A first constraint on basal melt-water production of the Greenland ice sheet

Karlsson, Nanna B.; Solgaard, Anne; Mankoff, K. D.; Gillet-Chaulet, Fabien; MacGregor, Joseph A.; Box, Jason E.; Citterio, Michele; Colgan, William; Larsen, Signe Hillerup; Kjeldsen, Kristian K.; Korsgaard, Niels J.; Benn, Douglas I.; Hewitt, Ian; Fausto, Robert S.

doi:10.1038/s41467-021-23739-z

Cited by 55 publications

(65 citation statements)

References 57 publications

(90 reference statements)

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“…This value represents the fraction by which local topography enhances measured heat flow. For both existing IHFC 2018 sites and new sites, where available, this is derived from an existing data product (Colgan et al, 2021). Where unavailable in this product, topographic correction remains unavailable in the database.…”

Section: Topographic Correction [Unitless]mentioning

confidence: 99%

“…Uncertainty in topographic correction for geothermal heat flow for each entry in the database. For both existing IHFC 2018 sites and new sites, this is derived from the Colgan et al (2021) Uncertainty in topographically corrected geothermal heat flow for each entry, where topographic correction is available.…”

Section: Uncertainty In Topographic Correction [Unitless]mentioning

confidence: 99%

“…For all subglacial sites, heat flow is calculated using a slightly modified version of the temperature gradient approach. We use ice temperature profiles from the Greenland Ice Borehole Temperature Profiles database (Mankoff, 2021; https://github.com/GEUS-PROMICE/greenland_ice_ borehole_temperature_profiles, last access: 8 February 2022). At sites where the ice temperature profile is complete, meaning it spans the full ice thickness from surface to bed (Devon73, PrinceWales05, Meighen67, Agas-siz77/79A/79B/84, Penny96, CampCentury, DYE-3, GISP2, NEEM, HansTausen_Dome, HansTausen_Hare), we fit a second-order temperature-depth function in the bottom 10 % of the borehole (Paterson, 1968;Weertman, 1968;Paterson et al, 1977;Fisher and Koerner, 1984;Gundestrup and Hansen, 1984;Clarke et al, 1987;Fisher et al, 1988;Clausen et al, 2001;Kinnard et al, 2008;Rasmussen et al, 2013;Mac-Gregor et al, 2015).…”

Section: Type 1 -Not Included In Ihfc 2018mentioning

confidence: 99%

“…First, if the temperature profile is not deep enough to make a reasonable extrapolation of the temperature gradient at the icebed interface (i.e., Site II), then heat flow cannot be estimated from the temperature gradient approach. Second, if the basal ice is at the pressure melting point additional glaciological data are needed to characterize basal frictional heating, which warms ice temperatures, and/or basal melting, which cools ice temperatures (Karlsson et al, 2021). At temperate sites, where frictional heating or basal melting is not constrained, heat flow cannot be estimated using the standard basal-temperature-gradient approach due to complex thermodynamics associated with ice-water phase changes (i.e., Jakobshavn_A).…”

Section: Type 3 -No Heat Flow (Insufficient Data)mentioning

confidence: 99%

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Greenland Geothermal Heat Flow Database and Map (Version 1)

Colgan

Wansing

Mankoff

et al. 2022

Earth Syst. Sci. Data

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Abstract. We compile and analyze all available geothermal heat flow measurements collected in and around Greenland into a new database of 419 sites and generate an accompanying spatial map. This database includes 290 sites previously reported by the International Heat Flow Commission (IHFC), for which we now standardize measurement and metadata quality. This database also includes 129 new sites, which have not been previously reported by the IHFC. These new sites consist of 88 offshore measurements and 41 onshore measurements, of which 24 are subglacial. We employ machine learning to synthesize these in situ measurements into a gridded geothermal heat flow model that is consistent across both continental and marine areas in and around Greenland. This model has a native horizontal resolution of 55 km. In comparison to five existing Greenland geothermal heat flow models, our model has the lowest mean geothermal heat flow for Greenland onshore areas. Our modeled heat flow in central North Greenland is highly sensitive to whether the NGRIP (North GReenland Ice core Project) elevated heat flow anomaly is included in the training dataset. Our model's most distinctive spatial feature is pronounced low geothermal heat flow (< 40 mW m−2) across the North Atlantic Craton of southern Greenland. Crucially, our model does not show an area of elevated heat flow that might be interpreted as remnant from the Icelandic plume track. Finally, we discuss the substantial influence of paleoclimatic and other corrections on geothermal heat flow measurements in Greenland. The in situ measurement database and gridded heat flow model, as well as other supporting materials, are freely available from the GEUS Dataverse (https://doi.org/10.22008/FK2/F9P03L; Colgan and Wansing, 2021).

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Section: Topographic Correction [Unitless]mentioning

confidence: 99%

Section: Uncertainty In Topographic Correction [Unitless]mentioning

confidence: 99%

Section: Type 1 -Not Included In Ihfc 2018mentioning

confidence: 99%

Section: Type 3 -No Heat Flow (Insufficient Data)mentioning

confidence: 99%

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Greenland Geothermal Heat Flow Database and Map (Version 1)

Colgan

Wansing

Mankoff

et al. 2022

Earth Syst. Sci. Data

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“…Melting at the bottom of the ice sheet (not just surface melting) accounts for a significant amount of Greenland ice loss [3].…”

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confidence: 99%

Sustaining the Arctic in Order to Sustain the Global Climate System

Bodansky

Pomerance

2021

Sustainability

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The unraveling of the Arctic is bad enough for the Arctic itself, but it will have enormous consequences for the entire planet since the Arctic is a crucial component of the global climate system. Current policies do not provide much hope to prevent these harms. We have committed the earth to too much warming to take a step-by-step approach. We have entered a period of history when planetary management has become unavoidable and must move forward on many fronts simultaneously. Key components of a multiprong approach include decarbonization, focus on short-lived climate forcers, greenhouse gas removal, adaptation, Arctic interventions, and solar climate intervention. This article discusses the last option, which may be the only means of cooling the earth quickly enough to save Arctic ice and permafrost. Scientific research is essential to better understand its feasibility, effectiveness, and safety. However, research is not enough; we need to be ready to respond right away if Arctic or global temperatures need to be lowered quickly. This means we need significant technology research and development so that solar climate intervention technologies are deployment-ready in the relatively near future, perhaps in a decade or two, and could be used should the need arise and should research show that they are effective and safe.

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Mass Balances of the Antarctic and Greenland Ice Sheets Monitored from Space

et al. 2023

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Satellite data have revealed that the Greenland and Antarctic Ice Sheets are changing rapidly due to warming air and ocean temperatures. Crucially, Earth Observations can now be used to measure ice sheet mass balance at the continental scale, which can help reduce uncertainties in the ice sheets’ past, present, and future contributions to global mean sea level. The launch of satellite missions dedicated to the polar regions led to great progress towards a better assessment of the state of the ice sheets, which, in combination with ice sheet models, have furthered our understanding of the physical processes leading to changes in the ice sheets' properties. There is now a three-decade-long satellite record of Antarctica and Greenland mass changes, and new satellite missions are planned to both continue this record and further develop our observational capabilities, which is critical as the ice sheets remain the most uncertain component of future sea-level rise. In this paper, we review the mechanisms leading to ice sheets' mass changes and describe the state of the art of the satellite techniques used to monitor Greenland’s and Antarctica’s mass balance, providing an overview of the contributions of Earth Observations to our knowledge of these vast and remote regions.

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A first constraint on basal melt-water production of the Greenland ice sheet

Cited by 55 publications

References 57 publications

Greenland Geothermal Heat Flow Database and Map (Version 1)

Greenland Geothermal Heat Flow Database and Map (Version 1)

Sustaining the Arctic in Order to Sustain the Global Climate System

Mass Balances of the Antarctic and Greenland Ice Sheets Monitored from Space

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