A recent discovery of a rare sediment core in a remote Arctic lake provides compelling evidence of unprecedented environmental changes occurring over the past few decades.
The research team was composed of scientists from Queen’s University, the University of Alberta, University of Buffalo and University of Massachusetts.
The Queen’s University press release
quotes Neal Michelutti, a research scientist at the Paleoecological Environmental Assessment and Research Lab (PEARL) at Queen’s as saying, “Our findings show that the last several decades have been the most ecologically unique in 200,000 years.”
Michelutti was working with biology professor John Smol, Canada Research Chair in Environmental Change, and master’s student Cheryl Wilson, the Queen’s researchers are part of a multidisciplinary team led by University of Colorado scientist Yarrow Axford.
The study is published on-line today in the journal,
Proceedings of the National Academy of Sciences.
The researchers obtained the sediment core of the bottom of Lake Baffin. The core predates by about 80,000 years the oldest cores from the Greenland Ice Sheet.
“Lake sediments are natural recorders of climate and environmental changes, as they preserve archives of past geochemical and physical conditions, as well as a diverse record of important biological indicators,” Wilson explains.
Algae and aquatic insect fossils, preserved in the sediment core, were used to reconstruct past climatic and other environmental conditions.
“The 20th century is the only period during the past 200 millennia in which aquatic indicators reflect increased warming, despite the declining effect of slow changes in the tilt of the Earth’s axis which, under natural conditions, would lead to climatic cooling,” the press release states the University of Colorado’s Dr. Axford noted.
The effect of massive ice shifts, in glacial regions during past ice ages, has been comparable to operating a massive bulldozer over the terrain. The ice shifts reformed the underlying bedrock.
This did not happen in the Baffin Island lake due to the presence of what is known as cold-based ice. Cold-based ice is non-erosive and acts to preserve landscape features such as lakes and the sediments contained within their basins.
“Our results show that the ‘human footprint’ is overpowering long-standing natural processes, even in remote Arctic regions,” the release quotes Dr. Smol, winner of the 2004 NSERC Herzberg Gold Medal as Canada’s top scientist.
“This historical record shows that we are dramatically affecting the ecosystems on which we depend. We have started uncontrolled experiments on this planet, and we have entered unchartered territory. The situation is far worse than we thought and this is only the beginning.”
