Climate change and resultant excessive heat may increase the mortality rate by six times by the end of the century according to a new modelling study.
The findings of the study published in a recent issue of The Lancet Planetary Health journal reveal that the ambient heat during the night may interrupt the normal physiology of sleep and less sleep can then lead to immune system damage and a higher risk of cardiovascular disease, chronic illnesses, inflammation and mental health conditions.
The study conducted by University of North Carolina researchers found that the average intensity of hot night events will nearly double by 2090, from 20.4 degrees Celsius to 39.7 degrees Celsius across 28 cities from east Asia, increasing the burden of disease due to excessive heat that disrupts normal sleep.
The results suggest that warming from climate change could have a troubling impact, even under restrictions from the Paris Climate Agreement that aims to limit global warming to well below 2 degrees Celsius, compared to pre-industrial levels.
University of North Carolina climate scientist and co-author of the study Yuqiang Zhang said, "The risks of increasing temperature at night were frequently neglected, however, in our study, we found that the occurrences of hot night excess (HNE) are projected to occur more rapidly than the daily mean temperature changes."
The study shows that the frequency and mean intensity of hot nights would increase more than 30% and 60% by the 2100s, respectively, compared with less than 20% increase for the daily mean temperature.
The researchers estimated the mortality due to excess heat in 28 cities in China, South Korea, and Japan between 1980 and 2015 and applied it to two climate change modelling scenarios that aligned with carbon-reduction scenarios adapted by the respective national governments.
The team was able to estimate that between 2016 and 2100, the risk of death from excessively hot nights would increase nearly six-fold. This prediction is much higher than the mortality risk from daily average warming suggested by climate change models.
The authors of the study said that a more complete health risk assessment of future climate change can help policymakers for better resource allocation and priority setting.
The researchers also found that regional differences in temperature accounted for many of the variances in night time temperature, and areas with the lowest average temperature were projected to have the largest warming potential.
"To combat the health risk raised by the temperature increases from climate change, we should design efficient ways to help people adapt," said Mr. Zhang.
"Locally, heat during the night should be taken into account when designing the future heatwave warning system, especially for vulnerable populations and low-income communities who may not be able to afford the additional expense of air conditioning."
Mabadiliko ya hali ya hewa na joto la kupita kiasi linalofuata yanaweza kuongeza kiwango cha vifo kwa mara sita kufikia mwisho wa karne, kulingana na utafiti mpya wa mfano. Utafiti huo uliochapishwa katika jarida la The Lancet Planetary Health, ulionyesha kuwa joto la mazingira wakati wa usiku linaweza kuvuruga utendaji wa kawaida wa usingizi na kupungua kwa usingizi kunaweza kusababisha uharibifu wa mfumo wa kinga na hatari kubwa ya ugonjwa wa moyo, magonjwa ya muda mrefu, uvimbe na hali za afya ya akili. Utafiti uliofanywa na watafiti wa Chuo Kikuu cha North Carolina uligundua kuwa kiwango cha wastani cha joto usiku cha joto kitazidi mara mbili kufikia mwaka 2090 kutoka 20.4 ° C hadi 39.7 ° C katika miji 28 ya Asia Mashariki, na kuongeza mzigo wa magonjwa kutokana na joto kupita kiasi ambalo linaharibu usingizi wa kawaida. Matokeo ya utafiti huo yanaonyesha kuwa ongezeko la joto kutokana na mabadiliko ya hali ya hewa linaweza kuwa na athari mbaya, hata chini ya vizuizi vya Mkataba wa Hali ya Hewa wa Paris, ambao unakusudia kupunguza ongezeko la joto la dunia hadi chini ya digrii mbili za celsius, ikilinganishwa na viwango vya kabla ya viwanda. "Yu Qiang Zhang, mwanasayansi wa hali ya hewa wa Chuo Kikuu cha North Carolina na mwandishi mwenza wa utafiti huo, alisema: ""Tatizo la kuongezeka kwa joto wakati wa usiku mara nyingi lilipuuzwa, hata hivyo, katika utafiti wetu, tuligundua kuwa matukio ya joto la usiku kupita kiasi (HNE) yanatarajiwa kutokea haraka kuliko mabadiliko ya wastani wa joto la kila siku.""" Utafiti huo unaonyesha kuwa mzunguko na kiwango cha wastani cha usiku wa joto kitaongezeka zaidi ya 30% na 60% ifikapo miaka ya 2100, ikilinganishwa na ongezeko la chini ya 20% kwa joto la wastani la kila siku. Watafiti walipima vifo kutokana na joto la kupita kiasi katika miji 28 nchini China, Korea Kusini na Japan kati ya 1980 na 2015 na kuitumia kwa hali mbili za ubunifu wa mabadiliko ya hali ya hewa ambazo zililingana na hali za kupunguza kaboni zilizobadilishwa na serikali za kitaifa. Watafiti hao walifikia mkataa kwamba kati ya mwaka 2016 na 2100 hatari ya kifo kutokana na usiku wenye joto la juu itazidi mara sita. Utabiri huu ni juu sana kuliko hatari ya vifo kutokana na joto la wastani wa kila siku lililopendekezwa na mifano ya mabadiliko ya hali ya hewa. "Wanahabari wa utafiti huo wanasema ""utathmini kamili zaidi wa hatari za kiafya za mabadiliko ya hali ya hewa ya siku zijazo inaweza kusaidia watunga sera kwa ajili ya ugawaji bora wa rasilimali na kuweka kipaumbele.""" Watafiti pia waligundua kuwa tofauti za kikanda katika joto ziliwakilisha tofauti nyingi katika joto la usiku, na maeneo yenye joto la wastani la chini zaidi yalidhaniwa kuwa na uwezekano mkubwa wa joto. "Kupambana na hatari ya afya inayotokana na ongezeko la joto kutokana na mabadiliko ya hali ya hewa, tunapaswa kubuni njia bora za kuwasaidia watu kukabiliana na hali hiyo,"" alisema Zhang." "Kwenye eneo hilo, joto wakati wa usiku linapaswa kuzingatiwa wakati wa kubuni mfumo wa baadaye wa onyo la wimbi la joto, haswa kwa watu walio hatarini na jamii zenye mapato ya chini ambao wanaweza kutoweza kulipia gharama ya ziada ya hali ya hewa. """