That sinking feeling

Carbon sinks are part of the Kyoto Protocol's strategy to reduce carbon dioxide levels in the atmosphere. But will they really have the impact on emissions their supporters claim? Jane Morecroft investigates

Carbon sinks - forests planted or managed to absorb carbon dioxide - have grown in political importance following the recognition of their role in mitigating climate change within the Kyoto Protocol.

The Protocol sets out commitments to reduce greenhouse gas (GHG) emissions to a collective 5.2% below 1990 levels in the first commitment phase (2008-2012). For the EU, this means a reduction of 8%; for the UK it is 12.5%. The planting of new forests could help countries meet these commitments.

Under the terms of the agreement, there are a number of guidelines for using carbon sinks. Permissible methods comprise reforestation and afforestation (the planting of new forestry).

However, caps have been placed on the amount of reductions that can be claimed though sink use and baseline years have been introduced for project accreditation. "Avoided deforestation" remains off the agenda for the first commitment phase.

The controversy

While sinks may seem like a relatively simple and low-cost way to reduce the amount of carbon in the atmosphere, the reality is much more complex. Foremost is the lack of scientific consensus on how much carbon can be absorbed by carbon sinks.

Sequestration rates are measured using tree size, biomass and carbon absorption estimates, all of which vary a great deal depending on the location, type and age of the tree. Generic absorption figures set northern forestry absorption rates at around 2-4t of carbon/ha/year, as opposed to tropical forestry, which absorbs around 5-10Ct/ha/yr.

Also, sinks are susceptible to fires and other natural disasters, which can release the stored CO2 and play havoc with absorption rate predictions - a vulnerability that is of concern with extreme weather events on the increase.

Bill Hare, the director of climate change policy at Greenpeace, says that changes in global temperatures could undermine all the predictions made about sequestration rates. "As ecological instability increases, sink advocates are going to end up with egg on their faces," he says.

The UK's Hadley Centre for Climate Prediction and Research warns that global warming could trigger vast areas of carbon sinkland to die off in the next fifty years or so, releasing vast amounts of carbon dioxide.

Calculating the potential

Under Kyoto, the potential for carbon sink sequestration has mainly been based on vegetation's above-ground mass (up-ground biomass), as opposed to leaf mould, root matter or soil. There is little data available on soil sequestration, and this has also led to controversy.

"Working out where the carbon in soil goes is a massive scientific problem. And if you don't know how it behaves, you don't know how stable the stored carbon is," says Hans Dolman, chairman of CarboEurope, an EU-funded research consortium which investigates carbon balance.

Dolman has raised concerns that forestry projects on wet or peaty soils could emit greater quantities of carbon dioxide than they consume and that simply calculating the carbon content of standing trees in misleading.

However, while uncertainties exist, most researchers argue that soil is likely to absorb far more carbon than trees (up to six times more according to some estimates).

Another problem, and one with implications for reaching Kyoto's time limitations, is that newly-planted forests may actually release more carbon dioxide than they absorb in their first 10-20 years of growth.

Impacts on the carbon industry and policies

There are also concerns that because forestry land management projects are considered difficult to monitor and control, there is a risk of exaggerated carbon absorption rate claims. This could be exploited by developed nations that wanted to delay or avoid actions to cut fossil-fuel emissions at source, on cost grounds.

But conservationists such as Professor Ian Swingland, who is part-author and editor of a new book on the subject called Capturing Carbon & Conserving Biodiversity, maintain that the issue of carbon storage permanence can be dealt with by well-managed projects and insurance, while fears that the potential of carbon sink sequestration has been exaggerated should be catered for with more sinks.

He says that reliable monitoring methods for carbon sinks do currently exist and are being successfully used by carbon monitoring companies.

Swingland believes carbon sinks will never offer a viable get-out clause to countries seeking an easy solution, because, as statistics from the Intergovernmental Panel on Climate Change make clear, carbon sinks will only ever play a small part in the overall fight to reduce carbon emissions.

"Forest carbon sequestration should only be viewed as a component of a mitigation strategy, not as a substitute for changes in energy supply, use and technology that will be required if atmospheric carbon dioxide concentrations are to be stabilised," he says.

Policy implications

Although Kyoto is a step in the right direction, overzealous regulation and negotiators set on forwarding their individual country's political interests have combined in a failure to produce a crediting system that provides meaningful incentives for carbon sinks.

Many developed nations, including EU members, have restricted the use of carbon sinks under their domestic climate change programmes - for instance the UK's carbon trading scheme does not allow for land forestry credits and nor will the EU's scheme, which will begin trading in 2005.

Also, the exclusion of credits for reducing tropical deforestation under the Protocol could create false incentives that actually cause ecological and environmental harm, leading to the degradation and clearing of rainforest for acceptable reforestation programmes.

The risk also exists that discrepancies between stricter forestry rules in industrialised and developing countries could lead to a displacement in CO2-emitting industries such as tree-felling and saw-milling from the former to the latter; and that stricter monitoring requirements for projects in developing countries could penalise them, and raise projects costs, thereby discouraging inward investment from developed countries.

Impacts on the carbon industry and policies

Policy uncertainties have had an impact on the fledgling carbon industry. FutureForests, a carbon management and forestry projects company that invests in both carbon sinks and clean technologies for its clients, has seen its business "treble year-on-year in the last three to four years", according to CEO Jonathan Shopley. However, he admits that the company's growth has been tempered "by the uncertainties over Kyoto and carbon sinks".

Eric Bettelheim, board director of carbon management company Sustainable Forestry Management, argues that the development of the carbon marketplace will be the best mechanism for dealing with the uncertainties surrounding carbon sinks. "The market wants to protect its commodities and is able to test systems much more rapidly than regulation," he says. "This commodity - carbon sink mitigation - is no different."

Assessing its worth

Despite the conflicts of opinion and lack of comprehensive, solid data on potential performance, carbon sinks do have advantages over some of the new mitigation technologies entering the marketplace. The most striking of these is cost - well-designed forestry projects could reduce emissions at a significantly lower cost than other techniques.

According to Bettelheim, reforestation could yield as much as £60-120ha/year in rents, based on an assumed carbon credit rate of £12.50/t. "There is no alternative technology that could be as profitable as that," says Bettelheim, adding that growing complimentary crops among the forestry could further increase revenues.

The controversy continues

The argument against carbon sinks remains controversial due to the range of unknowns, but the same is largely true for other fledgling carbon-neutral technologies. And while the business world may play some part in advancing the role of carbon sinks by developing more concrete pricing signals, it is also true that they are largely dependent on policy-makers to create them.

As long as developed nations such as the EU fail to fully embrace the potential of carbon sinks, they could be hampering the fight against global change.

For Swingland and the authors of Capturing Carbon & Conserving Biodiversity, the potential benefits to the rural poor, indigenous people, habitat preservation, biodiversity, watershed protection and the climate as a whole from such carbon sink projects "makes it hard to understand why some environmentalists and policy makers have chosen to do their utmost to prevent their implementation," as Swingland says. Kyoto policy-makers are expected to hammer out final rules on sinks this November. Meanwhile, the controversy continues.



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