Three kinds of warming in the Arctic

The Arctic is prone to suffer from three kinds of warming. Firstly, the Arctic is hit particularly hard by emissions, as discussed in earlier posts such as this one and this one.

Secondly, warming in the Arctic is accelerating due to feedbacks, as discussed on the feedbacks page. Many such feedbacks are related to decline of the snow and ice cover in the Arctic, which is in turn made worse by emissions such as soot.

Thirdly, the most dangerous feedback is release of methane from the Arctic Ocean seafloor, due to hydrates getting destabilized as heat reaches sediments.

Last year, Arctic sea ice reached its maximum extent on February 25, 2015. This year, there was a lot less sea ice in the Arctic on February 25 than there was last year, as illustrated by above image. The difference is about 300,000 square km, more than the size of the United Kingdom.

The image below shows that global sea ice on February 22, 2016, was only 14.22086 million square km in area. It hasn't been that low since satellite records started to measure the sea ice.

A number of feedbacks are associated with the decline of sea ice, such as more sunlight being absorbed by the water, instead of being reflected back into space as it was previously. Furthermore, there are three kinds of warming active in the Arctic, as described above and as depicted by the image below.

Sea ice can reflect as much as 90% of the sunlight back into space. Once the ice has melted away, however, the water of the ocean reflects only 6% of the incoming solar radiation and absorbs the rest. This is depicted in above image as feedback #1.

As Professor Peter Wadhams once calculated, warming due to Arctic snow and ice loss could more than double the net warming now caused by all emissions by all people of the world.

Professor Peter Wadhams on albedo changes in the Arctic, image from Edge of Extinction

As the sea ice melts, sea surface temperatures will remain at around zero degree Celsius (32°F) for as long as there is ice in the water, since rising ocean heat will first go into melting the ice. Only after the ice has melted will ocean heat start raising the temperature of the water. Sea ice thus acts as a buffer that absorbs heat, preventing water temperatures from rising. As long as sea ice is melting, each gram of ice will take 334 Joule of heat to change into water, while the temperature remains at 0° Celsius or 32° Fahrenheit.

Once all ice has turned into water, all further heat goes into heating up the water. To raise the temperature of one gram of water by one degree Celsius then takes only 4.18 Joule of heat. In other words, melting of the ice absorbs 8 times as much heat as it takes to warm up the same mass of water from zero to 10°C. This is depicted in the image on the right as feedback #14.

Above video, created by Stuart Trupp, shows how added heat at first (A) goes mainly into warming up water that contains ice cubes. From about 38 seconds into the movie, all heat starts going into the transformation of the ice cubes into water, while the temperature of the water doesn't rise (B). More than a minute later, as the ice cubes have melted (C), the temperature of the water starts rising rapidly again.

Methane is a further feedback, depicted as feedback #2 on the image further above. As the water of the Arctic Ocean keeps getting warmer, the danger increases that heat will reach the seafloor where it can trigger release of huge amounts of methane, in an additional feedback loop that will make warming in the Arctic accelerate and escalate into runaway warming.

Sediments underneath the Arctic Ocean hold vast amounts of methane. Just one part of the Arctic Ocean alone, the East Siberian Arctic Shelf (ESAS, see map below), holds up to 1700 Gt of methane. A sudden release of less than 3% of this amount could add 50 Gt of methane to the atmosphere, and experts have warned for many years that they consider such an amount to be ready for release at any time.

Above image gives a simplified picture of the threat, showing that of a total methane burden in the atmosphere of 5 Gt (it is meanwhile higher), 3 Gt that has been added since the 1750s, and this addition is responsible for almost half of all antropogenic global warming. The amount of carbon stored in hydrates globally was in 1992 estimated to be 10,000 Gt (USGS), while a more recent estimate gives a figure of 63,400 Gt (Klauda & Sandler, 2005). Once more, the scary conclusion is that the East Siberian Arctic Shelf (ESAS) alone holds up to 1700 Gt of methane in the form of methane hydrates and free gas contained in sediments, of which 50 Gt is ready for abrupt release at any time.

