H eatwaves are not as visible as floods and earthquakes, but they can be just as deadly. A recent study estimated that a ten-day spell of extreme heat starting on June 23rd killed around 2,300 people in 12 European cities. The researchers say that climate change made the heatwave between 1°C and 4°C hotter, enough to explain two-thirds of the deaths. High temperatures cause heat stroke, strain the heart and worsen chronic illnesses such as diabetes. More red alerts were issued across Europe on August 10th. Europe is both warming faster than most parts of the world and, compared with other rich regions, appears to be ill-equipped to cope. Since the mid-1990s average temperatures on the continent have risen by 0.53℃ per decade, more than double the global land average of 0.26℃. Changing weather patterns have created more frequent and intense heatwaves. Europe’s efforts to cut air pollution over the past few decades have also raised temperatures, as some pollutants reflect sunlight back into space. And the fact that some of Europe is in the Arctic matters, too. The Arctic is the fastest-warming region on Earth; as ice melts it reflects less sunlight, speeding up the process.
Decadal land temperature anomalies
By region, compared with 1991-2020 average, °C
Ten-year moving average
1.0
Arctic
Europe
0.5
World
0
-0.5
-1.0
-1.5
-2.0
1954
70
80
90
2000
10
24
Source: Copernicus, ERA5
Decadal land temperature anomalies
By region, compared with 1991-2020 average, °C
Ten-year moving average
1.0
Arctic
Europe
0.5
World
0
-0.5
-1.0
-1.5
-2.0
1954
60
65
70
75
80
85
90
95
2000
05
10
15
20
24
Source: Copernicus, ERA5
Decadal land temperature anomalies
By region, compared with 1991-2020 average, °C
Ten-year moving average
1.0
Arctic
Europe
0.5
World
0
-0.5
-1.0
-1.5
-2.0
1954
60
70
80
90
2000
10
20
24
Source: Copernicus, ERA5
But European cities appear to suffer more than cities in other rich regions even when peak temperatures are similar. Data from Kai Chen, of the Yale School of Public Health, and his colleagues shows that, when comparing cities with similar climates, the increase in mortality on days with temperatures in the 99th percentile for that location is far higher in Europe than in Asia or the Americas. For example, Turin, in northern Italy, and Toronto, Canada’s biggest city, have similar temperatures on their hottest days. But the risk of death on these days rises by more than 50% in Turin compared with 14% in Toronto.
Nature Communications
Europe’s lack of air conditioning is surely part of the problem. The share of homes with air con in Britain, the Netherlands and Italy is still estimated to be only 5%, 20% and 49%, respectively. In America and Japan the figure is 91%. In countries that have increased their use of air con, deaths have come down. In Spain the share of homes with air con rose from 5% in 1991 to more than 40% today. Over the same period the risk of death from heat on hot days fell by 30-60%.
- Northern
- Western
- Eastern
- Southern
Hotter places tend to have a greater mortality risk when temperatures rise. But Pierre Masselot and his colleagues at the London School of Hygiene and Tropical Medicine found that Europe’s cities vary widely in their vulnerability to heat. Accounting for differences in local temperatures, the riskiest cities tend to be some of the continent’s most built-up urban areas. Dark surfaces made of concrete and tarmac absorb and retain heat, which makes big cities, especially those with few green spaces, hotter than more rural areas (this is not always captured in air-temperature data that are based on modelling). Other building materials also play a role: the iconic grey zinc roofs in Paris bake the flats beneath them. The relative risk of death in Paris rises by 56% on 99th-percentile days, far more than in places with similar temperatures. Italian cities fare particularly poorly: Bologna tops the risk table and among large cities Milan is worst. Why it suffers more than Rome, which endures similar heat, is unclear. One reason may be that Milan is one of the most polluted cities in Italy: although pollutants can cool a region, high levels of particulates also worsen heat’s effects on health. Italy’s ageing population may add to the risk—40% of heat-related deaths occur in people aged over 85.
