South Greenland Research Articles

Vulnerability and adaptation on the icecap’s edge: farming communities in subarctic South Greenland

ABSTRACT Variability in climate and weather conditions and socio-economic shifts are dramatically altering the landscapes and livelihoods of peoples of the northern high-latitudes. Such escalating trends have distinctive consequences at the local and regional scale and the ability to adapt to such rapid changes will challenge cultural, social, and economic systems across Arctic regions. Using a cultural landscape approach, this study provides an in-depth qualitative analysis of sheep farming communities in subarctic South Greenland. Our study centers local voices and helps document shifting weather-related and other socio-economic challenges. We interview four farming households, one historian, and one local economic development expert to understand the broader context, the challenges and vulnerabilities, and the persistence of agriculture in this high north region. Our analysis reveals four overarching themes influencing the sustainability of sheep farming: (1) multi-generational farming heritage, (2) reciprocity and community support, (3) shifting weather and climate influences and farming livelihoods, and (4) farm operations and new opportunities. Findings from this study fill a gap in the literature on local and regional impacts of weather and socio-economic shifts in remote regions. Through the inclusion of local Inuit and other voices, we document how geographically dispersed subarctic communities are adapting to broader shifts.

Climate change, community well-being, and consumption: Reconsidering human-environment relationships in Greenland under global change

We reassess the research on the impact of climate change on society and propose examining the social dimensions of climate change from a perspective of community well-being. We argue that to better understand community dynamics in the Arctic, it is helpful to shift the research focus from the environment and view the environment and climate change as a backdrop to social phenomena. Specifically, we consider the increasing living standards and expanding basic needs that fall under consumption, one of the three domains of economic activity. This represents a shift from the conventional anthropological perspective, which focuses solely on production (food procurement, subsistence) and distribution, to a more balanced consideration of the three economic domains and their intricate relations. This shift also involves moving away from the conventional anthropological theory, which posits that the relationship to the environment influences, organizes, and shapes people's lives, to the reverse: people's increasing needs reshape, rearrange, or alter the human–environment relationship. The perspective of community well-being considers the interplay between the environment, social (local assets), and economic domains (consumption and increasing needs) of community dynamics. To illustrate this perspective in Arctic studies, we draw on two examples from our experience in Greenland: sheep farming in South Greenland and Greenland halibut fisheries in North Greenland.

Assessing the consequences of recent climate change on World Heritage sites in South Greenland

In the Arctic region, microbial degradation poses a significant threat to the preservation of archaeological deposits, actively consuming irreplaceable cultural and environmental records. In this study we assess the potential effects of the last 40 years of climate change on organic archaeological deposits within the UNESCO World Heritage area Kujataa in South Greenland. We use the dynamic process-oriented model, CoupModel to simulate soil temperatures and soil moisture contents at four archaeological sites in the area. The results show that the organic deposits have experienced a substantial warming the last 40 years, which combined with decreasing soil moisture contents creates a dangerous combination that can accelerate the degradation of organic materials. Currently, there are 583 archaeological sites registered within the area. Our findings highlight that the current climatic conditions are not conducive to organic preservation. The greatest risk of degradation lies within the relatively dry continental inland areas of the study region, where all Norse Viking Age settlements are situated. However, even at the "cold" and "wet" outer coast, the combined effects of rising summer temperatures and declining soil moisture levels may already be exerting a noticeable impact.

Uncrewed aerial vehicle with onboard winch system for rapid, cost-effective, and safe oceanographic profiling in hazardous and inaccessible areas

Interactions between coastal waters and marine-terminating glaciers in the Polar Regions play a significant role in global sea level rise fueled by a rapidly warming Arctic.The risk of glacier calving, and the abundance of ice, can make it impossible for surface vessels to access the waters near glacier termini. Alternative methods using manned aircraft are expensive. As a result, oceanographic measurements are limited near glacier termini.We present an uncrewed aerial vehicle (UAV) with an on-board winch system that allows oceanographic profiling in remote, hazardous areas using a commercial conductivity, temperature, and depth (CTD) sensor payload. The UAV is optimized for easy handling and deployment and is capable of high-speed and efficient cruise flight. An autopilot system provides pilot assistance and autonomous flight capabilities. The total weight of the UAV including payload is 6.5 kg with an endurance of 24 min.Testing of the system was conducted in South Greenland during winter conditions in March 2023 with successful profiles collected near a glacier terminus (<5 m) and in small openings in ice mélange (2.2 m). The system proved capable, reliable, and efficient. Further development of the system will allow other sensors for an even more flexible measurement suite.

