Arctic sea ice may well be gone by September 2017

The Arctic Ocean is warming up fast and this is melting the sea ice from below.

Sea surface temperature anomalies are well above 8°C (14.4°F) in several parts of the Arctic Ocean.

The image on the right shows sea surface temperature anomalies from 1961-1990 for the Arctic (60°N - 90°N) on August 2, 2017.

Global sea ice extent is at a record low for the time of the year, as illustrated by the graph below, by Wipneus. Lower sea ice extent means that less sunlight is reflected back into space.

Arctic sea ice extent in 2017 is shrinking along a path that currently looks similar to the years 2012, 2016 and 2007, when sea ice reached 1st, 2nd and 3rd place, respectively, regarding lowest extent (image right).

Arctic sea ice volume has been at record low since the start of 2017 and is currently similar to 2012, as illustrated by the graph below right, by Wipneus (click on images to enlarge them).

Arctic sea ice may look to be similar to what it was in 2012, when extent and volume reached lowest since satellite measurements began.

However, sea ice thickness has fallen dramatically over the years in the areas where previously was the thickest ice.

This is illustrated by the combination image below, showing Arctic sea ice thickness (in m) in July 31, 2012 (left panel) versus thickness on July 31, 2017 (right panel).

[ click to enlarge ]

The navy.mil animation on the right shows sea ice getting thinner recently, with especially the thicker sea ice disappearing fast.

There appear to be discrepancies between the PIOMASS calculation of ice volume and the ice thickness images by navy.mil.
This may be due to the way volume is calculated and may be similar to differences in extent and area.

Sea ice clearly has disappeared most where once the thickest ice was present.

Harold Hensel points out that extent may at first glance show more ice but each cell in a grid may only have 15% of ice present to be labeled 'ice-covered'. Harold adds an image showing ice concentration, which gives another insight in the shape and condition of the sea ice (above image).

Paul Beckwith and Patrick McNulty bluntly conclude that PIOMAS is wrong, as illustrated by the Twitter screenshot on the right.

Clearly, dramatic shrinking of the thicker sea ice has occurred over the past few years and one of the reasons for this is the ever warmer water that is getting pushed into the Arctic Ocean along the Gulf Stream. This is melting the sea ice from below. Warming of the Arctic Ocean heats up the air over the Arctic Ocean, as illustrated by the image below.

[ click on image to enlarge ]

The above image shows a 365-day surface temperature anomaly. The change over time is also illustrated by the animation on the right.

On average, surface temperatures over the Arctic Ocean have been more than 2.5°C (or 4.5°F) warmer than in 1981-2010. The warmer air is now also melting the sea ice from above, as temperatures over the Arctic have risen to well above the freezing point.

High temperatures over the Arctic Ocean means that precipitation no longer takes the form of snow, but instead falls in the form of rain.

Below is a further warning, against a more recent background image (situation on August 6, 2017).

[ click on image to enlarge ]

High temperatures of the surface of the ocean combined with strong winds makes that a lot of moisture is rising from the sea surface to the atmosphere.

The image on the right shows that sea surface temperatures in the Bering Strait were as high as 19°C (or 66.2°F) on July 22, 2017. This is partly the result of warm water from rivers entering the Bering Strait.

Furthermore, cyclones can make winds reach high speeds, as illustrated by the image below, showing Typhoon Noru approaching Japan.

The image shows a forecast for August 5, 2017, 18:00 UTC. Waves have been forecast to be as high as 16.15 m or 53 ft, while winds have been forecast to be as fast as 214 km/h or 133 mph or 116 kn.

[ click on image to enlarge ]

Total precipitable water has been forecast to be as much as 91.000 kg/m² and 3-hr Precipitation Accumulation has been forecast to be as much as 281.3 mm (or 281.3 kg/m²) or 11.07 in.

Back to the Arctic, where strong winds and moist air combine to make a lot of rain, as temperatures are well above freezing in most areas, as illustrated by the image on the right (showing air temperature at 2 m).

The image below shows how strong winds are pushing warm and moist air through the Bering Strait on July 31, 2017 at surface level (left), at 700 hPa (center) and at 250 hPa (right), where the jet stream used to separate the cold air in the Arctic from the warmer air further south.

As above image also shows, the jet stream is getting more and more out of shape, at places crossing the Arctic Ocean. In the video below, Paul Beckwith discusses the situation in the Arctic.

The image below shows trends for both Arctic and Antarctic sea ice area pointing downward.

When looking at sea ice volume, zero sea ice in September 2017 is within the margins of the trendline below on the right.

[ Arctic sea ice, gone by Sept. 2017? ]

Given the speed at which many feedbacks can kick in and the interaction between warming elements, Arctic sea ice volume may well be gone by September 2017.

The low sea ice volume means that there is very little sea ice left to act as a buffer this year. Therefore, a huge amount of heat will not be able to be consumed this year in the process of melting ice and will instead speed up warming of water of the Arctic Ocean.

Less sea ice additionally means that less sunlight will be reflected back into space, and this heat will instead further speed up Arctic warming.

