Secrets in the Ice – December 18, 2019


In this week’s Science Wednesday, we’re joined by Dr. Mike MacFerrin, a glaciologist at the University of Colorado who specializes in the ways Greenland meltwater is affecting the ice sheet and global sea level rise. MacFerrin and his teams have undertaken a half-dozen field campaigns on the ice sheet.

“As a Greenland glaciologist, I ostensibly study snow. But these days more of my time is spent studying water instead. I’m as much a hydrologist these days as a glaciologist. You may have heard, Greenland has been hit by some big melt summers recently as a consequence of a warming Arctic, and just this past July 2019 it melted all the way up at the coldest Summit of the ice sheet for the third time in 7 years, a feat that hadn’t occurred there for 160 years prior to that. A lot is changing there and it’s all we can do as scientists to stay on top of it.

Rewind a handful of years. As a beginning PhD student in 2012, I had the privilege to join a UK-Danish-Swedish team on a field expedition to a particular spot in the southwest Greenland ice sheet. High on the ice where snow builds up year-on-year and melt is low enough to be of little consequence, this spot seemed unremarkable at first sight. Like all of Greenland’s interior, the landscape’s surface is little more than flat snow that stretches for hundreds of miles in all directions in a seamless white blanket. The frigid -30 F air bites your face when the wind blows, and by all appearances it seems like the last place in the world where warming would be your chief concern. Our target that trip wasn’t on the surface though, we were more interested in the snow just under our feet. Using an ice drill to pull up cores, set instruments, and lay down a series of radar surveys, we discovered that the subsurface environment hadn’t just changed, it had transformed completely. Tens of feet of solid ice sat in a solid layer beneath the surface, clear evidence of the impact that prior melt summers had turned the snow-cone under our feet into a solid popsicle.

Two months later, Greenland had its biggest record melt in recorded history, and our field site turned into a slushy mess. Water flowed miles away off the ice instead of freezing in place like it’d always done before. A tractor was washed straight off a bridge as rivers flooded around Greenland to levels never before seen. Years of subsequent surveys, in collaboration with a NASA airborne mission called Operation IceBridge carrying a ground-penetrating radar that could detect these subsurface ice slabs, have allowed us to map areas that have been transformed by summer melt across the entire ice sheet in a way that no one else had been able to do before. The recently published work (…/greenland-ice-getting…/) is another big nugget of knowledge about the ways that a warming climate is fundamentally changing our environment in rapid and unexpected ways.

As is usual, the science in the end quietly hides the years of work that went into collecting measurements. Broken-down snowmobiles, lost drills, and hurricane-force winds that can shred a thousand-dollar mountaineering tent in minutes, hounded our team for years in the hopes that we could push the boundaries of knowledge just a tiny bit further forward. I’ve made lifelong friends and perfected my camp recipe of chicken-fried muskox made over a Coleman stove. The science itself is equal parts exciting (as a scientist) and terrifying (as a father). But if we hope to know what’s coming in a warming world, we have to keep pushing on.”

Check out another interesting story about Greenland in this podcast with Mike:…/centennial-e4-toxic-city-…/

Image posted with permission from Dr. Mike MacFerrin