Greenland melt season kicks off slowly in 2015; the new abnormal

June 8th, 2015

Sitting here in Kangerlussuaq west Greenland expecting not a large melt year. Like another late melt season, 2013, a sticky atmospheric circulation pattern in the past 5 months has favored cold air transport down the west coast of the island.

8 June snow on windshield

windshield snow 8 June, 2015 Kangerlussuaq west Greenland

The story goes like this…

Below average temperatures…


have promoted above average surface albedo, see red areas…



…above average albedo everywhere except the south southeast where precipitation is below average.


…caused in not a small degree by persistent atmospheric circulation anomalies, the hallmark of inter-annual variability.

SLP 2015

28 May, 2015, the heat turned on and albedo responded…


…but temperatures remain below normal…



All this has me expect it would take quite the opposite pattern for 2015 melt to hit the high melt in 2014 (in fits and spurts, with warmest June on record here in ‘Kanger’, west Greenland), extreme melt in 2012, 2010, high melt in 2011, 2009, 2008, 2007. The past warm episodes were due to persistent atmospheric circulation, a.k.a., stick weather patterns, favoring heating of west Greenland. What we have in 2015 and in 2013 the sticky cold pattern opposite.

There is evidence, two most recent of a growing list of citations, of Arctic warming slowing the jet stream, causing it to meander more, creating sticky weather patterns. Welcome to the new abnormal.

a conspicuous area of cold

March 23rd, 2015

While global surface temperatures are increasingly dominated by warm anomalies, a conspicuous area of cold has persisted south of Greenland and Iceland visible at the ocean surface in sea surface temperature observations. The abnormal cold there has been more anomalous than the US northeast winter. While the most recent northern winter was the warmest on record globally, the ocean surface area south of Greenland & Iceland had the lowest temperatures in the 136 year record. How could this be?


global map of winter 2014/2015 temperature anomalies.

A new study estimates the Atlantic Meridional Overturning Circulation (AMOC) using the sea surface temperature difference at that cold spot south of Greenland/Iceland with the Northern Hemispheric temperature from NASA GISS instrumental records since the 1880s (Hansen and others 1999) and from coral-based proxies after Sherwood and others (2011) that span years since 500 AD.

Rahmstorf, S., J.E. Box, G. Feulner, M.E. Mann, A. Robinson, S. Rutherford and E.J. Schaffernicht, Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation, Nature Climate Change, 23 MARCH 2015, DOI: 10.1038/NCLIMATE2554

Based on this AMOC reconstruction, the study finds that the slowdown of the Atlantic Meridional Overturning Circulation (AMOC) after 1975

  1. appears unprecedented in the past millennium;
  2. is expected to continue, even intensify through year 2100, as simulated with the MPI-ESM-MR global climate model of the Max Planck Institute in Hamburg (Jungclaus and others, 2013)
  3. may result to a large degree from Greenland melting.

My contribution was my work of 6 years, a 172 year Greenland mass balance reconstruction published in a 3 part series in the Journal of Climate (Box and others 2013; Box, 2013; Box and Colgan, 2013), enabling Greenland melting to be brought more into context of its ocean thermohaline perturbation.


increasing Greenland contribution to dilution of surrounding surface waters, figure in Rahmstorf and others (2015)

Melt from Greenland produces water that is lighter and colder than the sea surface waters. The meltwater is light enough to float above the saltier sea surface waters. Because Atlantic surface waters flow northward (see map below), an increasing ice melt freshwater supply ( blue line in the figure above) may pile up near the sea surface, capping or backing up the Gulf Stream North Atlantic Drift current that a.) delivers warmth to northwestern Europe and b.) is part of a global ocean heat conveyer. While Bamber and others (2012) set the stage with “Recent large increases in fresh- water fluxes from Greenland into the North Atlantic”, the new study more directly quantifies the possible impact from Greenland on the ocean thermohaline circulation.

Atlantic Conveyor - graph by Rahmstorf from PIK 20150317

Atlantic Conveyor after Rahmstorf 1997

Why should we care?

The North Atlantic ocean circulation is an important part of a global ocean circulation that exchanges heat from the equatorial surplus to the poles where the energy is lost by thermal radiation to space. A slowed global oceanic ‘conveyer belt’ may further destabilize our changing global climate. We expect no new ice-age – but major negative effects are possible. The effects could be on global climate, fisheries, or also for example storminess.

Influence on weather?

