#Economics of the #disintegration of the #Greenland #ice sheet (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Economics of the disintegration of the Greenland ice sheet

William Nordhaus

PNAS first published June 4, 2019 / DOI: https://doi.org/10.1073/pnas.1814990116

Edited by William C. Clark, Harvard University, Cambridge, MA, and approved April 5, 2019 (received for review August 30, 2018)

 

Significance

This study integrates an economic model of climate change with a small structural model of the Greenland ice sheet (GIS). As such, it provides a methodology for incorporating large earth system changes into standard economic cost–benefit or damage-limiting analyses. It finds that adding the GIS has only a small effect on the social cost of carbon (SCC) because melting is slow and damages are far in the future.

 

Abstract

Concerns about the impact on large-scale earth systems have taken center stage in the scientific and economic analysis of climate change. The present study analyzes the economic impact of a potential disintegration of the Greenland ice sheet (GIS). The study introduces an approach that combines long-run economic growth models, climate models, and reduced-form GIS models. The study demonstrates that social cost–benefit analysis and damage-limiting strategies can be usefully extended to illuminate issues with major long-term consequences, as well as concerns such as potential tipping points, irreversibility, and hysteresis. A key finding is that, under a wide range of assumptions, the risk of GIS disintegration makes a small contribution to the optimal stringency of current policy or to the overall social cost of climate change. It finds that the cost of GIS disintegration adds less than 5% to the social cost of carbon (SCC) under alternative discount rates and estimates of the GIS dynamics.

climate change – Greenland ice sheet – economics – DICE model – optimization

Keywords: Climate change; Global warming; Greenland; Economics.

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Forty-six years of #Greenland #IceSheet #mass balance from 1972 to 2018 (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018

Jérémie Mouginot, Eric Rignot, Anders A. Bjørk, Michiel van den Broeke, Romain Millan, Mathieu Morlighem, Brice Noël, Bernd Scheuchl, and Michael Wood

PNAS first published April 22, 2019 / DOI: https://doi.org/10.1073/pnas.1904242116

Edited by Mark H. Thiemens, University of California, San Diego, La Jolla, CA, and approved March 20, 2019 (received for review July 31, 2018)

 

Significance

We reconstruct the mass balance of the Greenland Ice Sheet for the past 46 years by comparing glacier ice discharge into the ocean with interior accumulation of snowfall from regional atmospheric climate models over 260 drainage basins. The mass balance started to deviate from its natural range of variability in the 1980s. The mass loss has increased sixfold since the 1980s. Greenland has raised sea level by 13.7 mm since 1972, half during the last 8 years.

 

Abstract

We reconstruct the mass balance of the Greenland Ice Sheet using a comprehensive survey of thickness, surface elevation, velocity, and surface mass balance (SMB) of 260 glaciers from 1972 to 2018. We calculate mass discharge, D, into the ocean directly for 107 glaciers (85% of D) and indirectly for 110 glaciers (15%) using velocity-scaled reference fluxes. The decadal mass balance switched from a mass gain of +47 ± 21 Gt/y in 1972–1980 to a loss of 51 ± 17 Gt/y in 1980–1990. The mass loss increased from 41 ± 17 Gt/y in 1990–2000, to 187 ± 17 Gt/y in 2000–2010, to 286 ± 20 Gt/y in 2010–2018, or sixfold since the 1980s, or 80 ± 6 Gt/y per decade, on average. The acceleration in mass loss switched from positive in 2000–2010 to negative in 2010–2018 due to a series of cold summers, which illustrates the difficulty of extrapolating short records into longer-term trends. Cumulated since 1972, the largest contributions to global sea level rise are from northwest (4.4 ± 0.2 mm), southeast (3.0 ± 0.3 mm), and central west (2.0 ± 0.2 mm) Greenland, with a total 13.7 ± 1.1 mm for the ice sheet. The mass loss is controlled at 66 ± 8% by glacier dynamics (9.1 mm) and 34 ± 8% by SMB (4.6 mm). Even in years of high SMB, enhanced glacier discharge has remained sufficiently high above equilibrium to maintain an annual mass loss every year since 1998.

Greenland – glaciology – sea level – climate change – glaciers

Keywords: Climate Change; Global Warming; Greenland.

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#Avian #Influenza Virus #Surveillance in High #Arctic Breeding #Geese, #Greenland (Avian Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Avian Dis. 2018 Jun;62(2):237-240. doi: 10.1637/11793-010418-ResNote.1.

Avian Influenza Virus Surveillance in High Arctic Breeding Geese, Greenland.

Gaidet N1,2,3, Leclercq I2,3, Batéjat C2, Grassin Q2, Daufresne T4, Manuguerra JC2.

Author information: 1 A CIRAD, UMR ASTRE, Département BIOS, TA C-47/F111, Campus international de Baillarguet, 34398 Montpellier Cedex 5, France. 2 B Institut Pasteur, Unité Environnement et Risques Infectieux, Cellule d’Intervention Biologique d’Urgence (CIBU), 28 rue du Dr Roux, Paris, France. 3 C Université Paris Diderot, Sorbonne Paris Cité (Cellule Pasteur), rue du Dr Roux 75015 Paris, France. 4 D INRA, UMR 210 Eco&Sols, Bat 12, 2 Place Viala, F-34060 Montpellier Cedex 1, France.

 

Abstract

The connectedness in Arctic regions between migratory waterbird populations originating from different continents and the potential for virus exchange at their shared Arctic breeding ground point to the need to explore the largely unstudied circumpolar circulation of avian influenza viruses (AIV). We here report the investigation of AIV in wild birds and lakes in a high Arctic area of Northeast Greenland. No AIV could be detected in the fecal, feather, and water samples collected from large flocks of pink-footed geese Anser brachyrhynchus and barnacle geese Branta leucopsis in and around refuge lakes, where they congregate at high density during their flightless molting period in summer.

KEYWORDS: arctic; environment; feather; ice; migratory bird; water; wildfowl

PMID: 29944408 DOI: 10.1637/11793-010418-ResNote.1

Keywords: Avian Influenza; Wild Birds; Greenland.

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