Retreating Glacier Fronts on the Antarctic Peninsula over the Past Half-Century

Cook, Alison; Fox, Adrian J.; Vaughan, David G.; Ferrigno, Jane G.

doi:10.1126/science.1104235

Cited by 752 publications

(572 citation statements)

References 21 publications

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“…The observed lowering is in agreement with observations of regional warming and glacier retreat in the AP over the last decades (Cook et al, 2005). The frontal lowering at Leonardo glacier (~64.7°S) is higher than at Nemo glacier (~67.7°S).…”

Section: Discussionsupporting

confidence: 80%

“…Increased air and sea surface temperatures have led to dramatic changes in glacier and iceshelf extent in recent decades (Meredith and King, 2005;Cook and Vaughan, 2010). Over the last 50 years more than 85 % of 244 observed glaciers showed retreat (Cook et al, 2005). An assessment of ice mass changes in the AP is very important to derive estimates of the region's recent and future contribution to sea-level rise.…”

Section: Introductionmentioning

confidence: 99%

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Application of Surface Matching for Improved Measurements of Historic Glacier Volume Change in the Antarctic Peninsula

Kunz

Mills

Miller

et al. 2012

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Climate records show that the Antarctic Peninsula is rapidly warming. Dramatic changes in ice shelf and glacier extent have been recorded over the last few decades. Mapping recent changes in the Antarctic Peninsula is relatively straightforward, as increased amounts of earth observation data become readily available for scientific purposes. However, long term measurements of volumetric changes within the region are rare and less is known of changes which have occurred over the second half of the 20th Century. Nonetheless, historical observations are available in the form of archival aerial stereo-photography. However, extracting information from historical data, i.e. to compare it to recent data, is not trivial, and to-date, this data source remains largely untapped, despite its rich potential. Often such imagery is stored in non-digital format and may have degraded over time. Other problems relate to insufficient metadata or ground control. Typically these difficulties result in poor registration of multi-temporal DEMs, which degrade subsequent measurements of surface change. This is one of the fundamental limitations of accessing archival datasets. In this research a least squares surface matching technique is introduced to overcome these challenges and achieve reliable registration of multi-temporal DEMs. Historical imagery acquired in the 1960s for two Antarctic Peninsula glaciers is processed to extract DEMs, which are subsequently compared to DEMs derived from modern ASTER satellite data and aerial photography. Through the surface matching approach, it is shown that the registration accuracy of the historical and modern-day datasets can be improved significantly. This enables precise quantification of glacier elevation changes on a multi-decadal time scale. Frontal glacier surface lowering of up to 50 m was observed over the last ~4 decades. Results of this study allow a better understanding of historical volumetric glacier changes of the Antarctic Peninsula and provide an efficient and automated method for improved DEM co-registration.

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Application of Surface Matching for Improved Measurements of Historic Glacier Volume Change in the Antarctic Peninsula

Kunz

Mills

Miller

et al. 2012

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…Average annual winter temperature on the Antarctic Peninsula has increased 6°C in the last 30 years (2), increasing the volume and frequency of glacier retreat and meltwater (29). In this region, there has been a transition from mean glacial growth (62% advancing in 1954) to retreat (87% retreating in 2004) (29).…”

Section: Resultsmentioning

confidence: 99%

Melting Glaciers: A Probable Source of DDT to the Antarctic Marine Ecosystem

Geisz

Dickhut

Cochran

et al. 2008

Environ. Sci. Technol.

160

110

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Persistent organic pollutants reach polar regions by long-range atmospheric transport and biomagnify through the food web accumulating in higher trophic level predators. We analyzed Adélie penguin (Pygoscelis adeliae) samples collected from 2004 to 2006 to evaluate current levels of ∑DDT (p,p′-DDT + p,p′-DDE) in these birds, which are confined to Antarctica. Ratios of p,p′-DDT to p,p′-DDE in Adélie penguins have declined significantly since 1964 indicating current exposure to old rather than new sources of ΣDDT. However, ∑DDT has not declined in Adélie penguins from the Western Antarctic Peninsula for more than 30 years and the presence of p,p′-DDT in these birds indicates that there is a current source of DDT to the Antarctic marine food web. DDT has been banned or severely restricted since peak use in the 1970s, implicating glacier meltwater as a likely source for DDT contamination in coastal Antarctic seas. Our estimates indicate that 1−4 kg·y−1 ΣDDT are currently being released into coastal waters along the Western Antarctic Ice Sheet due to glacier ablation.

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“…Some of the clearest signals of regional climate warming come from the Antarctic Peninsula (Smith et al, 1999;Vaughan et al, 2001;Gille, 2002;Cook et al, 2005), including significant long-term increases in air temperature, retreat of glaciers, and the collapse of large ice shelves. Emerging evidence suggests that warming has decreased the number of cold years with heavy winter sea ice and that as a consequence penguin populations are showing substantial concurrent population responses (Fraser et al, 1992;Fraser & Trivelpiece, 1996;Croxall et al, 2002;Smith et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Contrasting population changes in sympatric penguin species in association with climate warming

Forcada

Trathan

Reid

et al. 2006

Global Change Biology

204

230

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Climate warming and associated sea ice reductions in Antarctica have modified habitat conditions for some species. These include the congeneric Adélie, chinstrap and gentoo penguins, which now demonstrate remarkable population responses to regional warming. However, inconsistencies in the direction of population changes between species at different study sites complicate the understanding of causal processes. Here, we show that at the South Orkney Islands where the three species breed sympatrically, the less iceadapted gentoo penguins increased significantly in numbers over the last 26 years, whereas chinstrap and Adélie penguins both declined. These trends occurred in parallel with regional long-term warming and significant reduction in sea ice extent. Periodical warm events, with teleconnections to the tropical Pacific, caused cycles in sea ice leading to reduced prey biomass, and simultaneous interannual population decreases in the three penguin species. With the loss of sea ice, Adélie penguins were less buffered against the environment, their numbers fluctuated greatly and their population response was strong and linear. Chinstrap penguins, considered to be better adapted to ice-free conditions, were affected by discrete events of locally increased ice cover, but showed less variable, nonlinear responses to sea ice loss. Gentoo penguins were temporarily affected by negative anomalies in regional sea ice, but persistent sea ice reductions were likely to increase their available niche, which is likely to be substantially segregated from that of their more abundant congeners. Thus, the regional consequences of global climate perturbations on the sea ice phenology affect the marine ecosystem, with repercussions for penguin food supply and competition for resources. Ultimately, variability in penguin populations with warming reflects the local balance between penguin adaptation to ice conditions and trophic-mediated changes cascading from global climate forcing.

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Retreating Glacier Fronts on the Antarctic Peninsula over the Past Half-Century

Cited by 752 publications

References 21 publications

Application of Surface Matching for Improved Measurements of Historic Glacier Volume Change in the Antarctic Peninsula

Application of Surface Matching for Improved Measurements of Historic Glacier Volume Change in the Antarctic Peninsula

Melting Glaciers: A Probable Source of DDT to the Antarctic Marine Ecosystem

Contrasting population changes in sympatric penguin species in association with climate warming

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