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Savanna burning: carbon pays for conservation in northern Australia

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

Savanna burning: carbon pays for conservation in northern Australia

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.