:Effects of climate change on human health

The effects of climate change on human health can be grouped into direct and indirect effects.{{rp|1867 }} Extreme weather, including increased storms, floods, droughts, heat waves and wildfires can directly cause injury, illness, or death. The indirect impact of climate change happens through changes in the environment that alter the Earth's natural systems on a large-scale.{{Cite journal |last1=Myers |first1=Samuel S. |last2=Bernstein |first2=Aaron |date=2011-02-01 |title=The coming health crisis: indirect health effects of global climate change |journal=F1000 Biology Reports |volume=3 |page=3 |doi=10.3410/B3-3 |doi-access=free |pmc=3042309 |pmid=21399764}} These include worsening water quality, air pollution, reduced food availability, and faster spread of disease-carrying insects.{{Cite journal |last1=Di Napoli |first1=Claudia |last2=McGushin |first2=Alice |last3=Romanello |first3=Marina |last4=Ayeb-Karlsson |first4=Sonja |last5=Cai |first5=Wenjia |last6=Chambers |first6=Jonathan |last7=Dasgupta |first7=Shouro |last8=Escobar |first8=Luis E. |last9=Kelman |first9=Ilan |last10=Kjellstrom |first10=Tord |last11=Kniveton |first11=Dominic |last12=Liu |first12=Yang |last13=Liu |first13=Zhao |last14=Lowe |first14=Rachel |last15=Martinez-Urtaza |first15=Jaime |date=2022-04-06 |title=Tracking the impacts of climate change on human health via indicators: lessons from the Lancet Countdown |journal=BMC Public Health |language=en |volume=22 |issue=1 |page=663 |doi=10.1186/s12889-022-13055-6 |doi-access=free |issn=1471-2458 |pmc=8985369 |pmid=35387618}}

Both direct and indirect health effects and their impact vary across the world and between different groups of people according to age, gender, mobility and other factors. For example, differences in health service provision or economic development will result in different health risks and outcomes for people in different regions, with less developed countries facing greater health risks. In many places, the combination of lower socioeconomic status and gender roles result in increased health risks to women and girls as a result of climate change, compared to those faced by men and boys (although the converse may apply in other instances).

The various health effects that are related to climate change include cardiovascular diseases, respiratory diseases, infectious diseases, undernutrition, mental illness, allergies, injuries and poisoning.{{rp|Figure 2}}

The provision of health care can also be impacted by the collapse of health systems and damage to infrastructure due to climate-induced events such as flooding. Therefore, building health systems that are climate resilient is a priority.{{Cite web |date=2015 |title=Operational framework for building climate resilient health systems |url=https://www.who.int/publications-detail-redirect/9789241565073 |access-date=2022-04-13 |website=www.who.int |language=en}}{{rp|15}}

{{Further|Effects_of_climate_change#Weather|Extreme weather}}

Climate change is increasing the frequency and intensity of some extreme weather events.{{Cite book |last1=Seneviratne |first1=Sonia I. |title=Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate |last2=Zhang |first2=Xuebin |last3=Adnan |first3=M. |last4=Badi |first4=W. |last5=Dereczynski |first5=Claudine |last6=Di Luca |first6=Alejandro |last7=Ghosh |first7=S. |publisher=Cambridge University Press |year=2021 |page=1517 |chapter=Chapter 11: Weather and climate extreme events in a changing climate |display-authors=4 |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter_11.pdf}} Extreme heat and cold events are the most likely to increase and worsen followed by more frequent heavy rain or snow and increases in the intensity of droughts.{{cite report |url=https://www.nap.edu/read/21852/chapter/7 |title=Attribution of Extreme Weather Events in the Context of Climate Change |publisher=The National Academies Press |doi=10.17226/21852 |place=Washington, DC |pages=127–136 |isbn=978-0-309-38094-2 |access-date=2020-02-22 |archive-url=https://web.archive.org/web/20220215232008/https://www.nap.edu/read/21852/chapter/7 |archive-date=2022-02-15 |url-status=live |year=2016}}

Extreme weather events, such as floods, hurricanes, heatwaves, droughts and wildfires can result in injuries, death and the spread of infectious diseases.{{Citation needed|date=October 2024}} For example, local epidemics can occur due to loss of infrastructure, such as hospitals and sanitation services, but also because of climate changes creating a more suitable weather for disease-carrying organisms.{{Citation needed|date=October 2024}}

{{Further|Heat illness}}

Since the 1970s, temperature on the surface of Earth has become warmer each decade. This increase happened faster than in any other 50-year period over at least the last 2000 years. Compared to the second half of the 19th century, temperature in the 21st century show a warming of 1.09 °C.{{Cite book |author=IPCC |author-link=IPCC |title=The Physical Science Basis |year=2021 |isbn=978-92-9169-158-6 |series=Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |page=40 |chapter=Summary for Policymakers |ref={{harvid|IPCC AR6 WG1 Summary for Policymakers|2021}} |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf}}

Extreme heat is a direct threat to health, especially for people over 65 years, children, people living in cities and those who have already existing health conditions. Rising global temperatures impact the health and wellbeing of people in multiple ways. In the last few decades, people all over the world have become more vulnerable to heat and experienced an increasing number of life-threatening heatwave events. Extreme heat has negative effects on mental health as well, raising the risk of mental health-related hospitalisations and suicidality.

Although heat itself is not a direct threat to health on its own, a combination of factors of rising temperatures can detriment one's health.The effects of heat on an individual's health is influenced by temperatures, humidity, exercise, hydration, age, pre-existing health status and also by occupation, clothing, behavior, autonomy, vulnerability, and sense of obligation.

Physical exercise is beneficial for reducing the risk the many illnesses and for mental health. At the same time the number of hours per day when the temperature is dangerously high for outdoor exercise has been increasing. The rising heat also impacts people's ability to work and the number of hours when it is not safe to work outdoors (construction, agriculture, etc.) has also increased.

It is estimated that between 1960 and 1990, climate change has put over 600 million people (9% of the global population) outside the human climate niche which is the average temperature range in which people have been able to thrive in the past 6,000 years.{{Cite journal |last1=Lenton |first1=Timothy M. |last2=Xu |first2=Chi |last3=Abrams |first3=Jesse F. |last4=Ghadiali |first4=Ashish |last5=Loriani |first5=Sina |last6=Sakschewski |first6=Boris |last7=Zimm |first7=Caroline |last8=Ebi |first8=Kristie L. |last9=Dunn |first9=Robert R. |last10=Svenning |first10=Jens-Christian |last11=Scheffer |first11=Marten |display-authors=6 |date=2023-05-22 |title=Quantifying the human cost of global warming |url=https://www.nature.com/articles/s41893-023-01132-6 |journal=Nature Sustainability |volume=6 |issue=10 |language=en |pages=1237–1247 |doi=10.1038/s41893-023-01132-6 |bibcode=2023NatSu...6.1237L |issn=2398-9629|hdl=10871/132650 |s2cid=249613346 |hdl-access=free }} Unless greenhouse gas emissions are reduced, regions inhabited by a third of the human population could become as hot as the hottest parts of the Sahara within 50 years. The projected annual average temperature of above 29 °C for these regions would be outside the biologically suitable temperature range for humans.{{cite news |date=5 May 2020 |title=Climate change: More than 3bn could live in extreme heat by 2070 |work=BBC News |url=https://www.bbc.co.uk/news/science-environment-52543589 |url-status=live |access-date=6 May 2020 |archive-url=https://web.archive.org/web/20200505153614/https://www.bbc.co.uk/news/science-environment-52543589 |archive-date=5 May 2020}}{{cite journal |last1=Xu |first1=Chi |last2=Kohler |first2=Timothy A. |last3=Lenton |first3=Timothy M. |last4=Svenning |first4=Jens-Christian |last5=Scheffer |first5=Marten |date=26 May 2020 |title=Future of the human climate niche – Supplementary Materials |journal=Proceedings of the National Academy of Sciences |volume=117 |issue=21 |pages=11350–11355 |bibcode=2020PNAS..11711350X |doi=10.1073/pnas.1910114117 |pmc=7260949 |pmid=32366654 |doi-access=free}}

{{Further|Effects of climate change#Heatwaves|Heat illness}}

File:Overlap between future population distribution and extreme heat.jpg

Exposure to extreme heat poses an acute health hazard, especially for people deemed as vulnerable.{{Cite journal |last=Demain |first=Jeffrey G. |date=24 March 2018 |title=Climate Change and the Impact on Respiratory and Allergic Disease: 2018 |journal=Current Allergy and Asthma Reports |volume=18 |issue=4 |page=22 |doi=10.1007/s11882-018-0777-7 |pmid=29574605 |s2cid=4440737}} Vulnerable people with regard to heat illnesses include people with low incomes, minority groups, women (in particular pregnant women), children, older adults (over 65 years old), people with chronic diseases, disabilities and multiple long-term health conditions.{{rp|13}} Other people at risk include those living in urban environments (due to the urban heat island effect), outdoor workers and people who take certain prescription drugs.

Climate change increases the frequency and severity of heatwaves and thus heat stress for people. A 2022 global study found that heat-related deaths increased significantly between 2000 and 2019, particularly in tropical and low-income countries, underscoring the growing health burden from rising temperatures.Zhao, Q., Guo, Y., Ye, T., Gasparrini, A., Tong, S., & Wang, C. (2022). Global, regional, and national burden of mortality associated with non-optimal ambient temperatures from 2000 to 2019: a three-stage modelling study. The Lancet Planetary Health, 6(6), e491–e500. [https://doi.org/10.1016/S2542-5196(22)00091-0 https://doi.org/10.1016/S2542-5196(22)00091-0]

Human responses to heat stress can include heat stroke and overheating (hyperthermia). Extreme heat is also linked to acute kidney injury, low quality sleep,{{Cite journal |last1=Hajat |first1=Shakoor |last2=Casula |first2=Anna |last3=Murage |first3=Peninah |last4=Omoyeni |first4=Daniel |last5=Gray |first5=Tom |last6=Plummer |first6=Zoe |last7=Steenkamp |first7=Retha |last8=Nitsch |first8=Dorothea |date=1 March 2024 |title=Ambient heat and acute kidney injury: case-crossover analysis of 1 354 675 automated e-alert episodes linked to high-resolution climate data |journal=The Lancet Planetary Health |volume=8 |issue=3 |pages=e156–e162 |doi=10.1016/s2542-5196(24)00008-1 |issn=2542-5196|doi-access=free |pmid=38453381 }}{{Cite journal |date=13 August 2024 |title=Hot weather increases the risk of acute kidney injury |url=https://evidence.nihr.ac.uk/alert/hot-weather-increases-the-risk-of-acute-kidney-injury/ |journal=NIHR Evidence|doi=10.3310/nihrevidence_63987 |doi-access=free }} and complications with pregnancy.{{rp|1051}}Furthermore, it may cause the deterioration of pre-existing cardiovascular and respiratory disease.{{rp|1624}} Adverse pregnancy outcomes due to high ambient temperatures include for example low birth weight and pre-term birth.{{rp|1051}}Heat waves have also resulted in epidemics of chronic kidney disease (CKD). Prolonged heat exposure, physical exertion, and dehydration are sufficient factors for the development of CKD.{{Cite journal |last=Glaser |display-authors=etal |year=2016 |title=Climate Change and the Emergent Epidemic of CKD from Heat Stress in Rural Communities: the Case for Heat Stress Nephropathy |journal=Clinical Journal of the American Society of Nephrology |volume=11 |issue=8 |pages=1472–83 |doi=10.2215/CJN.13841215 |pmc=4974898 |pmid=27151892}}{{Cite news |last=Shih |first=Gerry |date=2023-01-06 |title=The world's torrid future is etched in the crippled kidneys of Nepali workers |url=https://www.washingtonpost.com/world/2023/01/06/climate-change-heat-kidney-disease/ |access-date=2023-01-20 |newspaper=The Washington Post |language=en}}

The human body requires evaporation of sweat to cool down and prevent overheating, even with a low activity level. With excessive heat and humidity human bodies would no longer be able to adequately cool the skin.{{cite news |first=Oliver |last=Milman |date=8 March 2021 |title=Global heating pushes tropical regions towards limits of human livability |work=The Guardian |url=https://www.theguardian.com/science/2021/mar/08/global-heating-tropical-regions-human-livability |access-date=24 June 2021}}{{Cite web |last=Chow |first=Denise |date=2022-05-07 |title=Deadly 'wet-bulb temperatures' are being stoked by climate change and heat waves |url=https://www.nbcnews.com/science/science-news/wet-bulb-temperature-weather-average-climate-human-heat-wave-rcna27478 |access-date=2022-07-22 |website=NBC News |language=en}} A wet-bulb temperature of 35 °C is regarded as the limit for humans (called the "physiological threshold for human adaptability" to heat and humidity).{{cite book |last1=Shaw |first1=R. |first2=Y. |last2=Luo |first3=T. S. |last3=Cheong |first4=S. Abdul |last4=Halim |first5=S. |last5=Chaturvedi |first6=M. |last6=Hashizume |first7=G. E. |last7=Insarov |first8=Y. |last8=Ishikawa |first9=M. |last9=Jafari |first10=A. |last10=Kitoh |first11=J. |last11=Pulhin |first12=C. |last12=Singh |first13=K. |last13=Vasant |first14=Z. |last14=Zhang |display-authors=6 |year=2022 |chapter-url=https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Chapter10.pdf |chapter=Asia |url=https://www.ipcc.ch/report/ar6/wg2/ |title=Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |editor-first1=H.-O. |editor-last1=Pörtner |editor-first2=D. C. |editor-last2=Roberts |editor-first3=M. |editor-last3=Tignor |editor-first4=E. S. |editor-last4=Poloczanska |editor-first5=K. |editor-last5=Mintenbeck |editor-first6=A. |editor-last6=Alegría |editor-first7=M. |editor-last7=Craig |editor-first8=S. |editor-last8=Langsdorf |editor-first9=S. |editor-last9=Löschke |editor-first10=V. |editor-last10=Möller |editor-first11=A. |editor-last11=Okem |editor-first12=B. |editor-last12=Rama |display-editors=6 |publisher=Cambridge University Press |location=Cambridge and New York |pages=1457–1579 |doi=10.1017/9781009325844.012|isbn=978-1-009-32584-4 }}{{rp|1498}} As of 2020, only two weather stations had recorded 35 °C wet-bulb temperatures, and only very briefly, but the frequency and duration of these events is expected to rise with ongoing climate change.{{cite journal |last1=Sherwood |first1=S. C. |last2=Huber |first2=M. |date=25 May 2010 |title=An adaptability limit to climate change due to heat stress |journal=Proceedings of the National Academy of Sciences of the USA |volume=107 |issue=21 |pages=9552–5 |bibcode=2010PNAS..107.9552S |doi=10.1073/pnas.0913352107 |pmc=2906879 |pmid=20439769 |doi-access=free}}{{Cite web |last=Madge |first=Grahame |date=2021-11-09 |title=One billion face heat-stress risk from 2°C rise |url=https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2021/2c-rise-to-put-one-in-eight-of-global-population-at-heat-stress-risk |access-date=2021-11-10 |website=Met Office |language=en}}{{cite journal |first1=Colin |last1=Raymond |first2=Tom |last2=Matthews |first3=Radley M. |last3=Horton |year=2020 |title=The emergence of heat and humidity too severe for human tolerance |journal=Science Advances |volume=6 |issue=19 |pages=eaaw1838 |bibcode=2020SciA....6.1838R |doi=10.1126/sciadv.aaw1838 |pmc=7209987 |pmid=32494693 |doi-access=free}}

Global warming above 1.5 degrees risks making parts of the tropics uninhabitable because the threshold for the wet bulb temperature may be passed. A wet-bulb temperature of 31 degrees is already considered dangerous, even for young and healthy people. This threshold is not uniform for all and depend on many factors including environmental factors, activity and age. If the global temperature will rise by 3 degrees (the most likely scenario without reducing the use of fossil fuels), temperatures will exceed this limit at large areas in Pakistan, India, China, sub-Saharan Africa, United States, Australia, and South America.{{cite web |date=16 October 2023 |title=Climate driven extreme heat threatens human habitation on earth |url=https://www.openaccessgovernment.org/climate-driven-extreme-heat-threatens-human-habitation-on-earth/168186/ |access-date=22 October 2023 |website=Open Access Government |publisher=Penn State College of Health and Human Development, Purdue University College of Sciences, Purdue Institute for a Sustainable Future}}

People with cognitive health issues (e.g. depression, dementia, Parkinson's disease) are more at risk when faced with high temperatures and ought to be extra careful{{cite journal |last1=Kovats |first1=R. Sari |last2=Hajat |first2=Shakoor |date=April 2008 |title=Heat Stress and Public Health: A Critical Review |journal=Annual Review of Public Health |volume=29 |issue=1 |pages=41–55 |doi=10.1146/annurev.publhealth.29.020907.090843 |pmid=18031221 |doi-access=free}} as cognitive performance has been shown to be differentially affected by heat.{{cite journal |last1=Hancock |first1=P. A. |last2=Vasmatzidis |first2=I. |year=2003 |title=Effects of heat stress on cognitive performance: the current state of knowledge |journal=International Journal of Hyperthermia |volume=19 |issue=3 |pages=355–372 |citeseerx=10.1.1.464.7830 |doi=10.1080/0265673021000054630 |pmid=12745975 |s2cid=13960829}} People with diabetes and those who are overweight, have sleep deprivation, or have cardiovascular/cerebrovascular conditions should avoid too much heat exposure.{{cite journal |last1=Koppe |first1=Christina |first2=Sari |last2=Kovats |first3=Gerd |last3=Jendritzky |first4=Bettina |last4=Menne |year=2004 |title=Heat-waves: risks and responses |url=http://www.euro.who.int/en/publications/abstracts/heat-waves-risks-and-responses |journal=Health and Global Environmental Change Series |volume=2 |access-date=2023-03-16 |archive-date=2023-03-22 |archive-url=https://web.archive.org/web/20230322220743/https://www.euro.who.int/en/publications/abstracts/heat-waves-risks-and-responses |url-status=dead }}

The risk of dying from chronic lung disease during a heat wave has been estimated at 1.8–8.2% higher compared to average summer temperatures.{{Cite journal |last1=Witt |first1=Christian |last2=Schubert |first2=André Jean |last3=Jehn |first3=Melissa |last4=Holzgreve |first4=Alfred |last5=Liebers |first5=Uta |last6=Endlicher |first6=Wilfried |last7=Scherer |first7=Dieter |date=2015-12-21 |title=The Effects of Climate Change on Patients With Chronic Lung Disease. A Systematic Literature Review |url= |journal=Deutsches Ärzteblatt International |volume=112 |issue=51–52 |pages=878–883 |doi=10.3238/arztebl.2015.0878 |issn=1866-0452 |pmc=4736555 |pmid=26900154}} An 8% increase in hospitalization rate for people with chronic obstructive pulmonary disease (COPD) has been estimated for every 1 °C increase in temperatures above 29 °C.

{{Further|Urban heat island}}

File:Atlanta thermal.jpgs are one effect of climate change that affect human health: Illustration of urban heat exposure via a temperature distribution map: red shows warm areas, white shows hot areas.]]

The effects of heatwaves tend to be more pronounced in urban areas because they are typically warmer than surrounding rural areas due to the urban heat island effect.{{cite book |year=2022 |chapter-url=https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Annex-II.pdf |chapter=Annex II: Glossary |last1=Möller |first1=V. |first2=R. |last2=van Diemen |first3=J. B. R. |last3=Matthews |first4=C. |last4=Méndez |first5=S. |last5=Semenov |first6=J. S. |last6=Fuglestvedt |first7=A. |last7=Reisinger |url=https://www.ipcc.ch/report/ar6/wg2/ |title=Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |editor-first1=H.-O. |editor-last1=Pörtner |editor-first2=D. C. |editor-last2=Roberts |editor-first3=M. |editor-last3=Tignor |editor-first4=E. S. |editor-last4=Poloczanska |editor-first5=K. |editor-last5=Mintenbeck |editor-first6=A. |editor-last6=Alegría |editor-first7=M. |editor-last7=Craig |editor-first8=S. |editor-last8=Langsdorf |editor-first9=S. |editor-last9=Löschke |editor-first10=V. |editor-last10=Möller |editor-first11=A. |editor-last11=Okem |editor-first12=B. |editor-last12=Rama |display-editors=6 |publisher=Cambridge University Press |location=Cambridge and New York |pages=2897–2930 |doi=10.1017/9781009325844.029}}{{rp|2926}} This results from the way many cities are built. For example, they often have extensive areas of asphalt, reduced greenery along with many large heat-retaining buildings that physically block cooling breezes and ventilation. Lack of water features are another cause.{{rp|2926}}

Extreme heat exposure in cities with a wet bulb globe temperature above 30 °C tripled between 1983 and 2016.{{Cite journal |last1=Tuholske |first1=Cascade |last2=Caylor |first2=Kelly |last3=Funk |first3=Chris |last4=Verdin |first4=Andrew |last5=Sweeney |first5=Stuart |last6=Grace |first6=Kathryn |last7=Peterson |first7=Pete |last8=Evans |first8=Tom |date=2021-10-12 |title=Global urban population exposure to extreme heat |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=118 |issue=41 |pages=e2024792118 |doi=10.1073/pnas.2024792118 |issn=1091-6490 |pmc=8521713 |pmid=34607944 |bibcode=2021PNAS..11824792T |doi-access=free }} It increased by about 50% when the population growth in these cities is not taken into account.

Cities are often on the front-line of climate change due to their densely concentrated populations, the urban heat island effect, their frequent proximity to coasts and waterways, and reliance on ageing physical infrastructure networks.

Health experts warn that "exposure to extreme heat increases the risk of death from cardiovascular, cerebrovascular, and respiratory conditions and all-cause mortality. Heat-related deaths in people older than 65 years reached a record high of an estimated 345 000 deaths in 2019".{{rp|9}} More than 70,000 Europeans died as a result of the 2003 European heat wave.{{cite journal |last1=Robine |first1=Jean-Marie |last2=Cheung |first2=Siu Lan K |last3=Le Roy |first3=Sophie |last4=Van Oyen |first4=Herman |last5=Griffiths |first5=Clare |last6=Michel |first6=Jean-Pierre |last7=Herrmann |first7=François Richard |year=2008 |title=Death toll exceeded 70,000 in Europe during the summer of 2003 |journal=Comptes Rendus Biologies |volume=331 |issue=2 |pages=171–8 |doi=10.1016/j.crvi.2007.12.001 |pmid=18241810|url=https://comptes-rendus.academie-sciences.fr/biologies/articles/10.1016/j.crvi.2007.12.001/ }} Also more than 2,000 people died in Karachi, Pakistan in June 2015 due to a severe heat wave with temperatures as high as {{convert|49|C}}.{{cite news |last1=Haider |first1=Kamran |last2=Anis |first2=Khurrum |date=24 June 2015 |title=Heat Wave Death Toll Rises to 2,000 in Pakistan's Financial Hub |work=Bloomberg News |url=https://www.bloomberg.com/news/articles/2015-06-24/heat-wave-death-toll-rises-to-2-000-in-pakistan-s-financial-hub |access-date=3 August 2015}}{{cite news |last=Mansoor |first=Hasan |date=30 June 2015 |title=Heatstroke leaves another 26 dead in Sindh |newspaper=Dawn |url=http://www.dawn.com/news/1191234/heatstroke-leaves-another-26-dead-in-sindh |access-date=9 August 2015}}

Due to climate change temperatures rose in Europe and heat mortality increased. From 2003–12 to 2013–22 alone, it increased by 17 deaths per 100,000 people, while women are more vulnerable than men.{{cite journal |last1=Wong |first1=Carissa |title=How climate change is hitting Europe: three graphics reveal health impacts |url=https://www.nature.com/articles/d41586-024-02006-3 |journal=Nature |date=2024 |volume=630 |issue=8018 |pages=800–801 |publisher=Lancet Public Health |doi=10.1038/d41586-024-02006-3 |pmid=38890517 |bibcode=2024Natur.630..800W |access-date=27 June 2024}}

Increasing access to indoor cooling (air conditioning) will help prevent heat-related mortality but current air conditioning technology is generally unsustainable as it contributes to greenhouse gas emissions, air pollution, peak electricity demand, and urban heat islands.{{rp|17}}

Mortality due to heat waves could be reduced if buildings were better designed to modify the internal climate, or if the occupants were better educated about the issues, so they can take action on time.{{cite journal |last1=Coley |first1=D. |last2=Kershaw |first2=T. J. |last3=Eames |first3=M. |year=2012 |title=A comparison of structural and behavioural adaptations to future proofing buildings against higher temperatures |url=http://opus.bath.ac.uk/28878/1/Coley_Building%2DEnvironment_2012_i.pdf |journal=Building and Environment |volume=55 |pages=159–166 |doi=10.1016/j.buildenv.2011.12.011 |bibcode=2012BuEnv..55..159C |s2cid=55303235 |hdl=10871/13936}}{{cite journal |last1=Coley |first1=D. |last2=Kershaw |first2=T. J. |year=2010 |title=Changes in internal temperatures within the built environment as a response to a changing climate |url=http://opus.bath.ac.uk/25101/1/Pre_print.pdf |journal=Building and Environment |volume=45 |issue=1 |pages=89–93 |doi=10.1016/j.buildenv.2009.05.009|bibcode=2010BuEnv..45...89C }} Heatwave early warning and response systems are important elements of heat action plans.

Heat exposure can affect people's ability to work.{{rp|8}} The annual Countdown Report by The Lancet investigated change in labour capacity as an indicator. It found that during 2021, high temperature reduced global potential labour hours by 470 billion – a 37% increase compared to the average annual loss that occurred during the 1990s. Occupational heat exposure especially affects laborers in the agricultural sector of developing countries. In those countries, the vast majority of these labour hour losses (87%) were in the agricultural sector.{{cite journal |first1=Marina |last1=Romanello |first2=Claudia |last2=Di Napoli |first3=Paul |last3=Drummond |first4=Carole |last4=Green |first5=Harry |last5=Kennard |first6=Pete |last6=Lampard |first7=Daniel |last7=Scamman |first8=Nigel |last8=Arnell |first9=Sonja |last9=Ayeb-Karlsson |first10=Lea |last10=Berrang Ford |first11=Kristine |last11=Belesova |first12=Kathryn |last12=Bowen |first13=Wenjia |last13=Cai |first14=Max |last14=Callaghan |first15=Diarmid |last15=Campbell-Lendrum |first16=Jonathan |last16=Chambers |first17=Kim R. |last17=van Daalen |first18=Carole |last18=Dalin |first19=Niheer |last19=Dasandi |first20=Shouro |last20=Dasgupta |first21=Michael |last21=Davies |first22=Paula |last22=Dominguez-Salas |first23=Robert |last23=Dubrow |first24=Kristie L. |last24=Ebi |first25=Matthew |last25=Eckelman |first26=Paul |last26=Ekins |first27=Luis E. |last27=Escobar |first28=Lucien |last28=Georgeson |first29=Hilary |last29=Graham |first30=Samuel H. |last30=Gunther |first31=Ian |last31=Hamilton |first32=Yun |last32=Hang |first33=Risto |last33=Hänninen |first34=Stella |last34=Hartinger |first35=Kehan |last35=He |first36=Jeremy J. |last36=Hess |first37=Shih-Che |last37=Hsu |first38=Slava |last38=Jankin |first39=Louis |last39=Jamart |display-authors=6|url=https://www.thelancet.com/action/showPdf?pii=S0140-6736%2822%2901540-9 |title=The 2022 report of the Lancet Countdown on health and climate change: health at the mercy of fossil fuels |journal=The Lancet |volume=400 |date=November 5, 2022 |issue=10363 |pages=1619–1654 |doi=10.1016/S0140-6736(22)01540-9|pmid=36306815 |pmc=7616806 }}{{rp|1625}}

Working in extreme heat can lead to labor force productivity decreases as well as participation because employees' health may be weaker due to heat related health problems, such as dehydration, fatigue, dizziness, and confusion.{{Cite journal |last=Liu |first=Xingcai |date=February 2020 |title=Reductions in Labor Capacity from Intensified Heat Stress in China under Future Climate Change |journal=International Journal of Environmental Research and Public Health |volume=17 |issue=4 |page=1278 |doi=10.3390/ijerph17041278 |pmc=7068449 |pmid=32079330 |doi-access=free}}{{rp|1073–1074}}

With regards to sporting activities, it has been observed that "hot weather reduces the likelihood of engaging in exercise".{{rp|1625}} Furthermore, participating in sports during excessive heat can lead to injury or even death.{{cite report |last1=Cissé |first1=G. |first2=R. |last2=McLeman |first3=H. |last3=Adams |first4=P. |last4=Aldunce |first5=K. |last5=Bowen |first6=D. |last6=Campbell-Lendrum |first7=S. |last7=Clayton |first8=K. L. |last8=Ebi |first9=J. |last9=Hess |first10=C. |last10=Huang |first11=Q. |last11=Liu |first12=G. |last12=McGregor |first13=J. |last13=Semenza |first14=M. C. |last14=Tirado |display-authors=6 |year=2022 |chapter-url=https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Chapter07.pdf |chapter=Chapter 7: Health, Wellbeing, and the Changing Structure of Communities |url=https://www.ipcc.ch/report/ar6/wg2/ |title=Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |editor-first1=H.-O. |editor-last1=Pörtner |editor-first2=D. C. |editor-last2=Roberts |editor-first3=M. |editor-last3=Tignor |editor-first4=E. S. |editor-last4=Poloczanska |editor-first5=K. |editor-last5=Mintenbeck |editor-first6=A. |editor-last6=Alegría |editor-first7=M. |editor-last7=Craig |editor-first8=S. |editor-last8=Langsdorf |editor-first9=S. |editor-last9=Löschke |editor-first10=V. |editor-last10=Möller |editor-first11=A. |editor-last11=Okem |editor-first12=B. |editor-last12=Rama |display-editors=6 |publisher=Cambridge University Press |location=Cambridge and New York |pages=1041–1170 |doi=10.1017/9781009325844.009}}{{rp|1073–1074}} It is also well established that regular physical activity is beneficial for human health, including mental health.{{rp|1625}} Therefore, an increase in hot days due to climate change could indirectly affect health due to people exercising less.

{{Further|Drought#Social and health impacts}}

Climate change affects multiple factors associated with droughts, such as how much rain falls and how fast the rain evaporates again. Warming over land increases the severity and frequency of droughts around much of the world.{{Cite journal |last1=Cook |first1=Benjamin I. |last2=Mankin |first2=Justin S. |last3=Anchukaitis |first3=Kevin J. |date=2018-05-12 |title=Climate Change and Drought: From Past to Future |url=https://link.springer.com/article/10.1007/s40641-018-0093-2 |journal=Current Climate Change Reports |volume=4 |issue=2 |pages=164–179 |bibcode=2018CCCR....4..164C |doi=10.1007/s40641-018-0093-2 |issn=2198-6061 |s2cid=53624756}}Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, and O.  Zolina, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter08.pdf Chapter 8: Water Cycle Changes]. In [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I  to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1055–1210, doi:10.1017/9781009157896.010.{{rp|1057}} Many of the consequences of droughts have effects on human health.

