Study: Global warming pushing Arctic closer to point of no return

The latest study on the Arctic demonstrates the fragile ecosystem is more vulnerable to climate change than was previously thought.

An international team of scientists issued a press release Tuesday to announce their findings, published in Geology. The paper, titled Significantly warmer Arctic surface temperatures during the Pliocene indicated by multiple independent proxies, has a shocking conclusion -- that it might be too late to reverse the effects of global warming for the Arctic. The researchers studied Arctic temperatures during the Pliocene period, a time when the earth's temperatures were warmer than at present. Finding only slightly higher Co2 levels for the Pliocene period, with average temperatures much warmer at that time, the scientists are warning

"... current levels of Earth's atmospheric carbon dioxide may be high enough to bring about significant, irreversible shifts in Arctic ecosystems."

Lead researcher on the study, Ashley P. Ballantyne said

"Our findings indicate that CO2 levels of approximately 400 parts per million are sufficient to produce mean annual temperatures in the High Arctic of approximately 0 degrees Celsius (32 degrees F). As temperatures approach 0 degrees Celsius, it becomes exceedingly difficult to maintain permanent sea and glacial ice in the Arctic. Thus current levels of CO2 in the atmosphere of approximately 390 parts per million may be approaching a tipping point for irreversible ice-free conditions in the Arctic."

The Pliocene, NASA explains, was a period of time that occurred from 5 million to 1.8 million years ago. While no-one really knows what caused a significant portion of the Pliocene to be warm, the period is used to study climate change into the future. In December 2009, the latest US Geological Survey research on the Arctic concluded

"... Finally, these new data imply a major mid-Piacenzian reduction in sea ice similar to what has been observed in recent summers, strengthening the idea that the anomalous sea ice melting we have observed in the Arctic Ocean in recent years may be an early warning for significant global warming."

The conclusion of the latest study not only reinforces the 2009 study, but demonstrates that

"... The Arctic is clearly a bellwether for modern climate change. Arctic temperatures have increased more rapidly in response to anthropogenic greenhouse forcing than global temperatures. ... climate models do not incorporate the full array of atmospheric, biospheric, and cryospheric feedback mechanisms necessary to simulate Arctic climate. Regardless of the feedback mechanism responsible for amplified Arctic temperatures, our results indicate that a significant increase in Arctic temperatures may be imminent in response to current atmospheric CO2 levels."

Jaelyn Eberle, a Curator of the University of Colorado Museum of Natural History who participated in the research, said

"Our findings are somewhat disconcerting regarding the temperatures and greenhouse gas levels during the Pliocene. We already are seeing evidence of both mammals and birds moving northward as the climate warms, and I can't help but wonder if the Arctic is headed toward conditions similar to those that existed during the Pliocene."

Natalia Rybczynski, from the Canadian Museum of Nature, explained the study was conducted on Ellesmere Island because

"During the Pliocene, Ellesmere Island hosted forests of larch, dwarf birch and northern white cedar trees, as well as mosses and herbs, including cinquefoils. The island also was home to fish, frogs and now extinct mammals that included tiny deer, ancient relatives of the black bear, three-toed horses, small beavers, rabbits, badgers and shrews. Because of the high latitude, the Ellesmere Island site on the Strathcona Fiord was shrouded by darkness six months out of the year."

The remains of all those life-forms have been preserved as fossils on the island.

"Today, Ellesmere Island is a polar desert that features tundra, permafrost, ice sheets, sparse vegetation and a few small mammals. Temperatures range from roughly minus 37 degrees F, or minus 38 degrees C, in winter to 48 degrees F, or 9 degrees C, in summer. The region is one of the coldest, driest environments on Earth."

Warnings that the Arctic may have reached a tipping point have been issued for at least the past three years. In early June, the National Snow and Ice Data Center issued an update on Arctic ice saying

"In May, Arctic air temperatures remained above average, and sea ice extent declined at a rapid pace. At the end of the month, extent fell near the level recorded in 2006, the lowest in the satellite record for the end of May. Analysis from scientists at the University of Washington suggests that ice volume has continued to decline compared to recent years. However, it is too soon to say whether Arctic ice extent will reach another record low this summer—that will depend on the weather and wind conditions over the next few months."

Ballantyne noted that over the past 20 years, the average temperature in the Arctic has increased by 1 degree Celsius. The National Oceanic and Atmospheric Administration (NOAA) noted earlier this year that "global warming is continuing unabated." The research team was comprised of A.P. Ballantyne, University of Colorado; David Greenwood, Brandon University (Manitoba); Jaap Sinninghe Damste, the Royal Netherlands Institute for Sea Research; Adam Csank, University of Arizona; Natalia Rybczynski, the Canadian Museum of Nature; Jaelyn Eberle, University of Colorado Museum of Natural History. Funding was provided by National Science Foundation, the Natural Science and Engineering Research Council in Canada, the Netherlands Organization for Scientific Research and the European Research Council.