The study will stimulate discussion and research on how the large area of negative sea surface temperatures anomalies south of Greenland and Iceland may influence European and downstream weather. Given some heat exchange between a warm air mass with an anomalously cold North Atlantic sea surface, some strengthening of winds, lowering of central pressure of cyclonic systems, should result from increased “baroclinic instability” (see for example Holton et al. 1992) arising from an increased temperature difference between sea surface and atmosphere. As the subpolar North Atlantic cools and the atmosphere warms, the physics are set to strengthen cyclonic circulation in warm air masses. Converseley, cold air masses drifting off of N America would be less prone to baroclinic deepening. In any case, the perturbation may be felt not just in that part of the world, but downstream, and like the proverbial butterfly (seagull) flapping its wings, alters atmospheric and oceanic flow, with certain though hard to predict downstream consequences.

Work Cited

Bamber, J., M. van den Broeke, J. Ettema, J. Lenaerts, and E. Rignot (2012), Recent large increases in fresh- water fluxes from Greenland into the North Atlantic, Geophys. Res. Lett., 39, L19501, doi:10.1029/2012GL052552.

Box, J.E., N. Cressie, D.H. Bromwich, J. Jung, M. van den Broeke, J.H. van Angelen, R.R. Forster, C. Miège, E. Mosley-Thompson, B. Vinther, J.R. McConnell. 2013. Greenland ice sheet mass balance reconstruction. Part I: net snow accumulation (1600-2009). J. Climate, 26, 3919–3934. doi:10.1175/JCLI-D-12-00373.1 [2]. Box, J. E. 2013. Greenland ice sheet mass balance reconstruction. Part II: Surface mass balance (1840-2010), J. Climate,Vol. 26, No. 18. 6974-6989.  doi:10.1175/JCLI-D-12-00518.1 Box, J.E., W. Colgan. 2013. Greenland ice sheet mass balance reconstruction. Part III: Marine ice loss and total mass balance (1840–2010). Journal of Climate, 26, 6990–7002. doi:10.1175/JCLI-D-12-00546.1

Curry, R. & Mauritzen, C. 2005. Dilution of the northern North Atlantic Ocean in recent decades. Science 308, 17721774.

Hansen, J., Ruedy, R., Glascoe, J. & Sato, M. GISS analysis of surface temperature change. J. Geophys. Res. 104, 3099731022 (1999).

Holton, J .R. (1992): An Introduction to Dynamic Meteorology, 3rd ed., Academic Press.

Jungclaus, J. H. et al. Characteristics of the ocean simulations in the Max Planck Institute Ocean Model (MPIOM) the ocean component of the MPI-Earth system model. J. Adv. Model. Earth Syst. 5, 422446 (2013).

Rahmstorf, S., J.E. Box, G. Feulner, M.E. Mann, A. Robinson, S. Rutherford and E.J. Schaffernicht, Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation, Nature Climate Change, 23 MARCH 2015 | DOI: 10.1038/NCLIMATE2554

Sherwood, O. A., Lehmann, M. F., Schubert, C. J., Scott, D. B. & McCarthy, M. D. Nutrient regime shift in the western North Atlantic indicated by compound-specific delta N-15 of deep-sea gorgonian corals. Proc. Natl Acad. Sci. USA 108, 10111015 (2011).


fire, ice, soot, carbon: Dark Snow Project 2014 final field work in Greenland

August 1st, 2014

Arrived yesterday to Kangerlussuaq, west Greenland, now 6 AM, we’re just about out the door in effort to put more numbers on how fire and other factors are affecting Greenland’s reflectivity as part of the Dark Snow Project. 

I just received this 27 July, 2014 NASA MODIS satellite image showing wildfire smoke drifting over Greenland ice. 

Premier climate video blogger Peter Sinclair is a key component of the Dark Snow Project because of our focus on communicating our science to the global audience. The video below was shot and edited last night quickly as we prepare for a return to our camp a few hours from now. 

The video does not comment on the important issue of carbon. So, here’s a quick research wrap-up… Wildfire is a source of carbon dioxide, methane and black carbon to the atmosphere. Jacobson (2014) find that sourcing to be underestimated in earlier work. Graven et al. (2013) find northern forests absorbing and releasing more carbon by respiration due to Arctic warming’s effects on forest composition change. At the global scale, the land environment produces a net sink of carbon, taking up some 10% of the atmospheric carbon emissions due to fossil fuel combustion (IPCC, 2007). Yet, whether northern wildfire is becoming an important source of atmospheric carbon (whether from CO2 or CH4 methane) remains under investigation. University of Wisconsin-Madison researchers find:

“fires shift the carbon balance in multiple ways. Burning organic matter quickly releases large amounts of carbon dioxide. After a fire, loss of the forest canopy can allow more sun to reach and warm the ground, which may speed decomposition and carbon dioxide emission from the soil. If the soil warms enough to melt underlying permafrost, even more stored carbon may be unleashed.

