WASHINGTON, Nov. 20, 2025 (GLOBE NEWSWIRE) — Embora os líderes estejam se concentrando em evitar a violação do limite de +1,5° C do Acordo de Paris, uma nova análise científica abrangente das condições climáticas de verão mais perigosas em 100 grandes cidades globais revelou que as temperaturas noturnas mínimas aumentaram até 10 vezes mais rapidamente do que as máximas médias diurnas em muitas cidades durante um clima opressivamente quente.

O estudo da Climate Resilience for All, Extreme Heat and the Shrinking Diurnal Range: A Global Evaluation of Oppressive Air Mass Character and Frequency, analisou dados meteorológicos ao longo de um período de 30 anos, de 1994 a 2024, isolando os dois tipos de condições meteorológicas, ou “massas de ar”, consideradas mais perigosas para a saúde humana: clima “tropical seco” (DT), quente e seco, e clima “tropical úmido” (MT), quente e úmido.

A exposição ao calor tem sido tradicionalmente medida pela exposição a altas temperaturas diurnas e pelo aumento das temperaturas “médias”. Este estudo indica claramente a necessidade urgente de ações preventivas e responsivas ao calor extremo para explicar e abordar explicitamente a crescente ameaça das noites mais quentes.

As visualizações de dados globais, regionais e municipais podem ser acessadas por meio deste link.

A análise revelou:

O aumento das temperaturas noturnas e a diminuição da diferença entre as máximas diurnas e as mínimas noturnas em grande parte do mundo

• 83% das cidades do estudo estão tendo temperaturas noturnas consistentemente mais altas.
• As temperaturas noturnas estão aumentando mais rapidamente em Melbourne, Austrália (tropical seco), aumento de 1° C a cada 5,36 anos, e Dubai, Emirados Árabes Unidos (tropical úmido), aumento de 1° C a cada 8,81 anos.
  • No clima tropical úmido, Santa Maria, Upington, Seul, Samarcanda, Paris, Cidade do Kuwait, Portland e Abadan estão tendo a maior diminuição entre as temperaturas diurnas e noturnas. O número de cidades que apresentam reduções por região se divide da seguinte forma:
    • África: 13 de 15.
    • Ásia: 18 de 22.
    • América Central e do Sul: 10 de 11.
    • Europa: 7 de 12.
    • Oriente Médio: 5 de 5.
    • América do Norte: 14 de 16.
    • Oceania: 9 de 11.
  • No clima tropical seco, Melbourne, Agadir, Seul, Mumbai, Cairo, Luxor, Cidade de Kuwait e Santiago estão tendo a maior diminuição entre as temperaturas diurnas e noturnas. O número de cidades que apresentam reduções por região se divide da seguinte forma:
    • África: 10 de 14.
    • Ásia: 13 de 22.
    • América Central e do Sul: 7 de 11.
    • Europa: 4 de 6.
    • Oriente Médio: 6 de 7.
    • América do Norte: 11 de 14
    • Oceania: 5 de 9.
    • Algumas das regiões mostram uma diferenciação mais fraca, possivelmente porque os tipos de clima tropical seco raramente estão presentes nas cidades que avaliamos nessas regiões.

Aumentos na frequência de dias de calor extremo

• Ao longo do período de estudo de 30 anos, os padrões do clima tropical úmido de verão aumentaram perto ou mais de 50% na América Central e do Sul, Oceania e África – e 37% em todo o mundo.
• Os padrões do clima tropical seco aumentaram 13% no mesmo período, com o maior aumento observado na Austrália, de 29%.

“Antes desta análise, não tínhamos conhecimento da rapidez do aumento do calor noturno nas massas de ar mais perigosas”, disse Larry Kalkstein, climatologista, Conselheiro Chefe de Ciência do Calor da Climate Resilience for All e principal autor do estudo. “É fundamental entendermos como o calor do verão – que leva as pessoas ao pronto–socorro – está mudando e o que estamos ignorando quando falamos sobre isso.”

“Queremos que essa análise mobilize líderes municipais e de saúde para ampliar urgentemente a visão do que é uma crise de calor de 24 horas. Esta pesquisa revela um ponto cego crítico da nossa compreensão do calor extremo ”, disse Kathy Baughman McLeod, CEO da Climate Resilience for All.

