Disappearing Sea Ice: Why It Matters To You

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In the Arctic, temperature has increased at twice the rate as the rest of the globe, and could increase by another 8°C (14°F) by the end of this century. The increased rate is caused when shrinking sea ice allows more sunlight to be absorbed, leading to an increasing rate of local warming.  The warming atmosphere along with new weather pattern extremes is causing Arctic sea ice to melt at an alarming rate.  Recent data suggests summer ice will be entirely gone by 2015, fifteen years earlier than more recent forecasts. The impacts of dwindling ice cover in the Arctic are far-reaching, from species endangerment (as reported in this blog) to enhanced global warming, to the weakening or shut-down of global ocean circulation.

Sea Ice and the Climate System

Sea ice forms and melts in sea water, as opposed to land-based ice such as glaciers, ice sheets or shelves, and grounded icebergs. In today's climate regime, sea ice has been observed as far south as Bohai Bay in China—a latitude comparable to the Mediterranean Sea. Sea ice begins to form when water temperature dips just below freezing. It grows into small sheets that look like pancakes, and eventually merge together to form large ice floes which can span miles. As the ice forms, it expels the salt, which increases the density of the surrounding water and thus plays a critical role in global ocean circulation.

Temperature in the Arctic has increased at twice the rate as the rest of the globe.  Increases are expected to throughout this century as a result of continued release of greenhouse gases, especially carbon dioxide. Winter temperature has increased more than summer temperature, a trend that is also expected to continue. While some have suggested that these variations in temperature and associated sea ice melt are a natural cycle, recent research tells us that the Arctic was in a 2,000 year cooling trend before the influence of greenhouse gases in the 20th century.

 

Bright white sea ice reflects almost all of the incoming solar radiation back to space, whereas the dark ocean surface absorbs nearly all of it. Image source: Stephen Hudson / Norsk Polarinstitutt.

Sea ice is generally moderated by sunlight—it grows in the winter and melts in the summer—but there are other factors at play in the decline of ice in the Arctic Ocean. Warm ocean currents travel north from the equator, ushering warmer water and making sea ice growth difficult. Weather patterns over the high mid-latitudes and the Arctic can also affect sea ice growth. Under normal climate conditions, cold air is confined to the Arctic by the polar vortex winds that circle counter-clockwise around the North Pole. As sea ice coverage decreases, the Arctic warms, high pressure builds, and the polar vortex weakens, sending cold air spilling southward into the mid-latitudes, bringing record cold and fierce snowstorms. At the same time, warm air will flow into the Arctic to replace the cold air spilling south, accelerating sea ice loss and leading to 'runaway' regional climate change.

The primary role that sea ice plays in global climate its ability to efficiently reflect the Sun's radiation. This property is called "albedo," the measure of the reflecting power of a surface. The albedo of snow-covered sea ice is 0.90, meaning it reflects 90% of the Sun's radiation. Just like wearing a white shirt will keep you cool when you're out in the Sun, sea ice covering the Arctic keeps the thermostat low. The ocean surface, however, is almost black, absorbing 90% of the incident light and reflecting only 10%.. After something absorbs sunlight, it emits heat.  This means that warming ocean waters will also accelerate the loss of sea ice.


Observed Sea Ice Melt

Satellite data show that since the late 1970s, September Arctic sea ice extent has decreased by about 11% per decade. What's especially alarming is the decrease in multi-year ice. Sea ice is classified by age, usually as "new ice" or "multi-year" ice (meaning it survived many summer melting seasons). While new ice is very shallow, multi-year ice can grow to be quite thick, typically between 6 and 12 feet, and is very stable. A remarkable study was published in 2007 which measured the amount of multi-year ice in the Arctic. In 1987, 57% of the observed ice pack was at least 5 years old, and around 25% of it was at least 9 years old. When they surveyed the Arctic again in 2007, only 7% of the ice pack was at least 5 years old, and the ice that was at least 9 years old had all but vanished. Likewise, sea ice thickness and volume have decreased markedly since the beginning of the satellite era.

Sea ice volume observations from PIOMAS (blue) and a simple mathematical function (orange)
to fit the data and produce a forecast, suggesting the Arctic would be ice-free by the year 2030. 
Recent data (below) shows a more dramatic loss.



Recent years have set a number of sea ice records in the Arctic. The summer of 2007 saw a "perfect storm" of weather conditions favorable for ice loss. Unusually strong high pressure over the Arctic led to clear skies and plenty of sunshine. The polar vortex weakened, injecting large amounts of warm air into the Arctic. Sea ice loss doubled to 39% in 2007, according to the National Snow and Ice Data Center. In one year, as much ice was lost as in the previous 28 years combined. In 2011, the University of Bremen reported that sea ice had reached a new all-time low on September 8th, and was 27,000 square kilometers below the previous record set in 2007.





