Recent extreme bushfire occurrences around the world including Southeast Asia and Australia, parts of the Mediterranean, boreal North America, the western side of temperate North America particularly California, and the Amazon rainforest in Brazil, have left many communities bewildered because of the severity and scale of destruction. These unplanned and uncontrollable fires cause direct and indirect environmental and economic consequences. As we speak, the deadly Mediterranean bushfires are raging havoc in Greece and other countries. In Greece, catastrophic bushfires have been reported in the Islands of Rhodes, Corfu and Evia, forcing emergency evacuation of tourists. This is happening just two years after the destructive fires of 2021, which wrecked unimaginable devastation in many parts of Greece. The current bushfires have also been reported in Algeria, Italy, Croatia and Portugal. According to news reports, total fatalities reported from the Mediterranean bushfires, so far, is about 40 with the highest deaths of 34 recorded in Algeria.
Quantifying the global losses due to extreme bushfires in monetary terms will run into trillions of dollars because of the enormity of damage. Apart from the direct destruction of human lives and physical structures such as buildings, natural and plantation forests, and orchards and farms, mega-fires have devastating impacts on biodiversity, environment, climate, economic livelihood and human health.
Photo by Malachi Brooks on Unsplash
Bushfire’s visible effects often attract a lot of attention in the news. It has become very common for TV networks to beam bushfire devastation for all to see. The combative firefighting with sprays and foams, and resultant patterned colouration on landscapes are often succinctly captured. Unfortunately, firefighting foams are major sources of dangerous ‘forever chemicals’ known as per- and polyfluoroalkyl substances (PFAs), a ubiquitous and persistent organic pollutant with detrimental health consequences. More so, what is salvaged through firefighting is often not comparable to what is lost to fire. Bushfires leave behind tales of woe, destroying everything on their way including houses, properties and infrastructural facilities. The total direct and indirect national economic losses caused by the Australian black summer bushfires, of 2019-20, was estimated to be AUD110 billion [1]. Painfully, human and animal lives were lost during the infernos with the fires claiming 28 human lives and 1.25 billion animals [1]. Previous catastrophic bushfires in Australia resulted in about 825 human fatalities between 1901 and 2011 [2].
Food security, in terms of quantity and quality, is another aspect of sustainability that can be affected by bushfires through direct crop mortality as a result of fire-caused agricultural land destruction. The flaming and smouldering effects of bushfires affect agricultural crops in different ways. While flaming fire-effect causes outright plant destruction, smouldering embers on agricultural lands might result in deferred effects [3, 4]. The high-intensity smouldering heat generated during bushfires have been shown to affect plant vascular tissues, altering phloem transportation of photosynthates and in very severe cases, water and mineral uptake [3]. These chronic fire effects may ultimately lead to delayed mortality in plants [3]. Both delayed and immediate plant and tree mortality could affect eventual agricultural productivity. Similarly, productivity losses may arise from indirect fire effects from smoke taints in fruits like grapes and resultant products such as wine [5]. The extra costs for restoring fire-impacted agricultural lands to optimum productivity, may add to the final cost of produce. One might think that these direct effects are enough to describe the devastating effects of catastrophic bushfires on human wellbeing, prosperity and sustainability, nevertheless more dreadful effects exist.
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Non-visible catastrophic bushfire effects on the environment are subtle and insidious. These effects could be more devastating than the visible impacts. Forests serve as natural sinks for carbon dioxide which is the major greenhouse gas responsible for global warming [6]. Catastrophic bushfires destroy forests thereby releasing the stored carbon and changing forest function from a net CO2 sink to a source. Such emissions add to global CO2 in the atmosphere thereby aggravating global warming [6]. The Brazilian Amazon forest for example, is reported to be responsible for 4 – 5% annual global anthropogenic carbon emissions, due to rampant bushfires [7]. In addition to CO2, dangerous pollutants in smoke (CO, CO2, NOx, hydrocarbons and inorganic elements), fine particulate matter, water soluble inorganic ions (WSIs), volatile organic compounds (VOCs), non-methane hydrocarbons, polycyclic aromatic compounds (PACs) and ozone-forming compounds, get introduced into the atmosphere during bushfires [8]. These pollutants elicit dangerous changes to global atmosphere and other environmental media. They could also pose great treat to human health [8]. For instance, the high levels of particulate matter resulting from bushfires could enter human respiratory tracts resulting in respiratory morbidity [9]. Likewise, some of the pyrogenic pollutants are known to be carcinogenic, mutagenic and teratogenic causing chronic diseases like cancers, and mutative and reproductive defects, respectively [8, 10].
