By Prof. Pat Hanscom, Mathis Wackernagel, Ph.D., David Lin, Ph.D., and Jenya Kirsch-Posner
The devastating fires of the Black Summer of 2019-2020 have turned Australia’s biocapacity reserve into a deficit, according to preliminary research by Global Footprint Network (1).
This is startling since Australia has long been considered a biocapacity giant. With its enormous landmass characterized by wide-open spaces and its relatively small population, it has been blessed with a significant biocapacity reserve: since record keeping started in 1961, its biocapacity was consistently estimated to be two to three times the size of its Ecological Footprint. But not for the year of the fire.
What reduces biocapacity
Simply put, biocapacity of Australia is the amount of living matter Australia’s ecosystems can regenerate. It is calculated on an annual basis. What was different about the Black Summer is the catastrophic loss of living matter. Full accounts of the biocapacity therefore need to subtract such losses from the regeneration.
The impact of fires
In general, Australia is fire-adapted. Bushfires are a regular part of many of its ecosystems, and these systems are resilient to the fires that come with regularity (Dijk 2019). For example, the new growth grassland and savannah can recapture the carbon released in a fire within a year or two. In contrast with this past year, Canadell suggests that the carbon released in the burn of the old growth temperate forests during the Black Summer fires will take decades, if not centuries, to recover (Hope 2020).
What was different about this fire season?
First, some of the forests affected have burned four times in the last 25 years. Yet in order to recover properly, Lindenmayer suggests that they should burn no more than once every 75 -125 years (Pickrell 2020). Second, the vegetation was drier than usual. In fact, last year was the driest year in Australia’s 119 years of recordkeeping. Third, it was also the hottest year on record (Dijk 2019). These three factors resulted in a greater spread and intensity of fire.
Overall, the fires burned 8.2 million hectares or 6.2% of Australia’s forested areas, mostly in New South Wales, Victoria, and Western Australia (ABARES 2020). By one estimate, regeneration for these broadleaf forest biomes is 50 years (Haverd et al. 2013). Therefore, the forest biocapacity lost in the fires could take 50 years to regenerate at a rate of about 2% regrowth per year. From a biocapacity perspective, this means that the losses in 2019 don’t just reduce biocapacity in this year, but rather remove 6.2% of 50 years’ worth of Australia’s biocapacity or 143 million global hectares.
As a rough comparison, the fire-induced loss this year is 3 times greater than the entire Australian forest biocapacity (46 million gha). This estimate is likely optimistic as it assumes all the burned forest can fully recover (2).
From biocapacity reserve to biocapacity deficit
Australia’s biocapacity―as adjusted for the fire-induced losses―is just 153 million global hectares (gha) rather than the usual 296 million gha. (3) In contrast, Australia’s Ecological Footprint of consumption is 160 million gha (2016 results). Consequently, Australia ran a biocapacity deficit during that season of massive fires. (4)
This abrupt change from having a large biocapacity reserve to running a biocapacity deficit is a tragedy. But the even bigger tragedy is the loss of biodiversity due to the destruction of mature ecosystems which were habitat to many unique species. For example, the Blue Mountain World Heritage Site lost 80% of its forest to the fires. Professor John Woinarski and others predict that this area may be condemned to grow back as weedy scrub (Pickrell 2020), unable to support its native species. This is an irreparable loss of special habitat, and with it, its native species.
The fragility of biocapacity
Biocapacity is our greatest asset and these fires demonstrate how fragile biocapacity can be. With climate change and resource overuse, we place greater demand on ecosystems that are essential for the survival of not only humanity but wildlife species as well. Growing demand met by less robust biocapacity becomes a dangerous combination. The lesson from these tragic fires is that our excessive demand is undermining our life-support systems in multiple arenas.
The even bigger lesson is that it is in our interest to take resource security far more seriously. Humanity is currently demanding as much from nature as if we lived on 1.6 Earth. Yet, there is no escaping the context of our only and finite planet going forward. Balancing human demands on nature with what our planet’s natural ecosystems can provide (one-planet compatibility), while improving well-being for all, make up the minimum threshold for sustainability. Both aspects (one-planet compatibility and well-being for all) define the framework for one-planet prosperity, a safe operating space that requires building through careful design. The only alternative available to us is one-planet misery, where one-planet compatibility is imposed to humanity by disaster. Australia’s Black Summer gave us a glimpse; the coronavirus pandemic showed us another.
Anyone can be part of the shift to one-planet prosperity by committing to one’s own long-term success. Opportunities for action are infinite, grouped into five key areas. The choices we make today will determine whether or not humanity is able to reach one-planet prosperity.
ENDNOTES
(1) The fires lasted until January 2020. The Ecological Footprint and biocapacity calculations are done on a yearly basis. Since 2016 is the latest year with full accounts, we use 2016 as a reference year. This means that Australia’s biocapacity for 2019 was assessed here as the biocapacity for 2016 adjusted for the loss in forest. And that amount was less than Australia’s latest Footprint results (which are also for the year 2016).
(2) Biocapacity losses are estimated based on recovery time to reach mature forest. This is likely an underestimate of biocapacity loss because the full recovery time of burned areas to return to mature forest may not restore soil carbon stocks to pre-fire conditions.
Also, not all the burnt forest may be able to recover as forest. An article in National Geographic reports on the assessments of Australian biologists: “The ecosystem has effectively collapsed, it’s transitioned into something else … more likely to be colonized by generalist, weedy plants,” says John Woinarski, a conservation biologist at Charles Darwin University in Australia’s Northern Territory. “They’ll converge into less interesting, less distinctive vegetation that supports fewer threatened plants and animals.” (Woody 2020).