Seasonal and Elevational Variability in Dwarf Birch VOC Emissions in Greenlandic Tundra

AbstractRising temperatures amplify biogenic volatile organic compound (VOC) emissions from Arctic vegetation, causing feedbacks to the climate system. Changes in climate also alter plant physiology and vegetation composition, all of which can influence VOC emissions. Moreover, leaf development and biotic stresses cause highly variable emissions during the growing season. Therefore, linking VOC emissions with plant traits and tracking responses to climate change might provide better understanding of VOC emission regulation under future conditions. We measured VOC emissions and other plant traits in dwarf birch (Betula glandulosa) at two elevations in Narsarsuaq, South Greenland. The measurements were performed in warming experiments that have run since 2016. We collected VOCs using the branch enclosure method from early June until late July 2019 (n = 200). Emissions of green leaf volatiles (GLVs), oxygenated monoterpenes (oMTs), and homoterpenes followed a seasonal trend. VOC emission rates and the diversity of the VOC blend decreased at the end of the measurement period. Differences in VOC emission rates between elevations were pronounced early in the season. Majority of the traits did not explain the variation in VOC emissions. We show strong seasonal variability in VOC emissions within the growing season, which is likely driven by leaf phenology. While the diversity of VOCs was greater at the milder low‐elevation site, VOC emission rates were higher or similar at the harsher high‐elevation site, showing stronger VOC emission potentials than previously assumed. Seasonal variations in the emissions of VOCs are crucial for accurate predictions of current and future VOC emissions from arctic ecosystems.

Evaluating altimetry-derived surface currents on the south Greenland shelf with surface drifters

Abstract. The pathways and fate of freshwater in the East Greenland Coastal Current (EGCC) are crucial to the climate system. The EGCC transports large amounts of freshwater in close proximity to sites of deep open-ocean convection in the Labrador and Irminger seas. Many studies have attempted to analyze this system from models and various observational platforms, but the modeling results largely disagree with one another, and observations are limited due to the harsh conditions typical of the region. Altimetry-derived surface currents, constructed from remote-sensing observations and applying geostrophic equations, provide a continuous observational data set beginning in 1993. However, these products have historically encountered difficulties in coastal regions, and thus their validity must be checked. In this work, we use a comprehensive methodology to compare these Eulerian data to a Lagrangian data set of 34 surface drifter trajectories and demonstrate that the altimetry-derived surface currents are surprisingly capable of recovering the spatial structure of the flow field on the south Greenland shelf and can mimic the Lagrangian nature of the flow as observed from surface drifters.

Glacial rock flour reduces the hydrophobicity of Greenlandic cultivated soils

AbstractSoil water repellency (WR) is ubiquitous across Greenlandic cultivated fields, which may constrain agricultural production. Fine‐grained glacial rock flour (GRF) is available in the surrounding landscape, which could serve as a soil amendment. We tested whether the application of GRF (rates of 0, 50, 100, 300, and 500 ton ha−1) reduced the WR across two field trials in South Greenland. The field trials, Upernaviarsuk (UP) and South Igaliku (SI), differed in clay (UP: 0.05–0.11 kg kg−1; SI: 0.03–0.05 kg kg−1) and organic carbon (OC) contents (UP: 0.04–0.13 kg kg−1; SI: 0.01–0.03 kg kg−1). We measured WR across gravimetric water contents (W) from oven‐dry to the W where WR ceased (WNON) to obtain whole WR‐W curves. Most soils became hydrophilic around air‐dry conditions at application rates of ≥300 ton ha−1, likely due to increased clay:OC ratios. Application rates of ≥300 ton ha−1 generally reduced the trapezoidal integrated area of the WR‐W curve (WRAREA), WNON, and WR after heat treatments at 105°C (WR105) and 60°C (WR60). The WR105 was significantly reduced in both fields at 500 ton ha−1, while WR60 was significantly reduced in UP at application rates of ≥300 ton ha−1. The GRF effects were masked by texture and OC variations. Normalizing WRAREA to the water vapor sorption isotherms (utilizing the Campbell‐Shiozawa model) revealed that GRF consistently reduced the normalized WRAREA. The SI field showed the largest reduction in the normalized WRAREA, likely due to its lower OC and clay contents. Thus, GRF could reduce WR across two Greenlandic field trials.

