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Savanna burning: carbon pays for conservation in northern Australia

Fire and biodiversity have a complex relationship in northern Australia. Tim Flannery and others blame the current northern biodiversity crisis, at least in part, on changed fire regimes. Improving fire…

An early season burn in Arnhem Land. Low intensity fires decrease greenhouse emissions and increase carbon stored in trees. Brett Murphy.

Fire and biodiversity have a complex relationship in northern Australia. Tim Flannery and others blame the current northern biodiversity crisis, at least in part, on changed fire regimes. Improving fire management is critical to conserving savanna landscapes – but who pays for it? A new funding model, tapping into the carbon economy, has emerged in the far north and is rapidly transforming fire management and biodiversity conservation.

A new funding model for fire management

The idea that land management could be funded by carbon credits emerged from Aboriginal-owned Arnhem Land in the Northern Territory. By the 1990s it was clear that the region’s enormous biodiversity values were being eroded by frequent, intense late dry season fires.

To address this problem, a trailblazing group of Western scientists and land managers, and Aboriginal Traditional Owners developed a program of prescribed burning early in the dry season to pre-empt large, intense wildfires late in the dry season.

The most innovative part of their work was to link improvements in fire management to reductions in greenhouse gas emissions. They also realised that this emissions reduction (or abatement) could be used to secure resources for land management.

The abatement occurs because early dry season fires tend to be patchier and less intense than late season fires, and therefore burn less fuel. Because less fuel is burnt, fewer emissions are produced.

The project that resulted from this early work - the 28,000 km² West Arnhem Land Fire Abatement project - has operated since 2005 and is funded by one of the world’s largest energy companies, ConocoPhillips. They provide $1 million annually in return for an abatement of greenhouse gases equivalent to 100,000 t of CO₂.

It is clear that fire management in western Arnhem Land has shifted the fire regime from one dominated by late dry season fires (decreasing from 29 to 13% of the landscape annually), to one dominated by early dry season fires (increasing from 9 to 17% of the landscape annually).

There is abundant evidence that an early-dominant fire regime favours many declining components of the biota, including endemic sandstone heaths (now federally listed as endangered), rainforests, and the northern cypress pine.

Extending the Arnhem Land model across the north

The viability of these projects was given a substantial boost in 2012 when the Commonwealth government approved the use of savanna fire management to generate carbon credits. This approach to funding fire management is now being adopted across northern Australia, on a range of land tenures, including conservation areas.

For example, Fish River Station is a new 1,781 km² reserve recently acquired jointly by the Commonwealth government, Indigenous Land Corporation and private conservation organisations. It has recently been given approval to operate a carbon offset project based on fire management.

Other, larger carbon–fire projects are being developed on Aboriginal lands in central Arnhem Land, the Kimberley, south of the Gulf of Carpentaria, and Cape York Peninsula. Private conservation organisations such as the Australian Wildlife Conservancy are also developing carbon projects on their savanna properties.

The potential for biosequestration

Under the existing accounting methodology, savanna fire projects generate carbon credits by reducing the emissions of two potent greenhouse gases - methane and nitrous oxide (with potencies 25 and 298 times that of CO₂, respectively). However, the effect of fire on the storage - or sequestration - of carbon by savanna systems is effectively ignored.

Several colleagues and myself analysed data from an array of long-term vegetation monitoring plots throughout savannas of the Top End, and found that even modest reductions in the frequency of intense fires cause a large increase in the amount of carbon stored as tree biomass.

Our “back of the envelope” calculations suggest that the recent improvements in fire management in Arnhem Land would increase tree biomass by an amount equivalent to around .22 t of CO₂ per hectare per year*. This is about five times the methane and nitrous oxide abatement that underpins existing fire projects.

We are now working on a more rigorous approach to modelling biosequestration across northern Australia. It seems likely that biosequestration can be worked into a carbon offset system and, once approved by the Commonwealth, the viability of carbon–fire projects will increase dramatically.

