One of the largest icebergs ever recorded is about to cleave off of Antarctica and drift to sea. The Larsen C iceberg is approximately the size of Delaware and has been separating from Antarctica at an amazing pace, with the canyon between the two growing by 18 km since mid-December 2016.

The Larsen C iceberg has been rifting from Antarctica for decades but appears to be hastening its departure in the recent months. In fact, the iceberg only has a 20 km long stretch of intact ice holding it in place until it fully calves. The 5,000-square kilometer iceberg comprises just a portion of the Larsen C ice sheet, which is roughly twice the size of the big island of Hawaii. This specific iceberg will cleave off about 10 percent of the ice sheet. Larsen C is roughly 350 m thick and floats on the seas to the edge of West Antarctica. While this is an incredible amount of ice breaking off, somewhat more important is the role the Larsen C iceberg played in maintaining the competency of the entire ice sheet. The Larsen C iceberg acts to hold back encroaching land-based glaciers and limits the disintegration of the entire ice sheet. The Larsen C iceberg won’t increase sea level as was already floating on the ocean while attached to the larger ice sheet. However, removing the barrier to flow will leave the entire shelf vulnerable and allow for the much larger Larsen C ice sheet to flow into the sea over time. This, in total, could lead to a 3.9-inch sea level rise. That may not seem significant but compare it to the 2.6-inch sea level rise that we’ve witnessed over the past 20 years.