Wildfires Are Melting Greenland: Expedition Notes
Last summer, I beheld my home state of Colorado on fire. Yet, as the media focused on record-setting property loss and devastated mountain communities, my mind was thousands of miles away, in Greenland. I wondered: How much could a growing supply of airborne wildfire soot be contributing to the ? How important is soot to amplifying Greenland’s melt?
My colleague McKenzie Skiles and I need to travel to Greenland to take samples and put hard numbers on these questions, which is why we launched the Dark Snow crowdfunding campaign. Specifically, we aim to sample Greenland ice and snow to gauge the impact of light-absorbing impurities from increasing wildfire and industrial soot. The ice sheet has been darkening, doubling ice melt rates since year 2000.
The project has so far been like a first ascent, with no guarantee we’d reach our objective, to mount the first Internet crowd-funded Greenland science expedition. Would we inspire enough people to pledge a crowd fund total of $120,000? That question has had me losing sleep since launching 6 December, 2012.
Wildfires Are Melting Greenland: Expedition Begins
Climate scientists Jason Box and McKenzie Skiles are packing up their ice core drills and heading to Greenland.
Six months in, we’ve raised $90,000 and committed to a field campaign. We’re charging up our spectrometer and assembling an ice core drill. We’ve by now booked commercial air travel and are heading to Greenland this 24 of June.
From Greenland’s coast, it’s not a short flight to the ice sheet southern topographic divide at an elevation of 8000 feet (2440 meters). Reacting to a funding constraint, we’ve abandoned the more expensive use of a ski-equipped airplane. We’ve instead committed to the more affordable helicopter option. The airplane would have afforded a larger field party but we have to settle for lean-and-mean. Even reducing our crew to the lightest possible 3 souls—the pilot, myself and McKenzie Skiles—and substituting more fuel for the weight of a 4th passenger, we needed to established a fuel depot halfway to our destination in Saddle, Greenland. Partnering with an earlier , we now have that fuel depot beside DYE-2, an abandoned Cold War-era radar station built by the United States.
(We’ve not yet reached our full funding objective but it’s not too late to help. Dark Snow project supports are effectively joining the expedition and will be the first to receive first-hand reports and updates. You can .)
Wildfires Are Melting Greenland: The Ice Cores
Climate scientists Jason Box and McKenzie Skiles are packing up their ice core drills and heading to Greenland.
We are to extract several ice cores, not miles deep but just to last summer’s layer. That water is now refrozen and buried by several feet of snow. I keep thinking of the ice cores as ice candle sticks with an extinguished wick symbolizing the fire layer. These candlesticks are to be kept frozen in a sleeping bag inside a duffel bag (weight is a premium!) until we reach freezers on the coast. The ice will make its way eventually to labs in Copenhagen, Denmark and Pasadena, California.
Wildfires Are Melting Greenland: The Measurements
Climate scientists Jason Box and McKenzie Skiles are packing up their ice core drills and heading to Greenland.
Snow is a highly reflective natural surface, when dark impurities are present they absorb more sunlight- and the snow reflectivity drops. This same effect can be felt on a sunny day if you wear a dark shirt, rather than a light one. McKenzie will use a “spectrometer” that measures sunlight intensity at high resolution across the visible and near-infrared spectrums, to quantify how much solar energy the snow is absorbing and how much it is reflecting. She will do this first at the surface, collecting measurements of both incoming and reflected sunlight, and then will dig a snow pit down to measure the snow reflectivity at the 2012 surface layer. The combination of all of these measurements, along with impurity content from the ice core, will allow us to more accurately quantify how much additional energy the light absorbing impurities contributed to the
McKenzie will dig a snow pit while Jason cores. She’ll use a portable spectrometer (like the device she is wearing above) to “zap spectra,” which record the snow’s reflectance.
Our science is a philosophical climb and we’re not alone on the mountain. Others have sampled Greenland snow and ice for impurities. Yet, we target specifically the 2012 refrozen melt layer from the
Wildfires Are Melting Greenland: What’s Next
Climate scientists Jason Box and McKenzie Skiles are packing up their ice core drills and heading to Greenland.
The cores we gather from Greenland will get shipped back to (SOL), at NASA’s Jet Propulsion Laboratory, in Pasadena. SOL is designed to analyze snow and ice samples for impurity content. Here, McKenzie will separate impurities between black carbon and other light-absorbing components, like mineral dust. She then can use the optical and chemical properties to tie back the deposited impurities to their source—black carbon from industry or from wildfire. This “source attribution” utilizes a combination of advanced instrumentation and numerical modeling.
Once the impurity content has been determined, the impact due to the impurities can be quantified. Determining the additional energy light-absorbing impurities contribute to melt, known as the radiative forcing, requires a combination of field measured (snow grain size, density, and reflectivity), lab measured (impurity content and characteristics), and modeled (radiative transfer) components.
Living on the ice sheet in summer exposes you to big views of flat white, to deafening silence on rare occasions when it’s not windy, to incredible brightness with high-altitude sun reflecting 60-80 percent right back upward, 24 hours a day. Creature comforts are important, as you’re not bathing so often. To sleep after long days working in the field, we’ll need to wear dark face masks during bright nights. It is by no means a pleasure cruise, but it’s better than living next to a wildfire.
Jason Box is a professor at the Geological Survey of Denmark and Greenland. McKenzie Skiles is a doctoral candidate in the UCLA Department of Geography, and manager of Snow Optics Lab at the Jet Propulsion Lab at the California Institute of Technology.