The brave, new green world of the carbon economy hasn’t exactly taken off as desired. Perhaps it’s because it wasn’t really planned from the outset, or maybe it is still too abstract for most people to accept, digest and incorporate into their daily lives. An emergent property of society’s generally slow awakening to the challenge of climate disruption, is that it will be a long time before we accept its full suite of incarnations.
The infant carbon economy is, however, well and truly alive and kicking, so it is important to try and plan for its growing influence on our decision making. Bumps in the road aside, the carbon economy has mostly been a blessing (actual and potential) for biodiversity conservation projects the world over.
In principle, the aim of the carbon economy is rather straight-forward: charge people a certain amount for each unit of carbon dioxide equivalents they release, and then use that money to develop approaches that further increase carbon sequestration or limit emissions. It’s a ‘build-it-and-they-will-come’ framework, where increasing financial impetus to restrict emissions is enhanced by society’s evolution towards better approaches and technology.
Recently, a collection of 30 ecologists with various degrees of specialisation in landscape-scale environmental questions, produced a comprehensive review of the implications of the carbon economy for Australian biodiversity. We described how landscape-scale changes resulting from the flow of carbon finances would affect biodiversity in terms of (a) environmental plantings, (b) native regrowth, (c) fire management, (d) forestry, (e) agricultural practices and (f) feral animal control.
We concluded that environmental plantings were where the largest biodiversity benefits for our investment will come, but care will be needed to plant with ecological restoration in mind as we go. Regrowth vegetation in once-cleared areas is a substantial element of Australia’s future biomass carbon, so we need to manage this regrowth optimally, by which we mean the action of keeping (not clearing) existing, human-modified vegetation, or avoiding cropping and continuous grazing.
Fire management is also a big player in the Australian carbon game. By applying fire at the right time, one can potentially increase carbon storage indirectly and abate emissions via the reduction in intensity and frequency of high-intensity fires, thus minimising the total fuel burnt. For forestry, the once-common practice of using fire to remove logging debris is now much less attractive under the new carbon economy. Perhaps the most-touted capacity to retain more carbon in forests subject to harvest is by increasing rotation times, which would also benefit wildlife.
For agriculture, the two best candidates for landscape change that would provide marginal biodiversity improvements would be increasing the retention and encouraging the regrowth of shrubs, and reducing grazing pressure. Finally, while feral animal reductions are without doubt great outcomes for biodiversity, the avoided emissions from their removal are unlikely to make much difference to our national carbon budget.
As a result of these aspects, conservationists have been particularly aware of the carbon economy’s potential to strengthen existing and planned initiatives to preserve and restore native biodiversity. We have, therefore, been some of the first to benefit from this additional source of funding, even if it wasn’t necessarily targeted to biodiversity-specific goals. Additional funding is of course always welcome, because let’s face it, we don’t have nearly enough to do what this country needs.
Indeed, Australia has a long history of disrespect for its own home and the vital life-support system it provides us free of charge. With only about 4 per cent of the world’s forests in Australia, the little we have is too precious to degrade any further than the already ~ 40 per cent total forest cover loss we’ve realised since European colonisation. Believing the remaining 60 per cent is sufficient, ignores that over 50 per cent of remaining forests in Australia have been previously cleared or highly modified; for example, over 80 per cent of eucalypt forests have been altered in some way. Much of the remaining forest is highly fragmented, such that few areas of sufficient size remain to provide the spatial needs of many species.
While nothing can replace primary habitats in terms of biodiversity and the carbon they hold, it is not difficult to understand why so much emphasis has been placed on ‘restoring’ our highly degraded landscape into some vestige of its former ecological function. Combine this desire with the fact that plants incorporate atmospheric carbon dioxide into their tissues as they grow, and we have an effective means to fund some badly needed conservation initiatives in Australia.
Many questions remain, however, about the best approaches to restore an ecosystem with these two sometimes divergent aims. For example, an accounting approach to terrestrial carbon sequestration would place emphasis on planting the fastest-growing and readily available (often non-native) tree species. This ‘plantation’-style reforestation might be an effective approach to sequester the greatest amount of carbon, but it does little good for native biodiversity. Such ‘bio-perversities’ are a real and present danger. The other extreme is planting as many native plant species as possible, while taking future climate into consideration, to benefit the greatest component of the ecosystem’s other constituent species — an approach that is largely cost-prohibitive. So what’s the balance, and how do we achieve it?
Fortunately, a few biodiversity-carbon replanting experiments designed to answer just such questions are in progress around Australia — one in far north Queensland in the tropical rainforests of the Atherton Tablelands, one in the semi-arid Mallee forest of South Australia, and one in the wheatbelt of south-western Western Australia. Here, experimental manipulation of various planting densities and species assists in determining what the ‘ideal’ mix of planting effort and species composition is required to give both the biggest biodiversity and carbon bangs for our buck. With greater replication of such experiments in, for example, riparian areas, arid zones, savannas and coastal heathlands, we could eventually be able to provide a generalised approach to biodiversity-friendly, carbon-financed restoration projects across the entire country.
There is no question that we can improve our landscape practices and restore vast areas of Australia’s degraded ecosystems. The current lack of political will notwithstanding, the fact that at least one ecosystem service has the economic framework in place to fund such a lofty agenda gives us hope that real, effective climate change mitigation and biodiversity conservation can be achieved.