Arctic Sea Ice

Aerosols and Arctic sea ice loss

A great article was posted on the Guardian website yesterday, written by Dr John Abraham, in which he highlights research that shows that if it weren't for aerosols, Arctic sea ice loss would've been even greater:

Pollution is slowing the melting
of Arctic sea ice, for now

Human carbon pollution is melting the Arctic,
but aerosol pollution is slowing it down

NASA satellite photo of the minimum extent of Arctic sea ice in 2005 that occurred on September 21, when the sea ice extent dropped to 2,05 million square miles (53 094 969 million square kilometers). Photograph: HO/AFP/Getty Images

The Arctic is one of the “canaries in the coal mine” for climate change. Long ago, scientists predicted it would warm quicker than other parts of the planet, and they were right. Currently, the Arctic is among the fastest-warming places on the planet. Part of the reason is that as the Arctic warms, ice melts and ocean water is uncovered. The ocean is darker than ice so it in turn absorbs more sunlight and increases its warming. This is a feedback loop.

Another reason is that the Arctic doesn’t get that much sunlight so increased energy from the atmosphere has a bigger influence there than it would have elsewhere.

Scientists have looked to the Arctic for clues and hints of human climate change over the past decades. The fact that the Arctic is warming has led to a 70% reduction in the volume of summer sea ice – an enormous loss of ice.

Decline in September Arctic ice extent (not volume). Illustration: NASA

A recent paper just published in the Journal of Climate by the American Meteorological Society takes an in-depth look at how fast the Arctic ice is melting and why. According to the paper, the authors completed a detection and attribution study of Arctic sea ice decline from 1953 to 2012. That is 60 years of data that tell the picture of climate change. The “detection” part of this study was about detecting what long-term trends are apparent over these six decades. The “attribution” part of the study is figuring out what is the cause of the trends.

Why six decades? Well the authors wanted to go back as far as they could while still accessing high-quality records of the ice extent. They used three different sets of data that record the extent of ice in the region.

In terms of attribution, the authors looked for “fingerprints” of human activity. Humans emit greenhouse gases that trap heat. We know that and we have known that for a long time. Greenhouse gases make the Arctic warmer. But, other things are happening too. There are natural changes to the Arctic. There are also other human pollutants that affect the ice. For instance, humans emit small particles called “aerosols” that can get into the atmosphere and block sunlight. So, these human aerosol emissions can actually cause cooling. 

The authors concluded that the combined cooling effect from human aerosols was detected in all three datasets of ice. That means, it didn’t matter whose measurements you used – the effect of aerosol cooling was present. 

So how much of an effect do aerosols have? It turns out 23% of the warming caused by greenhouse gases was offset by the cooling from aerosols. Unfortunately, this isn’t good news. It means that if/when humans reduce our aerosol pollution, the warming in the Arctic and the ice loss there will be worse.

Read the rest of the article here (I get quoted at the end of it!).

Guest blog: Rock ‘n’ Roll, Ice ‘n’ Slide

Here's a second guest blog by Sam Hayes, a PhD student from Northumbria University and regular commenter on the Arctic Sea Ice Forum. For his studies Sam was part a research expedition in the Arctic Circle.

In his first guest blog Sam described his impressions so far, and in this second installment he goes into more detail on some of the sites that he has visited and the methods the research team has been using. Sam has just about returned home now and will share some more as soon as he has become used to his old, comfortable life again. No more digging! ;-)

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Rock ‘n’ Roll, Ice ‘n’ Slide
by Sam Hayes

Our first full day in action was August 11^th. In sunshine and mid teen temperatures, we loaded the truck with the day’s gear and headed to the floating dock where we met with our local Inuvialuit boat driver, Frank. He would be our primary means of access to local sites for the next 7 days, as well as assisting us with collecting moorings and other instruments. His wife, Nelly, would even provide us with freshly caught trout and whitefish, yum!

 

Our hired boat and from left to right, Dustin, Mike, Frank and Vlad

As well as Frank and his 150hp harbour craft, we also had a smaller zodiac with a 20hp motor, great for getting to those tighter, shallower spots — and a whole lot of fun! As with all places in the Arctic, polar and other bears are a risk. At all times, when in the field, you have to take certain items with you, such as bear spray and bear bangers. When you go further afield, an armed wildlife monitor is a legal requirement, and an option we availed of on two separate days. Other than spotting a grizzly while flying out to one site, we never saw anything of concern. Still, better safe than sorry!

Anywho, the first port of call was a site called Peninsula Point, located in Pingo National park, just west of Tuk (https://goo.gl/maps/kFFpc2etsCN2). We took off there in the 2 boats, and the water quickly turned choppy, which made the journey a fun one for those in the zodiac!

