New paper finds decline in Eastern European carbon sink due to land use change
Researchers recalculate carbon stores in Eastern Europe using models, satellite data and statistics.
Carbon sinks on the land surface can mitigate the greenhouse effect. Scientists at the Karlsruhe Institute of Technology (KIT) and other research institutions have brought together various data sources and determined that the majority of Europe's total carbon storage is through above-ground biomass in Eastern Europe. However, mainly due to changes in land use, this carbon sink has declined. The researchers report in Communications Earth & Environment. (DOI: https://doi.org/10.1038/s43247-023-00893-4)
Forests can sequester large amounts of carbon on the land surface and thus contribute decisively to the reduction of net greenhouse gas emissions. For some areas, however, there is a lack of comprehensive inventories. Especially in Eastern Europe, there is only a thin network of measuring stations, so that little is known about the carbon fluxes there and their drivers. "Yet Eastern European forests in particular hold great potential as a long-term carbon sink," says Karina Winkler of the Institute for Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), KIT's Alpine Campus in Garmisch-Partenkirchen. "Eastern Europe, however, is characterised by major land use changes as a result of political upheavals. In addition, climate change is increasingly affecting forests there. Therefore, socio-economic and climatic factors interact in a unique way on carbon reservoirs."
Area studied spans 13 countries
Researchers from the Land Use Change & Climate group at IMK-IFU, together with scientists from other European research institutions, have now recalculated the carbon stocks in Eastern Europe. The area studied extends over 13 countries - from Poland in the west to the Russian Ural Mountains in the east, from Estonia in the north to Romania in the south. The researchers combined various data sources for the calculation: Models, satellite-based biomass estimates as well as forest inventories and national statistics.
"From the data sets, we deduced that Eastern Europe is responsible for the majority of the total European carbon storage from 2010 to 2019," Winkler reports. The comparison of the carbon balance showed that the land surface of Eastern Europe bands around 410 million tonnes of carbon in biomass per year. This corresponds to about 78 percent of the carbon sink of all of Europe. The largest carbon reservoirs are found primarily in the border region between Ukraine, Belarus and Russia, in the southern Ural Mountains and on the Kola Peninsula.
Timber extraction has the greatest influence on the carbon sink in Eastern Europe
But the data also show that carbon uptake in Eastern Europe has not been constant at all over time, but has been declining: the Eastern European carbon sink is getting smaller. To determine the reasons for this, the researchers compared the trends in carbon changes with land use factors, i.e. land conversion for agriculture, timber extraction and the proportion of abandoned agricultural land, and with environmental factors, namely temperature, precipitation, soil moisture and carbon dioxide (CO2) and nitrogen concentrations in the atmosphere.
The study found that environmental factors, such as changes in soil moisture, have a significant impact on the overall carbon budget, but that the spatial patterns of the carbon sink in Eastern Europe can be explained mainly by land-use changes. According to the study, timber extraction had the greatest impact on the land-based carbon sink in Eastern Europe from 2010 to 2019. The data analysis indicates that it was mainly an increase in timber extraction in western Russia and a reduction in forest cover on former agricultural land that caused the carbon sink in Eastern Europe to decline between 2010 and 2019.
According to the researchers, it is now necessary to predict how Eastern European forests and their important carbon reservoirs will develop in the future under the influence of land use changes and climate change. However, the increasing number of extreme weather events and reduced water availability already give rise to fears that the Eastern European carbon sink will continue to shrink in the future.
From the KIT press release, to read in German: https://www.kit.edu/kit/pi_2023_056_pi_klimaschutz-kohlenstoffsenke-schrumpft-durch-landnutzungsanderungen.php
Original publication (Open Access):
Karina Winkler, Hui Yang, Raphael Ganzenmüller, Richard Fuchs, Guido Ceccherini, Grégory Duveiller, Giacomo Grassi, Julia Pongratz, Ana Bastos, Anatoly Shvidenko, Arnan Araza, Martin Herold, Jean-Pierre Wigneron & Philippe Ciais: Changes in land use and management led to a decline in Eastern Europe's terrestrial carbon sink. Communications Earth & Environment, 2023. DOI: 10.1038/s43247-023-00893-4