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.: 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. heatwave early warning and response systems are important elements of heat action plans. reduced labour capacity heat exposure can affect people's ability to work.: 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 affects especially 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.: 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.: 1073–1074 sports and outdoor exercise with regards to sporting activities it has been observed that "hot weather reduces the likelihood of engaging in exercise".: 1625 furthermore, participating in sports during excessive heat can lead to injury or even death.: 1073–1074 it is also well established that regular physical activity is beneficial for human health, including mental health.: 1625 therefore, an increase in hot days due to climate change could indirectly affect mental health due to people exercising less. however, the evidence on hours of outdoor exercise is still weak: a review in 2021 reported data on the increase of hours per year during which temperatures were too high for safe outdoor exercise (indicator 1.1.3).: 1625 but the follow-up review in the following year did not report the same kind of data but reported an increase in "hours of moderate risk of heat stress during light outdoor physical activity".: 1625 impacts caused by weather and climate events other than heat further information: effects of climate change § extreme weather events, and extreme weather a schematic showing the regions where more disasters will occur due to climate change climate change is increasing the periodicity and intensity of some extreme weather events. confidence in the attribution of extreme weather to anthropogenic climate change is highest in changes in frequency or magnitude of extreme heat and cold events with some confidence in increases in heavy precipitation and increases in the intensity of droughts. extreme weather events, such as floods, hurricanes, droughts and wildfires can result in injuries, death and the spread of infectious diseases. for example, local epidemics can occur due to loss of infrastructure, such as hospitals and sanitation services, but also because of changes in local ecology and environment. floods further information: effects of climate change § floods, and flood § health effects due to an increase in heavy rainfall events, floods are expected to become more severe in future when they do occur.: 1155 however, the interactions between rainfall and flooding are complex. there are in fact some regions in which flooding is expected to become rarer. this depends on several factors, such as changes in rain and snowmelt, but also soil moisture.: 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. for example, in the 2022 pakistan floods (which were likely more severe because of climate change) people's health was affected through various direct and indirect ways. there were outbreaks of diseases like malaria, dengue, and other skin diseases. hurricanes and thunderstorms further information: effects of climate change § tropical cyclones and hurricanes, and tropical cyclones and climate change stronger hurricanes create more opportunities for vectors to breed and infectious diseases to flourish. extreme weather also means stronger winds. these winds can carry vectors tens of thousands of kilometers, resulting in an introduction of new infectious agents to regions that have never seen them before, making the humans in these regions even more susceptible. another result of hurricanes is increased rainwater, which promotes flooding. hurricanes result in ruptured pollen grains, which releases respirable aeroallergens. thunderstorms cause a concentration of pollen grains at the ground level, which causes an increase in the release of allergenic particles in the atmosphere due to rupture by osmotic shock. around 20–30 minutes after a thunderstorm, there is an increased risk for people with pollen allergies to experience severe asthmatic exacerbations, due to high concentration inhalation of allergenic peptides. droughts further information: effects of climate change § droughts 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.: 1057 many of the consequences of droughts have impacts on human health. this can be through destruction of food supply (loss of crop yields), malnutrition and with this, dozens of associated diseases and health problems. wildfires air pollution from a surface fire in the western desert of utah. wildfires become more frequent and intense due to climate change. climate change increases wildfire potential and activity. 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. wood smoke from wildfires produces particulate matter that has damaging effects to human health. the primary pollutants in wood smoke are carbon monoxide and nitric oxide. through the destruction of forests and human-designed infrastructure, wildfire smoke releases other toxic and carcinogenic compounds, such as formaldehyde and hydrocarbons. these pollutants damage human health by evading the mucociliary clearance system and depositing in the upper respiratory tract, where they exert toxic effects. 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. health risks due to climate-sensitive infectious diseases main article: climate change and infectious diseases infectious diseases that are sensitive to climate can be grouped into: vector-borne diseases (transmitted via mosquitos, ticks etc.), water-borne diseases and food-borne diseases.: 1107 climate change is affecting the distribution of all these diseases.: 12 this occurs for example via expanding the geographic range and seasonality of these diseases and their vectors. climate change may also lead to new infectious diseases due to changes in microbial and vector geographic range. microbes that are harmful to humans can adapt to higher temperatures, which will allow them to build better tolerance against human endothermy defenses. vector-borne diseases aedes aegypti, the mosquito that is the vector for dengue transmission. an anopheles stephensi mosquito shortly after obtaining blood from a human (the droplet of blood is expelled as a surplus). this mosquito is a vector of malaria, and mosquito control is an effective way of reducing its incidence. mosquito-borne diseases further information: climate change and infectious diseases § malaria mosquito-borne diseases that are sensitive to climate include for example malaria, elephantiasis, rift valley fever, yellow fever, dengue fever, zika virus, and chikungunya. scientists found in 2022 that rising temperatures are increasing the areas where dengue fever, malaria and other mosquito-carried diseases are able to spread.: 1062 warmer temperatures are also advancing to higher elevations, allowing mosquitoes to survive in places that were previously inhospitable to them.: 1045 this risks malaria making a return to areas where it was previously eradicated. diseases from ticks ticks are changing their geographic range because of rising temperatures, and this puts new populations at risk. ticks can spread lyme disease and tick-borne encephalitis. it is expected that climate change will increase the incidence of these diseases in the northern hemisphere.: 1094 for example, a review of the literature found that "in the usa, a 2°c warming could increase the number of lyme disease cases by over 20% over the coming decades and lead to an earlier onset and longer length of the annual lyme disease season".: 1094 waterborne diseases main article: waterborne disease and climate change there are a range of waterborne diseases and parasites that will pose greater health risks in future. this will vary by region. for example, in africa cryptosporidium spp. and giardia duodenalis (two protozoan parasites) will increase. this is due to increasing temperatures and drought.: 1095 scientist expect that disease outbreaks caused by vibrio (in particular the bacterium that causes cholera, which is called vibrio cholerae) are increasing in occurrence and intensity.: 1107 one reason is that the area of coastline with suitable conditions for vibrio bacteria has increased due to changes in sea surface temperature and sea surface salinity caused by climate change.: 12 these pathogens can cause gastroenteritis, cholera, wound infections, and sepsis. it has been observed that in the period of 2011–21, the "area of coastline suitable for vibrio bacterial transmission has increased by 35% in the baltics, 25% in the atlantic northeast, and 4% in the pacific northwest.: 12 furthermore, the increasing occurrence of higher temperature days, heavy rainfall events and flooding due to climate change could lead to an increase in cholera risks.: 1045 other health risks influenced by climate change harmful algal blooms in oceans and lakes cyanobacteria (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. also, during droughts, surface waters are even more susceptible to harmful algal blooms and microorganisms. 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. 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. 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. ozone-related health burden signboard in gulfton, 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. 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. 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.: 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.: 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. there is a great deal of evidence to show that surface ozone can harm lung function and irritate the respiratory system. exposure to ozone (and the pollutants that produce it) is linked to premature death,