NEWS Uniquely old tree remains have recently been uncovered by the thawing of the rapidly shrinking Kårsa Glacier west of Abisko in Lapland, in northernmost Sweden. The finds show that in the last 7,000 years it has probably never been so warm as during the last century.
"If the area hadn't been covered by a glacier all these thousands of years, these tree remnants would never have made it. The finds yield information indicating that the 20th century was probably the warmest century in 7,000 years. The fact that the climate is so unique during the last century means that we must question whether this could be 100 percent the result of natural mechanisms," says Leif Kullman, professor of physical geography, who is directing the project.
Pines and birches grew on the site of the glacier during parts of or perhaps the entire period between 11,800 and 7,000 years ago. This is shown by carbon 14 dating of the remains of trees that have now been uncovered. During that period, the glacier did not continuously exist, and the climate was warmer than at any time afterward.
All in all, there are four finds, parts of birch and pine trunks, that have been uncovered under the shrinking glacier in the Lapland mountains. In most cases they are well preserved, but they are degrading rapidly as they come in contact with air and water. As early as 2003, tree remnants of a similar age were found in Sylarna, in Jämtland province. They have completely crumbled into dust at this point. The warmer climate during the last century, which is the reason the tree remnants have now seen the light of day, may therefore be unique in the perspective of many millennia.
The oldest tree, a pine, lived and died on the site of the Kårsa glacier around 12,000 years ago. The area is 400-450 meters above today's timberline. This discovery places the thawing of ice at the end of the latest ice age in an entirely new perspective.
"Previous research indicated that Lapland was covered with ice at this time. These finds show that the ice melted and life returned much earlier than we previously thought," says Leif Kullman.
The researchers are now continuing their examination of glaciers in northern Lapland and Västerbotten (West Bothnia). This ongoing research is part of a larger project that comprises glaciers throughout the entire range of mountains in Sweden. The project is funded by the Swedish Research Council and is directed by Professor Leif Kullman, Umeå University.
Leif Kullman, professor of physical geographyPhone: +46 (0)90-786 68 93; cell phone: +46 (0)70-5641848
E-post: leif.kullman@emg.umu.se
Editor: Karin Wikman