Guest blog: Tuk toy what?

Here's a guest blog that was sent to me by Sam Hayes, a PhD student from Northumbria University and regular commenter on the Arctic Sea Ice Forum. For his studies Sam is out on a research expedition in the Arctic Circle.

 

In this first guest blog Sam describes his impressions so far. If he finds the time (you're supposed to do science stuff day and night on these expeditions), he'll go into more detail on some of the sites that are are visited and the methods the research team is using.

 

Thanks for sharing, Sam!

 

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Tuk Toy what?
by Sam Hayes

 

For 7 days now I’ve been in Tuktoyaktuk, a small hamlet nestled along the Arctic coastline in the Northwest Territories, Canada (picture 1). In that time, I’ve been soaked by ocean water, covered in mud, sun burned, drenched in sweat, shivered with cold, ached, pained, bled and loved every moment of it!

 

Map view and aerial view of Tuktoyaktuk

 

The landscape often appears to be pulled straight from works of science fiction, with lakes, ice cliffs, pingos and all manner of thermokarst wherever you look (picture 2,3). The Inuvialuit people, who account for the majority of the 850 inhabitants, have a culture that is rich, fascinating and generous, with incredible local knowledge and wonderful stories, while the motley crew of researchers, academics, field assistants, pilots, drivers, etc., all with their own interests, stories and personalities make this a fantastic team to be a part of. Of course, lest we forget, there’s also a science element to all this!

 

Thaw slumping and thermokarst lakes near Tuktoyaktuk

Will Petermann calve another one this summer?

Here's a blog post I just read on Andreas Muenchow's Icy Seas blog:

Is Petermann Gletscher Breaking Apart this Summer?

I am disturbed by new ocean data from Greenland every morning before breakfast these days. In 2015 we built a station that probes the ocean below Petermann Gletscher every hour. Data travels from the deep ocean via copper cables to the glacier surface, passes through a weather station, jumps the first satellite overhead, hops from satellite to satellite, falls back to earth hitting an antenna in my garden, and fills an old computer.

A 7-minute Washington Post video describes a helicopter repair mission of the Petermann data machine. The Post also reported first result that deep ocean waters under the glacier are heating up.

Sketch of Petermann Gletscher’s ice shelf with ocean sensor stations. The central station supports five cabled sensors that are reporting hourly ocean temperatures once every day. Graphics made by Dani Johnson and Laris Karklis for the Washington Post.

After two years I am stunned that the fancy technology still works, but the new data I received the last 3 weeks does worry me. The graph below compares ocean temperatures from May-24 through June-16 in 2017 (red) and 2016 (black). Ignore the salinity measurements in the top panel, they just tell me that the sensors are working extremely well:

The red temperature line in the bottom panel is always above the black line. The 2017 temperatures indicate waters that are warmer in 2017 than in 2016. We observed such warming for the last 15 years, but the year to year warming now exceeds the year to year warming that we observed 10 years ago. This worries me, but three features suggest a new ice island to form soon:

Read the rest here.

EGU 2017 call for abstracts

Here's a short blog post for all of you out there publishing in the scientific literature (you know who you are). There's little less than a week left to submit your papers to the various sessions organized at this year's EGU General Assembly.

The first session I'd like to mention, is one chaired by my namesake Neven S. Fučkar from the Barcelona Supercomputing Center, the invitation for which I received in my mail box yesterday:

We hope that you will be interested in attending and presenting your Arctic work at the following session at EGU 2017, 23-28 April 2017 (deadline for abstract submission: 11 January 2017, Wednesday 13:00 Central European Time):

Polar Climate Predictability and Prediction (co-organized: CL3.03/AS1.22/CR1.6/OS1.15)

The Arctic sea ice cover and many other elements of the cryosphere are experiencing significant changes over the modern observational era. The polar climate is crucial for the Earth’s energy and water budget, and its variability and change have direct socio-economic impacts. However, most of climate models are not yet in position to provide us with accurate predictions of polar climate. We welcome presentations advancing understanding of the mechanisms that control polar climate variability on sub-seasonal to multi-decadal timescales and climate change in both hemispheres. We encourage submissions that examine sources of polar climate predictability in a hierarchy of models, and link polar processes and predictions with mid- and low-latitude climate. We look forward to studies using remote sensing data, field observations, proxy data, theory and numerical models encompassing climate projections, reanalyses and forecast systems. This session aims to further connection between the atmospheric, oceanic and cryospheric research and operational communities. Furthermore, the session is an opportunity to present and discuss plans for the Year of Polar Prediction (YOPP), with its Core Phase commencing mid-2017.

