Wenn Wälder nicht mehr genutzt würden: Wie viel mehr Kohlenstoff könnte gespeichert werden?

Climate change is increasingly putting strain on ecosystems and societies. International policy frameworks such as the Paris Agreement and the European Green Deal have been put in place to prevent the worst effects. These agreements stress the importance of combining strong reductions in emissions with strategies that remove some of the CO₂ already in the atmosphere. Forests play a large role in this, as they naturally absorb atmospheric CO₂ and store it in their biomass.

A hypothetical stop of forest management

One proposed forest-based strategy is to reduce management – such as logging – in order to increase the amount of carbon that can be stored in forests. This study evaluated how much carbon could be stored in forests under the hypothetical scenario of completely removing forest management. This hypothetical scenario gives us an insight into how much this strategy could, at best, contribute to climate change mitigation. We found that a reduction of forest management can mitigate climate change only to a limited extent. The hypothetical scenario of removing all forest management, and thus stopping any interference with forests, would only compensate 4 years of CO₂ emissions (at the 2019 rate).

An area larger than Germany

Another forest-based climate-change-mitigation strategy put forward is to increase the amount of land covered with forests, by reforesting previously forested areas or afforesting areas that have not (recently) been covered with trees. This strategy is complicated by the strong competition for land presented by agriculture and urban expansion, which is especially prevalent given the projected population increase in the coming decades. If this competition for land were somehow to be overcome, storing enough carbon to mitigate climate change in a meaningful way still requires massive amounts of land. Our study suggests that, to compensate for even a single year of global CO₂ emission, an area larger than Germany, France and Spain together would need to be reforested/afforested and allowed to fully grow.

The scale of compensation

Together, storing carbon in existing forests by forgoing management practices and planting new forests has the potential of sequestering CO₂ from the atmosphere, and compensating for carbon emissions. The scale of these processes is, however, insufficient to really compensate for the current rates of emissions. This carbon sink should instead be used to reach carbon neutrality by compensating for the emissions of sectors which we currently cannot decarbonise (quickly), such as construction and agriculture, when all other remissions have been drastically reduced.