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Effects & Impacts: Increasing extreme wildfires

Image: Macrocarpa and gorse hedge fire at Cust, Sonny Whitelaw

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More extreme wildfires

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Summary

Among the many consequences of climate change, wildfires are growing in intensity and spreading in range across Earth’s ecosystems – UNEP 2022

  • Climate change doesn’t cause wildfires. But in a warming world and more intense El Niños results in increasing evaporation that dries out vegetation faster, making it more prone to fires. This is particularly true of non-native species, including macrocarpa and gorse hedges (top image) and vast stands of exotic

We tried, and tried, and tried to stop it going on to Elephant Hill, and we couldn’t,’ he said. ‘It got in some dead, standing trees, and it just exploded. There was no stopping it.’ A striking feature of the hills, even two weeks ago, were large stands of dead wilding trees – part of a national programme to rid our landscapes of quick-growing and fast-spreading pines. Fires need three key things, Turner said: heat, air and fuel. ‘We gave them lots of fuel.’ – Newsroom 2025

  • This was predictable, and it will get worse across Aotearoa:

..wildfire weather conditions will increase on average, both in wildfire season length and in the intensity of fires that may take hold, with the most severe wildfire dangers in the central-south inland areas of the South Island becoming noticeably worse… For the first time, we find that very-extreme conditions that led to the devastating 2019–2020 ‘Black-Summer’ fires in Australia can occur in Aotearoa every 3–20 year for areas of the South Island (Mackenzie Country, Upper Otago, and Marlborough). Our findings have important implications for communities near pine forests, the Government’s tree planting plan to tackle climate change, and financial investment stored in plantation forests. – Melia et al, 2022

  • This raises the question: how will plantation forests owners repay all the carbon credits they’ve been earning (sometimes for decades) if their plantation catches fire?

  Effects

Home > Climate wiki > Effects > Wildfires increasing

Summary

Among the many consequences of climate change, wildfires are growing in intensity and spreading in range across Earth’s ecosystems – UNEP 2022

  • Climate change doesn’t cause wildfires. But in a warming world and more intense El Niños results in increasing evaporation that dries out vegetation faster, making it more prone to fires. This is particularly true of non-native species, including macrocarpa and gorse hedges (top image) and vast stands of exotic commercial forestry and wilding pines. This was made all-too clear in the December 2024 fires that devastated Craigieburn, Canterbury:

We tried, and tried, and tried to stop it going on to Elephant Hill, and we couldn’t,’ he said. ‘It got in some dead, standing trees, and it just exploded. There was no stopping it.’ A striking feature of the hills, even two weeks ago, were large stands of dead wilding trees – part of a national programme to rid our landscapes of quick-growing and fast-spreading pines. Fires need three key things, Turner said: heat, air and fuel. ‘We gave them lots of fuel.’ – Newsroom 2025

  • This was predictable, and it will get worse across Aotearoa:

..wildfire weather conditions will increase on average, both in wildfire season length and in the intensity of fires that may take hold, with the most severe wildfire dangers in the central-south inland areas of the South Island becoming noticeably worse… For the first time, we find that very-extreme conditions that led to the devastating 2019–2020 ‘Black-Summer’ fires in Australia can occur in Aotearoa every 3–20 year for areas of the South Island (Mackenzie Country, Upper Otago, and Marlborough). Our findings have important implications for communities near pine forests, the Government’s tree planting plan to tackle climate change, and financial investment stored in plantation forests. – Melia et al, 2022

  • This raises the question: how will plantation forests owners repay all the carbon credits they’ve been earning (sometimes for decades) if their plantation catches fire?
  • Impact of Australian fires on Aotearoa:
    Fig. 3: Smoke plumes from bushfires in southeast Australia on January 4, 2020, sent ash over New Zealand. (Image: NASA Earth Observatory)
    Fig. 3: Smoke plumes from bushfires in southeast Australia on January 4, 2020, sent ash over New Zealand. (Image: NASA Earth Observatory)

    The effects of the 2019/2020 fires were felt here when ash and smoke blew across the Tasman (Fig. 3). 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.

    Fig. 4: Ash landed on Franz Josef glacier. The albedo effect increases the melt rate of snow and ice on New Zealand’s glaciers. This in turn has a feedback effect by changing river flows and water storage. (Image: Twitter/ @Rachelhatesit)
    Fig. 4: Ash landed on Franz Josef glacier. The albedo effect increases the melt rate of snow and ice on New Zealand’s glaciers. This in turn has a feedback effect by changing river flows and water storage. (Image: Twitter/ @Rachelhatesit)