We look forward to seeing you in Vienna,

Neven S. Fuckar, Virginie Guemas, Torben Koenigk, Matthieu Chevallier, Ed Hawkins, Edward Blanchard-Wrigglesworth, Rym Msadek, and Helge Goessling

But there are many other interesting sessions as well. Here's a list:

The 11th Key Science Moment of 2016

Regular readers of the Arctic Sea Ice Blog will be aware that Neven has, not entirely successfully, been "on sabbatical" for a while. During that time assorted inaccuracies about Neven himself and about the state of sea ice in the Arctic have been propagating through both "social" and "mainstream" media.

In this guest post, reproduced from the Great White Con blog, I endeavour to set part of the Arctic sea ice record straight, whilst wondering "Why?" so many wires were apparently crossed.

A brief history of scientific "churnalism" in the age of social media. The "post-truth" of The Guardian's 11th Key Science Moment of 2016.

On November 7th 2016 we broke this astonishing news on Twitter:

Global #SeaIce area is at an astonishingly low level for the date: https://t.co/uhiBXcY8C8 pic.twitter.com/mCKkTGXYdO

— Snow White (@GreatWhiteCon) November 7, 2016

Nobody noticed! Then on November 16th 2016 Zack Labe did likewise:

This is not normal. Global #seaice area...

(via https://t.co/qwD3k8Ku3h) pic.twitter.com/LppEwpCidm

— Zack Labe (@ZLabe) November 16, 2016

The story got some legs. Zack got pushback from some "skeptics" and then the AGU blogged about the story:

My attention was called to this issue last week thanks to the Twitter feed of Zack Labe, a PhD student in Earth Systems Science at the University of California – Irvine. He makes great graphics showing the latest data on polar climate.

Then he got interviewed by the AGU. The AGU linked back to the graphic graphic in question in the clouds at Google, but there was no mention of our November 6th article or the real source of the story. The Arctic Sea Ice Forum (ASIF for short).

It's now December 18th, and as far as I'm aware that remains the case in the mainstream media (MSM for short). The Arctic Sea Ice Forum grew out the earlier Arctic Sea Ice Blog (ASIB for short). The proprietor of both the ASIB and ASIF has been revealed by CBC to be one Neven Curlin. They recently interviewed Neven, and even gave him top billing above Sir David Attenborough in the resulting podcast:

Beaufort Gyre guest blog

Not an update of current conditions in the Beaufort Sea, but some science for your reading pleasure.

This is a guest blog by Alek Petty, a postdoc at NASA’s Goddard Space Flight Center and the University of Maryland, specializing in Arctic and Antarctic sea ice variability. Alek has just published a paper in the Journal of Geophysical Research called Sea ice circulation around the Beaufort Gyre: The changing role of wind forcing and the sea ice state, and below he explains in detail what the paper is about (also be sure to check out his website).

Sea ice circulation around the Beaufort Gyre

The Beaufort Sea ice pack has experienced a significant breakup event in recent weeks. This has coincided with some classic Beaufort Gyre ice drift circulations. In this blog, I want to talk a bit more about the sea ice circulation around the Beaufort Gyre, why it’s important, and why it might have changed over the last few decades.

The Arctic is replenished with around ten thousand gigatons of fresh water every year from river run-off into the Arctic basin, Pacific Water inflow (through the Bering Strait), precipitation and – increasingly – sea ice melt.

Figure 1: Mean dynamic topography (MDT) of the Arctic Ocean [from Farrell et al., 2012, GRL]. Grey lines are bathymetry contours [Jakobsson et al., 2012] and the black boxes indicate the Beaufort Gyre study region.

The predominantly clockwise winds over the northern Beaufort Sea draw in a significant fraction of this freshwater – through a process called Ekman pumping – resulting in a characteristic doming of the ocean surface (a ‘spin-up’ of the ocean as it is often called).

The combined forces of gravity and Coriolis drive a clockwise ocean current that circulates this relatively fresh surface water – along with its overlying sea ice cover – around the center of the dome (also clockwise). The end result is one of the most prominent features of the Arctic Ocean: the Beaufort Gyre (see Figure 1).

The sea ice sandwiched between the atmosphere and ocean responds to the combined effects of wind and ocean drag and thus modulates how effectively the winds can ‘spin up’ the ocean. The interaction between winds, ocean currents and sea ice are intrinsically linked, making it an extremely challenging system to study. We’ll get back to this point later.

EGU2016, my impressions

Just like last year, I had the opportunity and time to visit
the European Geosciences Union General Assembly 2016. There were several sessions on subjects related to the cryosphere and remote sensing, but most of the interesting Arctic sea ice-related stuff was happening on Thursday.
So, that's when I went to Vienna.

