Eine neue Bedrohung der stratosphärischen Ozonschicht durch anthropogene kurzlebige Halogenverbindungen
Zusammenfassung der Projektergebnisse
We have investigated the impact of anthropogenic activities on oceanic halocarbon emissions and the atmospheric bromine budget. In a first step, we have focused on the oxidative water treatment of ship ballast water. We show that, despite VSLS concentrations in chemically treated ballast water being up to a million times higher than in the natural environment, this pathway provides only a small contribution (<1%) to global emissions. This result is highly relevant for the shipping and cruise ship industry, as it provides information on the side-effects of chemical treatment systems. In a second step, we have investigated anthropogenic bromine from industrial cooling water, which we show to be a more important source of anthropogenic VSLS than expected, with industry in South-East Asia doubling the current natural VSLS emissions in this region. Future emissions of halocarbon from industrial water treatment are expected to increase by 1-2% per year. These results provide important input for the international Assessment of Disinfection By-Products in the Marine Environment from the German Federal Institute for Risk Assessment. In addition to industrial sources, we have quantified halocarbon production from natural and farmed macroalgae in East-Southeast Asia and demonstrated the growing impact of farmed macroalgae on atmospheric halogen budgets. Given that large‐scale industrial production of marine macroalgae is currently being discussed as a future opportunity to mitigate and adapt to climate change, thorough risk assessments of the side effects of such farms are needed. This project together with a follow-on study provides the basic approach for such assessments, where based on the species, agricultural practices and location of the farms a bottom up inventory of the expected halocarbon emissions can be derived. We have identified worst-case scenarios where future tropical open ocean macroalgae farming of Gracilaria sp., can lead to halocarbon emissions that would have similar effect on the ozone layer as the 1980s CFC-11/CFC12 emissions. In summary, we have derived the first systematic bottom-up estimates of anthropogenic CHBr3 emissions from various sources. Incorporating the anthropogenic CHBr3 distribution into the climatological bottom-up emission estimate from Ziska et al. (2013) leads to a global increase of the emissions of 10–38%. The anthropogenic bromine flux results mainly from CHBr3 produced during cooling water treatment while current macroalgae farming and desalination plants as well as future ballast water treatment play only a minor role. Our estimates show large uncertainty ranges driven by the variability of CHBr3 production during chemical water treatment processes and biological production. Anthropogenic CHBr3 sources are often found in the subtropics and midlatitudes thus being disconnected from the transport pathways into the stratosphere. In consequence their contribution to the stratospheric bromine budget (0.07–0.28 ppt Br) is rather small compared to the total contribution from all VSLSs (3–7 ppt Br). Our research has been of great public interest and was featured several times in the media and public presentations. The overall importance of halogenated VSLS from industrial sources as a progressive research topic has been evidenced by many recent publications including my invited Nature News & Views article and our invited Nature review paper.
Projektbezogene Publikationen (Auswahl)
- Anthropogenic chlorine under watch, Nature Geoscience, 12, 84–86, 2018
Tegtmeier, S.
(Siehe online unter https://doi.org/10.1038/s41561-018-0282-6) - How marine emissions of bromoform impact the remote atmosphere, Atmos. Chem. Phys., 19, 11089–11103, 2019
Jia, Y., Tegtmeier, S., Atlas, E., and Quack, B.
(Siehe online unter https://doi.org/10.5194/acp-19-11089-2019) - Simulating the spread of disinfection by-products and anthropogenic bromoform emissions from ballast water discharge in Southeast Asia, Ocean Sci., 15, 891–904, 2019
Maas, J., Tegtmeier, S., Quack, B., Biastoch, A., Durgadoo, J. V., Rühs, S., Gollasch, S., and David, M.
(Siehe online unter https://doi.org/10.5194/os-15-891-2019) - Anthropogenic bromoform from industrial water treatment
Maas, J.
- Natural and anthropogenic sources of bromoform and dibromomethane in the oceanographic and biogeochemical regime of the subtropical North East Atlantic, Environ. Sci.: Processes Impacts, 2020
Mehlmann, M., Quack, B., Atlas, E., Hepach, H., and Tegtmeier, S.
(Siehe online unter https://doi.org/10.1039/c9em00599d) - Renewed and emerging concerns over the production and emission of ozone-depleting substances. Nature Reviews Earth and Environment, 2020
Chipperfield, M.P., Hossaini, R., Montzka, S.A., Reimann, S., Sherry, D. and Tegtmeier, S.
(Siehe online unter https://doi.org/10.1038/s43017-020-0048-8) - Simulations of anthropogenic bromoform indicate high emissions at the coast of East Asia, Atmos. Chem. Phys. Discuss., 2020
Maas, J., Jia, Y., Quack, B., Durgadoo, J. V., Biastoch, A., and Tegtmeier, S.
(Siehe online unter https://doi.org/10.5194/acp-2019-1004) - Temperature and tropopause characteristics from reanalyses data in the tropical tropopause layer, Atmos. Chem. Phys., 20, 753–770, 2020
Tegtmeier, S., Anstey, J., Davis, S., Dragani, R., Harada, Y., Ivanciu, I., Pilch Kedzierski, R., Krüger, K., Legras, B., Long, C., Wang, J. S., Wargan, K., and Wright, J. S.
(Siehe online unter https://doi.org/10.5194/acp-20-753-2020) - Variability and past long-term changes of brominated very short-lived substances at the tropical tropopause, Atmos. Chem. Phys., 20, 7103–7123, 2020
Tegtmeier, S., Atlas, E., Quack, B., Ziska, F., and Krüger, K.
(Siehe online unter https://doi.org/10.5194/acp-20-7103-2020)