{{Further|Flood#Health impacts}}

Due to an increase in heavy rainfall events, floods are expected to become more severe in the future when they do occur.{{rp|1155}} However, the interactions between rainfall and flooding are complex. In some regions, flooding is expected to become rarer. This depends on several factors, such as changes in rain and snowmelt, but also soil moisture.{{rp|1156}} Floods have short and long-term negative implications to people's health and well-being. Short term implications include mortalities, injuries and diseases, while long term implications include non-communicable diseases and psychosocial health aspects.{{cite journal |last1=Alderman |first1=Katarzyna |last2=Turner |first2=Lyle R. |last3=Tong |first3=Shilu |date=June 2012 |title=Floods and human health: A systematic review |url=https://espace.library.uq.edu.au/view/UQ:346602/UQ346602_OA.pdf |journal=Environment International |volume=47 |pages=37–47 |bibcode=2012EnInt..47...37A |doi=10.1016/j.envint.2012.06.003 |pmid=22750033}} For example, the 2022 Pakistan floods (which were likely more severe because of climate change{{Cite news |last1=Zhong |first1=Raymond |date=15 September 2022 |title=In a First Study of Pakistan's Floods, Scientists See Climate Change at Work |url=https://www.nytimes.com/2022/09/15/climate/pakistan-floods-global-warming.html |work=The New York Times}}{{Cite web |title=Climate Change Likely Worsened Pakistan's Devastating Floods |url=https://www.scientificamerican.com/article/climate-change-likely-worsened-pakistans-devastating-floods/ |website=Scientific American}}) affected people's health directly and indirectly. There were outbreaks of diseases like malaria, dengue, and other skin diseases.{{Cite web |date=November 2022 |title=Public health risks increasing in flood-affected Pakistan, warns WHO |url=https://news.un.org/en/story/2022/11/1130082}}{{Cite web |date=3 October 2022 |title=UN Warns Deadly Diseases Spreading Fast in Flood-Ravaged Pakistan |url=https://www.voanews.com/a/un-warns-deadly-diseases-spreading-fast-in-flood-ravaged-pakistan/6773539.html#:~:text=9%2C%202022.&text=A%20senior%20U.N.,scabies%20and%20other%20skin%20diseases.}}File:Wildfire near Cedar Fort, Utah.jpg from a surface fire in the western desert of Utah. Wildfires become more frequent and intense due to climate change.]]

{{Further|Wildfire#Health effects}}

Climate change increases wildfire potential and activity.{{cite journal |last=Liu |first=Y. |author2=Stanturf, J. |author3=Goodrick, S. |date=February 2010 |title=Trends in global wildfire potential in a changing climate |journal=Forest Ecology and Management |volume=259 |issue=4 |pages=685–697 |doi=10.1016/j.foreco.2009.09.002|bibcode=2010ForEM.259..685L }} Climate change leads to a warmer ground temperature and its effects include earlier snowmelt dates, drier than expected vegetation, increased number of potential fire days, increased occurrence of summer droughts, and a prolonged dry season.{{cite journal |last=Westerling, A. |author2=Hidalgo, H. |author3=Cayan, D. |author4=Swetnam, T. |date=August 2006 |title=Warming and earlier spring increase Western U.S. Forest Wildfire Activity |journal=Science |volume=313 |issue=5789 |pages=940–943 |bibcode=2006Sci...313..940W |doi=10.1126/science.1128834 |pmid=16825536 |doi-access=free}} Wood smoke from wildfires produces particulate matter that has damaging effects to human health.{{cite journal |last1=Naeher |first1=Luke P. |last2=Brauer |first2=Mmichael |last3=Lipsett |first3=Michael |last4=Zelikoff |first4=Judith T. |last5=Simpson |first5=Christopher D. |last6=Koenig |first6=Jane Q. |last7=Smith |first7=Kirk R. |display-authors=3 |date=January 2007 |title=Woodsmoke health effects: A review |journal=Inhalation Toxicology |volume=19 |issue=1 |pages=67–106 |bibcode=2007InhTx..19...67N |citeseerx=10.1.1.511.1424 |doi=10.1080/08958370600985875 |pmid=17127644 |s2cid=7394043}} The health effects of wildfire smoke exposure include exacerbation and development of respiratory illness such as asthma and chronic obstructive pulmonary disorder; increased risk of lung cancer, mesothelioma and tuberculosis; increased airway hyper-responsiveness; changes in levels of inflammatory mediators and coagulation factors; and respiratory tract infection.

{{Further|Effects of climate change#Extreme storms|Tropical cyclones and climate change}}

Storms become wetter under climate change. These include tropical cyclones and extratropical cyclones. Both the maximum and mean rainfall rates increase. This more extreme rainfall is also true for thunderstorms in some regions.{{Cite book |last1=Seneviratne |first1=Sonia I. |title=Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate |last2=Zhang |first2=Xuebin |last3=Adnan |first3=M. |publisher=Cambridge University Press |year=2021 |page=1519 |chapter=Chapter 11: Weather and climate extreme events in a changing climate |display-authors=etal |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter11.pdf}} Furthermore, tropical cyclones and storm tracks are moving towards the poles. This means some regions will see large changes in maximum wind speeds.{{Cite journal |last1=Knutson |first1=Thomas |last2=Camargo |first2=Suzana J. |last3=Chan |first3=Johnny C. L. |last4=Emanuel |first4=Kerry |last5=Ho |first5=Chang-Hoi |last6=Kossin |first6=James |last7=Mohapatra |first7=Mrutyunjay |last8=Satoh |first8=Masaki |last9=Sugi |first9=Masato |last10=Walsh |first10=Kevin |last11=Wu |first11=Liguang |date=August 6, 2019 |title=Tropical Cyclones and Climate Change Assessment: Part II. Projected Response to Anthropogenic Warming |journal=Bulletin of the American Meteorological Society |volume=101 |issue=3 |pages=BAMS–D–18–0194.1 |bibcode=2020BAMS..101E.303K |doi=10.1175/BAMS-D-18-0194.1 |doi-access=free|hdl=1721.1/124705 |hdl-access=free }} Scientists expect there will be fewer tropical cyclones. But they expect their strength to increase.

{{excerpt|Climate change and infectious diseases|paragraphs=1-3}}

Indoor air pollution is known to affect the health, comfort, and well-being of building occupants. It has also been linked to sick building syndrome, respiratory issues, reduced productivity, and impaired learning in schools. Indoor air quality is linked inextricably to outdoor air quality.{{Cite web |title=Climate Change 2021: The Physical Science Basis |url=https://www.ipcc.ch/report/ar6/wg1/ |url-status=live |archive-url=https://web.archive.org/web/20230526182346/https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter09.pdf |archive-date=May 26, 2023 |access-date=April 15, 2024 |website=Intergovernmental Panel on Climate Change |language=en}} Climate change can affect indoor air quality by increasing the level of outdoor air pollutants such as ozone and particulate matter, for example through emissions from wildfires caused by extreme heat and drought.{{Cite journal |last1=Chen |first1=Guochao |last2=Qiu |first2=Minghao |last3=Wang |first3=Peng |last4=Zhang |first4=Yuqiang |last5=Shindell |first5=Drew |last6=Zhang |first6=Hongliang |date=19 July 2024 |title=Continuous wildfires threaten public and ecosystem health under climate change across continents |journal=Frontiers of Environmental Science & Engineering |language=en |volume=18 |issue=10 |page=130 |doi=10.1007/s11783-024-1890-6 |issn=2095-2201|doi-access=free |bibcode=2024FrESE..18..130C }}{{Cite journal |last1=Gherasim |first1=Alina |last2=Lee |first2=Alison G. |last3=Bernstein |first3=Jonathan A. |date=November 14, 2023 |title=Impact of Climate Change on Indoor Air Quality |url=https://linkinghub.elsevier.com/retrieve/pii/S0889856123000851 |url-status=live |journal=Immunology and Allergy Clinics of North America |language=en |volume=44 |issue=1 |pages=55–73 |doi=10.1016/j.iac.2023.09.001 |pmid=37973260 |archive-url=https://web.archive.org/web/20231115075718/https://linkinghub.elsevier.com/retrieve/pii/S0889856123000851 |archive-date=November 15, 2023 |access-date=April 15, 2024}} There are numerous predictions for how indoor air pollutants will change in future.{{Cite journal |last1=Lacressonnière |first1=Gwendoline |last2=Watson |first2=Laura |last3=Gauss |first3=Michael |last4=Engardt |first4=Magnuz |last5=Andersson |first5=Camilla |last6=Beekmann |first6=Matthias |last7=Colette |first7=Augustin |last8=Foret |first8=Gilles |last9=Josse |first9=Béatrice |last10=Marécal |first10=Virginie |last11=Nyiri |first11=Agnes |last12=Siour |first12=Guillaume |last13=Sobolowski |first13=Stefan |last14=Vautard |first14=Robert |date=February 1, 2017 |title=Particulate matter air pollution in Europe in a +2 °C warming world |url=https://linkinghub.elsevier.com/retrieve/pii/S1352231017300456 |url-status=live |journal=Atmospheric Environment |language=en |volume=154 |pages=129–140 |bibcode=2017AtmEn.154..129L |doi=10.1016/j.atmosenv.2017.01.037 |archive-url=https://web.archive.org/web/20231117225734/https://linkinghub.elsevier.com/retrieve/pii/S1352231017300456 |archive-date=November 17, 2023 |access-date=April 15, 2024}}{{Cite journal |last1=Lee |first1=J |last2=Lewis |first2=A |last3=Monks |first3=P |last4=Jacob |first4=M |last5=Hamilton |first5=J |last6=Hopkins |first6=J |last7=Watson |first7=N |last8=Saxton |first8=J |last9=Ennis |first9=C |last10=Carpenter |first10=L |date=September 26, 2006 |title=Ozone photochemistry and elevated isoprene during the UK heatwave of august 2003 |url=https://linkinghub.elsevier.com/retrieve/pii/S1352231006007254 |url-status=live |journal=Atmospheric Environment |language=en |volume=40 |issue=39 |pages=7598–7613 |bibcode=2006AtmEn..40.7598L |doi=10.1016/j.atmosenv.2006.06.057 |archive-url=https://web.archive.org/web/20221026103502/https://linkinghub.elsevier.com/retrieve/pii/S1352231006007254 |archive-date=October 26, 2022 |access-date=April 15, 2024}}{{Cite journal |last1=Salthammer |first1=Tunga |last2=Schieweck |first2=Alexandra |last3=Gu |first3=Jianwei |last4=Ameri |first4=Shaghayegh |last5=Uhde |first5=Erik |date=August 7, 2018 |title=Future trends in ambient air pollution and climate in Germany – Implications for the indoor environment |journal=Building and Environment |language=en |volume=143 |pages=661–670 |bibcode=2018BuEnv.143..661S |doi=10.1016/j.buildenv.2018.07.050 |doi-access=free}}{{Cite journal |last1=Zhong |first1=L. |last2=Lee |first2=C.-S. |last3=Haghighat |first3=F. |date=December 1, 2016 |title=Indoor ozone and climate change |url=https://linkinghub.elsevier.com/retrieve/pii/S2210670716302748 |url-status=live |journal=Sustainable Cities and Society |language=en |volume=28 |pages=466–472 |doi=10.1016/j.scs.2016.08.020 |archive-url=https://web.archive.org/web/20221128061645/https://linkinghub.elsevier.com/retrieve/pii/S2210670716302748 |archive-date=November 28, 2022 |access-date=April 15, 2024}} Models have attempted to predict how the forecasted scenarios will affect indoor air quality and indoor comfort parameters such as humidity and temperature.{{Cite journal |last1=Zhao |first1=Jiangyue |last2=Uhde |first2=Erik |last3=Salthammer |first3=Tunga |last4=Antretter |first4=Florian |last5=Shaw |first5=David |last6=Carslaw |first6=Nicola |last7=Schieweck |first7=Alexandra |date=December 9, 2023 |title=Long-term prediction of the effects of climate change on indoor climate and air quality |journal=Environmental Research |language=en |volume=243 |pages=117804 |doi=10.1016/j.envres.2023.117804 |pmid=38042519 |doi-access=free}}