Late Holocene Environmental History and Norse Settlement in Outer Fjords from South Greenland: A Case Study at Lake Qallimiut

To complement discussions about vegetation history and climate variations in south Greenland, especially during the Norse settlement, we developed a sedimentological multiproxy approach to study a 4300-year-old lacustrine core comprising pollen analysis, NPPs analysis, physical measurements (magnetic susceptibility, density, and grain size), and geochemical analyses (X-ray fluorescence, X-ray diffraction, and elemental analyses). Sediment archives were retrieved from a river-fed lake, Lake Qallimiut, located in the outer fjords of the Vatnahverfi area. The pollen analysis indicated a transition from juniper and willow cover to a dwarf birch forest. Non-pollen palynomorphs (NPPs) suggested grazing pressure and the presence of wild herbivores between 2300 and 1800 cal. BC. From ca. 1000 cal. AD, the presence of Norse farmers was evidenced in this area by archaeological surveys, and pollen analyses confirm the presence of human activities from the 11th century to the end of the 13th century. However, human impact progressively vanished between the 12th and 13th centuries, much earlier than at the other Vatnahverfi sites.

Evidence for a recent (0.65 Ma) formation of the Isthmus of Panama

The exact age of the final formation of the Isthmus of Panama is a critical reference point for oceanographic, climatic, biogeographic, and evolutionary hypotheses. The prevailing interpretation of geotectonic evidence is that the isthmus was completed between 12 Ma and 3 Ma, and an age of 3–4 Ma has been used as a benchmark in hundreds of studies over the past 30 years. Phylogeographic data indicate the existence of marine connections across the isthmus much more recently, however. Here, using the most updated data available, I reconsider the geological arguments invoked to conclude the age of 3–4 Ma and show that, in fact, this age is not supported by the current geological knowledge. Rather, recent geotectonic evidence, in conjunction with multiple lines of indirect phylogeographic, biostratigraphic, oceanographic, and paleoclimatic indications, suggests that as many as four transisthmian seaways persisted until as recently as the onset of the Middle Pleistocene (~0.65 Ma). The concurrence of the final formation of the Isthmus of Panama with the mid-Pleistocene Transition of glacial/interglacial periodicity suggests a tight relationship between these events. Unusual and contrasting climate phenomena, including the “900-Ka (cold) event” and the “greening” of South Greenland during the MIS 22 glacial maximum, can be explained by this palaeogeographical and palaeoceonographical scenario.

Organic carbon controls water retention and plant available water in cultivated soils from South Greenland

AbstractThe warming climate is rapidly changing the circumpolar region, presenting new opportunities and challenges for agricultural production in South Greenland. The warming climate is projected to increase the frequency of drought periods, but little is known about the soil–water retention (SWR) and the plant available water (PAW) of the agricultural soils in the region. This study aimed to measure the SWR and PAW of Greenlandic agricultural soils and evaluate the effect of organic carbon (OC) and clay (CL) content using pedotransfer functions based on OC and CL. The study included 464 South Greenlandic agricultural soil samples from 20 fields with a wide distribution in clay (0.016–0.184 kg kg−1) and OC contents (0.006–0.254 kg kg−1). Pedotransfer functions were successfully developed for estimating the gravimetric water content (w) at five soil–water potentials (−1500, −100, −30, −10, and −5 kPa) and PAW. The OC content was the primary variable governing the gravimetric water content at each soil–water potential, evidenced by R2 values consistently above 0.80. The effect of OC on the gravimetric water content at −1500 kPa was close to the range reported in the literature, but OC effects were markedly higher between −100 and −5 kPa. Overall, this study highlights a substantial effect of OC on the PAW as a 1% increase in OC increased PAW by more than 4%, which is almost twice the value of a recent meta‐study. Our study highlights the potentially dominating effects of organic matter on soil–water balance and availability in high‐latitude agriculture.

