Bushfires in Australia: a serious health emergency under climate change

Australia is burning. Both New South Wales and Queensland have declared a state of emergency after seeing new record high in property losses during this fire season. Recently, "fires near me" has become Google's most searched words in Australia, with perhaps months of serious fire weather still to come. The unprecedented fire conditions have threatened lives and homes. At least 2·7 million hectares of New South Wales has been burnt since September, 2019, which was a much earlier start of the fire season than in previous years. The burned area is three times larger than 2019 fires in the Amazon (906 000 hectares) and is still expanding. The ongoing bushfires (wildfires) have confirmed researchers' warnings several years ago about increasing bushfires due to climate change in Australia. 1Jones RN Young C Handmer J Keating A Mekala G Sheehan P Valuing adaptation under rapid change. https: //www. nccarf. edu. au/sites/default/files/attachedfilesₚublications/Jones₂013Valuingₐdaptationᵤnderᵣapidchange. pdfDate: 2013Google Scholar Bushfires in Australia have been promoted by both a decrease in rainfall and an increase in extremely hot temperatures (figure). 2Harris S Lucas C Understanding the variability of Australian fire weather between 1973 and 2017. PLoS One. 2019; 14: e0222328Crossref PubMed Scopus (62) Google Scholar According to the Australian Bureau of Meteorology, the Southern Downs (QLD) and Northern Tablelands (NSW) have had the record for lowest rainfall from January to August. Lack of rainfall makes vegetation very dry and flammable. Australia has warmed by more than 1°C since 1910. The warming climate in Australia has been accompanied by heatwaves characterised by increased frequency of occurrence, duration, and maximum temperatures. In 2019, both states entered the bushfire season after a year of hot temperatures and low rainfall, putting many districts under high risk of bushfires. A similar situation occurred in the 2009 Black Saturday fires in Victoria, when Melbourne reached a record-breaking high temperature (46·4°C) following a long drought. 3Dennekamp M Abramson MJ The effects of bushfire smoke on respiratory health. Respirology. 2011; 16: 198-209Crossref PubMed Scopus (115) Google Scholar Bushfires can be catastrophic to lives. The ongoing bushfires in New South Wales have destroyed about 700 homes and untold wildlife, including seriously threatening koala populations due to habitat loss. It has been estimated that major Australian bushfires during 1967–2013 resulted in over 8000 direct injuries and 433 direct fatalities, costing approximately Australian 4·7 billion. 4Ladds M Keating A Handmer J Magee L How much do disasters cost? A comparison of disaster cost estimates in Australia. Int J Disaster Risk Reduct. 2017; 21: 419-429Crossref Scopus (40) Google Scholar However, this estimate did not consider indirect costs, which mainly come from adverse health effects of bushfire smoke. According to the US Environmental Protection Agency, the indirect effects of air pollution from wildland fires on excess premature deaths and morbidity in the USA during 2008–12 had an estimated cost of US513 billion. 5Fann N Alman B Broome RA et al. The health impacts and economic value of wildland fire episodes in the US: 2008–2012. Sci Total Environ. 2018; 610–11: 802-809Crossref Scopus (130) Google Scholar The best documented hazardous components of bushfire smoke are PM10 and PM2·5. Because of the bushfire, in most areas of Sydney, 24-h average PM2·5 concentrations this Decemberhave exceeded 100 μg/m3 (and could reach 500 μg/m3), which is four-times higher than the WHO guideline value of 25 μg/m3). By comparison, the daily average PM2·5 concentration before the bushfire was around 20 μg/m3. Such an increase in daily PM2·5 concentration is estimated to induce an increase of at least 5·6% in daily all-cause mortality, 4·5% in cardiovascular mortality, and 6·1% in respiratory mortality, according to our global study from 2011, which included Sydney. 6Liu C Chen R Sera F et al. Ambient particulate air pollution and daily mortality in 652 cities. N Engl J Med. 2019; 381: 705-715Crossref PubMed Scopus (686) Google Scholar These estimates are close to a previous observation on the effects of bushfire events between 1997 and 2004, in Sydney. 7Johnston F Hanigan I Henderson S Morgan G Bowman D Extreme air pollution events from bushfires and dust storms and their association with mortality in Sydney, Australia 1994–2007. Environ Res. 2011; 111: 811-816Crossref PubMed Scopus (193) Google Scholar In addition to its fatal effects, bushfire smoke has also been related to increased risks of hospitalisation and emergency department visits due to respiratory diseases such as asthma, chronic obstructive pulmonary disease, and respiratory infections. 3Dennekamp M Abramson MJ The effects of bushfire smoke on respiratory health. Respirology. 2011; 16: 198-209Crossref PubMed Scopus (115) Google Scholar Increasing evidence also suggests bushfire smoke might increase cardiovascular morbidity, psychological disorders, adverse birth outcomes, and eye irritation. 