Why Arctic sea ice shouldn’t leave anyone cold

by Gareth on August 26, 2012

In this guest post Neven Acropolis, the man behind the excellent Arctic Sea Ice blog, looks at the reasons why we need to pay attention to the rapid loss of sea ice in the Arctic Ocean.

Arctic sea ice became a recurrent feature on planet Earth around 47 million years ago. Since the start of the current ice age, about 2.5 million years ago, the Arctic Ocean has been completely covered with sea ice. Only during interglacials, like the one we are in now, does some of the sea ice melt during summer, when the top of the planet is oriented a bit more towards the Sun and receives large amounts of sunlight for several summer months. Even then, when winter starts, the ice-free portion of the Arctic Ocean freezes over again with a new layer of sea ice.

Since the dawn of human civilisation, 5000 to 8000 years ago, this annual ebb and flow of melting and freezing Arctic sea ice has been more or less consistent. There were periods when more ice melted during summer, and periods when less melted. However, a radical shift has occurred in recent times.

1 kinnard2011

Ever since satellites allowed a detailed view of the Arctic and its ice, a pronounced decrease in summer sea ice cover has been observed (with this year setting a new record low). When the IPCC released its Fourth Assessment Report in 2007, it was generally thought that the Arctic could become ice-free somewhere near the end of this century. But changes in the Arctic have progressed at such speed that most experts now think 2030 might see an ice-free Arctic for the first time. Some say it could even happen this decade.

2 albedofeedbackWhat makes this event significant, is the role Arctic sea ice plays as a reflector of solar energy. Ice is white and therefore reflects a large part of incoming sunlight back out to space. But where there is no ice, dark ocean water absorbs most of the sunlight and thus heats up. The less ice there is, the more the water heats up, melting more ice. This feedback has all kinds of consequences for the Arctic region.

Disappearing ice can be good for species such as tiny algae that profit from the warmer waters and extended growing season, but no sea ice could spell catastrophe for larger animals that hunt or give birth to offspring on the ice. Rapidly changing conditions also have repercussions for human populations whose income and culture depend on sea ice. Their communities literally melt and wash away as the sea ice no longer acts as a buffer to weaken wave action.

3 jetstreamBut what happens in the Arctic, doesn’t stay in the Arctic. The rapid disappearance of sea ice cover can have consequences that are felt all over the Northern Hemisphere, due to the effects it has on atmospheric patterns. As the ice pack becomes smaller ever earlier into the melting season, more and more sunlight gets soaked up by dark ocean waters, effectively warming up the ocean. The heat and moisture that are then released to the atmosphere in fall and winter could be leading to disturbances of the jet stream, the high-altitude wind that separates warm air to its south from cold air to the north. A destabilised jet stream becomes more ‘wavy’, allowing frigid air to plunge farther south, a possible factor in the extreme winters that were experienced all around the Northern Hemisphere in recent years.

Another side-effect is that as the jet stream waves become larger, they slow down or even stall at times, leading to a significant increase in so-called blocking events. These cause extreme weather simply because they lead to unusually prolonged conditions of one type or another. The recent prolonged heatwave, drought and wildfires in the USA are one example of what can happen; another is the cool, dull and extremely wet first half of summer 2012 in the UK and other parts of Eurasia.

The accumulation of heat in Arctic waters also influences other frozen parts of the Arctic, such as glaciers and ice caps on Greenland and in the Canadian archipelago. As there is less and less sea ice to act as a buffer, more energy can go into melting glaciers from below and warming the air above them. This has a marked effect on Greenland’s marine-terminating glaciers and the Greenland ice sheet.

4 greenlandsurfacemeltjuly2012

Not only are glaciers flowing faster towards sea, but there is also a rapid increase in the summer surface melt Greenland experiences, leading to accelerating mass loss from the Greenland Ice Sheet. As the Arctic warms, an increased contribution to sea level rise is inevitable.

