Andreas Westergaard‐Nielsen

ORCID: 0000-0003-1021-0530
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About
Contact & Profiles
Research Areas
  • Climate change and permafrost
  • Cryospheric studies and observations
  • Geology and Paleoclimatology Research
  • Peatlands and Wetlands Ecology
  • Arctic and Antarctic ice dynamics
  • Methane Hydrates and Related Phenomena
  • Indigenous Studies and Ecology
  • Atmospheric and Environmental Gas Dynamics
  • Remote Sensing and LiDAR Applications
  • Tree-ring climate responses
  • Remote Sensing in Agriculture
  • Building materials and conservation
  • Geological Studies and Exploration
  • Archaeology and ancient environmental studies
  • Winter Sports Injuries and Performance
  • Climate variability and models
  • Atmospheric chemistry and aerosols
  • Coastal wetland ecosystem dynamics
  • Lichen and fungal ecology
  • Horticultural and Viticultural Research
  • Tree Root and Stability Studies
  • Fire effects on ecosystems
  • 3D Surveying and Cultural Heritage
  • Landslides and related hazards
  • Land Use and Ecosystem Services

University of Copenhagen
2016-2025

University of Tasmania
2021

Aarhus University
2016

University of Edinburgh
2016

Permafrost is a key element of the cryosphere and an essential climate variable in Global Climate Observing System. There no remote-sensing method available to reliably monitor permafrost thermal state. To estimate distribution at hemispheric scale, we employ equilibrium state model for temperature top (TTOP model) 2000–2016 period, driven by remotely-sensed land surface temperatures, down-scaled ERA-Interim reanalysis data, tundra wetness classes landcover map from ESA Landcover Change...

10.1016/j.earscirev.2019.04.023 article EN cc-by-nc-nd Earth-Science Reviews 2019-04-25

Arctic ecosystems are characterized by a wide range of soil moisture conditions and thermal regimes contribute differently to the net methane (CH4 ) budget. Yet, it is unclear how climate change will affect capacity those systems act as source or sink CH4 . Here, we present results in situ flux measurements made during growing season 2014 on Disko Island (west Greenland) quantify contribution contrasting landscape types budget responses summer warming. We compared gas from bare dry heath, at...

10.1111/gcb.13400 article EN cc-by-nc-nd Global Change Biology 2016-07-15

In this study, we quantified the spatiotemporal variability and trends in observations of multiple snow characteristics High Arctic Zackenberg Northeast Greenland through 18 years. Annual premelt snow-depth collected 2005–2014 along an elevation gradient showed significant differences depth between vegetation types. The seasonal cover was characterized by strong interannual region. Particularly timing snow-cover onset melt, annual maximum accumulation, varied up to order magnitude Hence,...

10.1657/aaar0016-028 article EN Arctic Antarctic and Alpine Research 2016-11-01

Abstract. An improvement in our process-based understanding of carbon (C) exchange the Arctic and its climate sensitivity is critically needed for response tundra ecosystems to a changing climate. In this context, we analysed net ecosystem (NEE) CO2 West Greenland (64° N) across eight snow-free periods 8 consecutive years, characterized key processes two main modulating components: gross primary production (GPP) respiration (Reco). Overall, acted as consistent sink CO2, accumulating −30 g C...

10.5194/bg-14-4467-2017 article EN cc-by Biogeosciences 2017-10-11

Abstract. Ecosystems exchange climate-relevant trace gases with the atmosphere, including volatile organic compounds (VOCs) that are a small but highly reactive part of carbon cycle. VOCs have important ecological functions and implications for atmospheric chemistry climate. We measured ecosystem-level surface–atmosphere VOC fluxes using eddy covariance technique at shallow subarctic lake an adjacent graminoid-dominated fen in northern Sweden during two contrasting periods: peak growing...

10.5194/acp-20-13399-2020 article EN cc-by Atmospheric chemistry and physics 2020-11-11

Climate-induced changes in vegetation phenology at northern latitudes are still poorly understood. Continued monitoring and research therefore needed to improve the understanding of abiotic drivers. Here we used 14 years time lapse imagery climate data from high-Arctic Northeast Greenland assess seasonal response a dwarf shrub heath, grassland, fen, inter-annual variation snow-cover, soil moisture, air temperatures. A late snow melt start growing season is counterbalanced by fast greenup...

10.1007/s13280-016-0864-8 article EN cc-by AMBIO 2017-01-23

Insect outbreaks can have important consequences for tundra ecosystems. In this study, we synthesise available information on of larvae the noctuid moth Eurois occulta in Greenland. Based an extensive dataset from a monitoring programme Kobbefjord, West Greenland, demonstrate effects larval outbreak 2011 vegetation productivity and CO2 exchange. We estimate decreased carbon (C) sink strength order 118-143 g C m-2, corresponding to 1210-1470 tonnes at Kobbefjord catchment scale. The was,...

10.1007/s13280-016-0863-9 article EN cc-by AMBIO 2017-01-23

Abstract Arctic tundra is a globally important store for carbon (C). However, there lack of reference sites characterising C exchange dynamics across annual cycles. Based on the Greenland Ecosystem Monitoring (GEM) programme, here we present 9–11 years flux and ecosystem data period 2008–2018 from two wetland in Greenland: Zackenberg (74°N) Kobbefjord (64°N). The fen was strong sink despite its higher latitude shorter growing seasons compared to fen. On average took up ∼−50 g m −2 yr −1...

10.1088/1748-9326/ab865b article EN cc-by Environmental Research Letters 2020-04-03

Abstract The long-term response of Greenland’s peripheral glaciers to climate change is widely undocumented. Here we use historical aerial photographs and satellite imagery document length fluctuations >1,000 land-terminating in Greenland over more than a century. We find that their rate retreat the last two decades double twentieth century, indicating ubiquitous transition into new, accelerated state downwasting.

10.1038/s41558-023-01855-6 article EN cc-by Nature Climate Change 2023-11-09

Abstract Temperature changes in the Arctic have notable impacts on ecosystem structure and functioning, soil carbon dynamics, stability of permafrost, thus affecting functions putting man-built infrastructure at risk. Future warming could accelerate important feedbacks permafrost degradation processes. Therefore it is to map vulnerable areas most likely be impacted by temperature higher risk degradation, particularly near communities, assist adaptation climate change. Currently, these are...

10.1038/s41598-018-19992-w article EN cc-by Scientific Reports 2018-01-19

Seasonal snow cover has an important impact on the difference between soil- and air temperature because of insulation effect, is therefore a key parameter in ecosystem models. However, it still uncertain how specific variations soil moisture, vegetation composition, surface warming, combined with dynamics such as compaction affect temperature. Here, we present analysis 8 years (2012–2020) Arctic manipulation experiment (using fences) Disko Island, West Greenland. We explore effect under...

10.1016/j.geoderma.2023.116632 article EN cc-by Geoderma 2023-08-25

Abstract Climate change is expected to accelerate the microbial degradation of many extraordinary well-preserved organic archaeological deposits found in Arctic. This could potentially lead a major loss wooden artefacts that are still buried within region. Here, we carry out first large-scale investigation wood done based on samples from 11 sites located along climatic gradient Western Greenland. Our results show Ascomycota fungi causing extensive soft rot decay at all regardless climate and...

10.1038/s41598-020-71518-5 article EN cc-by Scientific Reports 2020-09-03

ABSTRACT The Arctic is warming faster than the global average, making it critical to understand how this affects ecological structure and function in streams, which are key ecosystems. Microbial biofilms crucial for primary production decomposition streams support higher trophic levels. However, comprehensive studies across regions, particular within Greenland, scarce. This study analysed total biomass, autotrophic biomass (chlorophyll a ), general of major groups stream epilithic...

10.1111/1758-2229.70074 article EN cc-by Environmental Microbiology Reports 2025-03-12

Abstract Aim Tundra ecosystems are highly vulnerable to climate change, and climate–growth responses of Arctic shrubs variable altered by microsite environmental conditions biotic factors. With warming drought during the growing season, insect‐driven defoliation is expected increase in frequency severity with potential broad‐scale impacts on tundra ecosystem functioning. Here we provide first reconstruction spatio‐temporal dynamics past insect outbreaks assessing their effects shrub growth...

10.1111/jbi.13644 article EN Journal of Biogeography 2019-06-28

Climate change threatens many well‐preserved archaeological sites in the Arctic. The paper presents first Arctic multi‐threat assessment focusing on Nuuk region of Greenland. results suggest that majority 336 known are already exposed to impacts from microbial degradation, permafrost thaw and vegetation, these will increase over next 80 years. Additional coastal erosion only noted at a limited number due predominant consolidated uplifting coast. applied methods represent an important step...

10.1111/arcm.12593 article EN Archaeometry 2020-06-30

Abstract In the Arctic, spatiotemporal variation of net methane uptake in upland soils depends on unresolved interactive controls between edaphic and microbial factors not yet included current models, underpinning uncertainty upscaling Arctic budget. Here we show that Greenland are consistent sinks (−1.83 ± 0.19 nmol g −1 dw d ) across a N-S (64–83 °N) pedoclimatic transect. We demonstrate oxidizers abundance, soil pH, available copper important spatial oxidation. revised biogeochemical...

10.1038/s43247-023-01143-3 article EN cc-by Communications Earth & Environment 2023-12-07

Abstract The Arctic is warming twice as fast the global average with overlooked consequences for preservation of rich cultural and environmental records that have been stored millennia in archaeological deposits. In this article, we investigate oxic degradation different types organic deposits located climatic zones West South Greenland. rate investigated based on measurements O 2 consumption, CO production heat at temperatures water contents. Overall, there good consistency between three...

10.1038/srep28690 article EN cc-by Scientific Reports 2016-06-30
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