Natural environment and health

The natural environment comprises the atmosphere, land, water, oceans, and the diversity of living things (UN 2019). It provides essential resources for health and wellbeing including food, fresh water, wood and fibre, fuel and medicines. It also helps regulate weather, vegetation, soils, and the quality of water and air, and provides a range of aesthetic, cultural, recreational and spiritual services to people (Whitmee et al. 2015).

As a result of human activity, the health of most or all the planetary systems that provide these services is currently in decline, including some already considered irreversibly damaged (UN 2019).

The natural environment is a determinant of health due to its ability to affect health outcomes (see What are determinants of health?). This page presents a selection of evidence on the influence of the natural environment on human physical and mental health in Australia. For more information on the health impacts of the human-made surroundings, see Built environment and health.

Climate change and health

Climate change affects environmental determinants of human health through a range of different pathways, from the frequency of extreme weather events to the prevalence of infectious and communicable diseases, to the availability of safe water and food (Ebi et al. 2018). This can result in health effects such as thermal stress, injury, vector-borne (see glossary) and other infectious diseases, food insecurity and poor mental health (McMichael et al. 2006). The social determinants of health are also being affected by climate change (WHO 2018a).

Climate change affects some population groups more than others. Groups at greater risk include older people, children, people with chronic conditions and multimorbidity, outdoor workers, people living in rural and remote areas, those living in low-lying, flood- or bushfire-prone areas, and socioeconomically disadvantaged groups.

Climate change also is likely to affect First Nations people to a greater extent than non-Indigenous populations (Beggs et al. 2021; HEAL Network and CRE-STRIDE 2021; McNamara and Westoby 2011; Moggridge and Thompson 2021), for example, by disrupting their connection to Country, exacerbating existing risk factors or compounding historical injustices (Beggs et al. 2021; HEAL Network and CRE-STRIDE 2021).

Climate change is expected to challenge the health care system, for example through increased need for health care services (such as emergency department usage and hospital admissions), and disruptions to health service provision and health supplies during and in the aftermath of extreme weather events. Yet the health care system itself is estimated to be directly or indirectly responsible for around 5.3% of Australia’s total greenhouse emissions, which contribute to climate change (Department of Health and Aged Care 2023a).

To meet the health challenges posed by climate change, the Australian government released the National Health and Climate Strategy in 2023. The Strategy outlines a whole-of-government approach to build a climate-resilient, net zero health system, and to protect population health and wellbeing from the impacts of climate change (Department of Health and Aged Care 2023a).

The Strategy recognises the interconnectedness of the environment and health, and the need to take a Health in All Policies approach to address climate change and its impacts. Importantly, the Strategy acknowledges the inequitable distribution of health burden due to climate change, and is therefore informed by principles of health equity, including an explicit commitment to working with First Nations stakeholders to address the health impacts of climate change on First Nations people (Department of Health and Aged Care 2023a).

Extreme weather events

Australia is expected to experience changing weather patterns in the coming decades, with climate change intensifying many types of weather events. In Australia, it is predicted that there will be increases in the number, intensity or geographic spread of heatwaves, drought, bushfires, violent storms, heavy rainfall events and flooding, while a decrease in extreme cold weather is expected (Bureau of Meteorology and CSIRO 2022; Metcalfe and Costello 2021). These extreme weather events can have direct effects such as deaths, injuries and illness, and can affect mental health and wellbeing (Ebi et al. 2021; Matthews et al. 2019). Additionally, they can indirectly affect health of communities through impacts to critical infrastructure, essential services, food production, the economy and ecosystems (Reisinger et al. 2014). Without mitigation and adaptation (see glossary), the health impacts of these events are also likely to increase and disproportionately affect certain populations such as older people, as well as future generations (Beggs et al. 2019; WHO 2018b; Cheng et al. 2018; Thiery et al. 2021).

