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- ItemOverview: The Baltic Earth Assessment Reports (BEAR)(Göttingen : Copernicus Publ., 2023) Meier, H. E. Markus; Reckermann, Marcus; Langner, Joakim; Smith, Ben; Didenkulova, IraBaltic Earth is an independent research network of scientists from all Baltic Sea countries that promotes regional Earth system research. Within the framework of this network, the Baltic Earth Assessment Reports (BEARs) were produced in the period 2019-2022. These are a collection of 10 review articles summarising current knowledge on the environmental and climatic state of the Earth system in the Baltic Sea region and its changes in the past (palaeoclimate), present (historical period with instrumental observations) and prospective future (until 2100) caused by natural variability, climate change and other human activities. The division of topics among articles follows the grand challenges and selected themes of the Baltic Earth Science Plan, such as the regional water, biogeochemical and carbon cycles; extremes and natural hazards; sea-level dynamics and coastal erosion; marine ecosystems; coupled Earth system models; scenario simulations for the regional atmosphere and the Baltic Sea; and climate change and impacts of human use. Each review article contains an introduction, the current state of knowledge, knowledge gaps, conclusions and key messages; the latter are the bases on which recommendations for future research are made. Based on the BEARs, Baltic Earth has published an information leaflet on climate change in the Baltic Sea as part of its outreach work, which has been published in two languages so far, and organised conferences and workshops for stakeholders, in collaboration with the Baltic Marine Environment Protection Commission (Helsinki Commission, HELCOM).
- ItemGeoengineering climate by stratospheric sulfur injections: Earth system vulnerability to technological failure(Dordrecht [u.a.] : Springer, 2009) Brovkin, V.; Petoukhov, V.; Claussen, M.; Bauer, E.; Archer, D.; Jaeger, C.We use a coupled climate-carbon cycle model of intermediate complexity to investigate scenarios of stratospheric sulfur injections as a measure to compensate for CO2-induced global warming. The baseline scenario includes the burning of 5,000 GtC of fossil fuels. A full compensation of CO2-induced warming requires a load of about 13 MtS in the stratosphere at the peak of atmospheric CO2 concentration. Keeping global warming below 2°C reduces this load to 9 MtS. Compensation of CO 2 forcing by stratospheric aerosols leads to a global reduction in precipitation, warmer winters in the high northern latitudes and cooler summers over northern hemisphere landmasses. The average surface ocean pH decreases by 0.7, reducing the calcifying ability of marine organisms. Because of the millennial persistence of the fossil fuel CO2 in the atmosphere, high levels of stratospheric aerosol loading would have to continue for thousands of years until CO2 was removed from the atmosphere. A termination of stratospheric aerosol loading results in abrupt global warming of up to 5°C within several decades, a vulnerability of the Earth system to technological failure. © 2008 The Author(s).
- ItemPoor correlation between large-scale environmental flow violations and freshwater biodiversity: implications for water resource management and the freshwater planetary boundary(Munich : EGU, 2022) Mohan, Chinchu; Gleeson, Tom; Famiglietti, James S.; Virkki, Vili; Kummu, Matti; Porkka, Miina; Wang-Erlandsson, Lan; Huggins, Xander; Gerten, Dieter; Jähnig, Sonja C.The freshwater ecosystems around the world are degrading, such that maintaining environmental flow Environmental flow (EF): "The quantity, timing, and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods and well-being that depend on these ecosystems."- Arthington et al. (2018). (EF) in river networks is critical to their preservation. The relationship between streamflow alterations (subsequent EF violationsEF violations are deviations in streamflow beyond the upper and lower boundaries of environmental flow envelopes (EFEs). The EFEs establish an envelope for acceptable EF deviations based on pre-industrial (1801-1860) stream discharge (see Sect. 2.2 for more details)) and the freshwater biodiversity response is well established at the scale of stream reaches or small basins (g 1/4<100g km2). However, it is unclear if this relationship is robust at larger scales, even though there are large-scale initiatives to legalize the EF requirement. Moreover, EFs have been used in assessing a planetary boundaryPlanetary boundary: planetary boundary defines biogeophysical planetary-scale boundaries for Earth system processes that, if violated, can irretrievably impair the Holocene-like stability of the Earth system. for freshwater. Therefore, this study intends to conduct an exploratory evaluation of the relationship between EF violation and freshwater biodiversity at globally aggregated scales and for freshwater ecoregions. Four EF violation indices (severity, frequency, probability of shifting to a violated state, and probability of staying violated) and seven independent freshwater biodiversity indicators (calculated from observed biota data) were used for correlation analysis. No statistically significant negative relationship between EF violation and freshwater biodiversity was found at global or ecoregion scales. These findings imply the need for a holistic bio-geo-hydro-physical approach in determining the environmental flows. While our results thus suggest that streamflow and EF may not be the only determinant of freshwater biodiversity at large scales, they do not preclude the existence of relationships at smaller scales or with more holistic EF methods (e.g., including water temperature, water quality, intermittency, connectivity, etc.) or with other biodiversity data or metrics.