Is the permafrost's integrity breaking down?

The chart below shows very high methane levels over Antarctica in April and May 2013. High levels of methane over Antarctica were recorded before in 2013, as described in an earlier post at the methane-hydrates blog.

Meanwhile, a methane reading of 2475 ppb was recorded on April 26, 2013, appearing to originate from the Himalayan Plateau, as illustrated by the image below.

Recurring high readings could indicate that methane is bubbling up through the permafrost, both in Antarctica and on the Himalayan Plateau.

Loss of the integrity of the permafrost is particularly threatening in the Arctic, where the sea ice looks set to disappear within years, resulting in huge albedo changes in summer. Decrease of surface reflectivity results in increases in absorption of energy from sunlight and decreases in shortwave radiation in the atmosphere. The latter results in lower photo-dissociation rates of tropospheric gases. Photo-dissociation of the ozone molecule is the major process that leads to the production of OH (hydroxyl radical), the main oxidizing (i.e., cleansing) gas species in the troposphere. A 2009 NASA study projects this to lead to a decrease in OH concentrations and a weakening of the oxidizing capacity of the Arctic troposphere, further increasing the vulnerability of the Arctic to warming in case of additional methane releases.

Levels of greenhouse gases such as carbon dioxide and methane are already very high in the Arctic atmosphere, while large quantities of black carbon get deposited on snow and ice, further contributing to the albedo changes. This threatens to result in rapid summer warming of many parts of the Arctic Ocean with very shallow waters. Additionally, rivers can bring increasingly warm water into those shallow seas in summer, adding to the threat that heat will penetrate the seabed that contains huge quantities of methane.



Above image, earlier included in an animation at the Arctic-news blog, shows methane concentrations on January 23, 2013, when a reading of 2241 ppb was recorded in the Arctic.

Analysis of sediment cores collected in 2009 from under ice-covered Lake El'gygytgyn in the northeast Russian Arctic suggest that, last time the level of carbon dioxide in the atmosphere was about as high as it is today (roughly 3.5 to 2 million years ago), regional precipitation was three times higher and summer temperatures were about 15 to 16 degrees Celsius (59 to 61 degrees Fahrenheit), or about 8 degrees Celsius (14.4 degrees Fahrenheit) warmer than today.

As temperatures rose back in history, it is likely that a lot of methane will have vented from hydrates in the Arctic, yet without causing runaway warming. Why not? The rise in temperature then is likely to have taken place slowly over many years. While on occasion this may have caused large abrupt releases of methane, the additional methane from such releases could each time be broken down within decades, also because global methane levels in the atmosphere were much lower than today.

In conclusion, the situation today is much more threatening, particularly in the East Siberian Arctic Shelf (ESAS), as further described in the earlier post methane hydrates.

Above post is an extract of the full post at the methane-hydrates blog. 

1250 - New group calls for action on methane

A new group, named 1250, calls for governments around the world to take action on methane.

Just like 350 parts per million has become a popular target for carbon dioxide, the group similarly advocates a target for methane, aiming for a reduction of methane to 1250 parts per billion (ppb).

On several occasions in April, 2013, the hourly average carbon dioxide concentration in the atmosphere of Mouna Loa, Hawaii, surpassed 400 parts per million (ppm). On May 9, 2013, the daily mean concentration of carbon dioxide in the atmosphere of Mauna Loa also surpassed 400 ppm. The National Oceanic and Atmospheric Administration (NOAA) comments that before the Industrial Revolution in the 19th century, global average carbon dioxide was about 280 ppm. During the last 800,000 years, carbon dioxide fluctuated between about 180 ppm during ice ages and 280 ppm during interglacial warm periods. Today’s rate of increase is more than 100 times faster than the increase that occurred when the last ice age ended.

On May 9, 2013, at another place on Earth, another significant event took place. Methane levels above Antarctica reached a peak of 2249 ppb, highlighting the need for action on methane.

The group 1250 advocates a similar target for methane, i.e. a reduction of methane to 1250 parts per billion.

“Methane is far more potent than carbon dioxide as a greenhouse gas, making it important to reduce levels of methane in the atmosphere,” explains founder Nathan Currier; “1250 is not just an advocacy group for methane cuts, however. Rather, it is a group focusing on near-term climate as a whole, and on practical pathways to constructing a ‘climate bridge’ towards a stable and sustainable future.”

The launch of the group is accompanied by the release of the chart below showing the very high methane levels that have been recorded over Antarctica recently. The chart was prepared by Sam Carana, who also is a founding member of 1250.

These very high methane emissions occur on the heights of East Antarctica. Antarctica is covered in a thick layer of ice. It appears that these very high emissions are caused by methane from hydrates that is escaping in the form of free gas bubbling up through the ice sheet.

The danger is that such emissions will escalate, not only over Antarctica, but also on the Qinghai-Tibet Plateau and in the Arctic. For more on this, see the methane-hydrates blog.

The group 1250 was set up specifically to address to need for a comprehensive approach to the challenges posed by climate change. The group now invites other groups to a dialogue regarding the details.

The group has a website at http://1250now.org/ and encourages people to join its mailing list and sign its petition.