A new study published in the current issue of Science suggests that an ice-free Arctic may very well become a reality in the near future.
The research team set out to study Lake El’gygytgyn, “Lake E” for short, which was formed 3.6 million years ago when a meteorite hit earth. Because it has not been eroded by continental ice sheets, which is rare in the Arctic, it has an undisturbed sediment record that the team wanted to examine. The sediment samples examined were collected in 2009 from Lake E, and enabled the scientists to look back in time 2.2 to 3.6 million years ago.
The research team discovered that “[e]vidence from Lake El’gygytgyn, NE Arctic Russia, shows that 3.6-3.4 million years ago, summer temperatures were ~8°C warmer than today when pCO2 was ~400 ppm,” the article summary explains. Essentially, the summer temperatures were about 14 degrees warmer than current temperatures in the Arctic, significant because of the relatively small difference.
“There was probably no sea ice, and the whole Arctic was pretty well forested, so it was a very different world,” lead author of the study Julie Brigham-Grette told LiveScience. “So, how did we go from that to the tundra that we have today, and what does this tell us about the future?”
By examining the sediment pulled from Lake E, researchers were able to determine that both Hemlock and Douglas Fir trees were present. “Hemlock and Douglas fir can tolerate cold and relatively humid conditions but thrive best in relatively moist cool temperate areas with high rainfall, cool summers, and little or no water stress” Brigham-Grette writes. Discovery of the presence of these two trees and subsequent analysis allowed scientists a key look at the impact of the climate on the region.
“We can see that the Arctic is quite sensitive to CO2 changes, and levels in the Pliocene were thought to be similar to today,” Brigham-Grette explained to LiveScience. “Some of the changes we see going on now — sea ice melting, tree lines migrating and glaciers with tremendous ablation rate — suggest that we’re heading back to the Pliocene.” She continued to explain that this information is particularly vital in determining if there is a tipping point that we need to be aware of—the point of no return, so to speak.
Were the ice sheet to disappear, it would mean cascading and catastrophic effects throughout the Arctic food chain, from plankton to polar bears, USA Today predicts. And the effects are not just limited to the Arctic itself. Geopolitical fighting over navigation and mining rights have already begun due to concerns about landslides and other effects caused by melting permafrost.