“Historically, scientists believe the boreal forest has acted as a carbon sink, absorbing more atmospheric carbon dioxide than it releases, Gower says. Their model now suggests that, over recent decades, the forest has become a smaller sink and may actually be shifting toward becoming a carbon source.

“The soil is the major source, the plants are the major sink, and how those two interplay over the life of a stand really determines whether the boreal forest is a sink or a source of carbon

Works Cited
  • Danish Meterological Institute provided the NASA MODIS satellite image
  • Graven, H.D., R. F. Keeling, S. C. Piper, P. K. Patra, B. B. Stephens, S. C. Wofsy, L. R. Welp, C. Sweeney, P.P. Tans, J.J. Kelley, B.C. Daube, E.A. Kort, G.W. Santoni, J.D. Bent, 2013, Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960,  Science: Vol. 341 no. 6150 pp. 1085-1089, DOI: 10.1126/science.1239207
  • Climate Change 2007: Working Group I: The Physical Science Basis, IPCC Fourth Assessment Report: Climate Change 2007
  • Jacobson, M. Z., 2014, Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon, and cloud absorption effects, J. Geophys. Res. Atmos., 119, doi:10.1002/2014JD021861.

Siberian tundra holes are a mystery to me

July 30th, 2014

An Australian news piece juxtaposes mysterious Siberian holes with my Arctic tundra carbon release concerns but I have no idea about the cause of the holes. As a physical geographer, I’m aware of pingos that these features resemble but these features are holes and pingos are mounds. If you ask me, talk to field scientists with expertise in permafrost. For further reporting on the mysterious holes, see here.

screenshot searching “Sberian hole” in Google images


Is the climate dragon awakening?

July 27th, 2014

Using a vast and credible set of climate measurements and physics, James Hansen’s Storms of My Grandchildren makes the case that humans overloading the atmosphere with carbon would eventually trigger the release of vast additional carbon stores locked in shallow sea gas hydrates and from Arctic tundra.

In my professional opinion as a climatologist with more than 70 externally reviewed scientific publications, after 12 years of university education focused on atmospheric and oceanic science, and followed by 10 years of university lecturing on micro and mesoscale meteorology theory and instrumentation, Hansen’s warnings should be met with an aggressive atmospheric decarbonization program.  We have been too long on a trajectory pointed at an unmanageable climate calamity; runaway climate heating. If we don’t get atmospheric carbon down and cool the Arctic, the climate physics and recent observations tell me we will probably trigger the release of these vast carbon stores, dooming our kids’ to a hothouse Earth. That’s a tough statement to read when your worry budget is already full as most of ours is.

December 2013, I found myself in a packed room at the world’s largest science meeting, the AGU fall meeting. The session: “Cutting-Edge Challenges in Climate”. Invited speaker Dr. Lori Bruhwiler presented “Arctic Permafrost and Carbon Climate Feedbacks” - a cautious, objective, and science-only [politics-free] survey of the Arctic carbon issue and what data we have. Also invited, Dr. Peter Wadhams pitched “The cost to society of a methane outbreak from the East Siberian shelf”, off the fence, citing costs to humanity measured in trillions of $. My take home from the session was well paraphrased by Bruhwiler, citing a sparse observational network, concluding ‘we just can’t say much yet’. That was then…

The global network of greenhouse gas sampling stations as per NOAA

Clearly, considering the vastness of the Arctic, the network of ground-based observing stations does appear sparse, with a solitary station representing Siberia, at Tiksi, you’re left thinking that governments should do more to keep their finger on this pulse. On the pulse side, however, the measurements happening at Tiksi [and other sites in the network such as Alert and Pt. Barrow northern Alaska], I can tell you, are really high end; with BSRN radiometers, eddy covariance gas fluxes, gas flask sampling, etc., impressive and not inexpensive. What do these data tell us?