In Australia, in the decade between 2012 and 2022 there was an average of 912 hospitalisations per year for extreme weather-related injuries (AIHW 2024). This equates to an annual average crude rate of 3.7 hospitalisations per 100,000 people. However, climate change, and climate drivers such as the El Niño Southern Oscillation, the Indian Ocean Dipole and the Southern Annular Mode mean that Australia’s weather is subject to variation from year to year (Bureau of Meteorology and CSIRO 2022). Likewise, variations in patterns of extreme weather-related injury hospitalisations were observed across this time. In the years 2013–14, 2016–17 and 2019–20, hospitalisations due to injuries related to extreme weather conditions or natural hazards exceeded the 10 year average (2012–2022). In each of these years, there were greater than 1,000 hospitalisations, or more than 4.2 per 100,000 people (AIHW 2024). It should be noted that hospitalisations for extreme weather-related injuries represent only a small proportion of the combined direct and indirect health outcomes due to extreme weather, and that the full health impact is likely much higher. For more information, see Australia’s health 2024: data insights article Extreme weather related injuries in Australia over the last decade.

Heatwaves and very hot days

Data from the Bureau of Meteorology show that 2019 was Australia’s hottest year since Australian temperature records commenced in 1910, with average temperatures 1.52 degrees Celsius above the long-term average (1961–1990) (Bureau of Meteorology 2020). In 2019, there were 33 days when the national daily average maximum temperature was above 39 degrees Celsius – a larger number of days over 39 degrees than seen in the 59 years prior (1960–2018) (Bureau of Meteorology and CSIRO 2022). Very high monthly maximum temperatures occurred around 2% of the time for the period 1960–1989, compared with over 11% of the time for the period 2007–2020 (Bureau of Meteorology and CSIRO 2022). This increase in the number of very hot days is projected to continue as a result of climate change (Bureau of Meteorology and CSIRO 2022).

Heatwaves (see glossary) are associated with heat-related conditions ranging from minor rashes and body cramps to more serious conditions such as heatstroke (severe hyperthermia). Excessive heat can also exacerbate existing health conditions such as heart disease, diabetes, kidney disease and mental and behavioural conditions; reduce productivity; and increase the geographic spread of vector-borne diseases and transmission of food-borne diseases such as gastroenteritis (AMA 2015). Some medications can increase the risk of heat-related illness and may be less effective during prolonged high temperatures (Layton et al. 2020).

Increases in hospitalisations and deaths in Australia have been observed during heatwaves and extreme heat (Varghese et al. 2020; Williams et al 2018). For the period 2007–2017, in Australia, deaths increased by 2% during heatwaves (1,418 additional deaths over the 11-year period), with the highest increases occurring in Adelaide (8%) and regional Tasmania (11%) (Varghese et al. 2020). Single events can result in large numbers of additional deaths, for example, there were 374 additional deaths (a 62% increase in all-cause mortality) in Victoria during a heatwave from 26 January to 1 February 2009 (DHHS 2009). Extreme heat has the highest contribution to injury hospitalisation and deaths caused by extreme weather events – 7,104 hospitalisations (between 2012–2022) and 293 deaths (between 2011–2021) (AIHW 2023b).

Bushfires

Bushfire has long been a part of the Australian experience. However, the 2019–20 bushfire season in Australia saw an unusually large area of Australia’s temperate forest burnt – about one-fifth (21%) of the New South Wales and Victorian section of Australia’s temperate broadleaf and mixed forests biome burned, compared with the 2% typical of previous major fire years (Boer et al. 2020). Emissions from the fires are now thought to have contributed to the rare occurrence of 3 consecutive La Niña events in Australia between 2020 to 2022 by causing an imbalance in atmospheric and oceanic conditions (Fasullo et al. 2023). 

The adverse health effects during the 2019–20 bushfire season included:

• 35 deaths due to injuries resulting from the fires (AIHW 2023b) 
• increases in hospital admissions and emergency department presentations for respiratory conditions in areas affected by bushfire smoke (AIHW 2020, 2021c; Wen et al. 2022). For example, in the week beginning 5 January 2020, there was an 11% increase in admitted patient hospitalisations for respiratory conditions, nationally, compared with the previous 5-year average. In the Australian Capital Territory, the rate was 52% higher than the previous 5-year average for that week – the largest rate increase among the states and territories (AIHW 2021b)
• over half (54%) of Australian adults experienced anxiety or worry due to the bushfires (Biddle et al. 2020)
• disproportionate impacts on First Nations people as well as regions with high fire density and lower socioeconomic status (Nolan et al. 2021; Wen et al. 2022; Williamson et al. 2020). 