The warning signs keep getting stronger. Following a peak methane reading of 3096 ppb on February 20, 2016, a reading of 3010 ppb was recorded in the morning of February 25, 2016, at 586 mb (see image below).

Again, this very high level was likely caused by methane originating from the seafloor of the Arctic Ocean, at a location on the Gakkel Ridge just outside the East Siberian Arctic Shelf (ESAS), as discussed in the earlier post. This conclusion is supported by the methane levels at various altitudes over the ESAS, as recorded by both the MetOp-1 and MetOp-2 satellites in the afternoon, as illustrated by the combination image below showing methane levels at 469 mb.

The situation is dire a calls for comprehensive and effective action as described in the Climate Plan.


Links

- Feedbacks in the Arctic
http://arctic-news.blogspot.com/p/feedbacks.html

- Albedo changes in the Arctic
http://arctic-news.blogspot.com/2012/07/albedo-change-in-arctic.html

- The time has come to spread the message
http://arctic-news.blogspot.com/2013/12/the-time-has-come-to-spread-the-message.html

- Greenhouse gas levels and temperatures keep rising
http://arctic-news.blogspot.com/2016/01/greenhouse-gas-levels-and-temperatures-keep-rising.html

- Arctic sea ice area at record low for time of year
http://arctic-news.blogspot.com/2016/01/arctic-sea-ice-area-at-record-low-for-time-of-year.html

- Has maximum sea ice extent already been reached this year?
http://arctic-news.blogspot.com/2016/02/has-maximum-sea-ice-extent-already-been-reached-this-year.html

- Global sea ice extent record minimum - Arctic Sea Ice Blog
http://neven1.typepad.com/blog/2016/02/global-sea-ice-extent-minimum-record.html

- Warming of the Arctic Fueling Extreme Weather
http://arctic-news.blogspot.com/2014/06/warming-of-the-arctic-fueling-extreme-weather.html

- Climate Plan
http://arctic-news.blogspot.com/p/plan.html

Last year, Arctic sea ice reached its maximum extent on February 25, 2015. This year, there's a lot less sea ice in the...
Posted by Sam Carana on Friday, February 26, 2016

Ocean Heat Depth

Ocean heat at the equator

On November 24, 2015, equatorial waters at ≈100 m (328 ft) depth at 110-135°W were over 6°C (10.8°F) warmer than average in 1981-2000, as illustrated by above image. The animation below shows equatorial ocean heat over the past few months, illustrating that temperature anomalies greater than 6°C (10.8°F) occurred throughout this period at depths greater than 100 m (328 ft).

The danger of ocean heat destablizing clathrates in the Arctic

The danger is that ever warmer water will reach the seafloor of the Arctic Ocean and destabilize methane that is held there in sediments the form of free gas and hydrates.

So, how comparable is the situation at the equator with the situation in the Arctic? How much heating of the Arctic Ocean has taken place over the past few years?

The image on the right, produced with NOAA data, shows mean coastal sea surface temperatures of over 10°C (50°F) in some areas in the Arctic on August 22, 2007.

In shallow waters, heat can more easily reach the bottom of the sea. In 2007, strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, according to this study, and bottom water temperatures on the mid-shelf increased by more than 3°C (5.4°F) compared to the long-term mean.

This study finds that drastic sea ice shrinkage causes increase in storm activities and deepening of the wind-wave-mixing layer down to depth ~50 m (164 ft) that enhance methane release from the water column to the atmosphere. Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

The image below, replotted by Leonid Yurganov from a study by Chepurin et al, shows sea water temperature at different depths in the Barents Sea, as described in an earlier post.

The image below is from a study published in Nature on November 24, 2013, showing water temperatures measurements taken in the Laptev Sea from 1999-2012.