  1. A 30 year methane data series from Alert, far northern Canada, 30 year, includes an 8% increase in methane. This is the most recent 8% of the more than 250% humans have elevated methane since industrialism began year 1750 or so. The Tiksi record started recently is too short to deduce a trend. But it includes, like the other records in this network, 
  2. Methane records from this network include occasional spikes. Green symbols on the charts below indicate these extreme positive outliers. A reasonable hypothesis for the outliers marked below by me with dragon breath? [I had these labled WTF? ] would be: extreme outlying positive anomalies represent high methane concentration plumes emanating from tundra and/or oceanic sources. Another reasonable hypothesis would be: extreme outlying positive anomalies represent observational errors. What NOAA states:  the outliers “are thought to be not indicative of background conditions, and represent poorly mixed air masses influenced by local or regional anthropogenic sources or strong local biospheric sources or sinks. ” Fair enough. But, the dragon breath hypothesis has me losing sleep.
same spikes evident in 32 years of Pt. Barrow, Alaska data. here, I don’t bother to overlay the dragon breath?s.

While we don’t have permanent measurements floating over the oceanic centers of action, for example over the Eastern Siberian shallow continental shelf, we do have satellite data from the Infrared Atmospheric Sounding Interferometer (IASI) on board the Eumetsat Polar System (EPS) Metop-A Satellite. And as I know from installing/maintaing Arctic ground measurements and publishing articles assessing the quality of satellite-derived retrievals from the Arctic, most recently here, validation studies are needed. So, it’s good to find Xiong et al. (2013) who, using “596 methane vertical profiles from aircraft measurements by the HIAPER Pole-to-Pole Observations (HIPPO) program” find that the remotely sensed quantities are accurate and have a small (less than 2%) low bias. Yet, their assessment is for the part of the atmosphere well above the surface. Some accuracy findings for IASI over the Arctic are provided by the Yurganov et al. (AGU poster 2012) that concludes:

  • IASI data can be used as qualitative indicator of the Arctic Ocean methane emission.
  • Current methane growth in the Arctic, including 2012, is gradual.
  • Methane emission from the Arctic shelf has a maximum in September-October. [when sea ice minimum occurs]
  • Top-down emission estimates are difficult and may be very uncertain ( e. g., ± 100%)
  • If a sudden venting (bubbling) of methane would happen due to intense hydrates destruction, IASI would be able to detect it near real-time 

Now, a Sam Carana leads a group who have been blogging up a storm about methane estimates from the IASI sensor. Their messaging is alarming, connecting dots between methane maps they generate using IASI data and a number of rapidly changing Arctic climate elements: declining sea ice area, duration, volume; increasing air and sea surface temperature, wildfire.

My understanding was that the methane bubbles can’t or don’t make it to the surface, instead are converted to much less potent carbon dioxide before reaching the surface. Then, here’s what we hear from 4 days ago from a Swedish team now surveying the Laptev sea with a very high-end icebreaker, named for the main Norse god.

The Swedish team states “At several places, the methane “bubbles“ even rose to the ocean surface. That’s damn scary. Atmospheric methane release is a much bigger problem than atmospheric carbon dioxide release, since methane is ~20 times more powerful greenhouse gas. If as it seems, sea ice reduction is destabilizing the shallow Arctic Ocean continental shelf waters. Without the reflective cover, the ocean is taking on a lot more solar heating during the 24 h summer days, making it harder for the sea ice to reform, in a self compounding feedback process. Places like the Laptev and East Siberian seas, are shallow, and the water column can more easily be mixed by wind action than when sea ice cover was there. This new heating and mixing can be what unlocks the shallow sea gas hydrates, allowing the methane up to the surface.

The methane bubbles they filmed boiling up toward, even to the surface of the Arctic Ocean.

The story of methane bubbles coming to the surface is not actually that new. Here’s a 2011 pieceon the topic. Shakova et al (2013) suggest that: “significant quantities of methane are escaping the East Siberian Shelf as a result of the degradation of submarine permafrost over thousands of years. We suggest that bubbles and storms facilitate the flux of this methane to the overlying ocean and atmosphere, respectively


What’s the take home message, if you ask me? Because elevated atmospheric carbon from fossil fuel burning is the trigger mechanism poking the climate dragon. The trajectory we’re on is to awaken a runaway climate heating that will ravage global agricultural systems leading to mass famine, conflict. Sea level rise will be a small problem by comparison. We simply MUST lower atmospheric carbon emissions. This should start with limiting the burning of fossil fuels from conventional sources; chiefly coal, followed by tar sands [block the pipeline]; reduce fossil fuel use elsewhere for example in liquid transportation fuels; engage in a massive reforestation program to have side benefits of sustainable timber, reduced desertification, animal habitat, aquaculture; and redirect fossil fuel subsidies to renewable energy subsidies. This is an all hands on deck moment. We’re in the age of consequences.