As altas temperaturas noturnas impedem que o nosso corpo esfrie, e aumentam os riscos de exaustão pelo calor, de desidratação e de estresse cardiovascular. Quando o sono é interrompido pelo calor, o corpo perde a capacidade de se recuperar da exposição diurna, aumentando o perigo de doenças e morte – especialmente em adultos mais velhos, mulheres e pessoas que vivem em moradias mal ventiladas.

Os sistemas de alerta de calor estão focados nas altas temperaturas diurnas e minimizam o impacto das temperaturas noturnas. O estudo oferece orientação e insiste que as autoridades de saúde e os formuladores de políticas integrem esses padrões de mudança no seu trabalho e aumentem o número de sistemas de alerta de calor direcionados regionalmente que identificam a crescente probabilidade de eventos de alta intensidade durante vários dias que proporcionam pouco alívio à noite.

Sobre a Climate Resilience for All

A Climate Resilience for All é uma ONG de adaptação global dedicada a proteger a saúde, a renda e a dignidade das mulheres na linha de frente do calor extremo.

Contatos:

Geraldine Henrich–Koenis, [email protected]

Kelechukwu Iruoma, [email protected]

GLOBENEWSWIRE (Distribution ID 9579849)

WASHINGTON, 20 nov. 2025 (GLOBE NEWSWIRE) — Alors que les dirigeants se sont efforcés d’éviter de dépasser le seuil de +1,5 C fixé par l’Accord de Paris, une nouvelle analyse scientifique approfondie des conditions météorologiques estivales les plus dangereuses dans 100 grandes villes du monde a révélé que les températures minimales nocturnes avaient augmenté jusqu’à 10 fois plus vite que les températures maximales moyennes diurnes dans de nombreuses villes du monde lors des périodes de canicule.

L’étude menée par Climate Resilience for All et intitulée « Extreme Heat and the Shrinking Diurnal Range: A Global Evaluation of Oppressive Air Mass Character and Frequency » (« Chaleur extrême et réduction de l’amplitude thermique journalière : évaluation mondiale du caractère et de la fréquence des masses d’air accablantes »), a analysé les données météorologiques sur une période de 30 ans, de 1994 à 2024, en isolant les deux types de conditions météorologiques, ou « masses d’air », considérés comme les plus dangereux pour la santé humaine : le temps « tropical sec » (DT, de l’anglais « dry tropical »), qui est chaud et sec, et le temps « tropical humide » (MT, de l’anglais « moist tropical »), qui est chaud et humide.

Traditionnellement, l’exposition à la chaleur est mesurée via l’exposition aux températures élevées diurnes et l’augmentation des températures « moyennes ». Cette étude met clairement en évidence le caractère urgent de l’instauration de mesures préventives et réactives face à la chaleur extrême en vue de tenir compte de la menace croissante des nuits plus chaudes et de lutter contre cette menace.

Les visualisations des données au niveau mondial, régional et municipal sont accessibles via ce lien.

L’étude a révélé les faits suivants :

Augmentation des températures nocturnes et réduction de l’écart entre les températures maximales diurnes et les températures minimales nocturnes dans la majeure partie du globe

• 83 % des villes étudiées connaissent des températures nocturnes élevées et maintenues.
• Les températures nocturnes augmentent le plus rapidement à Melbourne, en Australie (climat tropical sec), où elles augmentent de 1 °C tous les 5,36 ans, et à Dubaï, aux Émirats arabes unis (climat tropical humide), où elles augmentent de 1 °C tous les 8,81 ans.
  • Pendant la saison tropicale humide, Santa Maria, Upington, Séoul, Samarcande, Paris, Koweït, Portland et Abadan connaissent les plus fortes baisses de température entre le jour et la nuit. Le nombre de villes enregistrant une baisse par région se répartit comme suit :
    • Afrique : 13 sur 15.
    • Asie : 18 sur 22.
    • Amérique centrale et Amérique du Sud : 10 sur 11.
    • Europe : 7 sur 12.
    • Moyen–Orient : 5 sur 5.
    • Amérique du Nord : 14 sur 16.
    • Océanie : 9 sur 11.
  • Pendant la saison sèche tropicale, Melbourne, Agadir, Séoul, Mumbai, Le Caire, Louxor, Koweït et Santiago connaissent les plus fortes baisses de température entre le jour et la nuit. Le nombre de villes enregistrant une baisse par région se répartit comme suit :
    • Afrique : 10 sur 14.
    • Asie : 13 sur 22.
    • Amérique centrale et Amérique du Sud : 7 sur 11.
    • Europe : 4 sur 6.
    • Moyen–Orient : 6 sur 7.
    • Amérique du Nord : 11 sur 14
    • Océanie : 5 sur 9.
    • Certaines régions présentent une différenciation moins marquée, peut–être en raison du fait que les climats tropicaux secs sont rares dans les villes étudiées dans ces régions.