Water temperatures in Laptev Sea. Red triangles: summer. Blue triangles: winter. Green squares: historic data.
From Shakhova et al., (2013) doi:10.1038/ngeo2007

Before drawing conclusions, let's examine some peculiarities of the Arctic Ocean more closely, specifically some special conditions in the Arctic that could lead to greater warming than elsewhere and feedbacks that could accelerate warming even more.

Amount of methane ready for release

Sediments underneath the Arctic Ocean hold vast amounts of methane. Just one part of the Arctic Ocean alone, the East Siberian Arctic Shelf (ESAS, rectangle on map below, from the methane page), holds up to 1700 Gt of methane. A sudden release of just 3% of this amount could add over 50 Gt of methane to the atmosphere, and experts consider such an amount to be ready for release at any time (see above image).



Total methane burden in the atmosphere now is 5 Gt. The 3 Gt that has been added since the 1750s accounts for almost half of the (net) total global warming caused by people. The amount of carbon stored in hydrates globally was in 1992 estimated to be 10,000 Gt (USGS), while a more recent estimate gives a figure of 63,400 Gt (Klauda & Sandler, 2005). The ESAS alone holds up to 1700 Gt of methane in the form of methane hydrates and free gas contained in sediments, of which 50 Gt is ready for abrupt release at any time.



Imagine what kind of devastation an extra 50 Gt of methane could cause. Imagine the warming that will take place if the methane in the atmosphere was suddenly multiplied by 11.

Whiteman et al. recently calculated that such an event would cause $60 trillion in damage. By comparison, the size of the world economy in 2012 was about $70 trillion.

Shallow waters in the Arctic Ocean

Shallow waters and little hydroxyl

The danger is particularly high in the shallow seas that are so prominent in the Arctic Ocean, as illustrated by the light blue areas on the image on the right, from an earlier post.

Much of the waters in the Arctic Ocean are less than 50 m deep. Being shallow makes waters prone to warm up quickly during summer temperature peaks, allowing heat to penetrate the seabed.

This can destabilize hydrates and methane rising through shallow waters will then also enter the atmosphere more quickly, as it rises abruptly and in plumes.

Elsewhere in the world, releases from hydrates underneath the seafloor will largely be oxidized by methanotroph bacteria in the water and where methane does enter the atmosphere, it will quickly be oxidized by hydroxyl. In shallow waters, however, methane released from the seabed will quickly pass through the water column.

Large abrupt releases will also quickly deplete the oxygen in the water, making it harder for bacteria to break down the methane.

Very little hydroxyl is present in the atmosphere over the poles, as illustrated by the image on the right, showing global hydroxyl levels, from an earlier post.

In case of a large abrupt methane release from the Arctic Ocean, the little hydroxyl that is present in the atmosphere over the Arctic will therefore be quickly depleted, and the methane will hang around for much longer locally than elsewhere on Earth.

Shallow waters make the Arctic Ocean more prone to methane releases, while low hydroxyl levels make that methane that enters the atmosphere in the Arctic will contribute significantly to local warming and threaten to trigger further methane releases.

High levels of insolation in summer in the Arctic

Furthermore, the amount of solar radiation received by the Arctic at the June Solstice is higher than anywhere else on Earth, as illustrated by the image below, showing insolation on the Northern Hemisphere by month and latitude, in Watt per square meter, from an earlier post.

Warm water enters Arctic Ocean from Atlantic and Pacific Oceans

What further makes the situation in the Arctic particularly dangerous is that waters are not merely warmed up from the top down by sunlight that is especially strong over the Arctic Ocean in summer on the Northern Hemisphere, but also by warm water that flows into the Arctic Ocean from rivers and by warm water that enters the Arctic Ocean through the Bering Strait and through the North Atlantic Ocean. The latter danger is illustrated by the image below, from an earlier post.

Feedbacks

Furthermore, there are feedbacks that can rapidly accelerate warming in the Arctic, such as albedo losses due to loss of sea ice and snow cover on land, and changes to the jet stream resulting in more extreme weather. These feedbacks, described in more details at this page, are depicted in the image below.

