Table of Contents
CO 2 sequestration by forests and bogs in the Alps
The vast amounts of fossil fuels being burned around the globe mean that carbon dioxide (CO2) is one of the most powerful drivers of global climate change. As no major reductions in CO2 pollution are occurring at a global scale, the capacity of natural environments to sequester CO2 is becoming more and more vital. Thus, any large-scale CO2 sinks have a positive regulating effect not just locally, but globally as well. In the Alpine Space, the ecosystems with the largest sequestration capacity are forests and bogs. Every year, these ecosystems sequester CO2 by storing it in biomass that is created as plants and trees grow. This yearly growth is known as “biomass increment” and is calculated using Intergovernmental Panel on Climate Change equations. These equations allow for the prediction of above- and below-ground changes in the amount of biomass, expressed in tonnes of carbon per year. The supply and flow indicators for sequestration are mapped together, because the supply is equal to the flow in this case;
all the carbon that these environments can sequester every year is in fact being sequestered. The demand indicator is calculated by assessing how much CO2 each alpine municipality is emitting. Understanding the alpine contribution to CO2 emission and sequestration is an important facet in coordinated action at local, regional, and global scales in the effort to mitigate global climate change. In this indicator set, only CO2 sequestration from forests was modelled. This is due to the lack of suitable knowledge about carbon cycling processes in bogs.
Flow/Supply
View this map in the AlpES webGIS
This indicator measures the amount of CO2 sequestered by Alpine forests, the effects of which are not only of benefit to the Alpine population, but represent the contribution of the Alpine area to global climate protection. As the amount of ES delivered and the de facto utilized amount are equal, ES flow and supply are represented in the same map. The map shows that the highest values of CO2 sequestration occur in Slovenia, Germany, and northern France and Switzerland. In these areas, the increase in biomass carbon stock due to biomass increment is the highest, thanks to the optimal altitudinal and climatic conditions and the extended woodland areas. Carbon is absorbed by growing trees and is only released back to the environment through decomposition and burning. Thus, forests act as one of the most effective and sizeable carbon sinks. Indeed, recent studies have shown that the world’s forests have absorbed as much as 30% of annual global anthropogenic CO2 emissions in the past few decades (Bellassen& Luyssaert, 2014). Peters et al. (2012) reported an increase in CO2 sequestration levels by forests and other types of vegetation per hectare of land in the past 50 years (Fig. 3.8), despite a decrease of 2% in forestcover globally since 1990. These findings reaffirm the importance of sustainable and far-sighted management plans for the world’s forests. The contribution of bogs was not evaluated in this indicator, due to lack of data on their distributionand CO2 sequestration potential. However, recent studies indicate that they play a key role incarbon storage and that their preservation may be one of the most cost-effective climate protectionmeasures (WWF Österreich, 2010).
<font 10px/inherit;;inherit;;inherit>Figure 3.8 Global land CO2 sink compared to anthropogenic emissions. Adapted from Peters et al., 2012.</font>
Demand
View this map in the AlpES webGIS
The demand indicator for CO2 sequestration provides an overview of the rate of CO2 emissions across the Alpine Space. Unsurprisingly, the values are elevated in and around industrialized and urbanized areas, and the biggest cities are particularly apparent in the map (e.g. Milan, Zurich, Lyon, Munich, Vienna, etc.). The valleys of the Adige and the Inn are also evident, as they cut through the Alpine range, which otherwise has low emission rates. The levels of atmospheric CO2 are increasing at an unprecedented rate worldwide. This trend is effectively described in Figure 3.9, in which the increase in CO2 levels in the last 22.000 years is compared to that registered in the last decades. Over the past 70 years, the rate of increase of atmospheric CO2 is nearly 100 times larger than that at the end of the last ice age, accounting for a vertiginous spike in CO2 concentrations. In an attempt to stop this deleterious trend, the international debate on this matter has become more serious, and binding environmental commitments to cut CO2 emissions were taken – most notably the Paris Agreement within the United Nations Framework Convention on Climate Change. Coordinated action at global and regional scales is essential to counteract the effects of these anthropogenic influences on climate. International commitment is needed for the effective preservation of forests and other ecosystems that provide regulation and maintenance services of atmospheric conditions. By comparing the Flow & Supply and the Demand indicators for carbon
sequestration, important local and regional sources and sinks become evident. It is vital that the role certain regions play in carbon sequestration are acknowledged and leveraged in such coordinated action.
<font 10px/inherit;;inherit;;inherit>Figure 3.9 Atmospheric CO2 increase in the last 22.000 years (left) and in the last 50 years (right). The vertical line in the left graph indicates the end of the last ice age, 11,5 thousand years ago. Adapted from World Meteorological Organization, 2017.</font>