‘Carbon debt’ refers to the situation where an increase in biomass production especially for bioenergy can lead to very high emissions. These emissions are essentially linked to the adverse effects of gathering biomass on carbon stocks in terrestrial vegetation and soil. They are considered a ‘debt’ that needs to be paid back by replacing fossil fuel consumption with bio-based products.
In a newly released report by PBL, entitled ‘On the Science of Carbon Debt’ , a group of scientists including Göran Berndes (@goran.berndes) from the Chalmers University of Technology, a partner of the UPTAKE Project has investigated ‘carbon debt’ and provided some recommendations to the Dutch government. The report does not lend credence to the claims that biomass obtained from the so-called ‘well-managed’ forests is either a totally ‘clean’ or a totally ‘dirty’ energy source. To illustrate this point, examples have been included in the report which demonstrate how obtaining and utilizing biomass from forests can lead to considerably elevated emissions (a ‘carbon debt’), low levels of net emissions (‘carbon neutrality’) or high amounts of carbon removal that exceed the emissions (‘carbon gain’). In this regard, various outcomes can emerge depending on the decisions that are made by those that manage forests for providing biomass and the manner in which biomass is put into use.
Projections that have been made by scientists with respect to the CO2 emissions that are released through the use of bioenergy resources vary considerably. Therefore, divergent views have been expressed regarding the impacts of technical studies in relation to the utilization of biomass to generate energy or manufacture products.
These studies reach to different conclusions since they:
- consider different kind of forests and activities carried out to manage forests
- presume diverse end uses and processing steps for the biomass
- implement methodologies to do calculations that differ from one another and are sometimes improper
- tackle with different research topics that are sometimes not clearly mentioned
The report cautions against reaching to general conclusions based on the results of different studies or by interpreting forest carbon balances without considering the complications that may arise. In addition, a chapter of the report studies how its conclusions impact policies that pertain to the provision of biomass from forests with a particular focus on its use as bioenergy. A provisional roadmap is presented that lays down the methods that can enable biomass to be used effectively for energy production and other purposes so as to eliminate C02 emissions or reduce their amount.
The report is available on the page below: