Natural environment and health is an Australia's health topic

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).

This page presents a selection of evidence on the influence of the natural environment on human physical and mental health in Australia. See Built environment and health for information on the health impacts of the human-made surroundings.

COVID–19, the natural environment and health

The interactions between human activity, the environment and its impact on health are complex. The COVID–19 pandemic has changed the way people interact with the environment and may have encouraged a greater awareness of people’s connectedness with the environment (McCunn 2020).

Population-based restrictions due to the pandemic affect not only humans, but also the natural environment. For example, as a result of lockdowns, reduced transport emissions were documented to have led to

  • decreases in global fossil CO2 emissions (Le Quéré et al. 2021)
  • improvements in air quality in Australian cities such as Sydney and Melbourne in the first half of 2020 (Boroujeni et al. 2021; Duc et al. 2021; Ryan et al. 2021).

Conversely, the pandemic has also had negative impacts on waste production in the environment from extensive use of:

  • face masks
  • protective personal equipment
  • other medical waste
  • plastics from online shopping and food deliveries (Patrício Silva et al. 2021). In Victoria, it was estimated that used face masks accounted for 104 tons of waste a day during the first wave of the pandemic and 160 tons a day during the second wave (Boroujeni et al. 2021).

Climate change and health

What is climate change?

Climate change refers to a change in the pattern of weather – which affects oceans, land surfaces and ice sheets – occurring over decades or longer (Australian Academy of Science 2019). Human activities associated with a range of sectors – such as energy supply, industry agriculture, forestry and transport – contribute to atmospheric greenhouse gas concentrations. Greenhouse gases (see Glossary) trap heat in the atmosphere, which heats the land and oceans and changes weather patterns, including increasing the likelihood of extreme events (IPCC 2014). Globally:

  • The average annual temperature in 2021 was estimated to be 1.11ºC above the pre-industrial (1850–1900) average (WMO 2022).
  • The 7 years from 2015 to 2021 were the hottest on record (WMO 2022).
  • Global greenhouse gas concentrations continue to increase (WMO 2022).

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 food and water (Ebi et al. 2018). This can result in health effects such as thermal stress, injury, vector-borne diseases (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 Aboriginal and Torres Strait Islander 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 connection to Country, exacerbating existing risk factors or compounding historical injustices (Beggs et al. 2021; HEAL Network and CRE-STRIDE 2021).

Extreme weather events 

The extreme weather events described here include heat waves, drought, bushfires, violent storms, heavy rainfall events and flooding, which cause deaths and injuries and affect the Australian community through impacts to critical infrastructure, essential services, food production, the economy and ecosystems (Reisinger et al. 2014). Under climate change, the intensity and the frequency of heatwaves and drought, and the number of days with fire weather conditions has increased and is projected to continue increasing (BOM and CSIRO 2020). Without mitigation and adaptation (see Glossary), the health impacts of these events are also likely to increase (Beggs et al. 2019; WHO 2018b) and disproportionately affect vulnerable populations such as older people as well as future generations (Cheng et al. 2018; Thiery et al. 2021).

Heatwaves and very hot days

The Bureau of Meteorology data show that 2019 was Australia’s hottest year on record, with average temperatures 1.52 degrees Celsius above the long-term average (BOM 2020). The number of extremely warm days has increased (BOM and CSIRO 2020), increasing the probability of heatwaves (see Glossary). Very high monthly maximum temperatures occurred around 2% of the time for the period 1960–1989, compared with over 12% of the time for the period 2005–2019 (BOM and CSIRO 2020). This increase in the number of very hot days is projected to continue (BOM and CSIRO 2020). 

Heatwaves 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).

Increases in hospitalisations and deaths in Australia have been observed during heatwaves (Varghese et al. 2020; Williams et al 2018). For the period 2007–2017, in Australia, deaths increased by 2% during heatwaves (1418 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).