PIOMAS graphs were updated this past summer, showing that sea ice volume was at an all-time
low in August, 2011.  Models now predict a complete disappearance of summer sea ice by 2015.

   
Commercial Traffic

Recent low sea ice levels have provided new opportunities for the shipping industry, opening both the Northeast and the Northwest Passages in the Arctic Ocean. The Northeast Passage is a shipping route that runs along the northern Russian coast and to the Bering Strait, sometimes called the "Northern Sea Route." On the other side of the Arctic Ocean, the Northwest Passage runs along the North American coast through waterways in the Canadian Arctic Archipelago. These passages have been elusive since the early 1900s, although climate change has recently freed up both of the typically ice-choked routes. The Northeast Passage opened for the first time in recorded history in 2005, and the Northwest Passage in 2007. For four years in a row, the Northwest Passage was open for ice-free sailing. It now appears that the opening of one or both of these northern passages is the new norm, and business interests are taking note—commercial shipping in the Arctic is on the increase, and there is increasing interest in oil drilling. The great polar explorers of past centuries would be astounded at how the Arctic has changed in the 21st century.

The Forecast



Sea ice extent observations (1970 to 2007) and forecast (2030 to 2100) reproduced using data
from the NOAA GFDL model. Yearly extent represents an average 80% sea ice concentration.
Click on the image for a larger view.

Scientists use numerical models to predict how fast Arctic sea ice is expected to melt in coming decades. So far, these climate models have done a poor job predicting the recent record loss of Arctic sea ice. None of the models used in the 2007 Intergovernmental Panel on Climate Change (IPCC) report have foreseen the recent, remarkable sea ice loss. This is likely because the models have a hard time understanding the transport of heat within the ocean itself, which some argue causes over 50% of Arctic sea ice loss. 

The prevailing view among climate scientists had been that an entirely ice-free Arctic ocean would occur in the 2070 - 2100 time frame. The February 2007 report from the IPCC warned that without drastic changes in greenhouse gas emissions, Arctic sea ice will "almost entirely" disappear by the end of the century. However, recent observations suggest that a complete loss of summer Arctic sea ice could occur much earlier. Using a simple equation to produce a forecast from the observations, we can now see that the Arctic could be entirely ice free by 2030 and this hypothesis is supported by numerous scientists and organizations. Dr. Wieslaw Maslowski and his team from the Naval Postgraduate School in Monterey, California have a model that predicts that increasing summer sea ice melt could lead to an ice-free Arctic during at least part of the northern hemisphere summer by 2016, with a margin of error of plus or minus three years.
 

Impacts of Disappearing Sea Ice

The impacts of an ice-free Arctic are far-reaching, and could be a trigger for abrupt, cataclysmic climate change in the future. Although it is difficult to see exactly how sea ice decline will impact the local and global environment, basic understanding of the Arctic as well as recent observations give us a good idea of how things might change.

     Sea level rise

Direct effect: The melting of the Arctic sea ice will not change ocean sea levels appreciably, since the ice is already floating in the ocean. Sea ice melting does slightly contribute to sea level rise since the fresh melt water is less dense than the salty ocean water it displaces. According to Dr. Robert Grumbine of NOAA's sea ice group, if all the world's sea ice melted, it would contribute to about 4 millimeters of global sea level rise. This is a tiny figure compared to the 20 feet of potential sea level rise locked up in the ice of the Greenland Ice Sheet, which is on land.

Indirect effect: The biggest concern regarding Arctic sea ice loss is the warmer average temperatures it will bring to the Arctic in coming years. Warmer temperatures will accelerate the melting of the Greenland ice sheet, which holds enough water to raise sea level 20 feet. Although the IPCC's 2007 report predicted only a 0.6-1.9 foot sea level rise by 2100 due to melting of the Greenland ice sheet and other factors, these estimates will probably need to be revised upwards in light of unexpectedly high sea ice loss in the Arctic.

     Weather patterns

Continued loss of Arctic sea ice may dramatically alter global weather and precipitation patterns in the decades to come. The jet stream will probably move further north in response to warmer temperatures over the pole, which will bring more precipitation to the Arctic. More frequent and intense droughts over the U.S. and other regions of the mid-latitudes may result from this shift in the jet stream. Changes to the course of the jet stream affect weather patterns for the entire planet, and we can expect impacts on the strength of the monsoons and recurvature likelihood of hurricanes. During 1979 to 2006, years that had unusually low summertime Arctic sea ice also had a 10-20% reduction in the temperature difference between the Equator and the North Pole. This resulted in reduced winter precipitation over all of the U.S., Alaska, and Northern Europe. In contrast, increased precipitation fell over Spain, Italy, and Japan during these winters. Although intense La Niña or El Niño events can have a much stronger influence on wintertime weather patterns, reduced summertime Arctic sea ice should give most of the Northern Hemisphere a delayed start to winter during most years for the foreseeable future.