There are still questions, of course, but the cautionary principle makes clear we have to keep this dragon in the ground.

Phoenix Glacier relic ice

September 10th, 2013

I’m in South Greenland drilling low tech metal pipes into the ice to calibrate high tech satellite, aircraft, and model data.

Flying over this landscape, it’s stunning how much the ice has retreated. Annual (let alone summer) average air temperatures at nearby Narsarsuaq have been above the melting point 39 of the past 51 years [1]. Unequivocal evidence of rapid ice retreat; relic stranded ice [2] was what led Denmark to support scientists at GEUS to install modern ice monitoring measurements in 2001. The observations are now called “Q transect” as part of the PROMICE network around Greenland.

I was stunned to witness (and photograph) more stranded relic ice on the sides of the glacier. Notice how no ice is feeding Phoenix’s wings from upstream.

The glacier’s current shape resembles a Phoenix, with wings (relic ice) outstretched to the front, and the phoenix has a demise, like this glacier.

We’re here surveying the damage with Shane Smith of Vice media for an up coming spot on HBO.

Vice supported the installation of six ablation stakes at elevations between 390 and 1100 m on the Qassimiut lobe of the ice sheet, hence the name Q transect.

 The stakes are carefully tied into a coordinate system using the antenna at the upper right recording the site elevation and horizontal position by differential GPS.

This Phoenix should of course rise again, but not until after another ice age. When that happens? It’s gonna be a while.

Follow @PromiceGL on Twitter.

Work Cited

  • [1] Cappelen, John, DMI Monthly Climate Data Collection 1768-2010, Denmark, The Faroe Islands and Greenland. Dansk Meteorol. Inst. Tech. Rap., 11-05, 54 pp, 2011.
  • [2] Podlech; Steffen, Christoph Mayer, Carl Egede Bøggild, Glacier Retreat, Mass-Balance and Thinning: Sermilik Glacier, South Greenland, Geografiska Annaler: Series A, Physical Geography, Volume 86, Issue 4, pages 305–317, December 2004, DOI: 10.1111/j.0435-3676.2004.00234.x

Visiting and monitoring South Greenland dark ice

August 16th, 2013

I’m spending a week flying out of Narsarsuaq, south Greenland, with colleague Dr. Robert Fausto, to maintain climate stations equipped to monitor surface ice melt in great detail. Part of the Danish PROMICE network, the stations obtain surface energy and mass budget closure. The closure means that calculated melt matches with observed melt.

coming in to land at a PROMICE climate station, one of 22 on Greenland ice operated by GEUSPhoto J. Box.

Flying across this vast space and on the ground, I’m is struck by how abundant snow algae and other light absorbing impurities can be. The low reflectivity impurities amplify the effects of the increasing melt season. Increased melt means a shorter duration of highly reflective snow cover. The prolonged exposure of an impurity-rich bare ice surface multiplies melt rates. I’ve calculated that without this albedo feedback, the increase in melt rates would amount to half of what’s observed. Some of this feedback is due to ice crystal rounding. Some is due to the impurities. Measuring the relative importance of metamorphic and impurity driven albedo reduction is a subject of our work.

boots on the ice offer a close look (and to sample) impurities concentrating at the surface. The fact is, much of this dark material is from cyanobacteria and blue-green algae. Photo J. Box.

puddles often form with this kind of algal slick’. Photo J. Box.

It’s exciting to be working with Dr. Marek Stibal who studies the microbial environment on Arctic ice. Together with his data, the surface energy exchange data from the PROMICE climate stations and Danish Meteorological Institute’s regional climate modeling (Follow @Greenlandsmb), we have a powerful approach to unravel more detail from the melt story in Greenland.

South Greenland Dark Ice. Photo J. Box.

Snow accumulates in crevasses forming snow bridges that one would rather fly over. In between, impurity-rich ice absorbs up to 80% of the Sun’s energy. Photo J. Box.

Surface melt water mingles with impurity rich Greenland ice. Photo J. Box.

Robert Fausto maintains a climate station equipped to measure downward and upward solar energy, among many other climate parameters as part of the Danish PROMICE network (Follow @PromiceGL). Photo J. Box. (Follow @Climate_Ice)

Greenland 2013 melt is over the hill

August 12th, 2013

While average sea ice minimum occurs in September, the Greenland ice albedo minimum occurs in July. This year, the albedo minimum occurred 31 July, coinciding with a record setting warm episode.