Methane

Above image shows that methane levels on December 3, 2015, were as high as 2445 parts per billion (ppb) at 469 millibars, which corresponds to an altitude of 19,810 feet or 6,041 m.

The solid magenta-colored areas (levels over 1950 ppb) that show up over a large part of the Arctic Ocean indicate very strong methane releases.

Note there are many grey areas on above image. These are areas where no measurements could be taken, which is likely due to the strength of winds, rain, clouds and the jet stream, as also illustrated by the more recent (December 5, 2015) images on the right.

The polar jet stream on the Northern Hemisphere shows great strength, with speeds as high as 243 mph or 391 km/h (over a location over japan marked by green circle) on December 5, 2015.

So, high methane levels may well have been present in these grey areas, but didn't show up due to the weather conditions of the moment.

Furthermore, the white geometric areas are due the way the satellite takes measurements, resulting in areas that are not covered.

Finally, it should be noted that much of the methane will have been broken down in the water, before entering the atmosphere, so what shows up in the atmosphere over the Arctic is only part of the total amount of methane that is released from the seafloor.

In conclusion, the high methane levels showing up over the Arctic indicate strong methane releases from the seafloor due to warm waters destabilizing sediments that contain huge amounts of methane in the form of free gas and hydrates.

Climate Plan

As global warming continues, the risk increases that greater ocean heat will reach the Arctic Ocean and will cause methane to be released in large quantities from the Arctic Ocean seafloor. The 2015 El Niño has shown that a huge amounts of ocean heat can accumulate at a depth greater than 100 m (328 ft). Conditions in the Arctic and feedbacks make that methane threatens to be released there abruptly and in large quantities as warming continues.

The situation is dire and calls for comprehensive and effective action as described at the Climate Plan. 

On November 24, 2015, equatorial waters at ≈100 m (328 ft) depth at 110-135°W were over 6°C (10.8°F) warmer than average...
Posted by Sam Carana on Friday, December 4, 2015

Ocean Heat

Sea Surface Temperatures

Sea surface temperatures were as high as 15.8°C or 60.4°F near Svalbard on November 7, 2015, a 13.7°C or 24.7°F anomaly. Let this sink in for a moment. The water used to be close to freezing point near Svalbard around this time of year, and the water now is warmer by as much as 13.7°C or 24.7°F.

[ click on image to enlarge ]

Above image further shows that sea surface temperature anomalies as high as 6.7°C or 12.1°F were recorded on November 7, 2015, off the coast of North America, while anomalies as high as 6°C or 10.9°F were recorded in the Bering Strait.

NOAA analysis shows that the global sea surface in September 2015 was the warmest on record, at 0.81°C (1.46°F) above the 20th century average of 16.2°C (61.1°F). On the Northern Hemisphere, the anomaly was 1.07°C (1.93°F).

[ click on image to enlarge ]

How did temperatures get so high near Svalbard? The answer is that ocean currents are moving warm water from the Atlantic Ocean into the Arctic Ocean. The ocean is warmer underneath the sea surface and at that location near Svalbard warm water from below the surface emerges at the surface.

Ocean Heat

The oceans are warming up rapidly, especially the waters below the sea surface. Of all the excess heat resulting from people's emissions, 93.4% goes into oceans. Accordingly, the temperature of oceans has risen substantially over the years and - without action - the situation only looks set to get worse.

NOAA's ocean heat content figures for 0-2000 m are very worrying, as illustrated by the image below.

The image below was created with data for January through to March, while adding non-linear trendlines for ocean heat at depths of 0-700 m and 0-2000 m. For growth of ocean heat content for 0-700 m, a polynomial trend is added, while for growth of ocean heat content for 0-2000 m an exponential trend is added.

[ click on images to enlarge ]

The image below shows a polynomial trend based on all available quarterly data for ocean heat content from 0 to 2000 m. The trendline shows even faster growth.