The Buffer has gone, feedback #14 on the Feedbacks page

Where can all this extra heat go? Sea ice is expected to start sealing off much of the surface of the Arctic Ocean by the end of September 2017, which will make it harder for heat to escape the Arctic Ocean by entering the atmosphere.

The danger is that much of the extra heat will instead reach sediments at the seafloor of the Arctic Ocean that contain huge amounts of methane in currently still frozen hydrates.

The image on the right shows that methane reached levels as high as 2583 ppb on July 31, 2017.

The image also shows high methane levels over Antarctica where hydrate destabilization also appears to be taking place, as discussed in an earlier post.

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


Links

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• 10°C or 18°F warmer by 2021?
https://arctic-news.blogspot.com/2017/04/10c-or-18f-warmer-by-2021.html

• Abrupt Warming - How Much And How Fast?
https://arctic-news.blogspot.com/2017/05/abrupt-warming-how-much-and-how-fast.html

• Accelerating growth in CO₂ levels in the atmosphere
https://arctic-news.blogspot.com/2017/02/accelerating-growth-in-co2-levels-in-the-atmosphere.html

• Feedbacks
https://arctic-news.blogspot.com/p/feedbacks.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• Methane Erupting From Arctic Ocean Seafloor
https://arctic-news.blogspot.com/2017/03/methane-erupting-from-arctic-ocean-seafloor.html

• Warning of mass extinction of species, including humans, within one decade
https://arctic-news.blogspot.com/2017/02/warning-of-mass-extinction-of-species-including-humans-within-one-decade.html

More heat on the way

Above image shows temperature anomalies over the Pacific Ocean on February 12, 2017. Note the 19.2°C (34.5 °F) anomaly off the coast of Japan, at the location marked by the green circle.

In 2016, the annually-averaged temperature for ocean surfaces around the world was 0.75°C (1.35°F) higher than the 20th century average, higher than the previous record of 2015, NOAA reports. The global annual land surface temperature for 2016 was 1.43°C (2.57°F) above the 20th century average, surpassing the previous record of 2015 by 0.11°C (0.19°F). Note that NOAA uses the the 20th century average as a baseline, for more on different baselines, see this earlier post.

There is more heat on the way, as illustrated by the image below.

As above image shows, the El Niño-Southern Oscillation (ENSO) temporarily raises (El Niño) or suppresses (La Niña) global temperatures. Generally, the stronger the event (El Niño or La Niña), the greater its impact on the average global temperature around that time. Note that one value for 2016 literally went off the chart.

As above image shows (at the end of the graph on the right), we've barely had a bit of a La Niña in 2017 and we're already facing another El Niño event.

[ click on images to enlarge ]

Above images shows ECMWF (European Centre for Medium-Range Weather Forecasts) plumes with strong positive anomalies in all three El Niño regions (on the right).

In other words, temperatures in 2017 look set to be very high, which spells bad news for the Arctic where temperature anomalies are already several times higher than in the rest of the world, as illustrated by the image below.

As the image below shows, Antarctic sea ice extent was at a record low for the time of the year on February 11, 2017.


The situation looks particularly grim for the Arctic sea ice. As the image below shows, Arctic sea ice extent on February 11, 2017, was also at a record low for the time of the year. In fact, it had fallen to 13,895,00 km² that day, raising the question whether perhaps the maximum for the year 2017 had already been reached.

Low global sea ice extent means that less sunlight is reflected back into space by the ice and that more heat is instead absorbed by the ocean, adding to the predicament the world is in. The situation in the Arctic is crucial, as huge amounts of methane, contained in sediments under the Arctic Ocean, could be released if warming continues, potentially triggering mass extinction of species, including humans, within one decade.

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



Links


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

• Extinction
http://arctic-news.blogspot.com/p/extinction.html

• How much warming have humans caused?
http://arctic-news.blogspot.com/2016/05/how-much-warming-have-humans-caused.html

• Warning of mass extinction of species, including humans, within one decade
http://arctic-news.blogspot.com/2017/02/warning-of-mass-extinction-of-species-including-humans-within-one-decade.html

Lake Baikal

The amount of methane stored in the form of hydrates at the bottom of Lake Baikal in Siberia is an estimated 1 trillion m³, which translates into 424 trillion kg of methane, or 424 Gt of methane. By comparison, the amount of methane in the atmosphere is about 5 Gt.

Aral Sea

Methane hydrates remain stable under a combination of sufficiently low temperatures and sufficiently high pressure. The temperature of the water at the bottom of the lake is about 3.5°C. This means that a large amount of water needs to remain present in the lake at any time, in order to keep the methane hydrates stable.

Lake Baikal is the world's deepest lake. Due to its depth, Lake Baikal is also the largest freshwater lake by volume in the world, containing roughly 20% of the world's unfrozen surface fresh water. Lake Baikal has 23,615.39 km³ (5,700 cu mi) of fresh water and a maximum depth of 1,642 m (5,387 ft).

