Wildfires add greenhouse gases to the atmosphere
We find that the magnitude of the (Canadian wildfire) carbon emissions is 647 TgC (570–727 TgC), comparable to the annual fossil fuel emissions of large nations, with only India, China and the USA releasing more carbon per year. – Brynes et al, 2024
Combining the extreme thermal sensitivities with projected increases in maximum temperatures globally, we predict that moderate warming scenarios can increase heat failure rates by 774% (terrestrial) and 180% (aquatic) by 2100. This finding suggests that we are likely to underestimate the potential impact of even a modest global warming scenario. – Jørgensen et al, 2022
Until 2019, Australia’s national fire-related carbon emissions averaged 439 million tonnes/year. An Australian Government report states that, “The 2019-20 bushfires will have negligible impact on Australia’s progress towards its 2020 or 2030 target.” – p3.
Contrary to this statement, in the first 6 weeks of 2020 alone, fires emitted 830 million tonnes.* These emissions are further accelerating warming, feeding the explosive growth of forest fires globally, in areas that have rarely experienced them. This in turn is leading to:
Permanent loss of CO2 absorbing ecosystems
The Australian Government report also states that “...affected forests are expected to recover over time, generating a significant carbon sink in the coming years.” -p9.
While Australian forest ecosystems have indeed adapted to fire, the 2019/2020 fires were extraordinary, wiping out 186,0002km. That’s an area 30% larger than the entire South Island of New Zealand.
Impact of Australian fires on Aotearoa
The effects of the 2019/2020 fires were felt here when ash and smoke blew across the Tasman (Fig. 3). One afternoon our skies turned orange, and for the next few weeks ash fell over already retreating glaciers, reducing their albedo, leading to faster melting (Fig. 4).
It also extended the hole in the ozone layer over Antarctica.
As the climate warms, the weather system in the Indian Ocean, the Indian Dipole (the Pacific ‘sister’ of El Niño/La Niña) is expected see more strong “positive” events similar to the one seen in 2019 that contributed to the Australian drought and bushfires.
When ecosystems tens millions of years in the making are decimated in just a few weeks, their recovery and replacement in a progressively warmer dryer climate may be vastly different and far less capable of storing carbon. More than 14,000 species of invertebrates alone (ie, not including mammals, reptiles, birds, and amphibians) lost habitat during these bushfires, at least one invertebrate species was identified has having gone extinct, and many provided important ecosystems services such as recycling nutrients. Many areas are unlikely to fully recover and certainly not become ‘carbon sinks’ as the climate conditions that fostered those those ecosystems no longer exist. The industry-led ‘Government’ report should be read in light of the Australian Government’s stance on climate change and ongoing land clearing and coal-mining policies.
* Note: the figures in tonnes (above) are from Copernicus, which use tons (Imperial). These have been converted to tonnes (metric) for consistency. For more detailed estimates see the van de Velde et. al. research paper.
Health impacts: wildfire smoke & toxic chemical legacy
Public health officials and researchers urge the public to cover up outside and clean carefully indoors, but many low-income and disabled residents, and those lacking air conditioning, have difficulty staying safe in bad air.
Incidences of heart attacks and strokes go up right after firestorms. Habre says more research is needed on potential long-term effects, but what’s been proven so far is harrowing. The “chronic” impacts include lower birth weights, enduring lung conditions in children, a variety of cancers in adults and increased cases of dementia. – Inside Climate News, 2025
The ash that fell on Aotearoa’s glaciers is a visual reminder that particulates from fires travel long distances. The journal Nature has compiled this open-access (free) series of peer-reviewed paper on wildfires and their impact on ecosystems, contribution to climate change, and damage to human health.
The important thing here is that the bike is gone. Where did it go? I’m not sure vaporized is the right word; aerosolized might be better. Regardless of the word choice, the bike was turned into smoke particles and dispersed across the city.
Of course, it wasn’t just this bike. The LA fires burned buildings and everything inside them (furniture, paints, plastics and electronics), and everything on the street (cars, metal tanks, street signs, bicycles, mailboxes, power lines, garbage bins, etc.). Many of these things were also turned into smoke that people then breathed in. – Dessler 2025
Preparing Aotearoa New Zealand for extreme fire
In 2016, Scion warned about the risk of extreme wildfires in New Zealand. Since then, we have witnessed large tracts of land blackened and homes destroyed in the Christchurch Port Hills (2017), Pigeon Valley (2019), Deep Stream (2019), Pukaki Downs (2019), Lake Ohau (2020) and in the Far North (February 2022), as well as the cataclysmic fires in Australia and North America….continue reading.
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In the 21st-century, the emergence of a new—more severe wildfire climate will occur
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We discover that “very-extreme” wildfire weather conditions are possible in regions formerly unaffected
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While the extent of emergence is dependent on future emissions, the frequency of very-extreme conditions is independent
Dangerous wildfire weather means that routine rural activities have the potential to ignite flammable vegetation and cause large-scale damage to the landscape and risk to life, as was likely the case in the 2019 Nelson/Tasman fire. The self-propelling nature and ferocity of extreme wildfire conditions can erase entire pine forest blocks that ignite under these conditions.
The response to life-threatening, “catastrophic” bushfire risks in Australia, where FWI values can exceed 200, is by evacuating and restricting activity and access (Dowdy et al., 2010; Handley, 2011). In Aotearoa New Zealand, daily FWI conditions exceed 100, and we recommend deploying the “very-extreme” wildfire conditions category for areas capable of these conditions. Wildfire weather conditions advancing to very-extreme should trigger measures such as limiting access, activities, and potentially evacuation in vulnerable areas. Many communities in the “very-extreme” risk zone are isolated and rely on one single State Highway in and out. – Meila et al; (recommend reading the full research paper).
Planting fire-resistant vegetation
…fire size persistently amplified decade-long postfire land surface warming in summer per unit burnt area. Both warming and its amplification with fire size were found to diminish with an increasing abundance of broadleaf trees, consistent with their lower fire vulnerability compared with coniferous species. – Chao Yue et al 2024
Lincoln University has worked with Fire & Emergency to develop a Plant Flammability directory (Video 1).Factors such as growing conditions, genetics, plant age, health and how the vegetation is managed can impact on a plant’s flammability. Plantings should always well-maintained, especially to remove dead or dry material, while watering during dry periods to help minimise the fire risk.
Low flammability planting is just one tool for fire mitigation. To minimise the risk of property and asset damage during fire, a range of mitigation measures should be used. – Fire & Emergency