While bushfires are a common part of the Australian summer season, the number of deaths they cause varies from year to year. For example, there was an average of 5.4 bushfire-related deaths per year between 1901 and 1964, and 10.5 per year between 1965 and 2011 (Blanchi et al. 2012) – noting that this comparison does not take population growth into account. A large proportion of these deaths occurred in 7 individual years – between 1926 and 2009 (Blanchi et al. 2012). The 2009 Victorian bushfires resulted in the death of 173 people (The 2009 Victorian Bushfires Royal Commission 2010).

Smoke generated by bushfires can affect respiratory and cardiovascular health over large geographical areas, as evidenced by increased respiratory and cardiovascular hospital attendances during bushfire events (AIHW 2020, 2021c; Chen et al. 2006; Johnston et al. 2002; Kolbe and Gilchrist 2009; Morgan et al. 2010; Tham et al. 2009; Wen et al. 2022). One study investigating the health impacts of bushfire smoke over the 4 months from October 2019 to February 2020 in the east of Australia (Queensland, New South Wales, Victoria and the Australian Capital Territory) estimated that it was responsible for more than 2,000 hospitalisations for respiratory conditions and more than 1,000 hospitalisations for cardiovascular conditions (Borchers Arriagada et al. 2020).

However, as exposure to bushfire smoke is typically infrequent and sporadic, there is limited information available about prolonged exposure to bushfire smoke or long-term physiological health effects and research is underway on this topic (enHealth 2021). For more information on smoke-related air quality, see air pollution.

There is evidence of both immediate and long-term impacts of bushfire on mental health. Lived experience of bushfire has been found to increase the occurrence of psychological and behavioural disorders such as anxiety, depression, post-traumatic stress disorder (PTSD) (see glossary) and substance misuse, and the effects can persist for years after the impact (Bryant et al. 2018; Finlay 2012; Gao et al. 2023; Gibbs et al. 2021). For example, a follow-up study of psychological outcomes 5 years after the 2009 Victorian bushfires found that 22% of people who had been in communities severely affected by the fires were suffering probable PTSD, major depressive episode or severe distress, compared with 5.6% of people who had been in regions that were less affected by the fires (Bryant et al. 2018). Ten years after the fires this figure remained at 22% for severely affected communities (Gibbs et al. 2021). Prolonged exposure to smoke from bushfires has also been found to have an impact on mental health (Rodney et al. 2021).

Drought

Australia is drought-prone and many areas have a dry climate. Long periods of below-average rainfall adversely affect the natural environment and have flow-on effects for human health (AIHW 2011; Kalis et al. 2009). 

Many of these health effects have been documented globally, including malnutrition and mortality, water-borne diseases such as those caused by Escherichia coli, airborne and dust-related diseases, vector-borne diseases such as dengue fever, mental health effects and distress (Stanke et al. 2013).

The mental health effects of drought are complex and may vary by demographic characteristics. From 2001–02 to 2007–08, people living in drought-affected areas in rural Australia had higher levels of distress than people living in urban areas (O’Brien et al. 2014). A 2012 study (Hanigan et al. 2012) found an increased risk of suicide among males aged 30–49 living in rural areas of Australia during periods of drought between 1970 and 2007. Findings on the effects of drought on the mental health of women are mixed (Hanigan et al. 2018; Powers et al. 2015). While mental health impacts are more pronounced in rural communities (Batterham et al. 2022), occupation also appears to play a role. One study found people working on farms were at a much greater risk of mental ill-health as a result of drought, when compared with people employed outside the agricultural sector (Edwards et al. 2015).

Drought can also restrict physical and financial access to healthy foods. For example, drought was identified as the primary contributor to substantial increases in the price of fresh fruit (43% rise) and vegetables (33% rise) between 2005 and 2007 (Quiggin 2007).

Storms and floods

There has been a decrease in the number of tropical cyclones in the Australian region in recent decades, but heavy rainfall events (typically caused by thunderstorms, cyclones and east coast lows) are increasing in intensity, with observed daily rainfall totals associated with thunderstorms increasing since 1979, particularly in northern Australia (Bureau of Meteorology and CSIRO 2022). In southern and eastern Australia, cool season rainfall is predicted to continue to decline with climate change, leading to more time spent in drought, on average. However, extreme rainfall events that are short in duration are predicted to increase. Furthermore, weather systems such as east coast lows and tropical cyclones are expected to become less frequent and this may influence changes in extreme rainfall in particular locations (Bureau of Meteorology and CSIRO 2022).

