Alfred Wegener Institute for Polar and Marine Research
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The landlocked ocean: landlocked states in BBNJ negotiations and the impact of fixed land-sea relations in global ocean governance
Get PDFThis article examines the multifaceted dimensions of landlockedness within the realm of international discourse, with a particular focus on its implications for managing global commons. Drawing from socio-legal literature and auto-ethnographic experiences during the recent intergovernmental negotiations for the BBNJ agreement under the 1982 Law of the Sea (UNCLOS) as a case study, the paper prompts essential inquiries into the true essence of being landlocked in the face of global environmental challenges. Beyond traditional geographical definitions, the paper reveals the dynamic nature of landlockedness and underscores the intricate interplay of social, economic, cultural, geographical, and political factors in determining who has access to ocean space and resources and who does not. It emphasizes that landlockedness is not a static legal or physical characteristic but an ongoing process shaped by historical and political constructs. Expanding beyond the national level, the article illustrates how individuals, whether coastal or inland, experience isolation from the ocean, influencing their interactions with, perceptions of, and regulatory proposals for the ocean. This approach illuminates existing paradigms in the access, use, and management of space and resources. In conclusion, the article advocates for more inclusive and adaptable approaches in international policy debates. It calls for a departure from rigid classifications, urging for upholding collective action, recognising the intricate connections between geography, politics, law, and the environment
Topography Controls Variability in Circumpolar Permafrost Thaw Pond Expansion
Get PDFOne of the most conspicuous signals of climate change in high-latitude tundra is the expansion of ice wedge thermokarst pools. These small but abundant water features form rapidly in depressions caused by the melting of ice wedges (i.e., meter-scale bodies of ice embedded within the top of the permafrost). Pool expansion impacts subsequent thaw rates through a series of complex positive and negative feedbacks which play out over timescales of decades and may accelerate carbon release from the underlying sediments. Although many local observations of ice wedge thermokarst pool expansion have been documented, analyses at continental to pan-Arctic scales have been rare, hindering efforts to project how strongly this process may impact the global carbon cycle. Here we present one of the most geographically extensive and temporally dense records yet compiled of recent pool expansion, in which changes to pool area from 2008 to 2020 were quantified through satellite-image analysis at 27 survey areas (measuring 10–35 km2 each, or 400 km2 in total) dispersed throughout the circumpolar tundra. The results revealed instances of rapid expansion at 44% ((Formula presented.) 15%) of survey areas. Considered alone, the extent of departures from historical mean air temperatures did not account for between site variation in rates of change to pool area. Pool growth was most clearly associated with upland (i.e., hilly) terrain and elevated silt content at soil depths greater than one meter. These findings suggest that, at short time scales, pedologic and geomorphologic conditions may exert greater control on pool dynamics in the warming Arctic than spatial variability in the rate of air temperature increases
Upland Yedoma taliks are an unpredicted source of atmospheric methane
Get PDFLandscape drying associated with permafrost thaw is expected to enhance microbial methane oxidation in arctic soils. Here we show that ice-rich, Yedoma permafrost deposits, comprising a disproportionately large fraction of pan-arctic soil carbon, present an alternate trajectory. Field and laboratory observations indicate that talik (perennially thawed soils in permafrost) development in unsaturated Yedoma uplands leads to unexpectedly large methane emissions (35–78 mg m−2 d−1 summer, 150–180 mg m−2 d−1 winter). Upland Yedoma talik emissions were nearly three times higher annually than northern-wetland emissions on an areal basis. Approximately 70% emissions occurred in winter, when surface-soil freezing abated methanotrophy, enhancing methane escape from the talik. Remote sensing and numerical modeling indicate the potential for widespread upland talik formation across the pan-arctic Yedoma domain during the 21st and 22nd centuries. Contrary to current climate model predictions, these findings imply a positive and much larger permafrost-methane-climate feedback for upland Yedoma
Revisiting the physical processes controlling the tropical atmospheric circulation changes during the Mid-Piacenzian Warm Period