8Finlay SE Moffat A Gazzard R Baker D Murray V Health impacts of wildfires. PLoS Curr. 2012; 4 (e4f959951cce2c) PubMed Google Scholar, 9Reid CE Brauer M Johnston FH Jerrett M Balmes JR Elliott CT Critical review of health impacts of wildfire smoke exposure. Environ Health Perspect. 2016; 124: 1334-1343Crossref PubMed Scopus (501) Google Scholar However, our knowledge about the health effects of bushfire smoke is still insufficient. The long-term and lasting effects of bushfire smoke and which subgroups are most vulnerable to bushfire smoke remain largely unknown. 8Finlay SE Moffat A Gazzard R Baker D Murray V Health impacts of wildfires. PLoS Curr. 2012; 4 (e4f959951cce2c) PubMed Google Scholar, 9Reid CE Brauer M Johnston FH Jerrett M Balmes JR Elliott CT Critical review of health impacts of wildfire smoke exposure. Environ Health Perspect. 2016; 124: 1334-1343Crossref PubMed Scopus (501) Google Scholar It has been suggested that PM10 generated from bushfires might have different health effects compared with PM10 from urban background sources (eg, traffic emissions). 3Dennekamp M Abramson MJ The effects of bushfire smoke on respiratory health. Respirology. 2011; 16: 198-209Crossref PubMed Scopus (115) Google Scholar Therefore, more studies are required to focus on air pollutants from bushfires. Unfortunately, there is no effective way to reduce the effects of bushfire smoke on human health, although wearing facemasks and staying indoors are commonly recommended, and many people consider facemasks the best protection. However, facemasks might be not effective or sometimes provide a false sense of security. Their effectiveness depends on their filtration capacity: fine particles can still get through them if capacity is low. Additionally, individual wearing behaviour and characteristics (eg, facial hair, or duration and frequency of wearing a facemask) also affect the efficiency of the facemask. Importantly, wearing a facemask can be uncomfortable in very hot weather when bushfires happen. Even if facemasks could protect adults, it is still questionable whether they could protect children, older individuals, pregnant women, and those with chronic diseases, as these groups often cannot tolerate the inconvenience and discomfort of wearing a mask. Staying indoors might provide some protection against bushfire smoke, but this depends on building quality and ventilation. In general, most residential houses are not equipped with air purifiers or air conditioning systems with high-efficiency filters. Hence, outdoor pollutants can still penetrate into houses, if they are in bad conditions or equipped with air conditioning systems without air filters. Therefore, indoor and outdoor concentrations of fine particles are often very close. Climate change will continue to exacerbate catastrophic bushfire conditions. It has been estimated that days with high-to-extreme risk of fire will increase by 15–70% by 2050, and by more than 100% by 2100, compared with 2010. 1Jones RN Young C Handmer J Keating A Mekala G Sheehan P Valuing adaptation under rapid change. https: //www. nccarf. edu. au/sites/default/files/attachedfilesₚublications/Jones₂013Valuingₐdaptationᵤnderᵣapidchange. pdfDate: 2013Google Scholar Although some politicians claim that climate action is too expensive, the increasing intensity and frequency of bushfires clearly indicate that the price of climate inaction is even higher. Unfortunately, the Australian Government has not engaged well in climate action over the past decade. 10Beggs PJ Zhang Y Bambrick H et al. The 2019 report of the MJA-Lancet Countdown on health and climate change: a turbulent year with mixed progress. Med J Aust. 2019; 211: 490-491Crossref PubMed Scopus (34) Google Scholar Australia is on the track to meet less than half of its carbon emission reduction targets, which are to reduce emissions by 26–28% relative to 2005, by 2030, and achieve net zero emissions by 2050. Without immediate and efficient climate action, catastrophic bushfires will become a common disaster and might destroy the future of Australia and possibly of humanity. This online publication has been corrected. The corrected version first appeared at thelancet. com/planetary-health on January 24, 2020 This online publication has been corrected. The corrected version first appeared at thelancet. com/planetary-health on January 24, 2020 PY and RX were supported by China Scholarship Council funds (number 201906210065 for PY and 201806010405 for RX) ; SL by an Early Career Fellowship of the Australian National Health and Medical Research Council (number APP1109193) ; and YG by Career Development Fellowships of the Australian National Health and Medical Research Council (numbers APP1107107 and APP1163693). We declare no competing interests. Correction to Lancet Planet Health 2020; 4: e7–8Yu P, Xu R, Abramson MJ, Li S, Guo Y. Bushfires in Australia: a serious health emergency under climate change. Lancet Planet Health 2020; 4: e7–8—In this Comment, the figure should not have been presented with a 95% CI of the linear trend. This correction has been made as of January 24, 2020. Full-Text PDF Open Access