If the water level in Lake Baikal were to fall, the pressure on the methane hydrates would decrease, resulting in huge methane eruptions, dwarfing the amount of methane currently in the atmosphere.

What are the chances that water levels in Lake Baikal will fall in future? The above animation shows the fate of the Aral Sea, further to the west in Asia (also on the map at top). The Aral Sea virtually disappeared over the course of the last few decades. Some people point at climate change as the cause. More people point at irrigation by farmers.

Yenisei River

Lake Baikal could go the same way. Climate change may well reduce the flow of the rivers that now feed Lake Baikal from Mongolia (image right). Furthermore, climate change may well reduce crop yields worldwide as well as the availability of fresh water, increasing temptations to use the water of Lake Baikal for irrigation.

Further decline of Arctic sea ice is likely to push up temperatures across Russia. The image below shows that temperatures as high as 36.6°C or 97.8°F were forecast for June 13, 2016, over the Yenisei River in Siberia that ends in the Arctic Ocean.

[ click on images to enlarge or go to original post ]

Even higher temperatures were recorded in 2015 at a location in Siberia well within the Arctic Circle.

Demands for water could increase even more dramatically due to wildfires and the need to fight such fires. The image below shows that on June 23, 2016, wildfires north of Lake Baikal caused emissions as high as 22,953 ppb CO and 549 ppm CO₂ at the location marked by the green circle.

[ click on images to enlarge or go to original post ]

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


Links

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

• Gone: endemic Baikal sponge has died completely in several areas of the vast lake
http://siberiantimes.com/ecology/casestudy/features/f0278-gone-endemic-baikal-sponge-has-died-completely-in-several-areas-of-the-vast-lake/

• Volume to weight conversion
http://www.aqua-calc.com/calculate/volume-to-weight

• Lake Baikal, Wikipedia
https://en.wikipedia.org/wiki/Lake_Baikal

• Aral Sea, Wikipedia
https://en.wikipedia.org/wiki/Aral_Sea

• Climate Feedbacks Start To Kick In More
http://arctic-news.blogspot.com/2016/06/climate-feebacks-start-to-kick-in-more.html

• High Temperatures In Arctic
http://arctic-news.blogspot.com/2016/06/high-temperatures-in-arctic.html

• East Siberian Heat Wave
http://arctic-news.blogspot.com/2015/07/east-siberian-heat-wave.html

• Wildfires in Russia's Far East
http://arctic-news.blogspot.com/2016/08/wildfires-in-russias-far-east.html

Seafloor Methane

Methane levels over the Arctic Ocean are higher than elsewhere on Earth. As the animation below shows, methane levels were as high as 2436 parts per billion (ppb) on the afternoon of December 5, 2016, with most methane rising up from the water, in particular over the Arctic Ocean.

Rise in the atmosphere of methane on December 5, 2016 (MetOp 1 pm), from 1000 mb, i.e. close to
sea level, up to a pressure of 586 mb, which corresponds with an altitude of 3833 m.

Methane levels over the Arctic Ocean have been high for more than a month. The video below, with a soundtrack by Daniel Kieve, shows methane levels from October 26, 2016 to November 25, 2016.

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These high methane levels come at a time when there's hardly any sunlight reaching the Arctic, which pretty much rules out the possibility that algae blooms or other biological sources were causing these high methane levels. Instead, these high methane levels appear to be the result of methane eruptions from the seafloor of the Arctic Ocean, caused by warming water of the oceans.

Indeed, large quantities of methane appear to be erupting from seafloor of the Arctic Ocean and, as this methane rises in the atmosphere, it moves closer to the Equator, resulting in higher methane levels there as well. Above image further illustrates that seafloor methane appears to be pushing up mean global methane level at higher altitudes.

The image below shows the temperature rise of the oceans. Temperatures are rising particularly rapidly on the Northern Hemisphere.

[ Ocean warming, from earlier post ]

The huge amounts of energy entering the oceans translate into higher temperatures of the water and of the air over the water, as well as higher waves and stronger winds. Much of that heat is carried by the Coriolis force along the Gulf Stream from the coast of North America via the North Atlantic into the Arctic Ocean.

As the image on the right shows, sea surface temperatures near Svalbard (green circle) were as high as 14.1°C / 57.3°F on December 6, 2016, 12.1°C / 21.7°F warmer than in 1981-2011.

The rise in ocean heat is threatening to cause ever larger eruptions of methane from the seafloor.

As described at the Extinction page, methane eruptions from the seafloor could well cause a 1.1°C temperature rise over the next ten years, and in combination with other elements, this is threatening to cause global temperature to rise 10°C or 18°F by 2026.

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


Links

• A pdf of the extinction page and an introduction to the Climate Plan can be downloaded from
https://sites.google.com/site/samcarana/climateplan/Climate-Plan-by-Sam-Carana.pdf?attredirects=0&d=1

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Methane
https://arctic-news.blogspot.com/p/methane.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• Old Mother Nature, by Daniel Kieve
https://soundcloud.com/danielkieve/old-mother-nature

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