By 9 August, fresh snowfall concentrated along the southeastern ice sheet brought up the ice sheet albedo.

Across the northwestern ice sheet, melting increased the first 10 days of August, darkening the surface from a brighter than normal pattern associated with abnormally large snow accumulation that made difficult the Japanese SIGMA expedition.

Ice sheet albedo remains anomalously low along the western upper ablation area. The most persistent low albedo this melt season has been along the northwest, in the vicinity of Storstrømmen glacier.

Heat transport into the Arctic bypassed Greenland to it’s east. Svalbard has had a warm summer.

A reliable feature of climate is the poleward transport of heat in the atmosphere (and ocean) and the main contuit into the Arctic is the North Atlantic. So, what we see in this figure is normal and Greenland just didn’t get much exposure to this warm air stream (marked with up-pointing purple arrows). This extra heat bypassed Greenland much of this summer.

Greenland high near-surface air temperature record set

August 3rd, 2013

It’s worth adding that the large scale circulation, if (likely) delivering (excess, anthropogenic) heat and moisture via south air advection, is arguably a legitimate part of a climate change narrative. The foehn effect may not be an aside if atmospheric humidity were increased by climate warming, yielding additional latent heat release in the downslope compression of the foehn effect…

Greenland soars to its highest temperature ever recorded, almost 80 degrees F.

By Jason Samenow, Published: August 1 at 1:47 pmE-mail the writer


The Danish Meteorological Institute is reporting that on Tuesday, July 30, the mercury rose to 25.9 C (78.6 F) at a station in Greenland, the highest temperature measured in the Arctic country since records began in 1958.

The balmy reading was logged at the observing station Maniitsoq / Sugar Loaf, which is on Greenland’s southwest coast, the DMI reports. It exceeded the 25.5 C (77.9 F) reading taken at  Kangerlussuaq on July 27, 1990, in the same general area. Mantiitsoq is Greenland’s sixth-largest town, with a 2010 population of 2,784.

4880007af6Weather pattern responsible for record warmth in southwest Greenland (Danish Meteorological Institute)

The DMI says the record warmth was brought about by southeasterly winds, funneled by the flow between a large area of high pressure over continental Greenland, and low pressure over Baffin Island to the west.

It adds the warmth may have been enhanced by a phenomenon known as the Foehn Effect, in which air flows over nearby elevated terrain and compresses and heats on its way down. In this case, DMI believes the air may have passed over the elevated Sugar Loaf ice cap and then dried and warmed up as it descended (or downsloped) on its leeward side into Maniitsoq.

Via the Danish Meteorological Institute: "Satellite photo of the area around Maniitsoq and Sugar Loaf Mountain on Tuesday 30 July 2013. Photo from NASA's Terra satellite."Via the Danish Meteorological Institute: “Satellite photo of the area around Maniitsoq and Sugar Loaf Mountain on Tuesday 30 July 2013. Photo from NASA’s Terra satellite.”
(IPCC)Conceptual model of how a warming baseline climate increases the chance of record-breaking weather (IPCC)

The DMI says the warmth was not “unnatural”, but explains it fits into a long-term pattern of climate warming.

“[T]here is an indisputable gradual increase in temperature in Greenland,”DMI writes. “Along the way, any ‘warm event’ thus have a higher probability of being slightly warmer than the previous one.”

Related, from 2012: Greenland ice sheet surface melt: massive meltdown or meaningless trickle?

This warm temperature extreme in Greenland comes on the heels of an astonishing heat wave in northern Siberia.

Wunderground weather historian Christopher Burt described a “perhaps unprecedented” streak of 10 days in the central Arctic region of Russia in which temperatures exceeded 86 degrees F (30 C) in mid-to-late July.

Prior to this, it was the desert southwest reaching heat milestones.  Recall Death Valley set the record for hottest U.S. temperature ever recorded in June, climbing to a blistering 129 degrees.

At the moment, China is in the midst of a record-breaking heat wave.  And in Alaska,Fairbanks and Anchorage have ongoing historically long streaks of warm weather.

These heat events were all likely set up predominantly by the configuration of naturally varying weather patterns.  But  elevated greenhouse gas concentrations may well be tacking on a small warming contribution, nudging these extreme events into record territory.

Jason Samenow is the Capital Weather Gang’s chief meteorologist and serves as the Washington Post’s Weather Editor. He earned BA and MS degrees in atmospheric science from the University of Virginia and University of Wisconsin-Madison.

mid 2013 melt season average Greenland ice sheet reflectivity 5% above 2012 value

July 26th, 2013