There is little doubt that the new carbon economy is transforming fire and biodiversity management across northern Australia. Many areas managed for biodiversity conservation can now generate a substantial income beyond the public purse. This will surely allow the further privatisation of biodiversity conservation, at a time when non-government organisations are already playing an increasingly central, and indeed successful, role in conservation in northern Australia.

Implementing biodiversity-friendly fire regimes remains an enormous management challenge in the north. Although the carbon economy is unlikely to be a panacea, it certainly provides a much-needed income stream for sustainable land management, especially for the vast lands outside of the traditional conservation estate.

*The article originally stated biomass would increase by 2.2t; this was incorrect.

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16 Comments sorted by

  1. John Newlands

    tree changer

    This article asks us to believe more burning = less C02.
    Colour me sceptical but it seems to me
    1) people get to play with matches
    2) coal burners get cheap carbon credits.
    It's almost too good to be true.

    My view is that the reliable form of biosequestration is coal seam formation over geological time scales. That is swamps are covered in silt and driven deep underground where eons later they are left in place by humans. I would like to see independent confirmation that savanna burning has a stable net carbon withdrawal effect. You'd kind of suspect that leaf litter would be burned off rather than accumulated. Not as soil carbon but atmospheric CO2. The soil drying and loss of nutrients would also reduce subsequent plant growth.

    Once proved we can all set fire to our front lawn and earn a carbon credit. Otherwise there will be a lingering suspicion the whole thing is fraudulent.

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    1. Murray Webster

      Forestry-Ecology Consultant/Contractor

      In reply to John Newlands

      My interpretation of the article is that Less burning = Less CO2. Early season burns are cooler and consume less biomass per hectare and less hectares than late season fires, thereby reducing C02 emissions.

      This makes sense to me, though it has been known for a lot longer than since the 1990's. Fire science lecturers during my undergraduate forestry degree referred to this phenomenon in the early 80's and they were referring to studies from the 60's. I'm guessing the traditional owners knew a long time before that. Environmental science seems to want to ignore a raft of existing knowledge and need to rediscover everything ecological by themselves.

      The 2.2 tonnes of CO2 per year should probably be qualified. Surely it will reach a point were it will increase no more.

      I have also read that the introduced African Gamba grass is a big problem in the top end and confounds the basic idea put forward here.

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    2. Chris O'Neill

      Victim of Tony Abbotts Great Big New Tax

      In reply to Murray Webster

      "The 2.2 tonnes of CO2 per year should probably be qualified. Surely it will reach a point were it will increase no more."

      Indeed. Once the soil is more than X% charcoal, I presume the original flora won't be able to grow in it anymore.

      Also, what's going to happen to this charcoal if, heaven forbid, there is an accidental "hot" fire, as happens when there is a bushfire on record hot days?

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    3. Brett Murphy

      Research Fellow at University of Melbourne

      In reply to John Newlands

      Thanks John

      Actually people get to play with more than matches - think helicopters and rapid-fire incendiaries!

      Regarding fire and biosequestration, the extra carbon isn't stored in litter, but in live and highly fire-resistant trees, so it doesn't get burned up when a high-intensity fire eventually occurs. By providing a milder fire regimes, trees are able to grow faster and bigger (hence storing more carbon).

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    4. Brett Murphy

      Research Fellow at University of Melbourne

      In reply to Murray Webster

      Thanks Murray, you are quite right - the uptake of carbon can't go on forever.

      The 2.2 t of CO2 was derived from a predicted increase of 220 t over 100 years, though in the early years the rate of increase is much faster, slowing as tree biomass approaches carrying capacity.

