One week later, the United Nations Climate Change Conference cop26 will open in Glasgow, Scotland. "Cop26 is the best time for the world to avoid the most serious impact of climate change - perhaps one of our last opportunities," said Michael Matheson, Scottish Cabinet Secretary for zero carbon, energy and transport. On October 20, the top medical journal the lancet released the 2021 Countdown: tracking the progress of health and climate change. Compared with previous years, this year's annual report is released very early. As for why it is intended to schedule the release before cop26, Renee Salas, a climate and health expert at the Institute of global health at Harvard University and one of the authors of the report, told the media, "I hope countries will make ambitious commitments on cop26 and prescribe the best prescription for promoting global public health and equity." This month, the World Health Organization also released a report on the impact of climate change. The two important reports have issued the same warning: "climate change is the biggest health threat facing mankind today". Compared with COVID-19, climate change poses a higher degree of health threat to the world and has a more lasting impact. "Climate change will have a direct and indirect impact on human health. The direct impact mainly comes from extreme weather events, such as heat wave, cold wave, drought, flood, etc.; the indirect impact comes from the change of climate conditions without extreme and obvious manifestations, which will increase the risk of people's original allergic reaction, asthma and infection with some infectious diseases." Huang Cunrui, Professor of Vanke School of public health and health of Tsinghua University, said in an interview with the Beijing News. Huang Cunrui said that in November this year, the second lancet countdown China report will also be released, which will specifically introduce the impact of climate change on people's health in all parts of China. How does climate change affect our health? // Extreme high temperature The health impact of extreme high temperature weather is the most important and direct impact of all kinds of climate change. The lancet report points out that at present, the global temperature has increased by 1.2 degrees Celsius compared with that before industrialization. The past seven years have been the hottest period on record, and 2020 and 2016 are the hottest years on record. In 2019, nearly 350000 people around the world died of high temperature related diseases. Renee Salas, a climate and health expert at the Institute of global health at Harvard University, pointed out in an interview that in the second half of the 19th century, extreme high temperature weather occurred about once every decade, but now it is three times more likely than before. On August 11, 2021 local time, Portland, Oregon ushered in hot weather, and people were in shelters. Figure / IC Photo In June this year, a record heat wave swept the northwest of the United States and Western Canada. At that time, the highest temperature in Canada reached an alarming 49.6 degrees Celsius. The heat wave caused mass casualties. Within a week, more than 600 people died from ultra-high temperatures in Washington and Oregon. The lancet report points out that such a heat wave is almost impossible without climate change. Huang Cunrui explained that high temperature weather will overload the body's own temperature regulation system, resulting in a significant increase in population mortality. Cardiovascular, cerebrovascular and respiratory diseases, heatstroke and other heat related diseases are common causes of death. High temperature weather will also lead to a significant increase in the admission rate of water electrolyte disorder, renal failure, urinary tract infection and sepsis. In addition, the lancet report points out that high temperature will also affect people's mental health and work ability. // Wildfire Research shows that climate change will make heat waves more frequent, lasting and intense, and further lead to more frequent wildfires. Extreme high temperatures coupled with long-term drought can trigger wildfires. There will be a record wildfire season in the western United States in 2020. By this year, wildfires in California and other places are still raging frequently. Australia also experienced devastating wildfires from 2019 to 2020. In addition to direct casualties, wildfires will also produce a large amount of smoke and dust containing harmful particles, which will pose a health threat to the population. The symptoms of slight influence include brief cough and mild throat pain; Serious effects include worsening lung disease, increased risk of preterm birth and increased risk of death. On August 5, 2021 local time, Dixie mountain fire continued to rage in California, USA. Figure / IC Photo Renee Salas said that near the wildfire, the concentration of harmful particles is more than 14 times the air health standard limit, and even 600 miles away from the wildfire, its concentration is about 4 times the standard limit. This shows that wildfires will also affect the air quality in remote areas and the health of local people. In addition, studies have found that the farther away from the place where the