The Greenland Ice Sheet, which is the largest ice sheet in the Northern Hemisphere, is revealing new secrets that are reshaping scientists' understanding of its behavior. Covering approximately 80% of Greenland's landmass, this colossal ice sheet is second only to Antarctica in size worldwide. Scientists have discovered that beneath its vast expanse, the ice sheet is cracking open at an alarming pace, leading to seismic events known as "ice quakes." These findings have significant implications for global sea level rise as meltwater from the Greenland Ice Sheet is currently the largest contributor to rising sea levels.
Researchers have recorded countless ice quakes sporadically shaking the Greenland Ice Sheet. These seismic events occur when ice fractures and two slabs grind against each other, functioning similarly to earthquakes. The Northeast Greenland Ice Stream, the island's largest frozen river, serves as a main artery for discharging ice from the interior into the North Atlantic Ocean. Scientists have drilled a 1.7-mile-deep borehole into this ice stream to study its dynamics more closely.
The discovery of ice quakes challenges previous assumptions about how ice streams move. Traditionally, scientists believed these streams flowed like viscous honey. However, recent findings indicate a more complex movement pattern where they switch between flowing smoothly and moving jerkily.
"The fact that we've now discovered these ice quakes is a key step towards gaining a better understanding of the deformation of ice streams on small scales." – Olaf Eisen, a professor of glaciology at the Alfred Wegener Institute for Polar and Marine Research in Germany.
Adding to the intrigue is the discovery of volcanic particles buried 2,950 feet beneath the ice. These particles originate from a massive eruption of Mount Mazama in what is now Oregon, dating back approximately 7,700 years. The buried volcanic particles act as a barrier, preventing ice quakes from reaching the surface.
"We were astonished by this previously unknown relationship between the dynamics of an ice stream and volcanic eruptions." – Andreas Fichtner, a professor of geophysics at the Swiss Federal Institute of Technology (ETH) in Zurich.
The presence of these volcanic particles suggests that historical geological events continue to influence the behavior of modern ice sheets. This insight opens new avenues for understanding how volcanic activity can impact ice dynamics and subsequently affect sea level rise.
Scientists have estimated that there is enough ice locked within Greenland to raise global sea levels by 23 feet. The rapid pace at which the ice sheet is cracking highlights the urgency for further research to mitigate potential impacts on coastal communities worldwide.
"The assumption that ice streams only flow like viscous honey is no longer tenable." – Andreas Fichtner, a professor of geophysics at the Swiss Federal Institute of Technology (ETH) in Zurich.