More detail on the carbon budget of Australia’s ecosystems is described in V. Haverd, M. R. Raupach, P. R. Briggs, J. G. Canadell, S. J. Davis, R. M. Law, C. P. Meyer, G. P. Peters, C. Pickett-Heaps, and B. Sherman, 2013, The Australian terrestrial carbon budget, Biogeosciences, 10, 851–869, 2013, www.biogeosciences.net/10/851/2013/, doi:10.5194/bg-10-851-2013
(3) Note that this assessment is preliminary. The challenge in this research is to understand which fires cause lasting damage to ecosystems. Pep Canadell from CSRIO commented that “fire consumes a very small part of [Australia’s] NPP [“Net Primary Productivity”], on average 5%. This year, we had a lot of emissions but we had other years in the past where we burned massive extensions of rangeland and savannas with also significant emissions. In steady climatic conditions, all the burning that is going on in Australia could be [carbon] neutral given that most ecosystems are well adapted to fire and recover over time. The tricky part is not so much how much has burned, but whether there are any trends on the rise, and whether there is evidence that the forest component of fires, show any slowdown of post-fire recovery and shortening of the fire return intervals.” (personal communication, May 11, 2020).
ABC news summarized the situation in their article entitled “The size of Australia’s bushfire crisis captured in five big numbers.” This article draws on a study by the Copernicus Atmosphere Monitoring Service (CAMS) of the European Union, which estimates carbon emissions of current and previous forest fires in Australia https://atmosphere.copernicus.eu/wildfires-continue-rage-australia.
ABC news refers to about 435 million tonnes of CO2 released in the Australian 2019 forest fires. However, the Copernicus site quotes refers to 400 million tonnes of CO2, with a graph showing a little less than 400. For New South Wales, the CO2 emissions for the 2019 fires seem extraordinary compared to the past. Yet for Australia as a whole, it looks like the 2011-2012 fires produced much higher carbon emissions (about 50% higher). As Pep Canadell points out, the most significant question is to what extant the fires damage post-fire recovery, i.e., NPP rates, post the fire (see also CONV).
For this reason, our assessment uses the data on burnt forest areas, rather than carbon emissions, as the input for our preliminary assessment.
(4) Will this one-year decline in biocapacity show up in future National Footprint and Biocapacity Accounts? Not necessarily. These accounts are built on UN data sets, which are limited. Forest data from FAO does not adequately capture catastrophic losses such as the Black Summer fire, which is another reason that the National Footprint and Biocapacity Accounts produce an overestimate of countries’ biocapacity. This makes complementary research necessary to estimate additional effects not covered by UN data sets.
REFERENCES
ABARES. 2020. “Forest Fire Data – Department of Agriculture.” Forest Fire Area Data for the 2019–20 Summer Bushfire Season in Southern and Eastern Australia. May 27, 2020. https://www.agriculture.gov.au/abares/forestsaustralia/forest-data-maps-and-tools/fire-data#area-of-native-forest-in-fire-area-by-forest-tenure-and-jurisdiction.
Dijk, Albert Van. 2019. “Australia’s Environment Summary Report 2019.” Centre for Water and Landscape Dynamics: Australian National University. https://www.wenfo.org/aer/wp-content/uploads/2020/03/AustraliasEnvironment_2019_SummaryReport.pdf.
Haverd, V., M. R. Raupach, P. R. Briggs, J. G. Canadell, S. J. Davis, R. M. Law, C. P. Meyer, G. P. Peters, C. Pickett-Heaps, and B. Sherman. 2013. “The Australian Terrestrial Carbon Budget.” Biogeosciences 10 (2): 851–69. https://doi.org/10.5194/bg-10-851-2013.
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Pickrell, John. 2020. “Wildfires Have Spread Dramatically—and Some Forests May Not Recover.” National Geographic. January 30, 2020. https://www.nationalgeographic.com/science/2020/01/extreme-wildfires-reshaping-forests-worldwide-recovery-australia-climate/.
Woody, Todd. 2020. “Koalas, Wombats, Other Marsupials Struggle to Recover from Australia’s Bushfires.” National Geographic. July 17, 2020. https://www.nationalgeographic.com/animals/2020/07/australia-marsupials-struggling-after-fires/.
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Hope, Mat. “Australia Burning.” The Lancet Planetary Health 4, no. 1 (January 1, 2020): e12–13. https://doi.org/10.1016/S2542-5196(20)30006-1.
Pickrell, John. “Wildfires Have Spread Dramatically—and Some Forests May Not Recover.” National Geographic, January 30, 2020. https://www.nationalgeographic.com/science/2020/01/extreme-wildfires-reshaping-forests-worldwide-recovery-australia-climate/.
ABARES. “Forest Fire Data – Department of Agriculture.” Forest fire area data for the 2019–20 summer bushfire season in southern and eastern Australia, May 27, 2020. https://www.agriculture.gov.au/abares/forestsaustralia/forest-data-maps-and-tools/fire-data#area-of-native-forest-in-fire-area-by-forest-tenure-and-jurisdiction.
Woody, Todd. “Koalas, Wombats, Other Marsupials Struggle to Recover from Australia’s Bushfires.” National Geographic, July 17, 2020. https://www.nationalgeographic.com/animals/2020/07/australia-marsupials-struggling-after-fires/.
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Haverd, V., M. R. Raupach, P. R. Briggs, J. G. Canadell, S. J. Davis, R. M. Law, C. P. Meyer, G. P. Peters, C. Pickett-Heaps, and B. Sherman. “The Australian Terrestrial Carbon Budget.” Biogeosciences 10, no. 2 (February 7, 2013): 851–69. https://doi.org/10.5194/bg-10-851-2013.