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Winters in Siberian permafrost regions have warmed since millennia (gradual warming for 7,000 years)
http://www.awi.de/en/news/press_releases/detail/item/winters_in_siberian_permafrost_regions_have_warmed_since_millenia/?cHash=d72eddb6d3efedc5d5a73bd7f5ba3128[font face=Serif]26. January 2015: [font size=5]Winters in Siberian permafrost regions have warmed since millennia[/font]
[font size=4]Bremerhaven, 26 January 2015. For the first time, researchers at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have successfully employed a geochemical method used in glacier research to decode climate data from millennia-old permafrost ground ice and reconstruct the development of winter temperatures in Russia’s Lena River Delta. Their conclusions: Over the past 7,000 years, winter temperatures in the Siberian permafrost regions have gradually risen. The researchers claim that this is due to the changing position of the Earth relative to the sun and is amplified by the rising greenhouse-gas emissions since the dawn of industrialisation. The study will be published as the cover story of the upcoming February issue of the scientific journal Nature Geoscience.[/font]
[font size=3]…
The new information represents the first well dated winter-temperature data from the Siberian permafrost regions and indicates a clear trend: “Over the past 7,000 years, the winters in the Lena River Delta have steadily warmed – a trend we haven’t seen in almost any other Arctic climate archive,” says Hanno Meyer. As the permafrost expert explains, the likely reason is: “To date, primarily fossilised pollen, diatoms and tree rings from the Arctic have been used to reconstruct the climate of the past. But they mostly record temperature information from the summer, when the plants grow and bloom. Ice wedges are among the few archives that can exclusively record winter data.”
…
Nevertheless, the researchers found clear indications for the causes of this warming. According to Hanno Meyer: “The curve shows a clear partitioning. Up to the dawn of industrialisation around 1850, we can attribute the development to changes in the Earth’s position relative to the sun. In other words, the duration and intensity of the solar radiation increased from winter to winter, causing temperatures to rise. But with industrialisation and the strong increase in the emissions of greenhouse gases like carbon dioxide, this was supplemented by the anthropogenic greenhouse effect. Starting at that point, our data curve shows a major increase that clearly differs from the gradual warming in the previous phase.”
In a next step, the researchers will investigate whether the same indicators for a gradual rise in winter temperatures in the Arctic can also be found in other permafrost regions around the globe. As Thomas Opel elaborates: “We already have data from an area 500 kilometres east of the Lena River Delta that supports our findings. But we don’t know how it looks for example in the Canadian Arctic. We suppose the development was similar there, but don’t yet have evidence to back up that assumption.”
…[/font][/font]
http://dx.doi.org/10.1038/ngeo2349[font size=4]Bremerhaven, 26 January 2015. For the first time, researchers at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have successfully employed a geochemical method used in glacier research to decode climate data from millennia-old permafrost ground ice and reconstruct the development of winter temperatures in Russia’s Lena River Delta. Their conclusions: Over the past 7,000 years, winter temperatures in the Siberian permafrost regions have gradually risen. The researchers claim that this is due to the changing position of the Earth relative to the sun and is amplified by the rising greenhouse-gas emissions since the dawn of industrialisation. The study will be published as the cover story of the upcoming February issue of the scientific journal Nature Geoscience.[/font]
[font size=3]…
The new information represents the first well dated winter-temperature data from the Siberian permafrost regions and indicates a clear trend: “Over the past 7,000 years, the winters in the Lena River Delta have steadily warmed – a trend we haven’t seen in almost any other Arctic climate archive,” says Hanno Meyer. As the permafrost expert explains, the likely reason is: “To date, primarily fossilised pollen, diatoms and tree rings from the Arctic have been used to reconstruct the climate of the past. But they mostly record temperature information from the summer, when the plants grow and bloom. Ice wedges are among the few archives that can exclusively record winter data.”
…
Nevertheless, the researchers found clear indications for the causes of this warming. According to Hanno Meyer: “The curve shows a clear partitioning. Up to the dawn of industrialisation around 1850, we can attribute the development to changes in the Earth’s position relative to the sun. In other words, the duration and intensity of the solar radiation increased from winter to winter, causing temperatures to rise. But with industrialisation and the strong increase in the emissions of greenhouse gases like carbon dioxide, this was supplemented by the anthropogenic greenhouse effect. Starting at that point, our data curve shows a major increase that clearly differs from the gradual warming in the previous phase.”
In a next step, the researchers will investigate whether the same indicators for a gradual rise in winter temperatures in the Arctic can also be found in other permafrost regions around the globe. As Thomas Opel elaborates: “We already have data from an area 500 kilometres east of the Lena River Delta that supports our findings. But we don’t know how it looks for example in the Canadian Arctic. We suppose the development was similar there, but don’t yet have evidence to back up that assumption.”
…[/font][/font]