wildfire occurs, the more serious the health hazards caused by wildfire smoke seem to be. "Some scientists believe that this may be due to the oxidation reaction of soot particles in the air. The longer they stay in the air, the greater the harm to human health. Other possible factors are that people who are farther away have less awareness of the hazards of wildfire soot, so the level of self-protection is lower," Renee Salas said. // air pollution Air pollution is also a "health killer". The burning of fossil fuels that cause climate change also exacerbates air pollution. According to a report released by the World Health Organization in September this year, it is estimated that about 7 million people worldwide die prematurely due to air pollution every year. Another environmental study released in April this year shows that air pollution caused by fossil fuel combustion kills more than 10 million people worldwide every year. For minors, air pollution can hinder lung development, lead to respiratory tract infection or aggravate asthma; For adults, air pollution can also increase the risk of stroke, diabetes and neurological diseases. Air pollutants mainly include particulate matter (PM), ozone, nitrogen dioxide, sulfur dioxide, etc. Therefore, reducing emissions can improve air quality and mitigate climate change. In addition, the smoke and dust produced by wildfires will also aggravate air pollution and seriously endanger human health. Last September, affected by wildfires in many states in the western United States, the four cities on the west coast of the country - Portland, Los Angeles, San Francisco and Seattle ranked among the top ten most polluted cities in the world. What is more noteworthy is that the air pollution caused by wildfires will further spread to other areas. Renee Salas pointed out that in the United States, its east coast is affected by air pollution caused by wild fires in the West. In July 2021, New York City had the worst air quality in 15 years. On July 21, 2021 local time, New York City was shrouded in smoke from wildfires. It is reported that wildfires continue to rage in the western United States, affecting the east coast of the United States, and the whole new york city is shrouded in thick smoke. Figure / IC Photo // Increased risk of infectious disease transmission Climate change has also led to a significant increase in the risk of the spread of some infectious diseases. "For example, in the past 30 to 40 years, the risk of dengue fever spreading in China has been increasing," Huang Cunrui said in an interview with the Beijing News. Dengue fever is a mosquito borne disease. Climate change has changed the ambient temperature and humidity, improved the survival and transmission environment of mosquitoes, increased the transmission risk of this infectious disease all over the world, and its epidemic range is also spreading to the colder northern region in the past. On August 14, 2021 local time, a child in a residential area in Makasar City, South Sulawesi, Indonesia, suffered from dengue fever. A health official was spraying insecticides in the residential area to prevent the spread of diseases caused by mosquitoes such as dengue fever. Figure / IC Photo A study by the lancet in July this year pointed out that if carbon emissions continue to increase in the future, nearly 90% of the world's population will be at risk of contracting malaria and dengue fever by the end of this century. Climate change causes "health inequality" In addition to pointing out the health risks faced by human beings around the world, the latest report of the lancet also emphasizes that climate change has caused inequality in the field of human health. Although the carbon emissions of some less developed countries are not high, the health of people in these areas is often more threatened by climate change. Infectious diseases such as malaria and dengue fever abound in sub Saharan Africa. The lack of local medical and health facilities and basic living security facilities makes this kind of disease cause a large number of deaths. "In less developed countries, due to the lack of public response resources and the imperfect health care system, the health impact caused by climate change is more prominent," Huang Cunrui said. In addition, the problem of "health inequality" is also reflected between generations - children are more vulnerable to the health threat brought by climate change. Lachlan McIver, a member of doctors without borders, told the Washington Post that infectious diseases such as dengue fever could kill up to 50 people a day in sub Saharan Africa, most of them children under the age of 5. This highlights a "cruel irony". "Those who are most affected by the health effects of climate change are those who are least responsible for causing climate change," macpher said. Huang Cunrui believes that climate justice needs to be reflected not only in different countries and regions, but also in different regions within a country and between different generations. If global warming cannot be controlled within the values set by the Paris climate agreement, the health of the next generation of children will be significantly affected by climate change, and these effects will last a lifetime. (Xinhua News Agency)