Augmentation de la fréquence des journées de canicule

• Au cours de la période d’étude de 30 ans, les phénomènes météorologiques tropicaux humides estivaux ont augmenté de près de 50 % ou plus en Amérique centrale et du Sud, en Océanie et en Afrique, et de 37 % à l’échelle mondiale.
• Les phénomènes météorologiques tropicaux secs ont, quant à eux, augmenté de 13 % au cours de la même période, la plus forte augmentation ayant été enregistrée en Australie, avec une hausse de 29 %.

« Avant cette étude, nous ne connaissions pas la vitesse d’augmentation de la chaleur nocturne au sein des masses d’air les plus dangereuses », a déclaré Larry Kalkstein, climatologue, conseiller en chef dans le domaine des sciences de la chaleur chez Climate Resilience for All et auteur principal de l’étude. « Il est capital pour nous de comprendre la façon dont la chaleur estivale, qui envoie des individus aux urgences, évolue et ce que nous négligeons lorsque nous abordons ce sujet. »

« Nous souhaitons que cette étude incite les responsables municipaux et sanitaires à élargir de toute urgence leur vision de la crise thermique journalière. Cette recherche révèle une lacune importante dans notre compréhension des chaleurs extrêmes », a déclaré Kathy Baughman McLeod, PDG de Climate Resilience for All.

Les températures nocturnes élevées empêchent le corps humain de se refroidir, ce qui augmente les risques d’épuisement liés à la chaleur, de déshydratation et de stress cardiovasculaire. Lorsque le sommeil est perturbé par la chaleur, le corps perd sa capacité à récupérer de l’exposition diurne, ce qui augmente le risque de maladie et de décès, en particulier chez les personnes âgées, les femmes et les personnes vivant dans des logements mal ventilés.

Les systèmes d’alerte canicule se concentrent sur les températures diurnes élevées et minimisent actuellement l’impact des températures nocturnes. L’étude fournit des recommandations et exhorte les professionnels de santé et les décideurs politiques à intégrer ces changements dans leur travail et à renforcer les systèmes d’alerte canicule ciblés au niveau régional, qui tiennent compte de la probabilité croissante d’événements de forte intensité sur plusieurs jours, sans répit nocturne.

À propos de Climate Resilience for All

Climate Resilience for All est une ONG internationale spécialisée dans l’adaptation au changement climatique qui se consacre à la protection de la santé, des revenus et de la dignité des femmes en première ligne face aux canicules extrêmes.

Contacts :

Geraldine Henrich–Koenis, [email protected]

Kelechukwu Iruoma, [email protected]

GLOBENEWSWIRE (Distribution ID 9579849)

WASHINGTON, Nov. 19, 2025 (GLOBE NEWSWIRE) — While leaders have been focusing on avoiding breaching the +1.5°C threshold of the Paris Agreement, a sweeping new scientific analysis of the most dangerous summer weather conditions across 100 major global cities revealed that minimum nighttime temperatures have been rising up to 10 times faster than daytime average highs in many global cities during oppressively hot weather.

The study by Climate Resilience for All, Extreme Heat and the Shrinking Diurnal Range: A Global Evaluation of Oppressive Air Mass Character and Frequency, analyzed weather data over a 30–year period from 1994 to 2024, isolating the two types of weather conditions, or “air masses”, considered most dangerous for human health: “dry tropical” (DT) weather, which is hot and dry, and “moist tropical” (MT) weather which is hot and humid.

