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Greenland ice sheet (CLIM 009) - Assessment published Nov 2012

Indicator Assessment Created 18 Sep 2012 Published 19 Nov 2012 Last modified 19 Nov 2012, 02:55 PM
Topics: ,

Update planned for February 2014 to include new results from the IPCC AR5

 
Contents
 

Indicator definition

  • Estimated changes of the ice mass in Greenland
  • Yearly cumulated melt area of Greenland ice sheet

Units

  • Gigatonnes/year  (Gt/yr)
  • % change compared to 1979

Key policy question: What is the trend in the mass and the melting area of the Greenland ice sheet , and what is the effect on global sea level?

Key messages

  • The Greenland ice sheet is the largest body of ice in the Northern Hemisphere and plays an important role in the cryosphere. It changed in the 1990s from being in near mass balance to losing about 100 billion tonnes of ice per year. Ice losses have since then more than doubled to 250 billion tonnes a year averaged over 2005 to 2009.
  • The contribution of ice loss from the Greenland ice sheet to global sea-level rise is estimated at 0.14–0.28 mm/year for the period 1993–2003 and has since increased. The recent melting of the Greenland ice sheet is estimated to have contributed up to 0.7 mm a year to sea-level rise, which is approximately one quarter of the total sea-level rise of about 3.1 mm/year.
  • Model projections suggest further declines of the Greenland ice sheet in the future but the processes determining the rate of change are still poorly understood.

Mass balance of the Greenland ice sheet from mass budget calculations

Note: The figure shows the mass balance of the Greenland ice sheet from mass budget calculations.

Data source:
Downloads and more info

Trend in yearly cumulated melting area of the Greenland ice sheet

Note: The figure shows the change in yearly cumulated area of the Greenland ice sheet and it's melt during the period 1979 to 2011 in percentage relative to area in 1979=100. The linear trend 1979–2011 is included.

Data source:
Downloads and more info

Key assessment

Past trends

The mass balance of the Greenland ice sheet is determined by snow fall, summer melting of snow, and the icebergs breaking off the glaciers. Several different methods are used to monitor the changes of the Greenland ice sheet [i].  The overall conclusion is that Greenland is losing mass at an accelerating rate (Figure 1). The yearly cumulated area where melting occurs has also increased significantly (Figure 2). Since 2006, high summer melt rates have led to a Greenland ice sheet mass loss of 273 billion tonnes a year [ii]. This ice loss corresponds to a sea-level rise of approximately 0.7 mm per year (about a quarter of the total sea-level rise of 3.1 mm a year). 

Exceptional melting was recorded on the Greenland ice sheet in the summer of 2012. On 12 July 2012 nearly the entire ice cover experienced some degree of surface melting [iii]. The extreme melt event coincided with an unusually strong ridge of warm air over Greenland. The ridge was one of a series that dominated Greenland's weather in the summer of 2012. Ice core data suggest that large-scale melting events of this type have occurred about once every 150 years on average, the most recent one in 1889. It is not currently possible to tell whether the frequency of these rare extensive melt events has changed.

Ice is lost from Greenland, in roughly equal amounts, through surface melting and ice motion [iv]. Surface melting occurs when warm air and sunlight first melt all the previous year’s snow and then the ice itself. At higher elevations snow accumulates and the local mass balance remains positive. With global warming the height at which melting occurs moves upwards and eventually a tipping point may be reached after which the whole ice sheet starts to melt [v].

Projections

Projections of the surface mass balance of the Greenland ice sheet with many global climate models indicate that the ‘tipping point’ above which the Greenland ice decline will completely melt is a global temperature rise of about 3 °C [vi]. However, this estimate is subject to considerable uncertainty [vii].

Climate models with an embedded dynamic ice sheet model have suggested that a melt of 10–20 % of the current ice sheet volume, inducing ice loss in southern Greenland, would lead to an irreversible sea-level rise of about 1.3 m over several centuries. The addition of contributions by outlet glaciers [viii] and the expected surface mass balance-driven losses give an upper bound of about 19 cm sea-level rise from the Greenland ice sheet by 2100.