No full textThe Mid-Piacenzian Warm Period (MPWP; 3.0–3.3 Ma), a warm geological period about three million years ago, has been deemed as a good past analog for understanding the current and future climate change. Based on 12 climate model outputs from Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), we investigate tropical atmospheric circulation (TAC) changes under the warm MPWP and associated underlying mechanisms by diagnosing both atmospheric static stability and diabatic processes. Our findings underscore the advantage of analyzing atmospheric diabatic processes in elucidating seasonal variations of TAC compared to static stability assessments. Specifically, by diagnosing alterations in diabatic processes, we achieve a quantitative understanding and explanation the following TAC changes (incl. Strength and edge) during the MPWP: the weakened (annual, DJF, JJA) Northern Hemisphere and (DJF) Southern Hemisphere Hadley circulation (HC), reduced (annual, DJF) Pacific Walker circulation (PWC) and enhanced (annual, JJA) Southern Hemisphere HC and (JJA) PWC, and westward shifted (annual, DJF, JJA) PWC. We further addressed that the increasing bulk subtropical static stability and/or decreasing vertical shear of subtropical zonal wind - two crucial control factors for changes in subtropical baroclinicity - may promote HC widening, and vice versa. Consequently, our study of spatial diabatic heating and cooling, corresponding to upward and downward motions within the TAC, respectively, provides a new perspective for understanding the processes controlling seasonal TAC changes in response to surface warming
Assessing collaboration, knowledge exchange, and stakeholder agency in coastal governance to enhance climate resilience
Get PDFCoastal governance plays a central role in building the capacities for adaptation and transformation towards climate resilience in coastal social-ecological systems (SES). However, enhancing climate resilience requires effective coordination between organisations involved in coastal governance. Therefore, more information about the role and agency of organisations and the relationships between them is needed. This paper aims to improve the understanding of collaboration, knowledge exchange, and stakeholder agency for enhancing climate resilience in coastal SES, using a case study in Algoa Bay, South Africa. We apply and combine stakeholder analysis and social network analysis, which is currently underrepresented in climate change adaptation research. Results suggest that different top-down and bottom-up processes are needed to improve knowledge exchange and enhance climate resilience in the coastal governance of the Algoa Bay SES. These include improved leadership, effective knowledge transfer, integration of climate information, support for bridging organisations, and inclusivity of marginalised stakeholders. These suggestions may also be more broadly applicable and transferable to similar coastal SES. Ultimately, the results of this study shed light on network structures in coastal governance facing climate change and advance research on combining stakeholder analysis and social network analysis in climate change adaptation and environmental governance research
Interlaboratory Comparison of Branched GDGT Temperature and pH Proxies Using Soils and Lipid Extracts
Get PDFRatios of glycerol dialkyl glycerol tetraethers (GDGT), which are membrane lipids of bacteria
and archaea, are at the base of several paleoenvironmental proxies. They are frequently applied to soils as well
as lake‐ and marine sediments to generate records of past temperature and soil pH. To derive meaningful
environmental information from these reconstructions, high analytical reproducibility is required. Based on
submitted results by 39 laboratories from across the world, which employ a diverse range of analytical and
quantification methods, we explored the reproducibility of brGDGT‐based proxies (MBT′5ME, IR, and
#ringstetra) measured on four soil samples and four soil lipid extracts. Correct identification and integration of 5‐
and 6‐methyl brGDGTs is a prerequisite for the robust calculation of proxy values, but this can be challenging as
indicated by the large inter‐interlaboratory variation. The exclusion of statistical outliers improves the
reproducibility, where the remaining uncertainty translates into a temperature offset from median proxy values
of 0.3–0.9°C and a pH offset of 0.05–0.3. There is no apparent systematic impact of the extraction method and
sample preparation steps on the brGDGT ratios. Although reported GDGT concentrations are generally
consistent within laboratories, they vary greatly between laboratories. This large variability in brGDGT
quantification may relate to variations in ionization efficiency or specific mass spectrometer settings possibly
impacting the response of brGDGTs masses relative to that of the internal standard used. While ratio values of
GDGT are generally comparable, quantities can currently not be compared between laboratories
Characterizing Batagay megaslump topography dynamics and matter fluxes at high spatial resolution using a multidisciplinary approach of permafrost field observations, remote sensing and 3D geological modeling