The net-zero challenge requires significant changes in the performance of both new and retrofitted buildings. Increased energy efficient housing (without good ventilation systems) can trap pollutants inside them, whether produced indoors or outdoors, and lead to an increase in human exposure.{{Cite journal |last=Niculita-Hirzel |first=Hélène |date=March 16, 2022 |title=Latest Trends in Pollutant Accumulations at Threatening Levels in Energy-Efficient Residential Buildings with and without Mechanical Ventilation: A Review |journal=International Journal of Environmental Research and Public Health |language=en |volume=19 |issue=6 |pages=3538 |doi=10.3390/ijerph19063538 |issn=1660-4601 |pmc=8951331 |pmid=35329223 |doi-access=free}}{{Cite book |last=UK Health Security Agency |url=https://www.gov.uk/government/publications/climate-change-health-effects-in-the-uk |title=Health Effects of Climate Change (HECC) in the UK: 2023 report |year=2024 |publication-date=15 January 2024 |chapter=Chapter 5: Impact of climate change policies on indoor environmental quality and health in UK housing |orig-date=1 September 2012}}

{{Further|Ozone#Ozone air pollution|Ozone#Low level ozone in urban areas|Ground-level ozone#Ozone and the climate}}

File:SignboardAirQualityHouston.JPG, Houston indicating an ozone watch]]

The relationship between surface ozone (also called ground-level ozone) and ambient temperature is complex. Changes in air temperature and water content affect the air's chemistry and the rates of chemical reactions that create and remove ozone. Many chemical reaction rates increase with temperature and lead to increased ozone production. Climate change projections show that rising temperatures and water vapour in the atmosphere will likely increase surface ozone in polluted areas like the eastern United States.{{cite journal |last1=Ebi |first1=Kristie L. |last2=McGregor |first2=Glenn |date=2008-11-01 |title=Climate Change, Tropospheric Ozone and Particulate Matter, and Health Impacts |journal=Environmental Health Perspectives |volume=116 |issue=11 |pages=1449–1455 |doi=10.1289/ehp.11463 |pmc=2592262 |pmid=19057695|bibcode=2008EnvHP.116.1449E }}

On the other hand, ozone concentrations could decrease in a warming climate if anthropogenic ozone-precursor emissions (e.g., nitrogen oxides) continue to decrease through implementation of policies and practices.{{Cite journal |last1=Diem |first1=Jeremy E. |last2=Stauber |first2=Christine E. |last3=Rothenberg |first3=Richard |date=2017-05-16 |editor-last=Añel |editor-first=Juan A. |title=Heat in the southeastern United States: Characteristics, trends, and potential health impact |journal=PLOS ONE |language=en |volume=12 |issue=5 |pages=e0177937 |bibcode=2017PLoSO..1277937D |doi=10.1371/journal.pone.0177937 |issn=1932-6203 |pmc=5433771 |pmid=28520817 |doi-access=free}} 50x50px Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Therefore, future surface ozone concentrations depend on the climate change mitigation steps taken (more or less methane emissions) as well as air pollution control steps taken.Szopa, S., V. Naik, B. Adhikary, P. Artaxo, T. Berntsen, W.D. Collins, S. Fuzzi, L. Gallardo, A. Kiendler-Scharr, Z. Klimont, H. Liao, N. Unger, and P. Zanis, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter06.pdf Chapter 6: Short-Lived Climate Forcers]. In [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 817–922, doi:10.1017/9781009157896.008.{{rp|884}}

High surface ozone concentrations often occur during heat waves in the United States. Throughout much of the eastern United States, ozone concentrations during heat waves are at least 20% higher than the summer average. Broadly speaking, surface ozone levels are higher in cities with high levels of air pollution.{{rp|876}} Ozone pollution in urban areas affects denser populations, and is worsened by high populations of vehicles, which emit pollutants NO₂ and VOCs, the main contributors to problematic ozone levels.{{Cite journal |last1=Sharma |first1=Sumit |last2=Sharma |first2=Prateek |last3=Khare |first3=Mukesh |last4=Kwatra |first4=Swati |date=May 2016 |title=Statistical behavior of ozone in urban environment |journal=Sustainable Environment Research |volume=26 |issue=3 |pages=142–148 |bibcode= |doi=10.1016/j.serj.2016.04.006 |doi-access=free}}

There is a great deal of evidence to show that surface ozone can harm lung function and irritate the respiratory system.[http://www.euro.who.int/__data/assets/pdf_file/0005/112199/E79097.pdf Health Aspects of Air Pollution with Particulate Matter, Ozone and Nitrogen Dioxide] {{Webarchive|url=https://web.archive.org/web/20120414204626/http://www.euro.who.int/__data/assets/pdf_file/0005/112199/E79097.pdf|date=2012-04-14}}. WHO-Europe report 13–15 January 2003 (PDF)[http://www.euro.who.int/document/E82790.pdf Answer to follow-up questions from CAFE (2004)] {{webarchive|url=https://web.archive.org/web/20050909162153/http://www.euro.who.int/document/E82790.pdf|date=2005-09-09}} (PDF) Exposure to ozone (and the pollutants that produce it) is linked to premature death, asthma, bronchitis, heart attack, and other cardiopulmonary problems.{{cite web |last1=EPA Course Developers |date=2016-03-21 |title=Health Effects of Ozone in the General Population |url=https://www.epa.gov/ozone-pollution-and-your-patients-health/health-effects-ozone-general-population |publisher=EPA}}{{cite journal |author=Weinhold B |year=2008 |title=Ozone nation: EPA standard panned by the people |journal=Environ. Health Perspect. |volume=116 |issue=7 |pages=A302–A305 |doi=10.1289/ehp.116-a302 |pmc=2453178 |pmid=18629332}} High ozone concentrations irritate the lungs and thus affect respiratory function, especially among people with asthma. People who are most at risk from breathing in ozone air pollution are those with respiratory issues, children, older adults and those who typically spend long periods of time outside such as construction workers.{{Cite web |last=US EPA |first=OAR |date=2015-06-05 |title=Health Effects of Ozone Pollution |url=https://www.epa.gov/ground-level-ozone-pollution/health-effects-ozone-pollution |access-date=2023-04-29 |website=www.epa.gov |language=en}}

{{Further|Effects of climate change on agriculture|Water security#Climate change|Effects of climate change on livestock}}

Climate change affects many aspects of food security through "multiple and interconnected pathways".{{Rp|1619|date=November 2012}} Many of these are related to the effects of climate change on agriculture, for example failed crops due to more extreme weather events. This comes on top of other coexisting crises that reduce food security in many regions. Less food security means more undernutrition with all its associated health problems. Food insecurity is increasing at the global level (some of the underlying causes are related to climate change, others are not) and about 720–811 million people suffered from hunger in 2020.{{Rp|1629|date=November 2012}}

The number of deaths resulting from climate change-induced changes to food availability are difficult to estimate. The 2022 IPCC Sixth Assessment Report does not quantify this number in its chapter on food security.Bezner Kerr, R., T. Hasegawa, R. Lasco, I. Bhatt, D. Deryng, A. Farrell, H. Gurney-Smith, H. Ju, S. Lluch-Cota, F. Meza, G. Nelson, H. Neufeldt, and P. Thornton, 2022: [https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Chapter05.pdf Chapter 5: Food, Fibre, and Other Ecosystem Products]. In: [https://www.ipcc.ch/report/ar6/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, doi:10.1017/9781009325844.007. A modelling study from 2016 found "a climate change–associated net increase of 529,000 adult deaths worldwide [...] from expected reductions in food availability (particularly fruit and vegetables) by 2050, as compared with a reference scenario without climate change."{{Cite journal |last1=Springmann |first1=Marco |last2=Mason-D'Croz |first2=Daniel |last3=Robinson |first3=Sherman |last4=Garnett |first4=Tara |last5=Godfray |first5=H Charles J |last6=Gollin |first6=Douglas |last7=Rayner |first7=Mike |last8=Ballon |first8=Paola |last9=Scarborough |first9=Peter |date=2016 |title=Global and regional health effects of future food production under climate change: a modelling study |url=https://ora.ox.ac.uk/objects/uuid:6cac6d6f-d5a2-4f45-9dbf-8ebf22ab7a9a |journal=The Lancet |language=en |volume=387 |issue=10031 |pages=1937–1946 |doi=10.1016/S0140-6736(15)01156-3 |pmid=26947322 |s2cid=41851492}}{{Cite journal |last1=Haines |first1=Andy |last2=Ebi |first2=Kristie |date=2019 |editor-last=Solomon |editor-first=Caren G. |title=The Imperative for Climate Action to Protect Health |journal=New England Journal of Medicine |volume=380 |issue=3 |pages=263–273 |doi=10.1056/NEJMra1807873 |pmid=30650330 |s2cid=58662802 |doi-access=free}}

A headline finding in 2021 regarding marine food security stated that: "In 2018–20, nearly 70% of countries showed increases in average sea surface temperature in their territorial waters compared within 2003–05, reflecting an increasing threat to their marine food productivity and marine food security".{{Rp|14|date=November 2012}} (see also climate change and fisheries).