Bushfires

Bushfire has long been a part of the Australian experience. However, the 2019–20 bushfire season in Australia saw an unprecedented area of Australia’s temperate forest burnt – more than 20%, compared with approximately 2% in previous major fire years (Boer et al. 2020). This was set against the hottest and driest year on record in 2019 and the highest Accumulated Forest Fire Danger Index value (see Glossary) since records begin in 1950.

The adverse health effects during this period included:

  • 33 deaths directly attributed to the fires (Royal Commission into National Natural Disaster Arrangements 2020)
  • increases in hospital admissions and emergency department presentations for respiratory conditions in areas affected by bushfire smoke (AIHW 2020, 2021c; Wen et al. 2022)
  • over half (54%) of Australian adults experiencing anxiety or worry due to the bushfires (Biddle et al. 2020)
  • disproportional impacts on Aboriginal and Torres Strait Islander 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. 2021) the 2009 Black Saturday bushfires killed 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). 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). See air pollution for more information on smoke-related air quality.

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; Gibbs et al. 2021). For example, a follow-up study of psychological outcomes 5 years after the 2009 Black Saturday 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).

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 disease such as those caused by Escherichia coli, airborne and dust-related disease, vector-borne diseases such as dengue fever, mental health effects and distress (Stanke et al. 2013).

The mental health effects of drought appear to be complex and may vary by sex. 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).

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

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). The floods in Australia in 2022 had major impacts across large parts of Queensland and New South Wales, the full extent of which will be determined as data become available. 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).

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 2021d). 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 55 cases per 100,000 persons in 2021. While the total number of deaths due to melanoma increased over this period, from 970 in 2000 to 1,300 in 2021, after adjusting for age, the rate of deaths decreased from 5.2 deaths per 100,000 persons to an estimated 4 deaths per 100,000 persons (AIHW 2021b).

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), though more research on the effects of biodiversity on mental health is needed (Dean et al. 2011).

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 about 1,950 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; DAWE 2022a,b).

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).  See Built environment and health.

Air pollution

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). Air pollution is recognised by the World Health Organization as a serious risk factor for non-communicable disease (Schwartz et al. 2021). PM2.5 sources can be man-made (for example, from industrial processes, vehicle emissions or wood heaters), 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).

Thunderstorm asthma

Air pollution can sometimes result in major single health events. In 2016, a major thunderstorm asthma epidemic was triggered in Melbourne when very high pollen counts coincided with adverse meteorological conditions resulting in 3,365 people presenting at hospital emergency departments over 30 hours, and 10 deaths (Thien et al. 2018). See Chronic respiratory conditions. 

Air quality is monitored across Australia and reported nationally (NEPC 2019). Air quality in Australian cities is generally good to very good in comparison with similar developed economies, but the majority of Australian capital cities exceeded the PM2.5 advisory standard (25µg/m3) (see Glossary) on at least one day each year during 2008–2014 (Keywood et al. 2016), due to extreme localised events (for example, bushfires and dust storms).

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 January 1, 2020, the average hourly PM2.5 value at Monash in the ACT peaked at 1197 ug/m3 – almost 48 times the PM2.5 advisory standard of 25µg/m3 (Figure 1). 

 

The line graph shows the daily PM2.5 concentrations from January 2019 to the month of October 2019 remaining relatively low at both Sydney and Canberra’s air quality monitoring stations, mainly rated as ‘Good’ or ‘Fair’ air quality. From October 2019 through to January 2020, there is a dramatic increase in average daily PM2.5 concentrations in both Canberra and Sydney stations, with more days rated as being ‘Poor’, ‘Very poor’ or ‘Extremely poor’ air quality.

Visualisation not available for printing

 

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).

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 2021c) for more information on the health effects of bushfire smoke pollution.

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. See also Infectious and communicable diseases.

While quite rare in Australia, exposure to flood waters poses a significant risk for transmission of leptospirosis (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, leptospirosis notifications for the period of 1 January to 3 April 2011 were 2.3 times greater than the average number of notifications for the previous 4 years (Queensland Government 2011, cited in Smith et al. 2013). 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 (Department of Health 2021c; 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 confirmed or probable human cases of the virus (as at 11 May 2022) (Department of Health 2022). 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: