Buried beneath 1.6 miles of solid ice, Greenland's bedrock reveals our planetary future

Illustration for article titled Buried beneath 1.6 miles of solid ice, Greenland's bedrock reveals our planetary future

After five years of drilling through 1.6 miles of solid ice, scientists finally hit Greenland's bedrock last week. The buried rock holds secrets to how Earth's climate changed 100,000 years ago, and what it means for today's climate upheaval.

Reaching the bedrock will allow researchers to collect ice cores - crystallized ice that contains air bubbles from previous time periods - that date back to the Eemian Period some 130,000 to 115,000 years ago. That particular period was the last time in Earth's history that average temperatures were significantly higher than they are now, and they hope careful analysis of these ice cores will help us better understand the impacts of global warming today.

Project head Dorthe Dahl-Jensen of the University of Copenhagen explained what they hope to determine:

"Our findings will increase our knowledge on the climate system and increase our ability to predict the speed and final height of sea level rise. If the Eemian was unstable, then the models of future change due to increased greenhouse effect are wrong as they cannot handle sudden changes."


The current scientific consensus holds that any temperature rise greater than 2 degrees Celsius above pre-industrial levels could have serious, dangerous consequences for the Earth as a whole. Climate levels have already risen 0.8 degrees Celsius over the last two centuries, and some experts project final levels as high as 5 or 6 degrees Celsius higher based on current greenhouse gas emissions.

During the Eemian Period, Greenland experienced temperatures about 3 to 5 degrees Celsius higher than today, which makes it a perfect test case to study the effects of such a drastic temperature increase. Above all, the researchers want to know just how much Greenland's gigantic ice sheet was reduced during these warmer periods. There's no clear agreement on what could happen to that ice sheet if global warming continues, with predictions ranging from pretty much no change at all to a partial melting that will raise ocean levels by over three feet.

Considering the latter could potentially displace hundreds of millions of people living in coastal areas, that's an unacceptably massive range of potential outcomes, and this project hopes to narrow down the possibilities. We know that ocean levels were raised about five feet during the Eemian period, but we don't know how the Greenland ice sheet fit into that.

If the ice cores reveal relatively little of the ice sheet melted back then, that's a cautiously positive indicator that it won't be a major factor during this period of warming. But if the cores reveal the sheet did experience significant melting, then it might be a good idea for anyone near the oceans to start thinking about higher, cooler ground. I hear Greenland is lovely this time of the century.



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Isn't a good deal of Greenland's interior actually supposed to be below sea level due to the weight of the ice cap that has been pressing down on it for hundreds of thousands of years? If it were to melt, you'd have two different issues—a) the volume of water that used to be on top of Greenland would now be in the ocean and b) the land mass under Greenland would slowly begin to rebound which over time would displace the water that covered any submerged sections. At least B wouldn't happen suddenly.