You’ve probably heard: 97% of Greenland’s ice cover has melted this summer…mostly within a four-day period. In fact, the change was so dramatic that NASA thought their satellites were malfunctioning. Seems like a cause for major concern, right? Some point to climate change; the Byronic Man, jokester that he is, theorizes that perhaps the Greenlanders just painted all their ice red :). Well, I thought I’d do a little digging to make sure I’ve got the whole story. Here’s what I found out:
On July 8, NASA satellites recorded that 40% of Greenland’s ice sheet had melted. On July 12, that number had jumped to 97%. Wow! Take a look at the satellite image:
Apparently, the ice has even melted at Summit Station, Greenland’s highest and coldest point, an occurrence that hasn’t happened since 1889. Additionally, no more than 55% of the ice sheet has melted over the last 30 years, so this is a dramatic increase from the norm. Is this cause for concern?
NASA scientists say that a melting event of this magnitude is expected once every 150 years, based on ice core samples that give scientists a glimpse into Greenland’s ecological history. And, according to NASA’s Lora Koenig, this event is, “right on time.” So, this melting would appear to be part of Greenland’s natural cycle. BUT, Koenig cautions that, “if we continue to observe melting events like this in upcoming years, it will be worrisome.”
Another four days after this image was taken, on July 16, a 59-square-mile chunk of ice broke off (or “calved off”) of Greenland’s Petermann glacier. While loss of ice is not uncommon (Greenland has lost 150 gigatons of ice each year over the last 20 years during its annual melt, which contributes 0.5mm to global sea rise per year), recent events have brought the glacier’s terminus (it’s edge) to a location it has not been for 150 years. Again, scientists say that such massive ice loss is expected every 150 years, but this type of melting event will be a major cause for concern if it happens again next year. Another key question is whether the ice cap can rebuild itself after these larger losses?
An interesting fact: glacier calving is typically due to a rise in water temperatures, while glacial melting is due to increases in air temperatures. So, it does not appear that these two events are related to one another. But, it is possible that they both stem from climate change, as anthropogenic climate change is believed to have caused a rise in both air and water temperatures.
Right now, I think most predictions for next year can only be considered speculations, but next summer’s melt will indicate whether this was a once-in-150-years event or a symptom of a rapidly changing climate. What do you think?