Photo by Malachi Brooks on Unsplash
Extreme bushfires could contribute to the loss of threatened and endangered plant and animal species, particularly, if they are endemic to the fire-impacted ecosystem. Many species in the Brazilian Amazon forest that have been lost to bushfire, for example, may have permanently gone into extinction. Extinction of endemic species is predicted to reach 39 – 43 %, in worst case climate change scenarios, for 25 major biodiversity hotspots [11]. Bushfires can also directly affect watersheds and other hydrological resources as observed with the Nattai River catchment in Australia, following the 2001 bushfires [12].
The effects of bushfires on environmental sustainability can have consequential effects on the economic and social wellbeing of people, industries and nations. Beyond the visible effects are the insidious impacts, which are more deleterious. Reducing the frequency and intensity of bushfires should be everyone’s business. As the changing climate is argued to be responsible for this dangerous trend, all efforts must be geared towards addressing the fundamental causes of climate change and bushfire if the earth sustainability is to be assured.
References
1. Deb, P., Moradkhani, H., Abbaszadeh, P., Kiem, A.S., Engström, J., Keellings, D., and Sharma, A., Causes of the widespread 2019–2020 Australian bushfire season. Earths’s future, 2020. 8.
2. Blanchi, R., Leonard, J., Haynes, K., Opie, K., James, M. and Oliveira, F. D. D., Environmental circumstances surrounding bushfire fatalities in Australia 1901-2011. Environmental Science and Policy, 2014. 37: p. 192-203.
3. Bär, A., Michaletz, S. T. and Mayr, S., Fire effects on tree physiology. New Phytologist, 2019. 223(4): p. 1728-1741.
4. Michaletz, S.T. and E.A. Johnson, How forest fires kill trees: A review of the fundamental biophysical processes. Scandinavian Journal of Forest Research, 2007. 22(6): p. 500-515.
5. Idowu, O., Pitt, T., Dodds, K, Golding, J., Fearnley, J., Petrie, P. and Holzapfel, B., Orchard fire-proofing and post-fire management strategies: A case study of the 2019–2020 bushfires. Autralian Fruitgrower, 2021. 15(3): p. 63 – 65.
6. Dieleman, C.M., Rogers, B.M., Potter, M., Veraverbeke, S., Johnstone, J.F., Laflamme, J., Solvik, K., Walker, X.J., Mack, M.C. and Turetsky, M.R., Wildfire combustion and carbon stocks in the southern Canadian boreal forest: Implications for a warming world. Glob Chang Biol, 2020. 26: p. 6062–6079.
7. Bowman, M.S., G.S. Amacher, and F.D. Merry, Fire use and prevention by traditional households in the Brazilian Amazon. Ecological Economics, 2008. 67(1): p. 117-130.
8. Idowu, O.D., Semple, K.T., Ramadass, K., O’Connord, W., Hansbro, P., Thavamani, P., Beyond the obvious: Environmental health implications of polar polycyclic aromatic hydrocarbons. Environment International, 2019. 123: p. 543–557.
9. Tse, K., Chen, L., Tse, M, Zuraw, B., and Christiansen, S., Effect of catastrophic wildfires on asthmatic outcomes in obese children: breathing fire. Ann Allergy Asthma Immunol, 2015. 114: p. 308-311.
10. Liu, J.C., Pereira, G., Uhl, S.A., Bravo, M.A., Bell, M.L., A systematic review of the physical health impacts from non-occupational exposure to wildfire smoke. Environmental Research, 2015. 136: p. 120–132.
11. Bellard, C., Bertelsmeier, C.y, Leadley, P., Thuiller, W. and Courchamp, F., Impacts of climate change on the future of biodiversity. Ecology Letters, 2012. 15: p. 365–377.
12. Wallbrink, P., English, P., Chafer, C., Humphreys, G., Shakesby, R., Blake, W., Doerr, S., Impacts of water quality by sediments and nutrients released during extreme bushfires: Report 1: A review of the literature pertaining to the effect of fire on erosion and erosion rates, with emphasis on the Nattai catchment, NSW, following the 2001 bushfires. CSIRO Land and Water Client Report, 2004.
Oluyoye Idowu is a multidimensional Environmental Research Scientist with expertise spanning forest management, climate change mitigation and environmental risk assessment. He holds a PhD in Environmental Remediation from the University of Newcastle, Australia. He is a proud Australian distinguished talent alumnus.