 


[i] W.B. Krabill et al., “Aircraft Laser Altimetry Measurement of Elevation Changes of the Greenland Ice Sheet: Technique and Accuracy Assessment,” Journal of Geodynamics 34, no. 3–4 (October 2002): 357–376, doi:10.1016/S0264-3707(02)00040-6; A Shepherd and D Wingham, “Recent Sea-level Contributions of the Antarctic and Greenland Ice Sheets,” Science 315, no. 5818 (2007): 1529–1532, doi:10.1126/science.1136776; H. Jay Zwally et al., “Greenland Ice Sheet Mass Balance: Distribution of Increased Mass Loss with Climate Warming; 2003-07 Versus 1992-2002,” Journal of Glaciology 57, no. 201 (2011): 88–102, doi:10.3189/002214311795306682; J. L. Chen, C. R. Wilson, and B. D. Tapley, “Interannual Variability of Greenland Ice Losses from Satellite Gravimetry,” Journal of Geophysical Research 116 (July 28, 2011): B07406, doi:10.1029/2010JB007789; E. Rignot et al., “Acceleration of the Contribution of the Greenland and Antarctic Ice Sheets to Sea Level Rise,” Geophysical Research Letters 38 (March 4, 2011): L05503, doi:10.1029/2011GL046583.

[ii] Rignot et al., “Acceleration of the Contribution of the Greenland and Antarctic Ice Sheets to Sea Level Rise.”

[iii] NASA, “Satellites See Unprecedented Greenland Ice Sheet Melt,” 2012, http://www.jpl.nasa.gov/news/news.php?release=2012-217.

[iv] M. van den Broeke et al., “Partitioning Recent Greenland Mass Loss,” Science 326, no. 5955 (November 12, 2009): 984–986, doi:10.1126/science.1178176.

[v] J. M Gregory and P. Huybrechts, “Ice-sheet Contributions to Future Sea-level Change,” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1844 (July 15, 2006): 1709–1732, doi:10.1098/rsta.2006.1796.

[vi] Gregory and Huybrechts, “Ice-sheet Contributions to Future Sea-level Change.”

[vii] Marion Bougamont et al., “Impact of Model Physics on Estimating the Surface Mass Balance of the Greenland Ice Sheet,” Geophysical Research Letters 34 (September 1, 2007): L17501, doi:10.1029/2007GL030700.

[viii] J. K. Ridley et al., “Elimination of the Greenland Ice Sheet in a High CO₂ Climate,” Journal of Climate 18, no. 17 (September 2005): 3409–3427, doi:10.1175/JCLI3482.1; W. T. Pfeffer, J. T. Harper, and S. O’Neel, “Kinematic Constraints on Glacier Contributions to 21st-Century Sea-Level Rise,” Science 321, no. 5894 (September 5, 2008): 1340–1343, doi:10.1126/science.1159099.

Data sources

Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.

Targets

No targets have been specified.

Related policy documents

  • Climate-ADAPT: Mainstreaming adaptation in EU sector policies
    Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
  • Climate-ADAPT: National adaptation strategies
    Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
  • DG CLIMA: Adaptation to climate change
    Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives later. This webportal provides information on all adaptation activities of the European Commission.
  • EU Adaptation Strategy Package
    In April 2013 the European Commission adopted an EU strategy on adaptation to climate change which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it will enhance the preparedness and capacity of all governance levels to respond to the impacts of climate change.

Methodology

Methodology for indicator calculation

Estimates are based on the mass budget method based on a combination of the output from regional climate models and various satellite-borne datasets (altimetry and gravimetry data).

The graphs show the data as delivered by the authors of the referenced publications; a linear trend line was added.

Methodology for gap filling

Not applicable

Methodology references

No methodology references available.

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

Data on the cryosphere vary significantly with regard to availability and quality. Snow and ice cover have been monitored globally since satellite measurements started in the 1970s. Improvements in technology allow for more detailed observations and higher resolution. Direct historical area-wide data on the Greenland ice sheet tracks about 20 years, but reconstructions give a 200 000 year perspective.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)


Rationale uncertainty

Not applicable

More information about this indicator

See this indicator specification for more details.

Generic metadata

Topics:

Climate change Climate change (Primary topic)

Tags:
climate change | cryosphere | greenland
DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CLIM 009
Dynamic
Temporal coverage:
1979-2011
Geographic coverage:
Greenland

Contacts and ownership

EEA Contact Info

Hans-Martin Füssel

Ownership

EEA Management Plan

2012 2.0.1 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled once per year

Comments

European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100