| 1. |
- Bliss, Andrew, et al.
(författare)
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Global response of glacier runoff to twenty-first century climate change
- 2014
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Ingår i: J GEOPHYS RES-EARTH. - 2169-9003. ; 119:4, s. 717-730
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Tidskriftsartikel (refereegranskat)abstract
- The hydrology of many important river systems in the world is influenced by the presence of glaciers in their upper reaches. We assess the global-scale response of glacier runoff to climate change, where glacier runoff is defined as all melt and rain water that runs off the glacierized area without refreezing. With an elevation-dependent glacier mass balance model, we project monthly glacier runoff for all mountain glaciers and ice caps outside Antarctica until 2100 using temperature and precipitation scenarios from 14 global climate models. We aggregate results for 18 glacierized regions. Despite continuous glacier net mass loss in all regions, trends in annual glacier runoff differ significantly among regions depending on the balance between increased glacier melt and reduction in glacier storage as glaciers shrink. While most regions show significant negative runoff trends, some regions exhibit steady increases in runoff (Canadian and Russian Arctic), or increases followed by decreases (Svalbard and Iceland). Annual glacier runoff is dominated by melt in most regions, but rain is a major contributor in the monsoon-affected regions of Asia and maritime regions such as New Zealand and Iceland. Annual net glacier mass loss dominates total glacier melt especially in some high-latitude regions, while seasonal melt is dominant in wetter climate regimes. Our results highlight the variety of glacier runoff responses to climate change and the need to include glacier net mass loss in assessments of future hydrological change.
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| 2. |
- Pfeffer, W. Tad, et al.
(författare)
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The Randolph Glacier Inventory : a globally complete inventory of glaciers
- 2014
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Ingår i: Journal of Glaciology. - 0022-1430 .- 1727-5652. ; 60:221, s. 537-552
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Tidskriftsartikel (refereegranskat)abstract
- The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance. The RGI was created with limited resources in a short period. Priority was given to completeness of coverage, but a limited, uniform set of attributes is attached to each of the similar to 198 000 glaciers in its latest version, 3.2. Satellite imagery from 1999-2010 provided most of the outlines. Their total extent is estimated as 726 800 +/- 34 000 km(2). The uncertainty, about +/- 5%, is derived from careful single-glacier and basin-scale uncertainty estimates and comparisons with inventories that were not sources for the RGI. The main contributors to uncertainty are probably misinterpretation of seasonal snow cover and debris cover. These errors appear not to be normally distributed, and quantifying them reliably is an unsolved problem. Combined with digital elevation models, the RGI glacier outlines yield hypsometries that can be combined with atmospheric data or model outputs for analysis of the impacts of climatic change on glaciers. The RGI has already proved its value in the generation of significantly improved aggregate estimates of glacier mass changes and total volume, and thus actual and potential contributions to sea-level rise.
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| 3. |
- Radic, Valentina, et al.
(författare)
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Glaciers in The Earth’s Hydrological Cycle : Assessments of Glacier Mass and Runoff Changes on Global and Regional Scales
- 2014
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Ingår i: Surveys in geophysics. - 0169-3298 .- 1573-0956. ; 35:3, s. 813-837
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Tidskriftsartikel (refereegranskat)abstract
- Changes in mass contained by mountain glaciers and ice caps can modify theEarth’s hydrological cycle on multiple scales. On a global scale, the mass loss fromglaciers contributes to sea-level rise. On regional and local scales, glacier meltwater is animportant contributor to and modulator of river flow. In light of strongly acceleratedworldwide glacier retreat, the associated glacier mass losses raise concerns over the sus-tainability of water supplies in many parts of the world. Here, we review recent attempts toquantify glacier mass changes and their effect on river runoff on regional and global scales.We find that glacier runoff is defined ambiguously in the literature, hampering directcomparison of findings on the importance of glacier contribution to runoff. Despite con-sensus on the hydrological implications to be expected from projected future warming,there is a pressing need for quantifying the associated regional-scale changes in glacierrunoff and responses in different climate regimes.
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| 4. |
- Radic, Valentina, et al.
(författare)
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Regional and global volumes of glaciers derived from statistical upscaling of glacier inventory data
- 2010
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 115:1, s. F01010-
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Tidskriftsartikel (refereegranskat)abstract
- Very few global-scale ice volume estimates are available for mountain glaciers and ice caps, although such estimates are crucial for any attempts to project their contribution to sea level rise in the future. We present a statistical method for deriving regional and global ice volumes from regional glacier area distributions and volume area scaling using glacier area data from similar to 123,000 glaciers from a recently extended World Glacier Inventory. We compute glacier volumes and their sea level equivalent (SLE) for 19 glacierized regions containing all mountain glaciers and ice caps on Earth. On the basis of total glacierized area of 741 x 10(3) +/- 68 x 10(3) km(2), we estimate a total ice volume of 241 x 10(3) +/- 29 x 10(3) km(3), corresponding to 0.60 +/- 0.07 m SLE, of which 32% is due to glaciers in Greenland and Antarctica apart from the ice sheets. However, our estimate is sensitive to assumptions on volume area scaling coefficients and glacier area distributions in the regions that are poorly inventoried, i.e., Antarctica, North America, Greenland, and Patagonia. This emphasizes the need for more volume observations, especially of large glaciers and a more complete World Glacier Inventory in order to reduce uncertainties and to arrive at firmer volume estimates for all mountain glaciers and ice caps.
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| 5. |
- Radic, Valentina, et al.
(författare)
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Regionally differentiated contribution of mountain glaciers and ice caps to future sea-level rise
- 2011
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Ingår i: Nature Geoscience. - : Springer Nature. - 1752-0894 .- 1752-0908. ; 4:2, s. 91-94
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Tidskriftsartikel (refereegranskat)abstract
- The contribution to sea-level rise from mountain glaciers and ice caps has grown over the past decades. They are expected to remain an important component of eustatic sea-level rise for at least another century(1,2), despite indications of accelerated wastage of the ice sheets(3-5). However, it is difficult to project the future contribution of these small-scale glaciers to sea-level rise on a global scale. Here, we project their volume changes due to melt in response to transient, spatially differentiated twenty-first century projections of temperature and precipitation from ten global climate models. We conduct the simulations directly on the more than 120,000 glaciers now available in the World Glacier Inventory(6), and upscale the changes to 19 regions that contain all mountain glaciers and ice caps in the world (excluding the Greenland and Antarctic ice sheets). According to our multi-model mean, sea-level rise from glacier wastage by 2100 will amount to 0.124 +/- 0.037 m, with the largest contribution from glaciers in Arctic Canada, Alaska and Antarctica. Total glacier volume will be reduced by 21 +/- 6%, but some regions are projected to lose up to 75% of their present ice volume. Ice losses on such a scale may have substantial impacts on regional hydrology and water availability(7).
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