January 24, 2013
Greenland Ice Core Research Points To Higher Seas, Warmer Past
Brett Smith for redOrbit.com - Your Universe Online
New research findings based on Greenland ice cores show that if climate change patterns repeat themselves, the Earth will become much warmer and sea levels will rise significantly.
In a new report published in the latest edition of the journal Nature, scientists have used Greenland ice cores over 1.5 miles long to collect data on the Eemian period, around 115 to 130 thousand years ago. An analysis of the cores allowed the international team of researchers to reconstruct Greenland´s temperature and ice sheet size back through the last interglacial period. Most scientists consider the last interglacial period to be analogous to our current time period and, more importantly, the near future.
"Even though the warm Eemian period was a period when the oceans were four to eight meters higher than today, the ice sheet in northwest Greenland was only a few hundred meters lower than the current level, which indicates that the contribution from the Greenland ice sheet was less than half the total sea-level rise during that period," co-author Dorthe Dahl-Jensen, a professor from the Niels Bohr Institute at the University of Copenhagen, said in a statement.
After being extracted from the Arctic ice, the cores were analyzed for their content of a certain heavy oxygen isotope, O18. The analysis revealed the historical temperatures in clouds during snowfall, giving a window into the climate of the past. The cores were also examined for air bubbles, which could provide snapshots about the atmosphere during past climates.
The results of the series of analyses gave scientists a "road map" that showed where Earth´s climate could be headed in the future. According to the report, about 128,000 years ago, the elevation of the site where the ice cores were drawn from was more than 650 feet higher than present. The scientists estimated that between 122,000 and 115,000 years ago, Greenland's surface elevation had dropped to about 425 feet below the present level as a result of melting.
The scientists noted that the drop in the size of Greenland´s ice sheet occurred with the increasing amounts of carbon dioxide emissions currently being tracked in the Earth´s atmosphere.
"Unfortunately, we have reached a point where there is so much carbon dioxide in the atmosphere it's going to be difficult for us to further limit our impact on the planet," co-author Jim White, the director of the University of Colorado, Boulder's Institute of Arctic and Alpine Research, said in a separate statement. "Our kids and grandkids are definitely going to look back and shake their heads at the inaction of this country's generation. We are burning the lion's share of oil and natural gas to benefit our lifestyle, and punting the responsibility for it."
The research was driven by the North Greenland Eemian Ice Drilling (NEEM) project, a 14-nation research team, which has spent the past four years drilling and analyzing the island´s core. The project researchers said the current conditions on the Arctic island are just as alarming as their study´s findings.
"We were quite shocked by the warm surface temperatures observed at the NEEM ice camp in July 2012," said Dahl-Jensen. "It was raining at the top of the Greenland ice sheet, and just as during the Eemian period, meltwater formed subsurface ice layers. While this was an extreme event, the present warming over Greenland makes surface melt more likely, and the predicted warming over Greenland in the next 50-100 years will very likely be so strong that we will potentially have Eemian-like climate conditions."