Methane levels for March 2012 are highest above ESAS

NASA has made available the monthly methane levels for March 2012. As the polar projection below shows, extremely high levels of methane are concentrated above the East Siberian Arctic Shelf (ESAS).

The image below further shows how the anomalies have increased over the years, especially on the Northern Hemisphere; note the wide gaps between anomalies on the Northern Hemisphere (blue) and the Southern Hemisphere (green) over the past few months. 

The images, based on AIRS NASA data, were produced by Dr. Leonid Yurganov, Senior Research Scientist, JCET, at University of Maryland - Baltimore County. For further images, see Dr. Yurganov's archive at asl.umbc.edu/pub/yurganov/methane 

High methane levels in Arctic - April 2012

Below are two images produced with NASA GES DISC Giovanni data system, showing methane levels for early April 2012.

The top image shows where methane levels exceed 1.9 parts per million.

The image below is a polar projection; note the different scale on the right, which is the default one that is automatically calculated and exceeds 2 parts per million.

Below the same image as the above one, this time with the same custom scale as the top image. 

Below is an animation showing the recent surface temperature anomalies 

This animation is a 774 kb file and may take some time to fully load. 

Methane levels at Mauna Loa, Hawaii (directly below) and Barrow, Alaska (further down below). 

Highlights of EGU General Assembly 2012

If you will be attending the European Geosciences Union (EGU) General Assembly on April 25, 2012, make sure to attend, from 14:00 to 14:15 in room 23, the presentation:

Methane release from the East-Siberian Arctic Shelf and its connection with permafrost and hydrate destabilization: First results and potential future developments
by Natalia Shakhova and Igor Semiletov

The East Siberian Arctic Shelf (ESAS) is home to the world’s largest hydrocarbon stocks, which consist of natural gas, coal bed methane (CH4), and shallow Arctic hydrates. Until recently, the ESAS was not considered a CH4 source due to the supposed impermeability of sub-sea permafrost, which was thought to completely isolate the CH4 beneath from modern biogeochemical cycles.

However, the ESAS represents an enormous potential CH4 source that could be responsive to ongoing global warming. Such response could occur in substantially shorter time than that of terrestrial Arctic ecosystems, because sub-sea permafrost has experienced long-lasting destabilization initiated by its inundation during the Holocene ocean transgression. ESAS permafrost stability and integrity is key to whether sequestered ancient carbon escapes as the potent greenhouse gas CH4.

Recent data suggest the sub-sea permafrost is currently experiencing significant changes in its thermal regime. For example, our recent data obtained in the ESAS during the drilling expedition of 2011 showed no frozen sediments at all within the 53 m long drilling core at water temperatures varying from -0.6˚C to -1.3˚C.

Unfrozen sediments provide multiple potential CH4 migration pathways. We suggest that open taliks have formed beneath the areas underlain or influenced by the nearby occurrence of fault zones, under paleo-valleys, and beneath thaw lakes submerged several thousand years ago during the ocean transgression. Temporary gas migration pathways might occur subsequent to seismic and tectonic activity in an area, due to sediment settlement and subsidence; hydrates could destabilize due to development of thermokarst-related features or ice-scouring.

Recently obtained geophysical data identified numerous gas seeps, mostly above prominent reflectors, and the ubiquitous occurrence of shallow gas-charged sediments containing numerous gas chimneys, underscoring the likelihood that the ability of sub-sea permafrost to capture CH4 released from the seabed is failing.

Available data suggest the ESAS sub-sea permafrost is currently leaking a substantial amount of CH4. We propose that a few different types of CH4 exist, and are becoming involved in the modern carbon cycle due to permafrost destabilization in the ESAS: modern biogenic CH4 produced from ancient substrate, relatively old biogenic CH4 mobilized from hydrate deposits, and old thermogenic CH4 accumulated within seabed deposits. Isotopic data obtained by sampling CH4 in the water column and atmospheric CH4 in close proximity to the sea surface confirm the contribution from different sources, and demonstrate that the isotopic signature of CH4 from the ESAS can be used to create an interpretive plot for defining hydrates. CH4 fluxes could occur as numerous weak seeps, as large areas of strong bubble plumes, or as sites where CH4 releases are flare- or torch-like and the emissions are non-gradual.

Due to the shallow and oligotrophic nature of the ESAS, the majority of aqueous CH4 may avoid biological oxidation in the water column and escape to the atmosphere.

Further investigations should be focused on quantifying the total CH4 pool of the ESAS, improving our understanding of the mechanisms responsible for sub-sea permafrost destabilization and gas migration pathways formation, and decreasing uncertainties regarding the current CH4 emission mode and its future alteration by progressing permafrost degradation.

Geophysical Research Abstracts
Vol. 14, EGU2012-3877-1, 2012
EGU General Assembly 2012

Above presentation is part of the session:
Methane cycling in marine and terrestrial systems

which also features, as part of the poster program:
Display Time: Wednesday, 25 Apr 08:00–19:30
Attendance Time: Wednesday, 25 Apr 17:30–19:00
Poster Area BG

First drilling subsea permafrost in the southeastern Laptev Sea, the East Siberian Arctic Shelf: results and challenges
by Igor Semiletov, et al.
highlighting the following two challenges:

1) observed Arctic warming in early 21st century is stronger than predicted by several degrees, which may accelerate thaw release of methane from the upper seafloor layer by increasing bottom erosion and from deeper stratums (including hydrates) by sediment settlement and adjustment;

2) drastic sea ice shrinkage causes increase in storm activities and deepening of the wind-wave-mixing layer down to depth ~50 m that enhance methane release from the water column to the atmosphere.

Geophysical Research Abstracts
Vol. 14, EGU2012-3913, 2012
EGU General Assembly 2012

NSDIC Arctic Sea Ice News & Analysis April 4, 2012

The National Snow and Ice Data Center (NSDIC) has released an update of its Arctic Sea Ice News & Analysis (April 4, 2012). 

Ice age data shows thin ice cover

Ice age data this year show that the ice cover remains much thinner than it was in the past, with a high proportion of first-year ice, which is thin and vulnerable to summer melt.

After the record low minimum of 2007 the Arctic lost a significant amount of older, thicker ice, both from melting and from movement of ice out of the Arctic the following winter. In the last few years, the melt and export of old ice was less extreme than in 2007 and 2008, and multiyear ice started to regrow, with second and third-year ice increasing over the last three years.

After the near-record melt last summer, second-year ice declined again, but some of the ice that had survived the previous few summers made it through another year, increasing the proportion of third- and fourth-year ice. However the oldest, thickest ice, more than four years old, continued to decline.

Ice older than four years used to make up about a quarter of the winter sea ice cover, but now constitutes only 2%. First-year ice (0 to 1 years old) this year makes up 75% of the total ice cover, the third highest at this time of year in the satellite record. In 2008 the proportion of first-year ice was 79%, and in 2009 it was 76%.

Rapid Arctic warming is altering the course of the jet stream

NSDIC also points at a study by Jennifer Francis of Rutgers University and Steve Vavrus of the University of Wisconsin that suggests that warming in the Arctic is causing weather patterns in mid-latitudes to become more persistent. This persistence can lead to conditions like heat waves, cold spells, drought, flooding, and heavy snows. The researchers found that as temperatures in the Arctic warm and become closer to temperatures in lower latitudes, the waves of the jet stream tend to spread out, and west-to-east winds slow down in the upper level of the atmosphere (where storm tracks form). Both of these effects tend to slow the progression of weather patterns, which means that a weather pattern, whether hot or cold, is more likely to stick around.