The Application of RGB, Multispectral, and Thermal Imagery to Document and Monitor Archaeological Sites in the Arctic: A Case Study from South Greenland

Over the past decades, climate change has accelerated the deterioration of heritage sites and archaeological resources in Arctic and subarctic landscapes. At the same time, increased tourism and growing numbers of site visitors contribute to the degradation and manipulation of archaeological sites. This situation has created an urgent need for new, quick, and non-invasive tools and methodologies that can help cultural heritage managers detect, monitor, and mitigate vulnerable sites. In this context, remote sensing and the applications of UAVs could play an important role. Here, we used a drone equipped with an RGB camera and a single multispectral/thermal camera to test different possible archeological applications at two well-known archaeological sites in the UNESCO World Heritage area of Kujataa in south Greenland. The data collected were used to test the potential of using the cameras for mapping (1) ruins and structures, (2) the impact of human activity, and (3) soil moisture variability. Our results showed that a combination of RGB and digital surface models offers very useful information to identify and map ruins and structures at the study sites. Furthermore, a combination of RGB and NDVI maps seems to be the best method to monitor wear and tear on the vegetation caused by visitors. Finally, we tried to estimate the surface soil moisture content based on temperature rise and the Temperature Vegetation Dryness Index (TVDI), but did not achieve any meaningful connection between TVDI and on-site soil moisture measurements. Ultimately, our results pointed to a limited archaeological applicability of the TVDI method in Arctic contexts.

Volatile responses of dwarf birch to mimicked insect herbivory and experimental warming at two elevations in Greenlandic tundra.

Plants release a complex blend of volatile organic compounds (VOCs) in response to stressors. VOC emissions vary between contrasting environments and increase with insect herbivory and rising temperatures. However, the joint effects of herbivory and warming on plant VOC emissions are understudied, particularly in high latitudes, which are warming fast and facing increasing herbivore pressure. We assessed the individual and combined effects of chemically mimicked insect herbivory, warming, and elevation on dwarf birch (Betula glandulosa) VOC emissions in high-latitude tundra ecosystems in Narsarsuaq, South Greenland. We hypothesized that VOC emissions and compositions would respond synergistically to warming and herbivory, with the magnitude differing between elevations. Warming increased emissions of green leaf volatiles (GLVs) and isoprene. Herbivory increased the homoterpene, (E)-4,8-dimethyl-1,3,7-nonatriene, emissions, and the response was stronger at high elevation. Warming and herbivory had synergistic effects on GLV emissions. Dwarf birch emitted VOCs at similar rates at both elevations, but the VOC blends differed between elevations. Several herbivory-associated VOC groups did not respond to herbivory. Harsher abiotic conditions at high elevations might not limit VOC emissions from dwarf birch, and high-elevation plants might be better at herbivory defense than assumed. The complexity of VOC responses to experimental warming, elevation, and herbivory are challenging our understanding and predictions of future VOC emissions from dwarf birch-dominated ecosystems.

Assimilation and extensive metasomatism of agpaitic rocks from the transitional layered kakortokite, Ilímaussaq Intrusion, South Greenland

AbstractThe peralkaline Ilímaussaq Intrusion of the Gardar Province in South Greenland consists of several intrusive phases that have been related to different magmatic pulses and igneous cumulate processes. The lowermost exposed part of the intrusion is kakortokite, a eudialyte‐nepheline syenite, with distinctive sub‐horizontal layering which passes upwards into lujavrite, a fine‐grained melanocratic eudialyte‐nepheline syenite. Along the contact between kakortokite and lujavrite lies a transitional layered kakortokite, which has been defined previously based on textural and mineralogical criteria. However, published literature presents conflicting descriptions of this sequence in terms of thickness, layering, contacts, and mode of origin. Our own and previous field and petrographic investigations suggest that parts of the eudialyte‐rich zones in the transitional layered kakortokite comprise metasomatized and partially assimilated naujaite autoliths, a sodalite‐rich eudialyte nepheline syenite, detached probably from the roof of the intrusion. Here, we focus on the nature of the transitional layered kakortokite and conclude, in contrast to the conventional model, that it was formed by metasomatic transformation and assimilation of naujaite autoliths. We propose that the breakdown and replacement of sodalite locally increased chlorine and sodium concentrations, which may have catalyzed the precipitation of eudialyte. In detail, we suggest that the uppermost four eudialyte‐rich horizons were strongly influenced by metasomatic processes caused by mineral‐melt reaction, and were not simply the result of conventional igneous magmatic cumulate formation, as has been inferred for the underlying kakortokite layered units. Recognition of a significant metasomatic process has important bearing on the distribution of minerals with specific elements, like REE in eudialyte, both from a petrological and an economic perspective.