{{excerpt|Effects of climate change on mental health|paragraphs=1}}

A warming climate can lead to increases of pollen season lengths and concentrations in some regions of the world. For example, in northern mid-latitudes regions, the spring pollen season is now starting earlier.{{rp|1049}} This can affect people with pollen allergies (hay fever).{{cite journal |last1=Anderegg |first1=William R. L. |last2=Abatzoglou |first2=John T. |last3=Anderegg |first3=Leander D. L. |last4=Bielory |first4=Leonard |last5=Kinney |first5=Patrick L. |last6=Ziska |first6=Lewis |date=16 February 2021 |title=Anthropogenic climate change is worsening North American pollen seasons |journal=Proceedings of the National Academy of Sciences |volume=118 |issue=7 |pages=e2013284118 |bibcode=2021PNAS..11813284A |doi=10.1073/pnas.2013284118 |pmc=7896283 |pmid=33558232 |doi-access=free}} The rise in pollen also comes from rising CO₂ concentrations in the atmosphere and resulting CO₂ fertilisation effects.{{rp|1096}}

{{excerpt|Effects of climate change on agriculture#Reduced nutritional value of crops|paragraphs=1}}

{{See also|Harmful algal bloom}}

File:Blue-gree_algae_bloom_Lake_Erie.png (blue-green algae) bloom on Lake Erie (United States) in 2009. These kinds of algae can cause harmful algal blooms.]]

The warming oceans and lakes are leading to more frequent harmful algal blooms.{{cite book |last1=Epstein |first1=Paul R. |url=https://archive.org/details/unset0000unse_c1j4/page/29 |title=Changing Planet, Changing Health: How the Climate Crisis Threatens Our Health and what We Can Do about it |last2=Ferber |first2=Dan |publisher=University of California Press |year=2011 |isbn=978-0-520-26909-5 |pages=[https://archive.org/details/unset0000unse_c1j4/page/29 29–61] |chapter=The Mosquito's Bite |chapter-url=https://books.google.com/books?id=nnOkFhXo8rEC&pg=PA29}}{{cite journal |last1=McMichael |first1=A.J. |last2=Woodruff |first2=R.E. |last3=Hales |first3=S. |date=11 March 2006 |title=Climate change and human health: present and future risks |journal=The Lancet |volume=367 |issue=9513 |pages=859–869 |doi=10.1016/s0140-6736(06)68079-3 |pmid=16530580 |s2cid=11220212}}{{cite book |last1=Epstein |first1=Paul R. |url=https://archive.org/details/unset0000unse_c1j4/page/6 |title=Changing Planet, Changing Health: How the Climate Crisis Threatens Our Health and what We Can Do about it |last2=Ferber |first2=Dan |publisher=University of California Press |year=2011 |isbn=978-0-520-26909-5 |pages=[https://archive.org/details/unset0000unse_c1j4/page/6 6–28] |chapter=Mozambique |chapter-url=https://books.google.com/books?id=nnOkFhXo8rEC&pg=PP1}} Also, during droughts, surface waters are even more susceptible to harmful algal blooms and microorganisms.{{cite web |title=NRDC: Climate Change Threatens Health: Drought |url=http://www.nrdc.org/health/climate/drought.asp |work=nrdc.org|date=24 October 2022 }} Algal blooms increase water turbidity, suffocating aquatic plants, and can deplete oxygen, killing fish. Some kinds of blue-green algae (cyanobacteria) create neurotoxins, hepatoxins, cytotoxins or endotoxins that can cause serious and sometimes fatal neurological, liver and digestive diseases in humans. Cyanobacteria grow best in warmer temperatures (especially above 25 degrees Celsius), and so areas of the world that are experiencing general warming as a result of climate change are also experiencing harmful algal blooms more frequently and for longer periods of time.{{cite journal |last1=Paerl |first1=Hans W. |last2=Huisman |first2=Jef |date=4 April 2008 |title=Blooms Like It Hot |journal=Science |volume=320 |issue=5872 |pages=57–58 |citeseerx=10.1.1.364.6826 |doi=10.1126/science.1155398 |pmid=18388279 |s2cid=142881074}}

One of these toxin producing algae is Pseudo-nitzschia fraudulenta. This species produces a substance called domoic acid which is responsible for amnesic shellfish poisoning.{{cite journal |last1=Tatters |first1=Avery O. |last2=Fu |first2=Fei-Xue |last3=Hutchins |first3=David A. |date=February 2012 |title=High CO₂ and Silicate Limitation Synergistically Increase the Toxicity of Pseudo-nitzschia fraudulenta |journal=PLOS ONE |volume=7 |issue=2 |pages=e32116 |bibcode=2012PLoSO...732116T |doi=10.1371/journal.pone.0032116 |pmc=3283721 |pmid=22363805 |doi-access=free}}{{cite journal |last1=Wingert |first1=Charles J. |last2=Cochlan |first2=William P. |date=July 2021 |title=Effects of ocean acidification on the growth, photosynthetic performance, and domoic acid production of the diatom Pseudo-nitzschia australis from the California Current System |journal=Harmful Algae |volume=107 |page=102030 |doi=10.1016/j.hal.2021.102030 |pmid=34456015 |s2cid=237841102 |doi-access=free|bibcode=2021HAlga.10702030W }} The toxicity of this species has been shown to increase with greater CO₂ concentrations associated with ocean acidification. Some of the more common illnesses reported from harmful algal blooms include; Ciguatera fish poisoning, paralytic shellfish poisoning, azaspiracid shellfish poisoning, diarrhetic shellfish poisoning, neurotoxic shellfish poisoning and the above-mentioned amnesic shellfish poisoning.

It is possible that a potential health benefit from global warming could result from fewer cold days in winter:{{rp|1099}} This could lead to some mental health benefits. However, the evidence on this correlation is regarded as inconsistent in 2022.{{rp|1099}}

{{See also|Climate change mitigation#Co-benefits}}

The potential health benefits (also called "co-benefits") from climate change mitigation and adaptation measures are significant, having been described as "the greatest global health opportunity" of the 21st century.{{rp|1861}} Measures can not only mitigate future health effects from climate change but also improve health directly.{{cite journal |last1=Workman |first1=Annabelle |last2=Blashki |first2=Grant |last3=Bowen |first3=Kathryn J. |last4=Karoly |first4=David J. |last5=Wiseman |first5=John |date=April 2018 |title=The Political Economy of Health Co-Benefits: Embedding Health in the Climate Change Agenda |journal=International Journal of Environmental Research and Public Health |language=en |volume=15 |issue=4 |page=674 |doi=10.3390/ijerph15040674 |pmc=5923716 |pmid=29617317 |doi-access=free}} Climate change mitigation is interconnected with various co-benefits (such as reduced air pollution and associated health benefits){{cite web |last1=Molar |first1=Roberto |title=Reducing Emissions to Lessen Climate Change Could Yield Dramatic Health Benefits by 2030 |url=https://climate.nasa.gov/news/3134/reducing-emissions-to-lessen-climate-change-could-yield-dramatic-health-benefits-by-2030/ |access-date=1 December 2021 |website=Climate Change: Vital Signs of the Planet}} and how it is carried out (in terms of e.g. policymaking) could also determine its effect on living standards (whether and how inequality and poverty are reduced).{{cite news |last1=Swenarton |first1=Nicole |title=Climate action can lessen poverty and inequality worldwide |language=en |work=Rutgers University |url=https://phys.org/news/2021-12-climate-action-lessen-poverty-inequality.html |access-date=1 December 2021}}

There are many health co-benefits associated with climate action. These include those of cleaner air, healthier diets (e.g. less red meat), more active lifestyles, and increased exposure to green urban spaces.{{Rp|26|date=November 2012}} Access to urban green spaces provides benefits to mental health as well.{{Rp|18|date=November 2012}}

In the transportation sector mitigation strategies could enable more equitable access to transportation services and reduce congestion.IPCC (2022) [https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_SPM.pdf Summary for policy makers] in [https://www.ipcc.ch/report/ar6/wg3/ Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change], Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States{{rp|SPM-32}} Biking reduces greenhouse gas emissions{{cite book |last1=Blondel |first1=Benoît |url=https://ecf.com/sites/ecf.com/files/ECF_CO2_WEB.pdf |title=Cycle more Often 2 cool down the planet ! |last2=Mispelon |first2=Chloé |last3=Ferguson |first3=Julian |date=November 2011 |publisher=European Cyclists’ Federation |archive-url=https://web.archive.org/web/20190217135036/https://ecf.com/sites/ecf.com/files/ECF_CO2_WEB.pdf |archive-date=17 February 2019 |url-status=dead |accessdate=16 April 2019}} while reducing the effects of a sedentary lifestyle at the same time{{cite web |title=Cycling - health benefits |url=https://www.betterhealth.vic.gov.au/health/healthyliving/cycling-health-benefits |accessdate=16 April 2019 |website=Better Health Channel}} According to PLoS Medicine: "obesity, diabetes, heart disease, and cancer, which are in part related to physical inactivity, may be reduced by a switch to low-carbon transport—including walking and cycling."{{cite journal |last1=A. Patz |first1=Jonathan |last2=C. Thomson |first2=Madeleine |date=31 July 2018 |title=Climate change and health: Moving from theory to practice |journal=PLOS Medicine |volume=15 |issue=7 |pages=e1002628 |doi=10.1371/journal.pmed.1002628 |pmc=6067696 |pmid=30063707 |doi-access=free}}

Future sustainable pathways scenarios may result in an annual reduction of 1.18 million air pollution-related deaths, 5.86 million diet-related deaths, and 1.15 million deaths due to physical inactivity, across nine countries by 2040. These benefits were attributable to the mitigation of direct greenhouse gas emissions and the accompanying actions that reduce exposure to harmful pollutants, as well as improved diets and safe physical activity.{{Cite journal |last1=Sampedro |first1=Jon |last2=Smith |first2=Steven J. |last3=Arto |first3=Iñaki |last4=González-Eguino |first4=Mikel |last5=Markandya |first5=Anil |last6=Mulvaney |first6=Kathleen M. |last7=Pizarro-Irizar |first7=Cristina |last8=Van Dingenen |first8=Rita |date=2020 |title=Health co-benefits and mitigation costs as per the Paris Agreement under different technological pathways for energy supply |journal=Environment International |language=en |volume=136 |pages=105513 |bibcode=2020EnInt.13605513S |doi=10.1016/j.envint.2020.105513 |pmid=32006762 |s2cid=211004787 |doi-access=free |hdl-access=free |hdl=10810/44202}} Globally the cost of limiting warming to 2 °C is less than the value of the extra years of life due to cleaner air - and in India and China much less.

Studies suggest that efforts to reduce consumption of goods and services have largely beneficial effects on 18 constituents of well-being.{{cite news |title=MCC: Quality of life increases when we live, eat and travel energy-efficiently |url=https://idw-online.de/de/news781561 |access-date=11 December 2021 |work=idw-online.de}}{{Cite journal |last1=Creutzig |first1=Felix |author1-link=Felix Creutzig |last2=Niamir |first2=Leila |last3=Bai |first3=Xuemei |last4=Callaghan |first4=Max |last5=Cullen |first5=Jonathan |last6=Díaz-José |first6=Julio |last7=Figueroa |first7=Maria |last8=Grubler |first8=Arnulf |last9=Lamb |first9=William F. |last10=Leip |first10=Adrian |last11=Masanet |first11=Eric |last12=Mata |first12=Érika |last13=Mattauch |first13=Linus |last14=Minx |first14=Jan C. |last15=Mirasgedis |first15=Sebastian |date=2022 |title=Demand-side solutions to climate change mitigation consistent with high levels of well-being |journal=Nature Climate Change |language=en |volume=12 |issue=1 |pages=36–46 |bibcode=2022NatCC..12...36C |doi=10.1038/s41558-021-01219-y |issn=1758-678X |s2cid=234275540 |doi-access=free}}

Addressing inequality can assist with climate change mitigation efforts.{{rp|38}} Placing health as a key focus of the Nationally Determined Contributions could present an opportunity to increase ambition and realise health co-benefits.

Air pollution generated by fossil fuel combustion is both a major driver of global warming and the cause of a large number of annual deaths with some estimates as high as {{tooltip|2=A review of this and a more nuanced assessment of mortality impacts in terms of contribution to death, rather than number of deceased, may be needed|8.7 million}} excess deaths during 2018.{{cite news |last1=Green |first1=Matthew |date=9 February 2021 |title=Fossil fuel pollution causes one in five premature deaths globally: study |url=https://www.reuters.com/article/us-health-pollution-fossil-idUSKBN2A90UB |url-status=live |archive-url=https://web.archive.org/web/20210225031944/https://www.reuters.com/article/us-health-pollution-fossil-idUSKBN2A90UB |archive-date=25 February 2021 |access-date=5 March 2021 |work=Reuters}}{{cite journal |last1=Vohra |first1=Karn |last2=Vodonos |first2=Alina |last3=Schwartz |first3=Joel |last4=Marais |first4=Eloise A.|author4-link=Eloise Marais |last5=Sulprizio |first5=Melissa P. |last6=Mickley |first6=Loretta J. |date=April 2021 |title=Global mortality from outdoor fine particle pollution generated by fossil fuel combustion: Results from GEOS-Chem |url=https://discovery.ucl.ac.uk/id/eprint/10119672/ |journal=Environmental Research |volume=195 |page=110754 |bibcode=2021ER....19510754V |doi=10.1016/j.envres.2021.110754 |pmid=33577774 |s2cid=231909881}} Climate change mitigation policies can lead to lower emissions of co-emitted air pollutants, for instance by shifting away from fossil fuel combustion. Gases such as black carbon and methane contribute both to global warming and to air pollution. Their mitigation can bring benefits in terms of limiting global temperature increases as well as improving air quality.{{cite journal |last1=Anenberg |first1=Susan C. |last2=Schwartz |first2=Joel |display-authors=etal |date=1 June 2012 |title=Global Air Quality and Health Co-benefits of Mitigating Near-Term Climate Change through Methane and Black Carbon Emission Controls |journal=Environmental Health Perspectives |volume=120 |issue=6 |pages=831–839 |doi=10.1289/ehp.1104301 |pmc=3385429 |pmid=22418651|bibcode=2012EnvHP.120..831A }} Implementation of the climate pledges made in the run-up to the Paris Agreement could therefore have significant benefits for human health by improving air quality.{{cite journal |last1=Vandyck |first1=Toon |last2=Keramidas |first2=Kimon |display-authors=etal |date=22 November 2018 |title=Air quality co-benefits for human health and agriculture counterbalance costs to meet Paris Agreement pledges |journal=Nature Communications |volume=9 |issue=1 |pages=4939 |bibcode=2018NatCo...9.4939V |doi=10.1038/s41467-018-06885-9 |pmc=6250710 |pmid=30467311 |doi-access=free}}

The replacement of coal-based energy with renewables can lower the number of premature deaths caused by air pollution and decrease health costs associated with coal-related respiratory diseases. This switch to renewable energy is crucial, as air pollution is responsible for over 13 million deaths annually.{{Cite web |last=IASS/CSIR |date=2019a |title=Improving health and reducing costs through renewable energy in South Africa. Assessing the co-benefits of decarbonising the power sector |url=https://www.cobenefits.info/wp-content/uploads/2019/03/COBENEFITS_SA_Health_Executive_Report_190322.pdf |url-status=live |archive-url=https://web.archive.org/web/20210420232336/https://www.cobenefits.info/wp-content/uploads/2019/03/COBENEFITS_SA_Health_Executive_Report_190322.pdf |archive-date=2021-04-20}}{{Cite web |last=Nations |first=United |title=Renewable energy – powering a safer future |url=https://www.un.org/en/climatechange/raising-ambition/renewable-energy |access-date=2024-05-13 |website=United Nations |language=en}}

File:Cascading_global_climate_failure.jpg{{Cite journal |last1=Kemp |first1=Luke |last2=Xu |first2=Chi |last3=Depledge |first3=Joanna |last4=Ebi |first4=Kristie L. |last5=Gibbins |first5=Goodwin |last6=Kohler |first6=Timothy A. |last7=Rockström |first7=Johan |last8=Scheffer |first8=Marten |last9=Schellnhuber |first9=Hans Joachim |last10=Steffen |first10=Will |last11=Lenton |first11=Timothy M. |date=2022 |title=Climate Endgame: Exploring catastrophic climate change scenarios |journal=Proceedings of the National Academy of Sciences |language=en |volume=119 |issue=34 |pages=e2108146119 |doi=10.1073/pnas.2108146119 |doi-access=free |issn=0027-8424 |pmc=9407216 |pmid=35914185|bibcode=2022PNAS..11908146K }}]]

Estimating deaths (mortality) or DALYs (morbidity) from the effects of climate change at the global level is very difficult. A 2014 study by the World Health Organization estimated the effect of climate change on human health, but not all of the effects of climate change were included.{{Cite book |title=Quantitative risk assessment of the effects of climate change on selected causes of death, 2030s and 2050s |date=2014 |publisher=World Health Organization |isbn=978-92-4-150769-1 |editor-last=Hales |editor-first=Simon |location=Switzerland |hdl=10665/134014 |hdl-access=free |editor-last2=Kovats |editor-first2=Sari |editor-last3=Lloyd |editor-first3=Simon |editor-last4=Campbell-Lendrum |editor-first4=Diarmid }}{{page needed|date=November 2022}} For example, the effects of more frequent and extreme storms were excluded. The study assessed deaths from heat exposure in elderly people, increases in diarrhea, malaria, dengue, coastal flooding, and childhood undernutrition. The authors estimated that climate change was projected to cause an additional 250,000 deaths per year between 2030 and 2050 but also stated that "these numbers do not represent a prediction of the overall impacts of climate change on health, since we could not quantify several important causal pathways".

Climate change was responsible for 3% of diarrhoea, 3% of malaria, and 3.8% of dengue fever deaths worldwide in 2004.{{cite book |author=WHO |url=https://www.who.int/healthinfo/global_burden_disease/global_health_risks/en/index.html |title=Global health risks: mortality and burden of disease attributable to selected major risks |publisher=WHO Press |year=2009 |isbn=978-92-4-156387-1 |location=Geneva, Switzerland |page=24 |chapter=Ch. 2, Results: 2.6 Environmental risks |format=PDF |access-date=4 October 2020 |chapter-url=https://www.who.int/entity/healthinfo/global_burden_disease/GlobalHealthRisks_report_part2.pdf |archive-url=https://web.archive.org/web/20131210002548/http://www.who.int/healthinfo/global_burden_disease/global_health_risks/en/index.html |archive-date=10 December 2013 }} Total attributable mortality was about 0.2% of deaths in 2004; of these, 85% were child deaths. The effects of more frequent and extreme storms were excluded from this study.

The health effects of climate change are expected to rise in line with projected ongoing global warming for different climate change scenarios.{{cite book |last1=Crimmins |first1=A. |url=https://digital.library.unt.edu/ark:/67531/metadc950291/ |title=The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment |last2=Balbus |first2=J. |last3=Gamble |first3=J.L. |last4=Beard |first4=C.B. |last5=Bell |first5=J.E. |last6=Dodgen |first6=D. |last7=Eisen |first7=R.J. |last8=Fann |first8=N. |last9=Hawkins |first9=M.D. |year=2016 |isbn=978-0-16-093241-0 |doi=10.7930/J0R49NQX |last10=Herring |first10=S.C. |last11=Jantarasami |first11=L. |last12=Mills |first12=D.M. |last13=Saha |first13=S. |last14=Sarofim |first14=M.C. |last15=Trtanj |first15=J. |last16=Ziska |first16=L.|bibcode=2016icch.book.....C }} A review{{Cite journal |last1=Pearce |first1=Joshua M. |last2=Parncutt |first2=Richard |date=January 2023 |title=Quantifying Global Greenhouse Gas Emissions in Human Deaths to Guide Energy Policy |journal=Energies |language=en |volume=16 |issue=16 |pages=6074 |doi=10.3390/en16166074 |issn=1996-1073 |doi-access=free }} found if warming reaches or exceeds 2 °C this century, roughly 1 billion premature deaths would be caused by anthropogenic global warming.{{Cite news |date=2023-08-29 |title=Human-caused climate change may lead to 1 billion premature deaths over next century: Study |work=The Times of India |url=https://timesofindia.indiatimes.com/home/environment/global-warming/human-caused-climate-change-may-lead-to-1-billion-premature-deaths-over-next-century-study/articleshow/103164287.cms?from=mdr |access-date=2023-09-18 |issn=0971-8257}}

{{Further|Climate change vulnerability}}

A 2021 report published in The Lancet found that climate change does not affect people's health in an equal way. The greatest impact tends to fall on the most vulnerable such as the poor, women, children, the elderly, people with pre-existing health concerns, other minorities and outdoor workers.{{rp|13}}

Social factors shape health outcomes as people are rendered more or less able to adapt to harms. For example there are "demographic, socioeconomic, housing, health (such as pre-existing health conditions), neighbourhood, and geographical factors" that moderate the effect of climate change on human health.{{cite journal |last1=Li |first1=Ang |last2=Toll |first2=Mathew |last3=Martino |first3=Erika |last4=Wiesel |first4=Illan |last5=Botha |first5=Ferdi |last6=Bentley |first6=Rebecca |date=March 2023 |title=Vulnerability and recovery: Long-term mental and physical health trajectories following climate-related disasters |journal=Social Science & Medicine |volume=320 |issue=115681 |page=115681 |doi=10.1016/j.socscimed.2023.115681 |pmid=36731303 |s2cid=256159626 |doi-access=free}}

{{Further|Climate justice |Climate migrant}}

Much of the health burden associated with climate change falls on vulnerable people (e.g. indigenous peoples and economically disadvantaged communities). As a result, people of disadvantaged sociodemographic groups experience unequal risks.{{cite journal |last1=Bergstrand |first1=Kelly |last2=Mayer |first2=Brian |last3=Brumback |first3=Babette |last4=Zhang |first4=Yi |title=Assessing the Relationship Between Social Vulnerability and Community Resilience to Hazards |journal=Social Indicators Research |date=June 2015 |volume=122 |issue=2 |pages=391–409 |doi=10.1007/s11205-014-0698-3 |pmid=29276330 |pmc=5739329 }} Often these people will have made a disproportionately low contribution toward man-made global warming, thus leading to concerns over climate justice.{{cite journal |last1=Epstein |first1=Paul R. |title=Climate Change and Human Health |journal=New England Journal of Medicine |date=6 October 2005 |volume=353 |issue=14 |pages=1433–1436 |doi=10.1056/NEJMp058079 |pmid=16207843 |doi-access=free }}{{Cite web |title=Human Health |url=https://nca2014.globalchange.gov/report/sectors/human-health |access-date=25 November 2020 |website=Global Change}}{{cite book |title=Climate Change and Global Public Health |publisher=Humana |year=2021 |isbn=978-3-030-54745-5 |editor=Kent E. Pinkerton , William N. Rom |chapter=1,2,6,12,13}}

Climate change has diverse effects on migration activities, and can lead to decreases or increases in the number of people who migrate.{{rp|1079}} Migration activities can have an effect on health and well-being, in particular for mental health. Migration in the context of climate change can be grouped into four types: adaptive migration (see also climate change adaptation), involuntary migration, organised relocation of populations, and immobility (which is when people are unable or unwilling to move even though it is recommended).{{rp|1079}}

The observed contribution of climate change to conflict risk is small in comparison with cultural, socioeconomic, and political causes. There is some evidence that rural-to-urban migration within countries worsens the conflict risk in violence prone regions. But there is no evidence that migration between countries would increase the risk of violence.{{rp|1008,1128}}

{{Further|Individual action on climate change|}}

Studies have found that when communicating climate change with the public, it can help encourage engagement if it is framed as a health concern, rather than as an environmental issue.{{cite journal |last1=Maibach |first1=Edward W |last2=Nisbet |first2=Matthew |last3=Baldwin |first3=Paula |last4=Akerlof |first4=Karen |last5=Diao |first5=Guoqing |date=December 2010 |title=Reframing climate change as a public health issue: an exploratory study of public reactions |journal=BMC Public Health |volume=10 |issue=1 |page=299 |doi=10.1186/1471-2458-10-299 |pmc=2898822 |pmid=20515503 |doi-access=free}}{{cite journal |last1=Dasandi |first1=Niheer |last2=Graham |first2=Hilary |last3=Hudson |first3=David |last4=Jankin |first4=Slava |last5=vanHeerde-Hudson |first5=Jennifer |last6=Watts |first6=Nick |date=20 October 2022 |title=Positive, global, and health or environment framing bolsters public support for climate policies |journal=Communications Earth & Environment |volume=3 |issue=1 |page=239 |bibcode=2022ComEE...3..239D |doi=10.1038/s43247-022-00571-x |s2cid=253041860 |doi-access=free}} This is especially the case when comparing a health related framing to one that emphasised environmental doom, as was common in the media at least up until 2017.{{cite journal |author=Anneliese Depoux |author2=Mathieu Hémono |author3=Sophie Puig-Malet |author4=Romain Pédron |author5=Antoine Flahault |year=2017|title=Communicating climate change and health in the media.|journal=Public Health Rev|volume=38|page=7|doi=10.1186/s40985-016-0044-1|pmid=29450079|pmc=5809944|doi-access=free}}

{{cite AV media|url=https://www.ted.com/talks/per_espen_stoknes_how_to_transform_apocalypse_fatigue_into_action_on_global_warming|title=How to transform apocalypse fatigue into action on global warming|date=September 2017|people=Per Espen Stoknes|publisher=TED (conference)|access-date=1 March 2021}}

Communicating the co-benefits to health helps underpin greenhouse gas reduction strategies. Safeguarding health—particularly of the most vulnerable—is a frontline local climate change adaptation goal.

Due to its significant impact on human health,{{cite news |last=Davenport |first=Coral |date=4 April 2016 |title=Global Warming Linked to Public Health Risks, White House Says |work=The New York Times |url=https://www.nytimes.com/2016/04/05/us/politics/climate-change-health-risks.html}}{{cite web |author=Kavya Balaraman |date=17 March 2017 |title=Doctors Warn Climate Change Threatens Public Health; Physicians are noticing an influx of patients whose illnesses are directly or indirectly related to global warming |url=https://www.scientificamerican.com/article/doctors-warn-climate-change-threatens-public-health/ |access-date=20 March 2017 |website=E&E News |via=Scientific American}} climate change has become a major concern for public health policy. The United States Environmental Protection Agency had issued a 100-page report on global warming and human health back in 1989.{{cite news |author=Dean Russell |author2=Elisabeth Gawthrop |author3=Veronica Penney |author4=Ali Raj |author5=Bridget Hickey |date=16 June 2020 |title=Deadly heat is killing Americans: A decade of inaction on climate puts lives at risk |work=The Guardian |url=https://www.theguardian.com/us-news/2020/jun/16/climate-deaths-heat-cdc |access-date=1 March 2021}} By the early years of the 21st century, climate change was increasingly addressed as a public health concern at a global level, for example in 2006 at Nairobi by UN secretary general Kofi Annan. Since 2018, factors such as the 2018 heat wave, the Greta effect and the IPCC's 2018 Special Report on Global Warming of 1.5 °C further increased the urgency for responding to climate change as a global health issue.{{cite journal |author=Fox, M. |author2=Zuidema, C. |author3=Bauman, B. |author4=Burke, T. |author5=Sheehan, M. |date=2019 |title=Integrating Public Health into Climate Change Policy and Planning: State of Practice Update |journal=International Journal of Environmental Research and Public Health |volume=16 |issue=18 |page=3232 |doi=10.3390/ijerph16183232 |pmc=6765852 |pmid=31487789 |doi-access=free}} 50px Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License]

The World Bank has suggested a framework that can strengthen health systems to make them more resilient and climate-sensitive.{{cite book |url=https://www.who.int/publications/i/item/9789241565073 |title=Operational framework for building climate resilient health systems |publisher=WHO |year=2015 |isbn=978-92-4-156507-3}}{{page needed|date=November 2022}}

Placing health as a key focus of the Nationally Determined Contributions could present an opportunity to increase ambition and realize health co-benefits.{{Cite journal |last1=Hamilton |first1=Ian |last2=Kennard |first2=Harry |last3=McGushin |first3=Alice |last4=Höglund-Isaksson |first4=Lena |last5=Kiesewetter |first5=Gregor |last6=Lott |first6=Melissa |last7=Milner |first7=James |last8=Purohit |first8=Pallav |last9=Rafaj |first9=Peter |last10=Sharma |first10=Rohit |last11=Springmann |first11=Marco |date=2021 |title=The public health implications of the Paris Agreement: a modelling study |journal=The Lancet Planetary Health |language=en |volume=5 |issue=2 |pages=e74–e83 |doi=10.1016/S2542-5196(20)30249-7 |pmc=7887663 |pmid=33581069}}{{CC-notice|by4}}

In 2019, the Australian Medical Association formally declared climate change as a health emergency.{{Cite news |author=Katharine Murphy |date=2 September 2019 |title=Australian Medical Association declares climate change a health emergency |url=https://www.theguardian.com/australia-news/2019/sep/03/australian-medical-association-declares-climate-change-a-health-emergency |access-date=19 April 2020 |work=The Guardian}}

Research shows that health professionals around the world agree that climate change is real, is caused by humans, and is causing increased health problems in their communities. Health professionals can act by informing people about health harms and ways to address them, by lobbying leaders to take action, and by taking steps to decarbonize their own homes and workplaces.{{cite journal |last1=Kotcher |first1=John |last2=Maibach |first2=Edward |last3=Miller |first3=Jeni |last4=Campbell |first4=Eryn |last5=Alqodmani |first5=Lujain |last6=Maiero |first6=Marina |last7=Wyns |first7=Arthur |date=May 2021 |title=Views of health professionals on climate change and health: a multinational survey study |journal=The Lancet Planetary Health |volume=5 |issue=5 |pages=e316–e323 |doi=10.1016/S2542-5196(21)00053-X |pmc=8099728 |pmid=33838130}}

• Effects of climate change on health in the United Kingdom
• Effects of climate change on health in the Philippines
• Effects of climate change
• Environmental health
• Occupational heat stress
• Water security

{{reflist|2}}

• [http://www.lancetcountdown.org/ Public health and climate change (Lancet)]
• [https://www.who.int/news-room/fact-sheets/detail/climate-change-and-health Climate change and health (World Health Organization)]

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