Heat exposure has traditionally been measured by exposure to daytime high temperatures and increasing “average” temperatures. This study points clearly to the urgent need for preventative and responsive actions on extreme heat to explicitly account for and address the rapidly rising threat of hotter nights.

Global, regional, and city level data visualizations can be accessed via this link.

The analysis found:

Increases in nighttime temperatures, and decreases in the gap between daytime highs and nighttime lows across much of the globe

• 83% of cities in the study are experiencing sustained, higher nighttime temperatures.
• Nighttime temperatures are rising fastest in Melbourne, Australia (dry tropical), where they increase by 1°C every 5.36 years, and Dubai, UAE (moist tropical), where they rise by 1°C every 8.81 years.
  • During moist tropical weather, Santa Maria, Upington, Seoul, Samarkand, Paris, Kuwait City, Portland, and Abadan are seeing the biggest decrease between daytime and nighttime temperatures. The number of cities seeing decreases per region breaks down as follows:
    • Africa: 13 out of 15.
    • Asia: 18 out of 22.
    • Central and South America: 10 out of 11.
    • Europe: Seven out of 12.
    • Middle East: 5 out of 5.
    • North America: 14 out of 16.
    • Oceania: Nine out of 11.
  • During dry tropical weather, Melbourne, Agadir, Seoul, Mumbai, Cairo, Luxor, Kuwait City, and Santiago are seeing the biggest decrease between daytime and nighttime temperatures. The number of cities seeing decreases per region breaks down as follows:
    • Africa: 10 out of 14.
    • Asia: 13 out of 22.
    • Central and South America: Seven out of 11.
    • Europe: Four out of six.
    • Middle East: Six out of seven.
    • North Americas: 11 out of 14
    • Oceania: Five out of nine.
    • Some of the regions show weaker differentiation, possibly because dry tropical weather types are rarely present in the cities we evaluated in those regions.

Increases in the frequency of extreme heat days

• Over the 30–year study period, summertime moist tropical weather patterns have increased close to or over 50 percent in Central and South America, Oceania, and Africa – and have grown by 37 percent globally.
• Dry tropical weather patterns have grown by 13 percent over the same period, with the largest increase in Australia, which had a 29 percent rise.

“Before this analysis, we did not know how rapidly nighttime heat has been rising within the most dangerous air masses,” said Larry Kalkstein, climatologist, Chief Heat Science Advisor at Climate Resilience for All, and the study's lead author. “It is critical for us to understand how the heat of summer—that sends people to the emergency room—is shifting, and what we are overlooking when we talk about it.”

“We want this analysis to mobilize city and health leaders to urgently broaden their view of what is a 24–hour heat crisis. This research uncovers a critical blind spot in our understanding of extreme heat,” said Kathy Baughman McLeod, CEO of Climate Resilience for All.

High nighttime temperatures prevent the human body from cooling down, increasing risks of heat exhaustion, dehydration, and cardiovascular stress. When sleep is disrupted by heat, the body loses its ability to recover from daytime exposure, heightening the danger of illness and death—especially for older adults, women, and those living in poorly ventilated housing.

Heat warning systems are focused on high daytime temperatures and currently minimize the impact of overnight temperatures. The study offers guidance and urges health officials and policymakers to integrate these changing patterns into their work and to ramp up regionally targeted heat warning systems that account for the growing probability of multi–day, high–intensity events that offer little nocturnal relief.

About Climate Resilience for All

Climate Resilience for All is a global adaptation NGO dedicated to protecting the health, income, and dignity of women on the frontlines of extreme heat.

Contacts:

Geraldine Henrich–Koenis, [email protected]

Kelechukwu Iruoma, [email protected]

GLOBENEWSWIRE (Distribution ID 9579038)

WASHINGTON, Nov. 19, 2025 (GLOBE NEWSWIRE) — While leaders have been focusing on avoiding breaching the +1.5°C threshold of the Paris Agreement, a sweeping new scientific analysis of the most dangerous summer weather conditions across 100 major global cities revealed that minimum nighttime temperatures have been rising up to 10 times faster than daytime average highs in many global cities during oppressively hot weather.