Indoor radon survey in Greenland and dose assessment

Indoor radon and its decay products are the primary sources of the population's exposure to background ionizing radiation. Radon decay products are one of the leading causes of lung cancer, with a higher lung cancer risk for smokers due to the synergistic effects of radon decay products and cigarette smoking. A total of 459 year-long radon measurements in 257 detached and semi-detached residential homes in southwest and south Greenland were carried out, and a dose assessment for adults was performed. The annual arithmetic and geometric means of indoor radon concentrations was 10.5 ± 0.2 Bq m−3 and 8.0 ± 2.3 Bq m−3 in Nuuk, 139.0 ± 1.0 Bq m−3 and 97.3 ± 2.1 Bq m−3 in Narsaq, and 42.1 ± 0.7 Bq m−3 and 22.0 ± 3.1 Bq m−3 in Qaqortoq. Arithmetic and geometric mean radon concentration of 79.0 Bq m−3 and 50.3 Bq m−3 were estimated for adult, person-weighted living in south Greenland. The total number of detached and semi-detached residential homes where indoor radon is exceeding 100 Bq m−3, 200 Bq m−3, and 300 Bq m−3 is 37 homes (15.0%), 13 homes (5.2%), and 8 homes (3.2%), respectively. A positive correlation between indoor air radon concentrations and underlying geology was observed.The indoor radon contribution to the annual inhalation effective dose to an average adult was 0.5 mSv in Nuuk, 6.5 mSv in Narsaq, 2.0 mSv in Qaqortoq, and 4.0 mSv for south Greenland adult person weighted. The estimated annual average effective dose to adults in Narsaq is higher than the world's average annual effective dose of 1.3 mSv due to inhalation of indoor radon. Cost-efficient mitigation methods exist to reduce radon in existing buildings, and to prevent radon entry into new buildings.

On Tide Aliasing in GRACE Time-Variable Gravity Observations

Aliasing error induced by tide-related high frequency mass variations is one of the most significant errors in the Gravity Recovery and Climate Experiment (GRACE). In the present work, we evaluated the 161.0-day S2, 171.2-day P1, and 322.1-day S1 ocean tide aliasing in GRACE latest RL06 data based on nearly 15 years of observation from 2002 to 2017. Tide aliasing was still obvious for current GRACE observations, especially for S2 and P1 aliasing. S2 aliasing was mostly evident over West Antarctica, and was a clearly eastward propagation that travelled around Antarctica in about 2 years, while P1 showed strongest aliasing over South Greenland. More seriously, we found that GRACE mascon data showed an extremely large aliasing error. The mascon data may have unintentionally amplified the aliasing error on land due to the regularization (or constraint) applied for reducing signal leakage. Enough attention must be paid to tide aliasing when using GRACE for assessing mass variations at high latitudes (e.g., glaciers in polar regions) which can cause potential obstacles to estimation of actual seasonality.

Younger Dryas and early Holocene climate in south Greenland inferred from oxygen isotopes of chironomids, aquatic Moss, and Moss cellulose

Ice core records have long indicated that the Younger Dryas began and ended with large, abrupt climate shifts over Greenland. Key climatic features remain unknown, including the magnitude of warming during the Younger Dryas-Holocene transition along with the seasonality and spatial variability of Younger Dryas climate changes across Greenland. Here, we use geochemical and paleoecological proxies from lake sediments at Lake N14 in south Greenland to address these outstanding questions. Radiocarbon dating and diatom assemblages confirm early deglaciation and isolation of Lake N14 before ∼13,600 cal yr BP, consistent with previous work. Oxygen isotope ratios (δ18O) of chironomid head capsules, bulk aquatic moss, and aquatic moss-derived cellulose are used to reconstruct oxygen isotopes of past lake water and annual precipitation. Oxygen isotope proxies indicate annual precipitation δ18O values increased by 5.9–7.7‰ at the end of the Younger Dryas. Following the Younger Dryas, moss and cellulose δ18O values show a clear decline in precipitation δ18O values of 2–3‰ from ∼11,540–11,340 cal yr BP that may correspond with the Preboreal Oscillation. Reconstructed precipitation δ18O values then gradually increased from 11,300–10,100 cal yr BP. All three aquatic organic materials register similar shifts in precipitation δ18O values over time, and they closely parallel the δ18O shifts observed in ice cores. This evidence strongly supports the utility of these methods for reconstructing lake water δ18O, and furthermore precipitation δ18O values where lake water reflects precipitation. The relatively large shift in isotopic composition of precipitation at Lake N14 suggests that shifts in temperature, precipitation seasonality, and/or moisture sources at the end of the Younger Dryas were even larger in south Greenland than they were in central Greenland, most likely because of the proximity to major changes in North Atlantic Ocean circulation. The annual air temperature change estimated at Lake N14 at the end of the Younger Dryas is also very large (∼18 ± 7 °C) compared to the summer warming previously inferred from chironomid species assemblages there (∼6 °C). This indicates that the strongest warming at the end of the Younger Dryas occurred in the winter season, consistent with past observations of intensified Younger Dryas seasonality at Lake N14 and elsewhere in Greenland.

Submarine melting of glaciers in Greenland amplified by atmospheric warming

Rapid ice loss from the Greenland ice sheet since 1992 is due in equal parts to increased surface melting and accelerated ice flow. The latter is conventionally attributed to ocean warming, which has enhanced submarine melting of the fronts of Greenland’s marine-terminating glaciers. Yet, through the release of ice sheet surface meltwater into the ocean, which excites near-glacier ocean circulation and in turn the transfer of heat from ocean to ice, a warming atmosphere can increase submarine melting even in the absence of ocean warming. The relative importance of atmospheric and oceanic warming in driving increased submarine melting has, however, not been quantified. Here, we reconstruct the rate of submarine melting at Greenland’s marine-terminating glaciers from 1979 to 2018 and estimate the resulting dynamic mass loss. We show that in south Greenland, variability in submarine melting was indeed governed by the ocean, but, in contrast, the atmosphere dominated in the northwest. At the ice sheet scale, the atmosphere plays a first-order role in controlling submarine melting and the subsequent dynamic mass loss. Our results challenge the attribution of dynamic mass loss to ocean warming alone and show that a warming atmosphere has amplified the impact of the ocean on the Greenland ice sheet.

Impacts of elevation on plant traits and volatile organic compound emissions in deciduous tundra shrubs.

The northernmost regions of our planet experience twice the rate of climate warming compared to the global average. Despite the currently low air temperatures, tundra shrubs are known to exhibit high leaf temperatures and are increasing in height due to warming, but it is unclear how the increase in height will affect the leaf temperature. To study how temperature, soil moisture, and changes in light availability influence the physiology and emissions of climate-relevant volatile organic compounds (VOCs), we conducted a study on two common deciduous tundra shrubs, Salix glauca (separating males and females for potential effects of plant sex) and Betula glandulosa, at two elevations in South Greenland. Low-elevation Salix shrubs were 45% taller, but had 37% lower rates of net CO2 assimilation and 63% lower rates of isoprene emission compared to high-elevation shrubs. Betula shrubs showed 40% higher stomatal conductance and 24% higher glandular trichome density, in the low-elevation valley, compared to those from the high-elevation mountain slope. Betula green leaf volatile emissions were 235% higher at high elevation compared to low elevation. Male Salix showed a distinct VOC blend and emitted 55% more oxygenated VOCs, compared to females, possibly due to plant defense mechanisms. In our light response curves, isoprene emissions increased linearly with light intensity, potentially indicating adaptation to strong light. Leaf temperature decreased with increasing Salix height, at 4 °C m-1, which can have implications for plant physiology. However, no similar relationship was observed for B. glandulosa. Our results highlight that tundra shrub traits and VOC emissions are sensitive to temperature and light, but that local variations in soil moisture strongly interact with temperature and light responses. Our results suggest that effects of climate warming, alone, poorly predict the actual plant responses in tundra vegetation.

