In principle, the international community is in agreement: the concentration of greenhouse gases in the Earth's atmosphere must be stabilised over the coming decades to acceptable levels. Opinions are divided, however, as to how this is to be achieved. For example, an ongoing controversy in the climate debate concerns the importance to be assigned to biological sinks in the solution of the problem. Under certain conditions terrestrial ecological systems can absorb more carbon – therefore also more anthropogenic CO2 emissions – from the atmosphere than they release into it. The Kyoto Agreement, which, in a modest step, reflects first efforts to reduce man-made greenhouse gas emissions, allows signatory states to use the effect produced by these sinks as a discount to set against their reduction obligations. At a specialist meeting (1) at the end of June around a hundred scientists met at ETH Zurich to discuss the importance of biological sinks for Switzerland and whether and to what extent they should be taken into account in domestic climate policy.

Important contribution to the cycle

For Andreas Fischlin from the ETH Institute of Terrestrial Ecology (ITÖ) (2) it's clear that the sinks are certainly not a panacea when it comes to reaching the aimed-for climate goals. Nevertheless, the part played by terrestrial ecological systems has to be taken into account in any successful climate protection measures because the exchange that takes place between these systems and the atmosphere accounts for a considerable part of the global carbon cycle. In addition, this would also discourage countries from overexploiting their forests in order to substitute fossile fuels.

The concrete implementation of this point under the terms of the Kyoto Agreement is a delicate matter. In principle, countries are only allowed to discount the effect of sinks in managed forests. But what, exactly, does "managed" mean in this context? Does it include high meadowland in alpine regions, which, for economic reasons, are no longer used for grazing and which undoubtedly raises carbon absorption? Or, conversely, fighting forest fires, which prevents CO2 emissions? And what happens when, after a heavy storm, a forest sink suddenly becomes a source of emission, because the trees felled by the storm start to rot and stored carbon is released into the atmosphere?

What is a forest?

Under today's condition Switzerland's forests are also part of the biological sink. In keeping with the Kyoto Agreement Switzerland could take the sink effect into account, which represents around three per cent of total CO2 emissions. Should the country decide to use this option it would mean that – in the first phase from 2008 to 2012 – it would only have to reduce its CO2 emissions by five instead of eight per cent measured against the year of reference, i.e. 1990.

In view of the current difficulties to meet the already chosen reduction goals politicians – above all those from the right – are calling for use to be made of this option. Beforehand, however, diverse legal questions have to be cleared up, as Erwin Hepperle from ITÖ explains. The Cantons currently have autonomous discretionary room to decide on the definition of a forest. The discounting mechanism allowed for in the Kyoto Agreement, however, means that there would have to be a common definition of what constitutes a forest. The autonomy of the Cantons in this area would have to be curtailed. Furthermore, there is the danger of unwanted side effects. The qualitative definition of forest in today's laws is not fully compatible with the quantifiable definition in the Kyoto Agreement. Small, ecologically valuable areas of forest could lose their legally protected status because they would no longer be classed as forest.

The Berneren forest near Unterägeri two years after hurricane "Lothar". In the years following the hurricane Switzerland's forests clearly absorbed less carbon than in the years preceding the storm. (Picture: Thomas Hess, Corporation Unterägeri) large

Counterproductive exploitation

If one wanted to base Switzerland's future forestry policy solely on a maximum absorption of CO2 then the best policy would be to leave the forest alone. This is the conclusion reached by Edgar Kaufmann from the Federal Institute for Forest, Snow and Landscape Research (WSL) based on simulation models. A strong exploitation and regeneration of the over-aged forests, as foreseen in the government's current forestry policy, tends to be counterproductive from the point of view of climate protection because it leads to a far less favourable carbon balance of the forest.

Nevertheless, Peter Hofer from the company "GEO Partner" doubts whether increased exploitation of the forest would really be so unfavourable where climate policy is concerned. If more wood is used, for example, in building houses the carbon stored in the wood does not immediately leak into the atmosphere. But the Kyoto Agreement does not allow the use of wood in construction to count towards reductions of emissions. International talks to change this are underway but it is unlikely that a result will emerge within the next eight or ten years.

Compensation for forest owners

During the concluding podium discussion at the meeting it became clear that there are still a number of open questions surrounding biological sinks. Peter Hofer, for example, appeals for an integral approach to wood and forest exploitation. He considers a one-sided concentration on the effects of sinks not appropriate, especially as biological sinks are saturated within a few decades. Christian Küchli, head of the team Forest and Social Change at the Federal Forest Ministry, also calls for a forest policy approach that takes conflicting interests and demands into account.

Felix Lüscher, representative of the Oberallmeind Corporation in Canton Schwyz, the biggest owner of forest in Switzerland, on the other hand, is strongly of the opinion that sinks should be used as a discount in Switzerland's CO2 accounts and that forest owners should receive compensation. Today's rate of 10 francs per ton for the CO2 compensation of sinks, while not exactly high, could rise sharply in coming years, said Lüscher, which would mean that a climate friendly tending of the forest would be well worthwhile.