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    5. Russell Camel Wattie

      logged in via Facebook

      In reply to John Newlands

      John you clearly missed the implications of this paragraph from above,
      It is clear that fire management in western Arnhem Land has shifted the fire regime from one dominated by late dry season fires (decreasing from 29 to 13% of the landscape annually), to one dominated by early dry season fires (increasing from 9 to 17% of the landscape annually).
      It is the reduction of late dry season fires that achives the saving of Green house gasses. I have seen a Doco in this and the difference in intesity…

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  2. Michael Shand
    Michael Shand is a Friend of The Conversation.

    Software Tester

    With Climate Change the bush is going to start burning every single year - we need to focus on mitigate this, I do not believe it is sustainable to use fire to prevent fire, as we will have to start burning more and more each year

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    1. Brett Murphy

      Research Fellow at University of Melbourne

      In reply to Michael Shand

      Thanks Michael. But this begs the question of how you mitigate increasingly frequent fires? We're talking about seriously huge landscapes here - e.g. Arnhem Land is about the same size as Tasmania! Prescribed burning is essentially the only fire management tool that land managers have at their disposal.

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  3. John Newlands

    tree changer

    Quite aside from the specifics of savanna burning there are several key issues around carbon sink offsets
    1) the moral hazard of not reducing coal burning in the first instance
    2) the lack of a debit mechanism if the credit needs to be reversed
    3) large amounts of diesel and avgas used in making the supposed carbon sink
    4) the inference that nature hasn't evolved optimally
    5) the Noel Kempff anomaly - more intensive biomass harvesting elsewhere

    Because these things promise to be a cheap antidote…

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  4. Rob Law

    Researcher

    Thanks for the article Brett.

    I notice that the estimate of sequestration is higher now than your previous estimate of 6.1tC/ha over a 100 year period under a well managed fire regime (from your chapter in Culture, Ecology and economy of fire management in northern australia). This seems quite a large difference, and I am wondering whether the 100 year period is a better way to look at biosequestration potential, as this would be more reflective of disturbances that happen on a longer cycle such…

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    1. Rob Law

      Researcher

      In reply to Rob Law

      Ha, sorry I had no idea I wrote such an essay, i fear ive become "one of those people"!

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    2. Brett Murphy

      Research Fellow at University of Melbourne

      In reply to Rob Law

      Thanks Rob

      You've very astutely picked up an error in my article. The figure of 2.2. t CO2 per hectare per year is too high by a factor of 10 - should be just 0.22 t CO2. Have emailed The Conversation to see if not too late to correct. This error does not affect my assertion that the carbon credits due to biosequestration are probably around five times those due to abatement of methane and nitrous oxide.

      There's no doubt that there are some pretty complex issues to work through, especially…

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  5. Greg Miles

    Conservation lobbyist

    It is all good stuff and I agree in principle. But there is one subtle danger here. And that is the claimed benefit to biodiversity conservation. Much of the landscape between central Arnhemland and Darwin and beyond is no longer what it was before whitefellas arrived. The collapse of traditional burning, concomitant with the well documented collapse of the indigenous population by the 1890s, meant that Trad. Aboriginal burning from west Arnhemland to Darwin ceased at about that time. Also in…

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    1. John Foley

      Various ...

      In reply to Greg Miles

      Thanks Greg for the context to this debate … the ‘post white fella’ context. It seems this discussion gets a bit side tracked when people get confused between learning from the past and trying to return to it. We need to find a solution, and to do that we need to ask the right questions and test them.

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  6. David Arthur

    resistance gnome

    Thanks Dr Murphy, the landscape management work you're describing gives cause for optimism in terms of ecological restoration and maintenance in Northern Australia, and also in terms of fertility-boosting carbon biosequestration.

    My only concern is with the funding model for the work, dependent as it is on continued industrial CO2 emissions. I expect that, as the severity of the carbon overshoot (extent to which atmospheric CO2 exceeds 350 ppm) becomes apparent to all but the most blinkered ideologues, the work you're undertaking continues long after persisting with fossil fuel use is recognised as among our greatest mistakes.

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