The danger is that, as ocean heat continues to grow, ocean currents will keep carrying ever warmer water from the Atlantic and Pacific Oceans into the Arctic Ocean.

Merely watching temperatures at the surface of the ocean may underestimate the warming that is taking place below the sea surface. At the sea surface, evaporation takes place that cools the water. Furthermore, melting of sea ice and glaciers will make that a layer of cold freshwater spreads at the surface, preventing much transfer of heat from the ocean to the atmosphere, as discussed at this earlier post. The blue-colored areas on the Northern Hemisphere on the top image are partly the result of this meltwater. There is another reason why these areas are relatively cool, i.e. sulfates, as further discussed in the section below.

Aerosols

Particulates, in particular sulfate, can provide short-term cooling of the sea surface. Large amounts of sulfate are emitted from industrial areas in the east of North America and in East Asia. On the Northern Hemisphere, the Coriolis effect makes that such emissions will typically reach areas over the nearby ocean to the east of such industrial areas, resulting in the sea surface there being cooled substantially, until the particulates have fallen out of the sky. Since the sulfate is emitted on an ongoing basis, the cooling effect continues without much interruption.

[ click on image to enlarge ]

This sulfate has a cooling effect on areas of the sea surface where ocean currents are moving warm water toward the Arctic Ocean. Because the sea surface gets colder, there is less evaporation, and thus less heat transfer from the ocean to the atmosphere during the time it takes for the water to reach the Arctic Ocean. As a result, water below the sea surface remains warmer as it moves toward the Arctic Ocean.

Similarly, as illustrated by above image, sulfur dioxide emitted in industrial areas in North America and East Asia can extend over the oceans, cooling the surface water of currents that are moving water toward the Arctic Ocean.

Methane

The image below shows that atmospheric methane levels in 2014 were 1833 parts per billion (WMO data) or 254% the pre-industrial level. WMO data are for 1984-2014 and are marked in red, while IPCC data (AR5) are for the years 1755-2011 and are marked in blue.

The image below shows the rise of methane levels from 1984 created with World Metereological Organization (WMO) data. The square marks a high mean 2015 level, from NOAA's MetOp-2 satellite images, and it is added for comparison, so it does not influence the trendline, yet it does illustrate the direction of rise of methane levels and the threat that global mean methane levels will double well before the year 2040.

The image below illustrates the danger that large amounts of methane will erupt from the Arctic Ocean, particularly in East Siberian Arctic Shelf, where the sea is quite shallow, so much of the methane can reach the atmosphere without being broken down by microbes on the way up through the water column.

The video below shows how methane concentrations start to rise close to sea level, and how concentrations strengthen at higher altitudes, and to eventually get lower at even higher altitudes.

The Threat

Ocean heat threatens to increasingly reach the seafloor of the Arctic Ocean and unleash huge methane eruptions from destabilizing clathrates. Such large methane eruptions will then warm the atmosphere at first in hotspots over the Arctic and eventually around the globe, while also causing huge temperature swings and extreme weather events, contributing to increasing depletion of fresh water and food supply, as further illustrated by the image below, from an earlier post.

[ click on image at original post to enlarge ]

The image below gives an indication of the ocean heat that is pushed by the Gulf Stream toward the Arctic Ocean. Note that this image shows the situation on November 15, 2015. Water off the east coast of North America is even warmer at the peak of the Northern Hemisphere summer and it is this water that is now arriving in the Arctic Ocean.

Below is a radio version of this post, roughly as read by Debba Kale Earnshaw at this episode and the next episode of extinctionradio.org

Malcolm Light comments:

To a geologist-oceanographer, the increasing rate of heat gain in the deep water seems obvious. Massive quantities of heat are generated in the earth's interior by radioactivity and find their way to the surface in rising convection systems to erupt along mid-ocean ridges as basaltic lava flows, pushing the plates apart. Under normal circumstances, prior to the arrival of civilized man, the plates cooled as they expanded by passing their heat into the oceans, which then was radiated into space.

Now, with the fast evolving atmospheric greenhouse Arctic methane global warming veil. the heat is simply being reflected back into the oceans and onto the land. Therefore, just like a pressure cooker, the Earth's interior heat is becoming trapped more and more and of course the end result will be a final blow-out. The more than 400 thousand years of ice core data show that we can expect a massive atmospheric methane peak caused by destabilization of the Arctic subsea methane hydrates very soon (8 to 16 years away) and it will produce a Permian style extinction event with a temperature increase of some 8 to 10 degrees C.

Climate Plan

The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.

Sea surface temperatures were as high as 15.8°C or 60.4°F near Svalbard on November 7, 2015, a 13.7°C or 24.7°F anomaly....
Posted by Sam Carana on Monday, November 9, 2015

Cyclones continue to hit Northern Hemisphere

As the 2015 El Niño gets stronger, the Northern Hemisphere continues to get hit by strong winds and cyclones. The image below shows strong winds over the Arctic Ocean, as hurricane Joaquin approaches the coast of North America.



On above image, hurricane Joaquin is clocked at a speed of 79 mph (127 km/h) on October 1, 2015. NOAA warned that on that day the maximum sustained wind speed had increased to near 120 mph (195 km/h) with higher gusts.

For reference, NOAA uses four categories:
D: Tropical Depression – wind speed less than 39 mph (63 km/h)
S: Tropical Storm – wind speed between 39 mph and 73 mph (63 km/h - 118 km/h)
H: Hurricane – wind speed between 74 mph and 110 mph (118 km/h - 177 km/h)
M: Major Hurricane – wind speed greater than 110 mph (over 177 km/h)

NOAA issued the image below on September 30, 2015, warning that Hurricane Joaquin is likely to cause wind damage across a large part of the eastern coast of North America.

The NOAA animation below gives an idea of the strength of hurricane Joaquin.

[ click on image to enlarge, note that this is a 1.4 MB file that may take some time to fully load ]

Meanwhile, sea surface temperatures off the North American coast, as well as in the Arctic Ocean, are very high, as illustrated with the image on the right.

In the Arctic Ocean, the sea ice in many places is now less thick than it was in 2012, as illustrated by the image further below, showing sea ice thickness on October 7, 2012 (panel left) and a forecast for October 7, 2015 (panel right).

The water in the Arctic Ocean was already very warm this year. The main factor causing both these strong winds and the dramatic decrease in thickness of the multi-year sea ice is ocean heat, as also illustrated by the image below, showing high sea surface temperature anomalies in the Arctic as at September 30, 2015.

As the image below shows, nearly all the thick (over 3 m) multi-year sea ice has now disappeared, setting up a dangerous situation for the future that is much more dangerous than the situation was back in 2012. The thicker sea ice used to act as a buffer, consuming ocean heat in the melting process. Without thicker sea ice, ocean heat threatens to melt the sea ice from below right up to the surface, causing the entire sea ice to collapse as more open water will go hand in hand with stronger winds and waves. In case of such a collapse, sunlight that was previously reflected back into space will instead be absorbed by the water, causing rapid rise of the temperature of the water. In places such as the East Siberian Arctic Shelf, the water is on a average only 50 m deep, so warmer water is able to reach the seafloor more easily there.

The water of the Arctic Ocean is very warm, not only at the surface, but even more so underneath the surface. The danger is that strong winds will mix warm water all the way down to the seafloor, where it could destabilize sediments that can contain huge amounts of methane in the form of hydrates and free gas.

[ click on image to enlarge ]

The image on the right illustrates the impact of winds over the East Siberian Arctic Shelf on September 26, 2015.

NSIDC specialist Julienne Stroeve recently warned: "In 2007 more than 3m of bottom melt was recorded by [an] ice mass balance buoy in the region, which was primarily attributed to earlier development of open water that allowed for warming of the ocean mixed layer. But perhaps some of this is also a result of ocean mixing."