The study by Climate Resilience for All, Extreme Heat and the Shrinking Diurnal Range: A Global Evaluation of Oppressive Air Mass Character and Frequency, analyzed weather data over a 30–year period from 1994 to 2024, isolating the two types of weather conditions, or “air masses”, considered most dangerous for human health: “dry tropical” (DT) weather, which is hot and dry, and “moist tropical” (MT) weather which is hot and humid.

Heat exposure has traditionally been measured by exposure to daytime high temperatures and increasing “average” temperatures. This study points clearly to the urgent need for preventative and responsive actions on extreme heat to explicitly account for and address the rapidly rising threat of hotter nights.

Global, regional, and city level data visualizations can be accessed via this link.

The analysis found:

Increases in nighttime temperatures, and decreases in the gap between daytime highs and nighttime lows across much of the globe

• 83% of cities in the study are experiencing sustained, higher nighttime temperatures.
• Nighttime temperatures are rising fastest in Melbourne, Australia (dry tropical), where they increase by 1°C every 5.36 years, and Dubai, UAE (moist tropical), where they rise by 1°C every 8.81 years.
  • During moist tropical weather, Santa Maria, Upington, Seoul, Samarkand, Paris, Kuwait City, Portland, and Abadan are seeing the biggest decrease between daytime and nighttime temperatures. The number of cities seeing decreases per region breaks down as follows:
    • Africa: 13 out of 15.
    • Asia: 18 out of 22.
    • Central and South America: 10 out of 11.
    • Europe: Seven out of 12.
    • Middle East: 5 out of 5.
    • North America: 14 out of 16.
    • Oceania: Nine out of 11.
  • During dry tropical weather, Melbourne, Agadir, Seoul, Mumbai, Cairo, Luxor, Kuwait City, and Santiago are seeing the biggest decrease between daytime and nighttime temperatures. The number of cities seeing decreases per region breaks down as follows:
    • Africa: 10 out of 14.
    • Asia: 13 out of 22.
    • Central and South America: Seven out of 11.
    • Europe: Four out of six.
    • Middle East: Six out of seven.
    • North Americas: 11 out of 14
    • Oceania: Five out of nine.
    • Some of the regions show weaker differentiation, possibly because dry tropical weather types are rarely present in the cities we evaluated in those regions.

Increases in the frequency of extreme heat days

• Over the 30–year study period, summertime moist tropical weather patterns have increased close to or over 50 percent in Central and South America, Oceania, and Africa – and have grown by 37 percent globally.
• Dry tropical weather patterns have grown by 13 percent over the same period, with the largest increase in Australia, which had a 29 percent rise.

“Before this analysis, we did not know how rapidly nighttime heat has been rising within the most dangerous air masses,” said Larry Kalkstein, climatologist, Chief Heat Science Advisor at Climate Resilience for All, and the study's lead author. “It is critical for us to understand how the heat of summer—that sends people to the emergency room—is shifting, and what we are overlooking when we talk about it.”

“We want this analysis to mobilize city and health leaders to urgently broaden their view of what is a 24–hour heat crisis. This research uncovers a critical blind spot in our understanding of extreme heat,” said Kathy Baughman McLeod, CEO of Climate Resilience for All.

High nighttime temperatures prevent the human body from cooling down, increasing risks of heat exhaustion, dehydration, and cardiovascular stress. When sleep is disrupted by heat, the body loses its ability to recover from daytime exposure, heightening the danger of illness and death—especially for older adults, women, and those living in poorly ventilated housing.

Heat warning systems are focused on high daytime temperatures and currently minimize the impact of overnight temperatures. The study offers guidance and urges health officials and policymakers to integrate these changing patterns into their work and to ramp up regionally targeted heat warning systems that account for the growing probability of multi–day, high–intensity events that offer little nocturnal relief.

About Climate Resilience for All

Climate Resilience for All is a global adaptation NGO dedicated to protecting the health, income, and dignity of women on the frontlines of extreme heat.

Contacts:

Geraldine Henrich–Koenis, [email protected]

Kelechukwu Iruoma, [email protected]

GLOBENEWSWIRE (Distribution ID 9579038)