- Northern
- Western
- Eastern
- Southern
The researchers also found that Amsterdam and London are far deadlier in hot weather than other European cities with similar temperatures. In both London and Copenhagen, for example, the 99th-percentile daily average is about 22°C (although daily maximums are several degrees higher). In London that raises the death risk by 45%, in Copenhagen by 14%. On average, a 22°C day in London is as deadly as 28°C across other European cities. Places with more poverty also suffer more during heatwaves. Poorer areas tend to have less green space, worse housing and residents who are more vulnerable. An analysis by Carbon Brief, a climate-news website, found that people in the most deprived neighbourhoods in English cities were three times more likely to experience extreme heat than those in the least deprived ones.
Nature Medicine
Scorching summers might also mean warmer winters. That could bring down deaths related to cold weather, which in Europe outnumber those from heat. A separate study by Dr Massalot found that many cooler cities may see a reduction in the overall death rate from extreme temperatures over the next 25 years. But, if no changes are made, already hot cities in Europe will see big increases in excess deaths related to heat. Florence is among the places that are forecast to suffer the most: by 2050 its death rate from heat may triple compared with the level in 2010, to 105 deaths per 100,000 people. Even cooler cities will feel the heat. Dublin’s heat-related mortality rate could increase more than ten-fold, albeit from a much lower base. To save lives, Europe needs to find ways to keep cool over the summer.■
논증 분석
유형: diagnosis
핵심 주장
유럽 도시들은 기후변화로 인한 폭염에 다른 부유한 지역보다 훨씬 더 취약하며, 이는 구조적·지리적 요인과 에어컨 보급률 부족이 복합적으로 작용한 결과다.
논리구조
- 전제: 폭염은 홍수나 지진만큼 치명적이지만 가시성이 낮다. 최근 연구에 따르면 6월 23일부터 시작된 10일간의 극단적 폭염으로 유럽 12개 도시에서 약 2,300명이 사망했으며, 기후변화가 이 폭염을 1~4°C 더 뜨겁게 만들어 사망자의 3분의 2를 설명한다.
- 진단: 유럽은 세계 대부분 지역보다 빠르게 온난화되고 있다. 1990년대 중반 이후 유럽의 평균 기온은 10년마다 0.53°C 상승해 전 세계 육지 평균(0.26°C)의 두 배 이상이며, 기상 패턴 변화로 폭염이 더 자주, 더 강하게 발생하고 있다.
- 진단: 유럽의 대기오염 감축 노력이 역설적으로 기온 상승에 기여했다. 일부 오염물질은 햇빛을 우주로 반사하는 역할을 했는데, 이를 제거함으로써 기온이 추가로 올랐다.
- 진단: 유럽 일부가 북극권에 걸쳐 있다는 지리적 요인도 중요하다. 북극은 지구에서 가장 빠르게 온난화되는 지역으로, 빙하가 녹으면서 햇빛 반사율이 낮아져 온난화가 가속화된다.
- 논거: Yale School of Public Health의 Kai Chen 연구팀 데이터에 따르면, 유사한 기후를 가진 도시들을 비교할 때 유럽 도시들의 99번째 백분위 기온 일수에 나타나는 사망률 증가폭은 아시아나 아메리카 대륙 도시들보다 훨씬 높다. 예를 들어 [Turin]은 최고 기온이 유사한 [Toronto]와 비교해 더운 날의 사망 위험이 50% 이상 상승하는 반면, Toronto는 14%에 불과하다.
- 진단: 유럽의 낮은 에어컨 보급률이 핵심 문제다. 영국, 네덜란드, 이탈리아의 가정 에어컨 보급률은 각각 5%, 20%, 49%에 불과하지만, 미국과 일본은 91%에 달한다.
- 논거: Spain의 사례는 에어컨 보급이 폭염 사망을 줄인다는 증거를 제공한다. 스페인의 가정 에어컨 보급률은 1991년 5%에서 오늘날 40% 이상으로 증가했고, 같은 기간 더운 날의 열 관련 사망 위험은 30~60% 감소했다.
결론
유럽은 세계 평균을 초과하는 빠른 온난화 속도, 지리적 취약성, 낮은 에어컨 보급률이 결합되어 폭염 사망에 특히 취약하며, Spain의 사례처럼 에어컨 보급 확대가 효과적인 대응책임을 시사한다.