Forests absorb greenhouse gases effectively

In 2014, Finnish forests absorbed a total of 27.7 million tonnes of greenhouse gases, thus playing a key role as sinks for these atmosphere-warming emissions.

The amount of greenhouse gases captured in trees, undergrowth and soil in forests exceeds emissions from energy consumed in Finland by more than half. Intense tree growth, which is most influenced by the volume of fellings, is the major reason for this.

Forests will continue to be efficient sinks in the future

According to model calculations made by the Natural Resources Institute Finland, forests will remain efficient sinks in the future even if – due to the uncertainties involved – no account is taken of the positive impact of climate change on tree growth. In scenarios where, to satisfy the near future growing needs of the bioeconomy, the annual volume of felling increases by less than 10 million cubic meters, the sink effect initially decreases a little until 2030. Thereafter, it is restored for the next 10 years.

Only in the scenario involving maximum felling volumes at around 20 million cubic metres above the present level – without compromising on future felling opportunities – did the greenhouse gas balance of forests vary between a minor sink effect and net emissions. Felling volumes could therefore increase by around 20 million cubic metres before forests become a source of emissions.

Forest © Erkki Oksanen / Luke

The amount of greenhouse gases captured in trees, undergrowth and soil in forests exceeds emissions from energy consumed in Finland by more than half.

Climate agreement will account forest carbon sinks

In international climate agreements, Finland is committed to an annual forest sink of 20.5 million tonnes until 2020. If we fail to meet this so-called reference level, the result will be an emission burden that must be offset. Further climate agreement negotiations will address the reference level of forest sinks, among other issues. Should this rise,  scenario calculations show that even a minor increase in felling volumes may result in an emission burden.

Climate agreements curb greenhouse gas emissions

The purpose of climate agreements is to curb the increase of atmospheric GHG concentrations, thereby slowing down climate change. However, the greenhouse gas sink effect of forests does not directly reveal how the use of forest biomass influences the atmosphere. We must also take account of what is achieved with the used biomass.

Fossil fuels can be replaced by using more wood, thereby avoiding emissions. On the other hand, the increase in wood harvesting will reduce forests’ greenhouse gas sink effect for at least the next few decades.

Scenario calculations indicate that, by mid-century, an increase in the use of wood would reduce the sink effect by more than the resulting emission reductions due to activities such as the replacement of fossil fuels and concrete structures. However, to achieve its climate targets,  Finland is committed to dramatically reducing its greenhouse gas emissions over the same period.

Greenhouse gas emission reductions achievable through the use of wood depend very much on the way in which it is used. From the climate perspective, it is therefore important that the increasing use of wood is targeted, insofar as possible, at activities that reduce emissions. These include the initial use of wood as building material, for example, before being used for energy at the end of the life cycle.

Further information

Olli Salminen, Senior Research Scientist, tel. +358 295 325 346, .illo sa iml nenΑT.l .eku fi 

Risto Sievänen, Principal Research Scientist, tel. +358 29 532 5487, otsir .siev ena nΑT.luke f. i 

Published: 12.9.2016
Categories: Research

Original press release