     Global ocean circulation

Surface global ocean currents are driven by the winds, but the vertical ocean circulation is determined by the temperature and salt content of the water (hence, is called the thermohaline circulation). The engine of the thermohaline circulation is in the North Atlantic, where warm surface waters travel north past Greenland and into the Arctic on the Gulf Stream current. As the warm water reaches cold air, evaporation cools the water, and sea ice formation increases the salinity (salt content) of the surrounding water (ice rejects the salt as it freezes). This new cold, salty water is very dense, and sinks in a process called overturning. This sinking motion in the Arctic is a driving force behind the "global conveyor belt," and the formation and maintenance of sea ice is a the heart of it all. Not only could the slowdown of new sea ice formation lead to the abatement of the thermohaline circulation, but as sea ice melts, it injects massive quantities of freshwater into the Arctic Ocean. The freshening of Arctic sea water due to manmade climate change could lead to exceptional changes in the world's ocean circulation and thus Earth's climate as well.

     Methane

Sea ice loss is correlated with warming of Northern latitudes. This has melting effects on permafrost, both in the sea and on land.   Current rapid melting of the sea ice induces a rapid melting of arctic permafrost.  This has consequential effects on methane release and on ecosystems.  Studies also predict cold air passing over ice will be replaced by warm air passing over the sea. This warm air carries heat to the permafrost around the Arctic and melts it.  This thawing permafrost then releases huge quantities of methane.   Methane release can be gaseous, but is can also be transported in solution by rivers. 

Methane has a 20:1 greenhouse gas ratio, compared to carbon dioxide.
This means one unit of methane is equivalent to 20 units of CO2.

NewScientist states that "Since existing models do not include feedback effects such as the heat generated by decomposition, the permafrost could melt far faster than generally thought."

Methane arises from destabilization of gas hydrates concentrated along the coastal margins of Arctic land masses such as Alaska, Siberia, Canada and Greenland.



Area in northern Alaska where subsurface temperature and pressure conditions are conducive
to the occurrence of gas hydrates (red outline), compiled for USGS Fact Sheet 2008-3073.
Note that gas hydrate could occur in sediments both onshore and at shallow water depths
offshore. TPS: Total Petroleum System.


Hydrates are ice-like crystalline solids formed from a mixture of water and natural gas, most commonly methane. Gas hydrates are stable at moderate pressures and low temperatures and are widespread in:

• continental-margin sediments at greater than 300-m water depth, and
• areas of continuous permafrost onshore and relict permafrost in the shallow offshore (less than 100-m water depth).

Globally, gas hydrate sequesters huge amounts of methane, which is known to be a far more potent greenhouse gas than CO₂. Climate perturbations could destabilize gas hydrate deposits and potentially release substantial amounts of methane to the atmosphere.

Research from the Monterey Bay Aquarium Research Institute suggests that 'Pingo' mounds at the floor of the Arctic ocean may have a cause that could contribute dramatically to climate change by adding the super greenhouse gas methane to the atmosphere.



Conceptual drawing (not to scale) shows the hypothesis that methane gas from deep
hydrate deposits could push sediment up from below the ocean bottom to create a
pingo-like feature. The gray lines in the background are from a seismic profile through
one of these enigmatic features.  Image:MBARI 2007

     Ecosystems



Polar bears and other Arctic mammals use sea ice as hunting platforms,
and are particularly susceptible to climate change.

Sea ice is important in marine ecosystems in at least three ways. First, it provides a habitat for algae and invertebrates and fish, and regulates the temperature of the water below it. Although it seems counterintuitive, the sea ice insulates the water beneath it, keeping it from becoming too cold. Second, as the ice melts in the summer, it releases the organisms into the water, providing fuel for Arctic marine food webs. Finally, it provides breeding and hunting grounds for marine mammals and birds that call the North their home.

The impacts of melting ice extend well beyond polar bears. Birds, seals, and whales also use the ice for hunting. Birds nest in the sea ice and use it for protection while raising their young in the potentially deadly environment of the Arctic. The retreat of sea ice, especially in the warm winter months, has decreased the available platforms that seals, walruses, and polar bears use to rest on and hunt from. Scientists estimate that retreating sea ice will result in a loss of 2/3 of the polar bear population, and force the remaining bears into a smaller, iceless area.

Because ecosystems are globally interconnected and interdependent, the collapse of the Artic ecosystem will have far reaching implications for other parts of the world. 

The Economist: Debating the Value of Wilderness

The Economist          Tuesday October 11th 2011

Economist Debates

Wilderness

This house believes that untouched wildernesses have a value beyond the resources and other utility that can be extracted from them.

Rebuttal statements:

Defending the motion

John Sauven             Executive Director, Greenpeace UK

To suggest that action to protect rainforests from further exploitation or campaigning to reduce our dependency on oil by opposing exploitation of the Arctic "would consign a non-trivial share of the world's people to continuing or increased poverty" is simply wrong. Far more likely to consign these communities to poverty is the rapid rise in temperatures caused by our addiction to fossil fuels and by deforestation.

Against the motion

Lee Lane                   Visiting Fellow, Hudson Institute

Economic development in the most vulnerable countries will be vital in building their capacity to lessen harm and cope with that which cannot be avoided. Trying to deprive these threatened states of access to their own forest and other natural resources is hardly a plausible way of helping them meet the coming challenges, and they are likely to subvert such efforts.

Thoughts?       Vote now or add your view   

William G. Coleman wrote:

Dear Sir,

Wild lands are the source of what is known as wild net primary productivity, or WNPP. This is where the combination of animal & plant species, intact within their native communities, produce the greatest measure of uninterrupted ecosystem services that are the foundation for all economic productivity.

The untouched wild ecosystem is like a factory producing fundamental goods & services to support economies locally, regionally, even globally.

There is measurable, high economic value in clean air & water, waste reduction & recycling, and of eco-services like pollination, erosion control and aquifer recharge stemming from protection of wilderness and similarly wild natural areas.

Not only do we need to protect every remaining wild area, but we need to build back WNPP as rapidly as possible in order to avoid the worst effects of cascading global change.

See www.gaiachange.blogspot.com for additional perspectives about the importance of WNPP

Thank you.

Yes, Time to the Nay-Sayers Too

The evidence for global environmental change is overwhelming. Doesn't matter which corner of the world you visit, which institution you query, the message is the same.  Yet there are nay-sayers who practice a very skilled art of denial.  Their motivations vary but their intent is the same: to downplay the significance of humanity's collective impact on planetary systems, and to confuse the issue as much and as often as possible so there can be no comprehensive societal response. Such a response would, by its very nature, restructure global social, political and economic institudions, placing in jeopardy the comfortable status or beliefs the nay-sayers enjoy.  A fine example of this maddening manipulation of the agenda can be seen in the following YouTube video, characterizing the environmental movement as part of the neo-communist agenda, and climate change science as 'discredited'.

Truth is, top flight scientific organizations the world over affirm the trend (despite these trends varying a bit depending on the kind of model one views or the quantity and timeliness of data): The planet is at a turning point. Political decisions made over the next 15 years will determine whether we head off the worst effects of global change, or whether we slide into the ever-accelerating economic and environmental chaos that has been foretold.

Though the information presented in this blog is clearly one sided, it's my belief that the nay-sayers deserve to be heard too. There is no effort here to screen out conservative business-as-usual appeals, right wing interpretations of the science, or mindless will-of-god type protestations. Those views will eventually prove themselves foolish and irresponsible if not a dangerous distraction from critical needs.

At the very end of the book Illusions author Richard Bach offers this warning -- 'Everything in this book may be wrong.'  His point being that readers should judge for themselves how the world works and why. Whether his themes are right or wrong will become apparent if the reader makes an effort to know.

We propose the same warning here:  Readers, we hope everything in this blog is wrong!  We hope that the data and the trends are in error, and that we are not falliing head first into an unknown, unstable future.  We hope that the nay-sayers are right (okay, except the part about 'red' environmentalism).

Last week David Mitchell solved the environment - and he's a bit miffed that didn't make more of a stir. So this week he thought he'd tackle climate change doubters. These disbelievers must concede that climate change is a 'possibility'. In which case, why take the risk – and continue ruining the planet, in the meantime?

Nay-sayers, we invite you to say on.  Only try to bring a hint of responsibility to the denials.  Try to depend less on smoke screens and deliberate misinformation.  In the mean time mindful ones will continue to look and listen, to scrutinize, inquire and contemplate the bigger picture. They will make an effort to really know.

The evidence presented here is, well, right in front of all our eyes.

Want Your Comments

The comment field was inadvertently left off the last few blog posts.  We are still learning our way around this HTML code stuff.  But we really DO want to have your reactions to the posts, your thoughts about the themes here, and your suggestions about how to make this this web long a more compelling contribution to the conversation about global change dynamics.