Get PDFRetrogressive thaw slumps (RTS) are an important landform of rapid permafrost degradation in regions with very high ground ice contents. RTS mobilize significant amounts of sediment, meltwater and organic carbon and impact downstream hydrological systems by directly affecting topography and water quality. The term megaslump has previously been coined for RTS exceeding 20 ha in size. The Batagay megaslump in the Yana highlands of NE Siberia with an area of 87.6 ha (in 2023, including the bowl-shaped part and the erosional outlet) has been identified as the largest megaslump on Earth. We use very high resolution remote sensing from satellite data and drones, geological structure modeling, and field data to assess how much and what material is thawed and mobilized in the Batagay megaslump. The total volume of permafrost thaw and material loss from the Batagay RTS amounts to about 1 million m3 per year. The material is by one third composed of thawed sediments and by two thirds of melted ground ice. About 4000 to 5000 tons of previously permafrost-locked organic carbon is released every year. Organic carbon content has been measured as Total Organic Carbon (TOC) of sediments and as Dissolved Organic Carbon (DOC) of ground ice. From its formation in the 1970s until 2023, the Batagay RTS – due to thermal denudation and headwalls retreat – mobilized a total volume of about 34.7 million m3 of which 23.4 million m3 were melted ground ice and 11.3 million m3 were thawed deposits including a total of about 169,500 t organic carbon. With these rates of sediment and carbon mobilization, the Batagay megaslump is not only a prominent local feature of rapid permafrost thaw, but offers excellent conditions to study rates and mechanisms of rapid permafrost degradations and to calculate the stock and release of, e.g., organic matter
Investigating marine carbon and ecosystem feedbacks with the AWI Earth System Model
Get PDFEarth System Models are routinely used for future projections of the carbon cycle and are by definition simplifications of the real world. The ocean uptake of anthropogenic carbon is to first order a physical-chemical process related to CO2 solubility and ocean circulation. However, changes in biological productivity may affect the ocean carbon cycle and ecosystems in the future under on-going climate change. For example, multiple co-occurring environmental changes act as stressors on the lower trophic levels (phytoplankton, zooplankton) of the ecosystem. To simulate such marine carbon and ecosystem feedbacks, relevant biological processes, so far mostly neglected for the sake of simplicity, need to be considered in the models as well.
Here, we present recent developments of the ocean biogeochemistry model REcoM that is also used in the AWI Earth System Model, specifically on the extended representation of zooplankton and on the response of phytoplankton growth to interactive effects of CO2, temperature and light availability. We further present the AWI-ESM results for CMIP6-type future projections in concentration- and emission-driven mode, where we touch upon the variability of air-sea CO2 fluxes in the historical period. Here, we identify atmospheric CO2 growth rate variability as the dominant driver, and highlight important model deficiencies in mixed layer depth trends. Finally, we showcase application examples identifying a weakening of the biological carbon pump in the future Arctic Ocean and on ocean-based negative emission simulations (alkalinity enhancement) with the emission-driven AWI-ESM
Investigating pelagic biodiversity and gelatinous zooplankton communities in the rapidly changing European Arctic: An eDNA metabarcoding survey
Get PDFFram Strait, the gateway between the Arctic and Atlantic Oceans, is undergoing major climate change-induced physical and biological transformations. In particular, rapid warming and ongoing “Atlantification” are driving species range shifts and altering food web structures in the Arctic. Understanding and predicting the consequences of these processes on future ecosystems requires detailed assessments of local and pelagic biodiversity. Gelatinous zooplankton (GZP) is an important component of pelagic communities, and recent evidence indicates that such communities are undergoing major changes in the Fram Strait. However, as sampling GZP is challenging, they are regularly underestimated in biodiversity, distribution, and abundance. To overcome this and address existing ecological knowledge gaps, we investigated patterns of pelagic metazoan diversity in Fram Strait using environmental DNA (eDNA) metabarcoding of the cytochrome c oxidase I (COI) gene. We successfully detected a broad range of taxa from the marine metazoan and GZP communities across sampling locations and ocean depth zones. We demonstrate the vertical structuring of diversity and elucidate relationships between taxa and water mass indicators, such as salinity and temperature. Furthermore, when comparing eDNA data with net and video transect data for GZP at the same period and location, we found that eDNA uncovered a higher number of taxa, including several that were not detected by the other methods. This study is a contribution to the formation of baseline Arctic GZP biodiversity datasets, as well as future research on changing marine metazoan biodiversity and community composition