Global warming: Dust in the wind …

Dirty snow and ice at the edge of the Greenland Ice Sheet. @bberwyn photo.

Study takes close look at organic debris in Arctic ice cores

Staff Report

Organic biomarkers, in the form of tiny soil and plant particles, have helped ice core scientists track climate shifts linked to changes in the Arctic Oscillation. The research suggests that global warming will lead to more dust in the Arctic, which could speed up the meltdown of sea ice and Greenland glaciers.

The study by scientists with the University of Birmingham examined organic dust  transported from Asia and deposited in the Arctic over the last 450 years. During warmer phases of the Arctic Oscillation, more dust was being deposited in the Arctic, according to the findings published in the journal Nature Scientific Reports.

The scientists studyied two ice-cores collected from ice-caps more than 6000 kilometers apart, one from Greenland, the other from Kamchatka, in eastern Russia.Deposits can be dated very accurately by studying the annual layers within the cores — similar to tree rings — which allow scientists to examine deposits going back many years.

‘We are applying a new type of measurement to ice cores for the first time, and have successfully obtained information on past climate change from measurement of organic biomarkers in the cores – molecules from plants and soils – which have been transported thousands of miles by the wind to the Greenland and Kamchatka ice-caps where the cores are extracted from,” said Dr. James Bendle, lead investigator from the University of Birmingham’s School of Geography, Earth and Environmental Sciences.

“The similarity of the ice core records is remarkable considering the geographical separation between the two sites. This gives us confidence that our records represent broad scale changes in the northern Hemisphere and not just local factors,” Bendle said.

The research has implications for climate change because most models project that the Arctic Oscillation will increasingly move into its positive mode of wetter and windier weather in the North as a response to increases in greenhouse gases and global warming.

“If this is the case, our research suggests that there could be increased transport of dust and carbonaceous aerosols to the Arctic. As these organic-rich dusts are dark in colour, they could start to lower the reflectance of the snow and ice covered surfaces in the Arctic, leading to an even warmer regional climate,” Bendle said.


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