Our understanding of the climate benefits of forests is often limited to the large amounts of CO₂ absorbed by growing trees. But forests also provide a lesser-known climate benefit – the substitution effect.
As forests are regenerated, we use every part of a tree to make products that can essentially replace more emission-intensive products. This is nothing new, but more and more researchers have recently become interested in how this effect can be measured.
Biogenic carbon is part of a natural carbon cycle in which emissions are constantly reabsorbed by growing trees and other vegetation, while the use of fossil carbon means that there is a net release into the atmosphere.
Substitution therefore creates a climate benefit when products based on renewable raw materials from the forest drive back products that are more emission-intensive, such as steel, concrete, plastic and fossil fuels.
The substitution factor varies for each type of material. What we measure is the amount of fossil carbon that is replaced per unit of biogenic carbon in forest products.
Sawn timber for construction has the highest substitution factor. But replacing plastic food packaging with bio-based trays or using biofuels instead of fossil fuels such as natural gas or oil, also have positive effects.
The climate-change impact of substitution can be measured in several ways. To be on the safe side, we have measured low in a model developed by Holmgren/Kolar (SCA February 2019). The method was reviewed by external researchers at a seminar hosted by the Royal Swedish Academy of Agriculture and Forestry (KSLA) in February 2019. Södra’s report has also been reviewed by researchers at Linnaeus University in Sweden.
Despite the cautious nature of our measurements, the effect of the substitution enabled by Södra is unmistakably high.
There is also a negative climate-change impact in Södra’s value chain. Since our mills are almost completely fossil-free, these emissions are mainly derived from the production of input products such as process chemicals and packaging materials, and from the transportation of raw materials to mills, and of products to customers.
We know, therefore, that the trees growing in our members’ forests have a positive climate-change impact, that our products are driving back those with a negative climate-change impact, and that we ourselves are responsible for some of the emissions from our operations. The sum of these three parameters provides a measure of Södra’s impact on global climate change. On an annual basis (2018), the total climate-change impact was positive and corresponded to 9.2 million tonnes of CO₂ equivalents.
We would prefer not to use the word ‘compensation,’ since this is a figurative expression that could result in forests having to bear the fossil emissions of other sectors. At the same time, the proportions are important and for the sake of comparison, Södra’s positive climate-change impact is equal to 20 percent of Sweden’s reported emissions. The greatest effect of substitution does not arise in Sweden, however, since Södra – and the rest of the Swedish forest industry – exports most of its products.
Climate emissions in Sweden equate to approximately 53 million tonnes of CO₂ per year, while the positive climate-change impact of Swedish forestry is 93 million tonnes of CO₂ equivalents.
Although substitution is not included in formal emissions reporting or climate agreements, it has long been recognised as a limiting factor in climate change.
Södra’s report (Holmgren 2019) uses substitution factors compiled from existing research findings. We believe that these measurements of climate-change impact can provide support for the ongoing strategic choices we are making to meet our climate targets. It also confirms that we are moving in the right direction – that we are striving for a longer life for our products and achieving a higher rate of substitution. We are achieving this by investing in liquid biofuels and timber building systems and by recycling textiles in our pulp production.
The report shows clearly that the forest industry has a key role to play in the response to climate change and gives us strong incentives to continue focusing on innovation, resource-efficiency and independence from fossil fuels throughout our entire value chain.
At the same time, we need more understanding and knowledge about why substitution is so important. The report is a first step in that direction.
In 2018, the forests owned by Södra’s members constituted a carbon sink equivalent to 2.1 million tonnes of CO₂ equivalents. That is the net carbon storage from forest growth of 13.1 million m³ (solid volume under bark, sub) and a harvesting volume of 11.9 million m³ (sub).
In 2018, Södra’s fossil CO₂ emissions amounted to 0.6 million tonnes of CO₂ equivalents, mainly from the production of input products and from the transportation of raw materials to industry and products to customers.
In 2018, Södra’s reduction of fossil emissions due to substitution amounted to 7.7 million tonnes of CO₂ equivalents.
In 2018, Södra’s positive climate-change impact was 9.2 million tonnes of CO₂ equivalents.