The day started quite strongly with a press conference called Sea ice decline in the Arctic. Dr. Alexandra Jahn from the University of Colorado talked about models and internal climate variability and Dr. Dobrynin from Uni Hamburg talked about how - as the Arctic loses more sea ice - there will be more, bigger waves eroding coasts and shallow seabeds, etc. This was all very interesting and how I expected a scientific press conference to be: about research looking at the past or the future, based on a painstaking and time-consuming process that involves lots of hypothesizing and data crunching.

However, to my surprise, yet another speaker was talking about the things we like to talk about here and on the Arctic Sea Ice Forum, things that are happening now, things that affect the melting season. Dr. Marcel Nicolaus from the Alfred Wegener Institute explained how a very warm winter resulted in less ice growth (check this previous blog post called CryoSat-2 confirms: sea ice volume is low), and as a consequence this melting season could be seeing new record lows. Depending on the weather, of course.

Robert McSweeney from Carbon Brief asked Dr. Nicolaus and several other scientists about their views on this:

So, that was pretty cool. After the press conference I had time to upload a few images to the ASIF and then went on my way to visit the oral session called Rapid changes in sea ice: processes and implications.

The session consisted of various interesting presentations.
Here's an overview:

Cryosat-2 confirms: sea ice volume is low

Last month I made a comparison of CryoSat-2 sea ice volume distribution maps for the 2015/2016 Winter analysis, but it was off because the dates didn't exactly match. Better images have emerged during this year's General Assembly of the European Geosciences Union (more on that later this week):

These images come from a poster that was presented at EGU2016 by Dr. Robert Ricker from the Alfred Wegener Institute. This poster, as well as some stunning images of the Arctic, is included in the latest AWI press release, which followed Thursday's Sea ice decline in the Arctic press conference at EGU2016 by Dr. Marcel Nicolaus (also from AWI):

The Arctic is facing a decline in sea ice that might equal the negative record of 2012

Data collected by the CryoSat-2 satellite reveal large amounts of thin ice that are unlikely to survive the summer

images courtesy of Stefan Hendricks, Alfred Wegener Institute

Sea ice physicists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), are anticipating that the sea ice cover in the Arctic Ocean this summer may shrink to the record low of 2012. The scientists made this projection after evaluating current satellite data about the thickness of the ice cover. The data show that the Arctic sea ice was already extraordinarily thin in the summer of 2015. Comparably little new ice formed during the past winter. Today Dr Marcel Nicolaus, expert on sea ice, has presented these findings at a press conference during the annual General Assembly of the European Geosciences Union in Vienna.

Read the rest of the press release here, and some good reports on The Carbon Brief, The Arctic Journal, and yes, The Daily Mail.

I attended the press conference and was surprised to see such an accurate and actual portrayal of current conditions in the Arctic. Usually these scientific press conferences are about things that are behind us, like the previous melting season or some such. But Dr. Nicolaus jumped right into it, discussing the temperature readings from buoys in the Arctic that showed the North Pole experienced temps above 0 °C at the end of December, after which he discussed the latest CryoSat-2 results.

Quite a bit of sea ice volume was indeed lost during last year's melting season (see this prescient guest article I wrote for John Abraham's Climate Consensus - the 97% blog on the Guardian website) and after a record warm/non-cold winter, the ice pack's overall thickness looks similar to that of March 2012. Regional differences with 2012 are displayed on this comparison map (red means more ice now than in 2012, blue the opposite):

Consensus and consequences

The following brief communication was published on the The Cryosphere Discussions website two days ago: Does it matter exactly when the Arctic will become ice-free?

It's a good question, albeit a rhetorical one. The authors argue that a "robust definition of ice-free may reduce confusion in the community and amongst the public", and start by asking what the exact definition of ice-free is.

We consider four plausible definitions of the date of an ‘ice-free Arctic’. We apply the commonly-used threshold, for which northern hemispheric sea ice extent (defined as the total area of ocean with a sea ice fraction greater than 15%) is less than 1 million km2. The threshold of 1 million km2, rather than zero, is used because ice can be expected to remain for some time along the northern coast of Greenland, whilst for navigational purposes the central Arctic is ice-free. The ‘first ice-free year’ is then defined as:

A. The first year that at least one day is ‘ice free’.
B. The first year when the September mean is ’ice free’.
C. The first time the final year of a 5 year running mean of September monthly mean extents is ice-free.
D. The final year of 5 consecutive September monthly means which are ’ice-free’.

The question is an interesting one to ponder, and not just from a scientific perspective. Still, discussing the exact definition of ice-free may itself become a smoke screen that shrouds a more important issue, and thus cause even more confusion. Fortunately, the authors seem to be aware of this when they state in their paper's final paragraph: