Methane's Role in Arctic Warming

Methane's Role in Arctic Warming

Arctic change climate methane ocean warming

Unknown 2/11/2016 Add Comment

Arctic Ocean hit most strongly by global warming

Over the past 12 months, global warming was felt most strongly over the Arctic Ocean, as above image illustrates. Over most parts of the Arctic Ocean, surface temperatures were above the top end of the scale, i.e. more than 2.5°C higher than in 1981-2010.

In January 2016, air temperatures close to sea level (at 925 hPa) were more than 6°C or 13°F above average across most of the Arctic Ocean, as NSIDC.org announced recenty. Moreover, daily average temperatures over many parts of the Arctic Ocean often exceed the top end of the scale, i.e. 20°C or 36°F higher than in 1979-2000, as illustrated by the Climate Reanalyzer forecast below.

So, how can temperature anomalies over the Arctic Ocean at this time of year be so much higher than elsewhere on Earth?

One factor is feedbacks such as changes to the jet stream and decline of snow and ice cover in the Arctic that makes that ever more sunlight is getting absorbed by the water of the Arctic Ocean, in turn causing further decline, as discussed in many earlier posts.

Right now, however, warming over the Arctic Ocean is very pronounced at a time of year when there is a wider temperature difference between the Arctic and the Equator, while there is little or no sunlight reaching the Arctic. So, albedo changes are less relevant, while changes to the jet stream would be expected to be less prominent now. Nonetheless, a strongly deformed jet stream can push a lot of warm air all the way up to the North Pole, while pushing a lot of cold air out of the Arctic over North America, as illustrated by the forecast on the right.

Let's look at some further factors that are at work.

High levels of greenhouse gases over the Arctic

The question was, why is warming hitting to Arctic Ocean so strongly at this time of year? Greenhouse gas levels are higher over the Arctic than elsewhere on Earth. Greenhouse gases trap heat that would otherwise be radiated out to space, and this greenhouse effect is occurring all year long.

[ click on images to enlarge them ]

Let's look more closely at carbon dioxide (CO2) levels. On February 4, 2016, CO2 level at Mauna Loa, Hawaii, was 405.83 ppm, as illustrated by the image on the right. 

The image below shows that global mean CO2 level on February 6, 2016, was 407 ppm at an altitude close to sea level (972 mb). The image also shows higher CO2 levels at higher latitudes north, with levels over 410 ppm showing up over most of the Northern Hemisphere. 

Carbon dioxide levels on Feb. 8, 2016, were as high as 416 ppm at a location over the Kara Sea (marked by the green circle at the top of the image on the right).

Nonetheless, the levels of carbon dioxide over the Arctic Ocean are not that much higher than elsewhere, i.e. not enough to explain such huge temperature anomalies.

Methane, another greenhouse gas, is also present over the Arctic Ocean at levels that are higher than the rest of the world, as illustrated by the image below, showing methane levels over 1900 ppb over most of the Arctic Ocean on February 4, 2016. 

In the case of methane, the situation is different than for carbon dioxide:

• levels at the North Pole are more than 10% higher than at the South Poles, a much larger difference than for carbon dioxide. 
• methane is reaching its highest levels over the Arctic Ocean from October onward to well into the next year. 
• methane persists longer over the Arctic due to low hydroxyl levels there. 
• methane levels over the Arctic Ocean are high, as increasingly large amounts of methane are rising up from the Arctic Ocean seafloor, making that this methane will inherently be highly concentrated over the Arctic, especially shortly after its release. 

In conclusion, it looks like methane is playing an increasingly large role in warming up the Arctic, especially given its large short-term potency as a greenhouse gas.

from: arctic-news.blogspot.com/p/methane.html

AMOC is carrying ever more heat into the Arctic Ocean

Besides methane, there is another big reason why temperature anomalies are so high over Arctic Ocean at this time of year. Huge amounts of heat are rising up from the water into the atmosphere over the Arctic Ocean, warming up the air over the water. The warmer the sea, the less ice will form. The weaker the ice, the more cracks and spots where heat gets transferred to the atmosphere.

The water of the Arctic Ocean is getting warmer, compared to previous years, as the Gulf Stream heats up. When referring to the full length from the Gulf of Mexico to the Arctic Ocean, this current is often referred to as the North Atlantic Meridional Overturning Circulation (AMOC). The direction of AMOC's flow is determined by two forces, i.e. the flow of warm water from the Equator to the north, and the the flow east due to the Coriolis force. The result is warm, salty water is carried by AMOC in the upper layers of the Atlantic toward the north-east, to Arctic Ocean. Eventually, the water sinks and flows back as colder water through the deep Atlantic. As the NOAA image below shows, the amount of heat that has been carried by AMOC toward the Arctic Ocean has been increasing over the past few years.



Overall ocean temperatures are increasing, as discussed in posts such as Ocean Heat and Temperature Rise. As a result, more heat is getting carried toward the Arctic Ocean now. The Gulf Stream off the coast of North America is warming up strongly and is pushing more heat toward the Arctic ocean, compared to previous years. The result is illustrated by the image below, showing huge sea surface temperature anomalies in the Arctic Ocean near Svalbard, despite the cold lid on the north Atlantic, indicating that the heat is continuing to travel underneath the cold freshwater lid to the Arctic Ocean.

Such high sea surface temperature anomalies are not uncommon in the Arctic Ocean these days. The image below shows that on January 24, 2016, sea surface temperature was 12.3°C or 54.2°F at a location near Svalbard marked by the green circle, a 10.4°C or 18.7°F anomaly.

from: Arctic sea ice area at record low for time of year

Water now much warmer off the North American coast

The water off the east coast of North America is much warmer than it used to be due to emissions that extend from North America over the Atlantic Ocean due to the Coriolis force. The image below, from an earlier post, shows carbon dioxide levels as high as 511 ppm over New York on November 5, 2015, and as high as 500 ppm over the water off the coast of coast of New Jersey on November 2, 2015.

from the post: 2015 warmest year on record

The image below shows carbon monoxide levels. Carbon monoxide depletes hydroxyl, making it harder for methane to be oxidized. So again methane appears to be a major factor.

from: Arctic sea ice area at record low for time of year

Such emissions heat up the Gulf Stream and make that ever warmer water is carried underneath the sea surface all the way into the Arctic Ocean. 

Cold freshwater lid on the North Atlantic

Finally, the cold freshwater lid on the North Atlantic makes that less heat transfer occurs from ocean to atmosphere. This cold freshwater lid makes that more heat is flowing toward the Arctic Ocean just below the sea surface of the North Atlantic. 

sea ice speed and drift, forecast for February 18, 2016

This cold freshwater lid is spreading over the North Atlantic for a number of reasons: 

• more melting of glaciers on Greenland, on Svalbard and in North Canada; 
• more sea ice drifting into the Atlantic Ocean due to stronger winds. Storms move up the Atlantic in a circular way, speeding up sea ice drift along the edges of Greenland, as illustrated by this video and the images on the right;
• stronger evaporation off the east coast of North America, with moisture being carried by stronger winds to the north-east, resulting in more precipitation settling on the water and thus freshwater getting added to the North Atlantic, as illustrated by the image below.

As above image also illustrates, this cold freshwater lid on the North Atlantic could also result in more heat being carried into the Arctic Ocean, due to reduced heat transfer to the atmosphere from water on its way to the Arctic Ocean.

Above image illustrates how higher temperatures over the Arctic (top panel) can go hand in hand with the cold freshwater lid over the North Atlantic (second panel), with high sea surface temperatures off the east coast of North America (third panel) and with higher precipitation over this cold freshwater lid (bottom panel).

The image below indicates that the cold freshwater lid on the North Atlantic also goes hand in hand with falling salinity levels.

Precipitation over the North Atlantic is increasing, due to stronger winds and storms there, as discussed in earlier posts such as this one and as illustrated by the images below. Stronger winds, storms with high levels of precipitation and higher waves can all make the cold freshwater lid spread further across the North Atlantic. 

Above image show that waves as high as 17.81 m or 58.4 ft were forecast for the North Atlantic on February 1, 2016, and as high as 17.31 m or 56.8 ft for February 8, 2016.

Conclusion

In conclusion, the danger is that ever more heat will arrive in the Arctic Ocean. This will result in greater melting of the sea ice, in a self-reinforcing feedback loop that makes that more sunlight gets absorbed by the Arctic Ocean (rather than being reflected back into space, as before).

On February 11, 2016, Arctic sea ice had - for this time of year - the lowest extent since satellite records started in 1979, as illustrated by the image below.

The biggest danger is that, as the Arctic Ocean continues to warm, huge amounts of methane will erupt abruptly from the seafloor of the Arctic Ocean, driving up temperatures over the Arctic dramatically and triggering ever more methane eruptions, resulting in a rapid escalation into runaway warming.

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

Over the past 12 months, global warming was felt most strongly over the Arctic Ocean. Over most parts of the Arctic...
Posted by Sam Carana on Thursday, February 11, 2016

Why America should lead on climate

Why America should lead on climate

action Arctic EPA legal methane ocean Paris Agreement rise seafloor temperature

Unknown 1/23/2016 Add Comment

There are many reasons why America should take the lead in action on climate change. 

It's fair and in everyone's interest that America takes the lead

It's fair that those who pollute most, do most to clean things up. America's current and historic emissions are huge, while a lot of what has been produced elsewhere is also consumed in America. Moreover, it's in everyone's interest if America takes the lead. That is confirmed by studies such as this one, showing that there are no technical or economic barriers against cleaning things up. Doing so has many benefits, including job and investment opportunities, and scope for exports. In order for American industries, such as car manufacture, to remain competitive with products from overseas, they must clean up their act. In addition, there are many health and the environmental benefits, while shifting to clean energy will remove perceived needs for America to send military forces across the world to protect global supply lines of fossil fuel.

Legal obligations to act

There are also legal obligations for America to act. Back in 2007, the Supreme Court ruled in Mass. v. EPA that the EPA must act on any air pollutant that endangers public health or welfare. The EPA subsequently found this to be the case for six greenhouse gases and took action, including by issuing plans to limit carbon emissions from power plants. More recently, the United States Court of Appeals for the DC Circuit ruled in favor of the EPA plans.

Furthermore, as Michael Burger points out, Section 115 of the Clean Air Act also authorizes the EPA to act on emissions that contribute to air pollution that endangers public health or welfare in other countries, the more so where the other countries provide the U.S. with reciprocal protections. At the Paris Agreement, such reciprocity was affirmed by some 190 nations (accounting for over 93% of current GHG emissions) pledging to hold the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels.

In other words, no new laws are needed and action can and should be taken now, as this blog has pointed out for years, e.g. in this 2014 post that featured the image below.




The threat of methane eruptions from the Arctic Ocean seafloor calls for urgent action

This blog has repeatedly pointed at another reason why especially America must act, and must do so rapidly, comprehensively and effectively. In October 2015, oceans reached record high temperatures, especially on the Northern Hemisphere, as illustrated by the image below.

Northern Hemisphere October ocean temperatures based on NOAA 1880-2015 data - plot area goes from 1900 to 2050 and from -1 to 4 degrees Celsius above baseline, i.e. compared to the period 1901-2000, the 20th century average.

Above image features a trendline showing that oceans on the Northern Hemisphere could, by the year 2043, be 4°C or 7.2°F warmer than the 20th century average. Increasingly, methane levels over the Arctic Ocean are showing strong increases from October onward, as huge amounts of ocean heat are reaching the seafloor of the Arctic Ocean from that month onward.

North America contributes strongly to accelerating warming of the Arctic Ocean. The Coriolis Effect makes that high levels of emissions originating from North America are extending over the Atlantic Ocean, and are warming up waters off the east coast of North America, as illustrated by the image below.

Top left: CO2 414 ppb green circle, up to 433 ppm in New Jersey. Top right: CO 274 ppb green circle, up to 890 ppb in New Jersey. Bottom left: Jet Stream 250 hPa. Bottom right: Sea surface temperature anomaly 8.5°C/15.3°F green circle.

2015 maximum nightly sea surface temperature anomaly

Carbon dioxide emissions are important, but also relevant are other emissions such as carbon monoxide that depletes hydroxyl, making it harder for methane to be oxidized.

As emissions keep rising, the Gulf Stream will carry ever warmer water into the Arctic Ocean, resulting in greater melting of the sea ice and associated albedo changes that in turn accelerate warming in the Arctic.

Surface temperature anomaly Jan 21, 2015 - Jan 20, 2016
 

This is further illustrated by the images on the right. The top image shows 2015 maximum nightly sea surface temperature anomalies, with anomalies of 5°C off the North American east coast as well as in the Arctic Ocean.

The second image on the right illustrate the extent at which warming in the Arctic Ocean is accelerating, compared to the rest of the world. The image also shows the cold freshwater lid over the North Atlantic.

Temperature anomaly forecast for January 28, 2016
 

As the temperature difference between the Arctic and the equator decreases, the jet stream gets more elongated, at times moving all across the Arctic Ocean. This is one of a multitude of feedbacks that contribute to accelerating warming of the Arctic Ocean. The result is illustrated by the third image on the right, showing strong warming over most of the Arctic Ocean, while at the same time some places on land at higher latitudes north are experiencing extremely cold conditions.

descending cold freshwater on January 25, 2016

Another one of such feedbacks is that warmer water off the coast of North America will result in stronger winds moving over the North Atlantic toward the Arctic Ocean. This can also speed up ocean currents, so it can result in more heat being carried toward the Arctic Ocean both in the atmosphere and the water.

Meltwater from glaciers and sea ice can descend along the edges of Greenland into the North Atlantic, forming a cold freshwater lid on the North Atlantic, where it accumulates at the surface over the years, as illustrated by the image on the right that points at a -4°C or -7.1°F anomaly compared to 1981-2011.

cold freshwater lid over the North Atlantic

In addition, precipitation (rain, snow, hail, fog, etc.) can further contribute to expansion of this cold freshwater lid over the North Atlantic, as illustrated by the images on the right.

While this cold freshwater may constitute a barrier that slows the flow of warm water toward the Arctic Ocean at the surface, the danger is that it prevents heat transfer to the atmosphere from warm water flowing below the sea surface, with the net result of more heat arriving in the Arctic Ocean.

Furthermore, if this cold freshwater lid also prevents water from sinking deeper in the North Atlantic, this may also contribute to more warm water arriving in the Arctic ocean, as illustrated by the bottom image on the right.

Such feedbacks can dramatically accelerate warming of Arctic Ocean, resulting in heat destabilizing sediments that can contain huge amounts of methane.

In conclusion, America must take the lead in action on climate change. It's fair to do so, it will benefit everyone, there are legal obligations to do so and there is great urgency to act in the light of looming methane eruptions from the seafloor of the Arctic Ocean.

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

In October 2015, oceans reached record high temperatures, especially on the Northern Hemisphere. The image features a...
Posted by Sam Carana on Saturday, January 23, 2016

2015 warmest year on record

2015 warmest year on record

anomaly Arctic extreme hydrates methane ocean temperature weather

Unknown 12/28/2015 Add Comment

1.1°C or 34.1°F at the North Pole

The year 2015 is shaping up to be the warmest year on record. In the media, a lot of attention has been given to the many floods, droughts, wildfires and heatwaves that have battered the world this year.

Sadly, though, little attention is given to the situation in the Arctic. The image on the right shows a forecast for December 30, 2015, with temperatures at the North Pole above freezing point, as further illustrated by the nullschool.net image below, showing a temperature forecast of 1.1°C or 34.1°F for the North Pole. Wind speed at the North Pole is forecast to be 105 mph or 168 km/h on December 30, 2015, and 133 mph or 215 km/h closer to Svalbard.

As the image below illustrates, very high temperatures are forecast to hit the Arctic Ocean on December 30, 2015.

Above image shows temperature anomalies at the highest end of the scale for most of the Arctic Ocean, with a temperature anomaly for the Arctic as a whole of 2.4°C or 4.32°F above what was common in 1979-2000. The situation isn't likely to improve soon. For January 3, 2016, the temperature in the Arctic is forecast to be as much as 4.56°C or 8.21°F warmer.

How is it possible for such high temperatures to occur over the Arctic Ocean? The image below shows how the year 2015 is shaping up in terms of temperature anomalies.

Global warming is felt most strongly in the Arctic as warming continues, as illustrated by above image and by the image on the right.

Warming in the Arctic is accelerating due to feedbacks. One of these feedbacks is the way the jet streams are changing. Changes in the jet streams are becoming more prominent as the Arctic is warming up more rapidly than the rest of the world.

jet streams

As the difference in temperature between the Arctic and the equator becomes smaller, the speed at which the jet stream circumnavigates the globe is decreasing and jet streams become more wavy.

Meanwhile, most of the extra heat caused by global warming goes into the oceans, and the Atlantic Ocean is warming up fast. At the same time, meltwater is accumulating at the surface of the North Atlantic, lowering sea surface temperatures there. With such large differences between high temperatures over North America and lower temperatures over the North Atlantic, the speed of the jet stream between those places can increase dramatically.

The result is that huge amounts of warm air are being pushed high into the Arctic. The image on the right shows the jet streams on December 27, 2015, when speeds as high as 263 mph or 424 km/h were reached at the location marked by the green circle. Also note the jet streams crossing the Arctic at the top of the image, while crossing the equator at the bottom of the image.

The image below shows sea surface temperature anomalies on the Northern Hemisphere in November.

For over a month now, storms over the North Atlantic have been pushing hot air high up into the Arctic. The video below uses surface wind content by Climate Reanalyzer (selected daily averages and sequences of forecasts) to cover the period from December 5, 2015, to January 8, 2016.

Best wishes for 2016

Above video stops at January 8, 2016, when two cyclones are visible, one in the North Atlantic and another one over the North Pacific, prompting me to create the image on the right.

What causes these storms to grow this strong? Waters keeps warming up dramatically off the east coast of North America. Emissions from North America tend to extend over these waters, due to the Coriolis effect, and this contributes to their extreme warming.

The image below shows carbon dioxide levels as high as 511 ppm over New York on November 5, 2015, and as high as 500 ppm over the water off the coast of coast of New Jersey on November 2, 2015. 

Emissions contribute to warmer waters - click to enlarge

The top panel of the image on the right shows that on December 11, 2015, carbon dioxide levels were as high as 474 ppm (parts per million, surface concentration) at the location marked by the green circle in New York.

The bottom panel of the image on the right shows that the water off the coast was warmer by as much as 10.3°C or 18.5°F at the location marked by the green circle on December 11, 2015.

The NASA video below shows carbon dioxide emissions over the year 2006.

It's not just CO2 off the North American coast that contributes to further warming of the Gulf Stream, many other emissions do so, including methane, CO, etc. Carbon monoxide (CO) is not a greenhouse gas, but it depletes hydroxyl, thus preventing oxidation of methane, a very potent greenhouse gas. The animation below shows a carbon monoxide level at green circle of 528 ppb on December 28, 2015, 0900z, while the sea surface temperature anomaly there was 15.8°F or 8.8°C on that day. 

Carbon monoxide reached much higher levels recently over land, as illustrated by the image below that shows a CO level of 2077 ppb in New York on January 6, 2016. 

These emissions heat up the Gulf Stream and make that ever warmer water is carried underneath the sea surface all the way into the Arctic Ocean, while little heat transfer occurs from ocean to atmosphere, due to the cold freshwater lid on the North Atlantic.

feedback #28 at the feedback page

The image on the right shows that it was warmer by as much as 9.6°C or 17.2°F near Svalbard on December 25, 2015, at the location marked by the green circle. The same anomalies were recorded on December 26, 2015, when the temperature of the water there was 11°C or 51.9 °F.

This gives an indication of how warm the water is that is being pushed underneath the sea surface into the Arctic Ocean.

Strong winds and high waves can cause more sea ice to be pushed along the edges of Greenland out of the Arctic Ocean, into the Atlantic ocean, expanding the cold freshwater lid on the North Atlantic, in a self-reinforcing feedback loop.

The image below shows the impact of these storms on sea ice speed and drift on December 31, 2015 (left) and a forecast for January 8, 2016 (right).

The danger is that, as warmer water reaches the seafloor of the Arctic Ocean, it will increasingly destabilize sediments that can contain huge amounts of methane in the form of free gas and hydrates.

Methane levels over the Arctic Ocean are already very high. Above image shows methane levels as high as 2745 ppb over the Arctic Ocean on January 2, 2016. High releases from the Arctic Ocean seafloor are pushing up methane levels higher in the atmosphere, as discussed in earlier posts such as this one.

So, while the extreme weather events that have occurred in the year 2015 are frightening, even more terrifying is the way the water of the Arctic Ocean is warming up. Sadly, this is rarely even discussed in the media. So, let's once more add the image below that should have been given more media attention.

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

The year 2015 is shaping up to be the warmest year on record. In the media, a lot of attention has been given to the...
Posted by Sam Carana on Monday, December 28, 2015

Ocean Heat Depth

Ocean Heat Depth

albedo Arctic clathrates depth feedbacks heat hydrates hydroxyl methane ocean

Unknown 12/04/2015 Add Comment

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