As discussed in an earlier post, sea surface anomalies of over 5°C were recorded in August 2007 in the Arctic Ocean. Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007 and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.

As the 2015 El Niño gets stronger, the Northern Hemisphere continues to get hit by strong winds and cyclones. The image...
Posted by Sam Carana on Thursday, October 1, 2015

Disappearance Of Thick Arctic Sea Ice

[ view full image at facebook ]

Arctic sea ice is in a horrible state. On August 16, 2015, Arctic sea ice extent was 5.786 million square km, the smallest extent on record for this time of year except for the years 2007, 2011 and 2012, as illustrated by the image on the right.

The situation today is even worse than one might conclude when looking at sea ice extent alone. Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by the image below comparing sea ice thickness on August 16, 2012 (left) with August 16, 2015 (right).

The ice used to be over 4 m thick, or over 13 ft thick, north of Greenland and the Canadian Archipelago. This thick multi-year ice has been a feature of the Arctic sea ice for over 100,000 years. It used to be there all year long, unlike the thinner ice that could melt away entirely during the melting season.

The disappearance of this thick multi-year ice is a major development. Why? Until now, the thicker multi-year sea ice used to survive the melting season, giving the sea ice strength for the next year, by acting as a buffer to absorb heat that would otherwise melt away the thinner ice. Without multi-year sea ice, the Arctic will be in a bad shape in coming years, and huge amounts of heat that would otherwise go into melting the ice will instead be warming up the Arctic Ocean, further accelerating warming of its waters.

Absence of thick sea ice makes it more prone to collapse, and this raises the question whether the sea ice could collapse soon, even this year. Sea ice works like a mirror. Without sea ice, sunlight that was previously reflected back into space, will instead be absorbed by the Arctic. Albedo changes in the Arctic alone could more than double the net radiative forcing resulting from the emissions caused by all people of the world, as calculated by Prof. Peter Wadhams back in 2012.

Furthermore, there is a danger that loss of the sea ice will weaken the currents that currently cool the bottom of the sea, where huge amounts of methane may be present in the form of free gas or hydrates in sediments. This danger is illustrated by the image below by Reg Morrison, from an earlier post.

Absence of sea ice also goes hand in hand with opportunities for storms to develop over the Arctic Ocean. Such storms could push the remaining sea ice out of the Arctic Ocean. Such storms could also mix surface heat all the way down to the seafloor, where methane could be contained in sediments.

As described in an earlier post, sea surface anomalies of over 5 degrees Celsius were recorded in August 2007 (NOAA image right). Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, as described in this study, and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past.

Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Since waters can be very shallow in the Arctic, much of the methane can then rise up through these waters without getting oxidized. As the methane causes further warming in the atmosphere, this will contribute to the danger of even further methane escaping, further accelerating local warming, in a vicious cycle that can lead to catastrophic conditions well beyond the Arctic. For additional feedbacks in the Arctic, see the feedbacks page. 

At the same time, ocean heat is at a record high and there's an El Niño that's still gaining strength. This ocean heat is likely to reach the Arctic Ocean in full strength by October 2015, at a time when sea ice may still be at its minimum. The image below shows sea surface temperatures on August 16, 2015 (left) and anomalies (right).

How warm is the water entering the Arctic Ocean? Merely looking at sea surface temperatures could make one overlook the full extent of the predicament we are in. Ocean heat traveling underneath the sea surface can be even warmer than temperatures showing up at the surface. This is illustrated by the image below indicating that on August 16, 2015, warm water emerged at the sea surface near Svalbard with temperatures as high as 14.9°C or 58.7°F, a 9.5°C or 17.1°F anomaly.

There still is about a month to go before sea ice can be expected to reach its minimum, at around half September 2015, while sea currents will continue to carry warmer water into the Arctic Ocean for months to come.

The situation is dire and calls for comprehensive and effective action, as discussed in the Climate Plan. 

Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by...
Posted by Sam Carana on Tuesday, August 18, 2015