Coasts as „climate protectors”
Joint press release of Hereon, ZMT and GEOMAR
A new study involving three German research centers shows: coastal wetlands and estuaries are collectively a net greenhouse gas sink
Coastal ecosystems in eight out of ten world regions are net greenhouse gas sinks, because the uptake of carbon dioxide CO2 is greater than the release of methane and nitrous oxide (laughing gas). This is the conclusion of a study led by Australia’s Southern Cross University with the participation of the Helmholtz-Zentrum Hereon, the Leibniz-Center for Tropical Marine Research (ZMT) and the GEOMAR Helmholtz-Center for Ocean Research Kiel. The study was recently published in Nature Climate Change.
“Understanding how and where greenhouse gases are released and absorbed in coastal ecosystems is an important first step in implementing effective climate change mitigation strategies,” said first author and study leader Dr Judith Rosentreter, senior research fellow at Southern Cross University in Australia. Protecting and restoring mangrove and salt marsh habitats, for example, is a promising strategy to increase the uptake of CO2 by these coastal wetlands, she said.
For this study, the international team of scientists evaluated measurements from coastal regions from every continent except the polar regions. “This study is part of the RECCAP2 project, which was is only possible with such a large and diverse collaboration,” says Hereon coastal researcher Dr Bryce Van Dam, working in the Institute of Carbon Cycles. RECCAP2 (Regional Carbon Cycle Assessment and Processes, Phase 2) is coordinated by the Global Carbon Project and collects and compiles regional greenhouse gas data for 14 major regions of the world. (Source: Joint Press Release of Hereon, ZMT and GEOMAR)
Read the complete joint press release:
==> Coasts as „climate protectors”
==> Website RECCAP2
Rosentreter, J.A., Laruelle, G.G., Bange, H.W., Bianchi, T.S., Busecke, J.J.M., Cai, W.-J., Eyre, B.D., Forbrich, I., Kwon, E.Y., Maavara, T., Moosdorf, N., Najjar, R.G., Sarma, V.V.S.S., Van Dam, B., & Regnie, P. (2023): Coastal vegetation and estuaries are collectively a greenhouse gas sink. Nat. Clim. Chang., doi:10.1038/s41558-023-01682-9
Abstract:
Coastal ecosystems release or absorb carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the net effects of these ecosystems on the radiative balance remain unknown. We compiled a dataset of observations from 738 sites from studies published between 1975 and 2020 to quantify CO2, CH4 and N2O fluxes in estuaries and coastal vegetation in ten global regions. We show that the CO2-equivalent (CO2e) uptake by coastal vegetation is decreased by 23–27% due to estuarine CO2e outgassing, resulting in a global median net sink of 391 or 444 TgCO2e yr−1 using the 20- or 100-year global warming potentials, respectively. Globally, total coastal CH4 and N2O emissions decrease the coastal CO2 sink by 9–20%. Southeast Asia, North America and Africa are critical regional hotspots of GHG sinks. Understanding these hotspots can guide our efforts to strengthen coastal CO2 uptake while effectively reducing CH4 and N2O emissions.