We have enjoyed over 500 views from all parts of the world since the blog went live two weeks ago.  Several reviewers have sent emails about new ideas to help combat global change.  Those emails will be reproduced here as comments for everyone to see.

Bottom line:  the comments box below will be a standard feature of every posting from now on.  If you cannot see the box on the main page here, click on the post title above to isolate the current post and the associated comments box.

Wildness is Preservation

Thoreau wrote the lines in 1862. 

"The West of which I speak is but another name for the Wild, and what I have been preparing to say is, that in Wildness is the preservation of the World. Every tree sends its fibers forth in search of the Wild. The cities import it at any price. Men plow and sail for it. From the forest and wilderness come the tonics and barks which brace mankind. . . ."  

Maybe he understood at a visceral, emotional level the power of this statement, but it's doubtful Thoreau could have foreseen the anthem his statement would become 150 years later.  In the current age we understand there is science behind these words.  We understand that air, land and water are interconnected aspects of wild, holistic natural systems.  We understand that a rich assemblage of animal and plant species creates an optimum mix of ecosystem serivces, and these services support a quality of life that all living things require. We understand that wild places are literal factories producing goods and services supporting the fabric of life.  Every time we humans appropriate a portion of the Wild for our own purposes we diminish the productivity of the landscape as a whole.  We transform the landscape into cities or simple monoculture forests & farms.  We degrade the landscape with our machines, our buildings and civilization's cast off byproducts.  We acquire, convert, diminish and discard pieces of wild nature ... at a rate and a scale that today threatens the ability of natural systems to support life at all in the very near future.

We refer to this dramatic transformation of the planet's surface as the human appropriation of net primary productivity, or HANPP.

Primary productivity is the creation by plants of organic compounds (like leaves, stems, bark and roots), mostly through the process of photosynthesis.  Primary production forms the base of the food chain.  Net primary production accounts for losses tied to cellular respiration in plants, or the metabolic processes that convert biochemical energy into plant tissue leading to waste products, including oxygen, that are released back into the environment.



Composite image showing the global distribution of photosynthesis,
including both oceanic phytoplankton and terrestrial vegetation


HANPP was first proposed by Stanford's Peter Vitousek in 1986.  His article in the journal BioScience, "Human Appropriation of the Products of Photosynthesis", observed that nearly 40% of land based net primary productivity is used directly, co-opted, or foregone because of human activities.  Vitousek writes:

"Homo sapiens is only one of perhaps 5-30 million animal species on Earth, yet it controls a disproportionate share of the planet's resources.  ...With current patterns of exploitation, distribution, and consumption, a substantially larger human population -- half again its present size or more -- could not be supported without co-opting well over half of terrestiral NPP.  Demographic projections based on today's human population structures and growth rates point to at least that large an increase within a few decades and a considerable expansion beyond that.  Observers who believe that limits to growth are so distant as to be of no consequence for today's decision makers appear unaware of these biological realities."

Vitousek's original argument was based on the presumption that there was simply a limitation of available land to support human settlement and consumption of natural resources.  Twenty five years ago his work would not have taken into consideration an additional reality of increasing HANPP -- that appropriation of natural capital for human purposes diminishes the capacity of ecosystem services necessary to support ecological productivity in the first place.  When we increase HANPP, it is at the expense of WNPP (wild net primary productivity).  WNPP is the source of rich eco-services that are the foundation of the ecosystem factory.

Imagine that we are operating a factory that consumes an ever-increasing quantity of raw materials to produce an ever-decreasing quantity of poorly made goods.  Or imagine we are driving a car that is growing in size as it moves down the highway with ever-increasing speed, consuming gasoline contained in an ever-decreasing sized fuel tank.  Pure folly.  But this is what we do when we blindly sacrifice WNPP for HANPP.




Geography of annual NPP resources required by the human population. 
Upper map illustrates NPP required to mitigate CO2 emissions to the environment. 
Lower map illustrates appropriation for NPP on land by infrastructure
or human activity (agriculture, forest monoculture, etc.)

 

How hard are we pushing the earth?  Humans are using an increasing amount
of the Earth's total land plant production for food, fiber, building
and packaging materials and biofuels.


What are the solutions?  Stop the continued loss of WNPP.  Build back lost WNPP as quickly as possible.  Confront and reverse self-destructive human behavior by slowing rates of population growth, reducing or transforming demands on natural capital, and by restoring humanity's respect for the natural world and all its living inhabitants.  We are mutually dependent, every leaf, feather, fin and follicle, every corner and every stone.