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TitleTrends of climate change and atmospheric deposition of toxic elements in Canadian high Arctic ice caps during the past 50 years
AuthorZheng, J; Fisher, D; Shotyk, W; Zdanowicz, C; Bourgeois, B; Burgess, D; Krachler, M
SourceThe arctic as a messenger for global processes - climate change and pollution, abstract volume; 2011 p. 33-34
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20110115
MeetingThe arctic as a messenger for global processes - climate change and pollution; Copenhagen; DK; May 3-6, 2011
Mediaon-line; digital
File formatpdf
Subjectssurficial geology/geomorphology; environmental geology; Nature and Environment; ice; ice samples; heavy metals contamination; climate, arctic; climatic fluctuations; climate effects; environmental analysis; environmental studies; environmental impacts; climate change
ProgramEnvironmental Geoscience, Program management and Transition Activities
AbstractIce/snow in Polar Regions and alpine glaciers, are specifically valuable because 1). Glaciers are remotely located with only atmospheric inputs; 2). Snow/ice accumulation rates can be much higher than other natural archives, therefore, results a higher resolution record; and 3). Once accumulated, ice/snow stays in place in the frozen matrix with little disturbance. Therefore, ice cores are media that are currently the best available and most reliable for reconstructing trends of climate changes and contamination history.
Since 1970s, we have carried out multi ice cap studies on climate change and ice caps/glaciers in Canadian High Arctic, including melting percentage changes and most concerned contaminants, such as lead (Pb), cadmium (Cd), antimony (Sb) and mercury (Hg). Our results reveal that
1) The most recent 25 years have been the hottest in several millennia. From the Holocene-long Agassiz 2 melt percentage series, we see that the last 25 years has the highest melt in 4200 years and the melt rates since the early 1990s resemble those of the early Holocene thermal maximum over 9000 years ago;
2) For atmospheric contaminants,
- Over the last 50 years, atmospheric deposition of Cd on Devon Island has decreased 69%. However, at least 39% of the current atmospheric Cd deposition is created by anthropogenic sources.
- The Arctic today is profoundly contaminated with anthropogenic Sb. The Arctic snow and ice data show that human impacts on the Sb cycle are global in extent. Although Sb concentration has been steadily decreasing since 1960s, its enrichment factor however is increasing since 1980s, which may be attributed to changes of source of origins.
- Although Pb concentration in snow and ice from Canadian High Arctic has continuously been decreasing since 1970s, due to the elimination of gasoline lead additives in Europe, North America and Japan, and the most of other countries, aerosols in the Canadian High Arctic today are still contaminated by anthropogenic Pb (over 90% anthropogenic sources).
3) A broad total Hg peak exists between the mid 1990s and 2005 on both the Agassiz Ice Cap and the Mt. Oxford Ice Field, which is almost twice the amplitude of peaks found between 1950 and the mid 1990s. A net deposition rate of total Hg on Canadian High Arctic ice caps could only be at a level < 0.1 ug m-2 y-1, which is much lower than those found in lake sediments, peat bogs and alpine ice cores.