Health effects from storms and floods may be short-term (for example, physical trauma), medium-term (for example, the spread of vector-borne disease) or long-term (such as post-traumatic stress and depression) (Fewtrell and Kay 2008; Ivers and Ryan 2006). Heavy rainfall and flooding can affect the quality of water resources, for example through pollution with run-off from by-products of industry and agriculture, contributing to waterborne disease (van Vliet et al. 2023). Between 1900 and 2015 there were 1,859 deaths identified as being associated with flooding (Haynes et al. 2017). While there was a significant decrease in the national death rate due to floods between 1900 and 1959, there was only a slight decrease in the flood fatality rate between 1960 and 2015 and this decrease was not statistically significant (Haynes et al. 2017). Remoteness increases risk of death from flooding (Peden et al. 2017), for example, widespread flooding contributed to a notable rise in the rate of unintentional drowning deaths in Remote and Very remote areas between 2015–16 and 2016–17 (AIHW 2019). There is also evidence of increased mortality risk during the weeks following floods (Yang et al. 2023).

The floods in Australia in 2021–22 had major impacts across large parts of Queensland and New South Wales. Nationally, there were 38 deaths attributed to either flooding or cataclysmic storms during the 2022 calendar year, compared with an average of 5.8 deaths annually over the previous 9 years (ABS 2023).

A survey of the disaster-related trauma from the 2010–2011 Queensland floods and cyclones found that 14% of respondents felt terrified, helpless or hopeless following the events and 7.1% of respondents continued to experience distress months later (Clemens et al. 2013). Persistent post-traumatic stress disorder has also been reported in children and adolescents, 18 months after a Category 5 cyclone (McDermott et al. 2014).

Like drought, storm and flood damage can also restrict food availability and increase food prices. These weather events may also have broader economic impacts. As an example, the reduced banana supply following Cyclone Yasi in 2011 resulted in a 0.7 percentage point increase in inflation (Debelle 2019) affecting the entire Australian economy.

Ultraviolet radiation

Ultraviolet radiation (UV) (see glossary) from the sun is essential for good health as it helps the body manufacture vitamin D (WHO 2019). However, it is also known to cause a number of cancers, such as non-melanoma skin cancers (including basal and squamous cell carcinomas), melanoma (including melanoma in situ) and cancer of the eye. It can also cause cataracts (estimated to be responsible for 20% of cataracts globally (WHO 2019)) and about 411,000 Australians (1.7% of the population) had cataracts in 2017–18 (AIHW 2021c). In Australia in 2018, high sun exposure was responsible for 0.7% of the total burden of disease (AIHW 2021a).

The age-standardised rate of melanoma in Australia increased from 46 cases per 100,000 persons in 2000, to an estimated 57 cases per 100,000 persons in 2023. While the total number of deaths due to melanoma increased over this period, from 970 in 2000 to 1,300 in 2023, after adjusting for age, the rate of deaths decreased from 5.2 deaths per 100,000 persons to an estimated 3.7 deaths per 100,000 persons (AIHW 2023a). The increased incidence, accompanied by overall decreased mortality during this period is thought to be the result of skin cancer awareness and preventative public health campaigns in Australia leading early detection and treatment of melanomas (Blazek et al. 2022, Aitken et al. 2018).

Exposure to UV can be moderated by protective behaviours (for example, wearing a hat, sunscreen and protective clothing, and seeking shade). However, only 47% of adults and 33% of adolescents typically employ 2 or more of these protective behaviours (Cancer Australia 2019).

Biodiversity and nature

Globally, biodiversity is fundamentally important for human health because ‘it helps to regulate climate, filters air and water, enables soil formation and mitigates the impact of natural disasters. It also provides timber, fish, crops, pollination, ecotourism, medicines, and physical and mental health benefits’ (UN 2019).