Assessment of future wind speed and wind power changes over South Greenland using the Modèle Atmosphérique Régional regional climate model

AbstractWind is an infinitely renewable energy source that is not evenly distributed in space and time. The interconnection of energy‐demanding and energy‐resourceful (yet remote) regions would help prevent energy scarcity in a world where fossil fuels are no longer used. Previous studies have shown that South Greenland and West Europe have complementary wind regimes. In particular, the southern tip of Greenland, Cape Farewell, has gained growing interest for wind farm development as it is one of the windiest places on Earth. In order to gain new insights about future wind speed variations over South Greenland, the Modèle Atmosphérique Régional (MAR), validated against in situ observations over the tundra where wind turbines are most likely to be installed, is used to build climate projections under the emission scenario SSP5‐8.5 by downscaling an ensemble of CMIP6 Earth System Models (ESMs). It appeared that between 1981 and 2100, the wind speed is projected to decrease by ~−0.8 m·s−1 at 100 m a.g.l. over the tundra surrounding Cape Farewell. This decrease is particularly marked in winter while in summer, a wind speed acceleration is projected along the ice sheet margins. An analysis of two‐dimensional wind speed changes at different vertical levels indicates that the winter decrease is likely due to a large‐scale circulation change while in summer, the katabatic winds flowing down the ice sheet are expected to increase due to an enhanced temperature contrast between the ice sheet and the surroundings. As for the mean annual maximum wind power a turbine can yield, a decrease of ~−178.1 W is projected at 100 m a.g.l. Again, the decrease is especially pronounced in winter. Considering the very high winter wind speeds occurring in South Greenland which can cut off wind turbines if too intense, the projected wind speed decrease might be beneficial for the establishment of wind farms near Cape Farewell.

The impact of climate oscillations on the surface energy budget over the Greenland Ice Sheet in a changing climate

Abstract. Climate change is particularly strong in Greenland, primarily as a result of changes in the transport of heat and moisture from lower latitudes. The atmospheric structures involved influence the surface mass balance (SMB) of the Greenland Ice Sheet (GrIS), and their patterns are largely explained by climate oscillations, which describe the internal climate variability. By using k-means clustering, we name the combination of the Greenland Blocking Index, the North Atlantic Oscillation index and the vertically integrated water vapor as NAG (North Atlantic influence on Greenland) with the optimal solution of three clusters (positive, neutral and negative phase). With the support of a polar-adapted regional climate model, typical climate features marked under certain NAG phases are inter-seasonally and regionally analyzed in order to assess the impact of large-scale systems from the North Atlantic on the surface energy budget (SEB) components over the GrIS. Given the pronounced summer mass loss in recent decades (1991–2020), we investigate spatio-temporal changes in SEB components within NAG phases in comparison to the reference period 1959–1990. We report significant atmospheric warming and moistening across all NAG phases. The pronounced atmospheric warming in conjunction with the increase in tropospheric water vapor enhance incoming longwave radiation and thus contribute to surface warming. Surface warming is most evident in winter, although its magnitude and spatial extent depend on the NAG phase. In summer, increases in net shortwave radiation are mainly connected to blocking systems (+ NAG), and their drivers are regionally different. In the southern part of Greenland, the atmosphere has become optically thinner due to the decrease in water vapor, thus allowing more incoming shortwave radiation to reach the surface. However, we find evidence that, in the southern regions, changes in net longwave radiation balance changes in net shortwave radiation, suggesting that the turbulent fluxes control the recent SEB changes. In contrast to South Greenland under + NAG, the moistening of North Greenland has contributed to decreases in surface albedo and has enhanced solar radiation absorption. Regardless of the NAG phase, increases in multiple atmospheric variables (e.g., integrated water vapor and net longwave radiation) are found across the northern parts of Greenland, suggesting that atmospheric drivers beyond heat and moisture originated from the North Atlantic. Especially in the northern ablation zone, sensible heat flux has significantly increased in summer due to larger vertical and horizontal temperature gradients combined with stronger near-surface winds. We attribute the near-surface wind intensification to the emerging open-water feedback, whereby surface pressure gradients between the ice/snow-covered surface and adjacent open seas are intensified.