of 415.26 ppm, which means that the mass of carbon dioxide exceeds 4.15 percent of the total atmospheric mass. This is the historical record of carbon dioxide concentration in the earth's atmosphere in human history.

What does this number mean? There are reports that,This means that human destruction of the environment has reached another milestone, from which the earth has entered a hot and seriously polluted period.According to the 2015 Paris Agreement, the global average temperature rise is expected to be controlled above the pre-industrialization level by the end of this century.

Above: The global average July temperature curve from 1850 to 2019. Below: The July mean temperature curve from 1979 to 2019 is very close to 2016. (Source: World Meteorological Organization)

The past July has been the hottest month in history.July this year was the hottest month in history and will break the hottest month in July 2016, according to satellite data released by (Copernicus Climate Change Service), the European Union's Copernicus climate change service, on August 5. The data show that July 2019 is about 1.2 higher than in the pre-industrial era.

Climate change has raised heat wave temperatures in Europe this year, Nature magazine reported.

Figure: in the absence of adaptive adjustment measures, in the case of very high greenhouse gas emissions (RCP8.5), that is, by the end of the 21st century (2081-2100), the global average surface temperature is likely to increase by 2.6 over the 1986-2005 RCP8.5 scenario.

In July 2018, Guo Yuming was published in thePLOS MedicineAccording to the study, If adjustments to future climate are considered,Heat wave-related mortality is expected to increase in most countries, with only a decline in heat wave-related mortality in Japan and Moldova, as their populations will decline in the future

Areas affected by heat waves are mainly distributed in tropical and subtropical regions, such as Brazil, Colombia and the Philippines.

What should China do? Jiang Tong believes that for China, on the one hand, the rate of temperature rise in China is higher than that in the world, and high-temperature heat waves will occur more frequently in the future. On the other hand, China has adopted a new population policy, and the future population structure will have an impact on urban population aggregation. However, this can not fundamentally reverse the aging process. Older people are extremely vulnerable to extreme events, and the number of deaths or illnesses caused by high temperature may increase significantly. This requires China to formulate corresponding climate change policies according to its actual situation, select appropriate socio-economic development paths, and strive to achieve sustainable development.

So how to fight the heat wave?

The Economist gives some suggestions.There is a need to make people more aware of the fatality of hot weather and to set up an early warning system so that people can stay indoors, cool and drink plenty of wateAndAir conditioning services can be provided 24 hours a day in some public places, such as communities and schools。 You know, it can be fatal on hot and humid nights. In addition,Some buildings should be transformed into a cooling style, such as changing the roof and walls to white, with green planting.

What needs to be emphasized is that,More attention needs to be paid to the less developed areas.In 2005, it was those poor areas that were more affected by extreme high temperature weather.

Jiang Tong's suggestion is that fighting the heat wave requires two hands.Adaptive adjustment and carbon emission reduction are necessary.

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