Another way Arctic warming could have worldwide consequences is through its influence on permafrost. Permanently frozen soils worldwide contain 1400-1700 Gigatons of carbon, about four times more than all the carbon emitted by human activity in modern times. A 2008 study found that a period of abrupt sea-ice loss could lead to rapid soil thaw, as far as 900 miles inland.

5 permafrostdistribution

Apart from widespread damage to infrastructure (roads, houses) in northern territories, resulting annual carbon emissions could eventually amount to 15-35 percent of today’s yearly emissions from human activities, making the reduction of greenhouse gases in the atmosphere a much more difficult task.

An even more worrying potential source of greenhouse gases is the methane in the seabed of the Arctic Ocean, notably off the coast of Siberia. These so-called clathrates contain an estimated 1400 Gigatons of methane, a more potent though shorter-lived greenhouse gas than carbon dioxide. Methane clathrate, a form of water ice that contains a large amount of methane within its crystal structure, remains stable under a combination of high pressure and low temperature. At a depth of 50 meters or less the East Siberian Arctic Shelf contains the shallowest methane clathrate deposits, and is thus most vulnerable to rising water temperatures. Current average methane concentrations in the Arctic already average about 1.90 parts per million, the highest in 400,000 years.

6 methaneconcentration

7 russiaplantsflagApart from these unrecoverable sources of fossil fuel the Arctic is also endowed with large amounts of recoverable oil and natural gas. As the sea ice retreats, the Arctic’s fossil treasures are eyed greedily by large corporations and nations bordering the Arctic Ocean. Not only might this lead to geopolitical tensions in a world where energy is rapidly becoming more expensive, it is also highly ironic that the most likely cause of the disappearance of Arctic sea ice – the extraction and burning of fossil fuels – could lead to more extraction of said fuels. Another feedback loop.

News articles referring to the Arctic and its sea ice usually have pictures of polar bears accompanying the text. But although many animals in the Arctic will be impacted negatively by the vanishing of Arctic sea ice, much more is at stake. After thousands of years in which the sea ice played a vital role in the relatively stable conditions under which modern civilisation, agriculture and a 7 billion strong world population could develop, it increasingly looks as if warming caused by the emission of greenhouse gases is bringing an end to these stable conditions. Whether there still is time to save the Arctic sea ice, is difficult to tell, but consequences will not disappear when the ice is gone. It seems these can only be mitigated by keeping fossil fuels in the ground and out of the air. Whichever way you look at it, business-as-usual is not an option.

For more information on Arctic sea ice, check out Neven’s Arctic Sea Ice blog.

Image credits:
Arctic sea ice extent reconstruction – Kinnard et al. 2011

Sea ice albedo feedback – NASA

Polar jet stream – NC State University

Greenland ice sheet surface melt – NASA

Permafrost distribution in the Arctic – GRID-Arendal

Atmospheric methane concentration – NOAA ESRL

Russia plants flag at North Pole – Reuters

{ 9 comments… read them below or add one }

Byron Smith August 27, 2012 at 12:22 am

I recently wrote a post on the various effects of a seasonally ice-free Arctic and came up with precisely the same nine as Neven just mentioned, so I feel pretty good about that.

1. Arctic ecosystem change/habitat loss
2. Arctic (human) communities culture/infrastructure loss
3. Albido change to global energy budget
4. Permafrost melt acceleration
5. Methane clathrates destabilisation
6. Greenland ice sheet melt acceleration
7. Geo-political tensions over Arctic resources
8. Exploitation of Arctic fossil hydrocarbon resources feedback
9. Complex effects on NH wind/weather patterns via polar jetstream effects.

10. I considered a tenth, namely, a further disruption to the global energy budget from the freeing of the latent heat energy that previously was being used to accomplish the phase transition of ice -> water, though my back of the envelope calculations suggest that this is a much smaller issue than albido change (I’d love to see some reputable work on this topic as I’m far from any kind of expert).

Now that I think about it a little more, I can think of a further seven issues that neither Neven nor I mentioned. Some of these I’m very tentative about (esp ##15&16).

11. The release of persistent toxins and heavy metals that had become trapped in the ice.

12. The opening up of Arctic shipping routes which (a) reduces fuel needs of global shipping by cutting distances (negative feedback) but (b) brings more diesel fuel into the Arctic region, leaving black soot on glaciers (positive feedback). Not sure which is the larger effect.

13. Reconnection of marine ecosystems previously separated by ice with unpredictable ecosystem changes from invasive species. This is already occurring.

14. Opening up of Arctic fishing grounds to greater exploitation (and noise pollution).

15. Potential effects on thermohaline circulation. I haven’t seen any work on this related to seasonal sea ice loss, so I have no idea whether it is significant.

16. Potential effects on ocean acidification by increasing surface area for atmosphere-ocean gas exchange. Would this make any difference to ocean capacity to act as CO2 sink or rate of acidification? Maybe this is irrelevant. I haven’t seen it mentioned anywhere and is just an idea that came to me.

17 . Highly visual and difficult to dispute sign of climate change, representing a potential tipping point in public awareness and concern. If we are waiting for that, however, before we make any serious efforts to slash emissions (esp if it doesn’t occur until 2030 or later), we’ll already have so much warming committed that we’ll pretty much be toast. At best, therefore, this point might consolidate public support for massive rapid emissions reductions already underway.

Byron Smith August 27, 2012 at 10:06 am

*albido –> albedo. (x2)

Same typo twice…

Dappledwater August 27, 2012 at 7:43 am

Byron – ocean acidification is an under appreciated threat to marine ecosystems in the polar regions. Surface waters in the Arctic will be corrosive to calcifying marine life by the end of this decade – maybe sooner given the events we are witnessing.

Byron Smith August 27, 2012 at 10:15 am

I was on a ferry off the coast of Norway a year ago and they had a marine biologist on board giving a brief and family-friendly presentation on local marine life. She had a row of about ten tanks with various strange little critters in them and she took us along the row pointing out the weird and wacky features of each of the creatures she’d selected. It was all quite light-hearted and good fun. At the end she opened it up for questions. Since no one else stepped forward to say anything, after a suitable pause I raised my hand and asked, “Have you been noticing any changes to the ecosystems you’ve been studying in this area?” I didn’t mentioned climate, acidification or any other stress factors, just asked about change. She started crying almost immediately as she spoke about the looming threat of acidification and was obviously struggling to keep her own fears at bay in front of quite a few children in the audience.

I felt bad for putting her on the spot in that public context, but I was struck by just how close to the surface her emotions were on the topic.

Gareth August 27, 2012 at 10:19 am

Thanks Byron. Meanwhile, other Norwegians are preparing for the oil boom in the Arctic.

Macro August 27, 2012 at 6:12 pm

An excellent summary of the perilous situation towards which the Arctic and the Earth in general is inexorably headed. Such a piece deserves a wide publication.

Thomas August 27, 2012 at 9:14 pm

Dear say, the top graphic looks familiar in shape, only upside down. Yes! The Hockey Stick inverted like a red rag dangling in front of the ‘bulls’ once more. The graph’s message and the speed of change it is laying bare is devastating.

I can already hear the cacophony of the unteachables howling from the margins of the gutter press….

bill September 5, 2012 at 10:09 pm

I invite andy, or any like-minded member of his tribe, to identify the point 3 weeks ago which explains why this happened.

Arctic Basin Sea Ice Area breaks 2 million Km2, incidentally. Not on the way up.

Overall Arctic extent still acting out the old Status Quo song. Idiots still pretending this don’t – and won’t – mean a thing.

Sometimes I actually wish I was an insouciant ninny. Because this is genuinely disturbing.

Gareth September 5, 2012 at 11:08 pm

I share your discomfort, bill. It is the perfect example of a “slow-motion train wreck”, but only when “slow” is defined as breathtakingly fast in geological terms.

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