International research has shown that contact with nature also has health benefits – increased attention, energy and tranquillity, and significantly decreased anxiety, anger, fatigue and sadness are all associated with exposure to natural environments (Bowler et al. 2010). Natural places such as parks provide opportunities for outdoor recreation, spiritual and cultural heritage connection, physical, mental, and social health benefits and neighbourhood amenity (Parks Victoria 2015). In Australia, biodiversity has been shown to correlate with respiratory health (Liddicoat et al. 2018) and subjective wellbeing (Mavoa et al. 2019). Research on the effects of biodiversity on mental health is ongoing, in an attempt to unravel the complex mechanisms and pathways involved (Cianconi et al. 2022; Wong and Osborne 2022). 

Planetary biodiversity (the range of living things) is declining rapidly (WWF and ZSL 2018) and the ‘status of biodiversity in Australia is generally considered poor and worsening’ (Cresswell and Murphy 2017), with more than 1900 species of plants and animals in Australia listed as threatened as a consequence of invasive species, habitat fragmentation and degradation, and the increasing impact of climate change (Cresswell and Murphy 2017; DCCEEW 2022b).

Access to urban biodiversity is also becoming increasingly important to human health and wellbeing as cities continue to grow, and enriching cities and towns with nature is a focus for governments (Commonwealth of Australia 2019). For more information, see Built environment and health.

Air quality

Air quality refers to the condition of the air that we breathe (DCCEEW 2022a). Air quality is degraded by human activities, such as burning of fossil fuels for industrial purposes, or through naturally occurring events such as bushfires and dust storms. Air quality is impacted by the presence of aeroallergens (see glossary) and air pollution.

Aeroallergens – allergy-causing airborne particles such as pollen and mould spores – also have the potential to affect air quality and can cause or worsen respiratory conditions, such as hay fever, in some people. 

Air pollution, in particular fine airborne particles (particulate matter) known as PM2.5 (see glossary) can have both long- and short-term adverse impacts on human health and can affect almost every organ in the body (AIHW 2011; Schraufnagel et al. 2018). For some pollutants, including PM2.5, there is evidence that even very low levels of exposure can have adverse health impacts (Emmerson and Keywood 2021). Air pollution is recognised by the World Health Organization as a serious risk factor for non-communicable disease (Schwartz et al. 2021). Air pollution can also increase the health impacts of infectious and other respiratory diseases (Tran et al. 2023). PM2.5 sources can be derived from human activity (for example, from industrial processes, vehicle emissions or wood heater emissions), or naturally occurring (such as pollen or smoke from bushfires). These particulates can decrease lung function, increase respiratory symptoms, chronic obstructive pulmonary disease, cardiovascular and cardiopulmonary disease and mortality (Pope and Dockery 2006), and decrease life expectancy (Pope et al. 2009). In 2013, the International Agency for Research on Cancer classified outdoor air pollution as a human carcinogen (Jackson et al. 2017). 

In 2018, more than 3,200 (2.0%) deaths and 1.3% of the total burden of disease in Australia was attributed to PM2.5 air pollution (AIHW 2021a). 

People with an underlying health condition, such as asthma, chronic obstructive pulmonary disease, or cardiovascular disease, are particularly at risk from poor air quality (Jackson et al. 2017).

Air quality is monitored across Australia and reported nationally (NEPC 2019). Air quality in Australian cities is generally classified as ‘good’ in comparison with similar developed economies, although there is variation depending on the location within Australia and which pollutant is being measured. 

While ozone pollution levels in Australian capital cities are considered ‘good’, levels have increased in many cities since the 2016, and therefore the air quality due to ozone pollution is considered to be worsening (Emmerson and Keywood 2021). Furthermore, the National Environment Protection Measure (NEPM) standard for ozone pollution was lowered in 2021, and as a result it is expected that more cities will exceed this new cut-off point when measured against the new standard (Emmerson and Keywood 2021).

Regarding PM2.5 air pollution, in order to meet the NEPM standard, 24-hour PM2.5 levels must be under of 25µg/m³ on every day of the year (Emmerson and Keywood 2021). The 2021 State of the Environment report states that in 2019, all Australian capital cities exceeded the 24-hour PM2.5 advisory standard of 25µg/m³. In addition, the air quality due to PM2.5 has deteriorated in 5 of the 8 capital cities since the 2016 reporting period (Emmerson and Keywood 2021). While much PM2.5 pollution is derived from human activity, it can also be generated from extreme weather-related events such as bushfires and dust storms (Emmerson and Keywood 2021).

The air quality, particularly in New South Wales, the Australian Capital Territory, Victoria and Queensland, was greatly affected by the widespread bushfires burning in 2019–20 (Johnston et al. 2021). Emergency department presentations and hospitalisations for respiratory conditions such as asthma increased during periods of poor air quality (AIHW 2020, 2021c). On 1 January 2020, the average hourly PM2.5 value at Monash in the ACT peaked at 1197ug/m³ – almost 48 times the PM2.5 advisory standard of 25µg/m³ (Figure 1). 

Figure 1: Daily average PM2.5 concentrations in Canberra and Sydney, January 2019 to January 2020

A 2022 study of New South Wales emergency department data estimated there were 6,177 additional presentations for respiratory diseases (a 6% increase) and 3,120 additional presentations for cardiovascular diseases (a 10% increase) during the 2019–20 bushfire season (Wen et al. 2022).

For more information on the health effects of bushfire smoke pollution, see Australian bushfires 2019–20: exploring the short-term health impacts (AIHW 2020) and Data update: Short-term health impacts of the 2019–20 bushfires (AIHW 2021b). 

Infectious diseases

Infectious diseases linked to the environment that are transmitted from animals to humans are called zoonotic diseases (see glossary). These diseases can be transmitted by vectors (such as mosquitoes) or through contact with infected animals (such as livestock, mice, rats), or soil or water contaminated with the urine or faeces of infected animals. These diseases are caused by micro-organisms such as bacteria, viruses and parasites and are a natural part of the Australian environment.

While leptospirosis infections are quite rare in Australia, exposure to flood waters is associated with increased risk of transmission of the disease (Mwachui et al. 2015; Naing et al. 2019). Leptospirosis is caused by bacteria which can survive in soil and infect both animals and humans. Following flooding in Queensland in 2011–2012, there were 103 leptospirosis notifications during the first quarter of 2011, compared with an average of 36 notifications (range 8–57) during the same quarter in the previous 4 years (National Notifiable Disease Surveillance System 2024). Increased rat and mouse populations that occurred following wet weather in the eastern regions of Australia have also been linked to increased cases of leptosporisis (Department of Health 2021b). Between February and May 2021, there were 107 cases of leptosporis reported in Australia, approximately 3 times more than the quarterly rolling 5-year average number of notifications (35.2) (Department of Health 2021b). Despite current small case numbers, it is predicted that climate change will lead to an increase in flood-related outbreaks of leptospirosis (Effler 2020; Lau et al. 2018). 

Vector-borne diseases (see glossary) in Australia include viral infections such as Ross River virus, Barmah Forest virus, Murray Valley encephalitis virus, Kunjin virus, Japanese encephalitis virus and dengue virus. In 2016, there were 2,227 notifications of dengue virus, 98% of which were overseas-acquired (Department of Health 2021a). This was equivalent to a 40% increase relative to the mean rate of the previous 5 years (2011–2015) and was likely linked to patterns of international travel and the global epidemiology of the virus (Department of Health 2021a). In 2022, there was an outbreak of Japanese encephalitis virus which led to 41 human cases of the virus (Department of Health and Aged Care 2023b). Australian cases of the mosquito-borne parasitic infection, malaria, currently occur only as a result of international travel.

While it is likely that factors such as land use change and increased trade and travel are most influential in driving increases in infection and transmission of vector-borne diseases (Kilpatrick and Randolph 2012), changes in climate are likely to extend the geographic spread, and lengthen the transmission seasons, of important vector-borne diseases (Bambrick et al. 2011; Jackson et al. 2017; WHO 2018b).

Where do I go for more information?

For more information on the natural environment, adaptation and health, see:

• Australian Institute of Health and Welfare Let’s talk about the weather: injuries related to extreme weather
• Bureau of Meteorology and CSIRO State of the climate 2022
• Department of Climate Change, Energy, the Environment and Water Australia State of the Environment 2021
• Department of Climate Change, Energy, the Environment and Water National Climate Risk Assessment and National Adaptation Plan
• Department of Health and Aged Care Environmental health publications (enHealth)
• United Nations (UN) Intergovernmental Panel on Climate Change (IPCC)