Methane levels as high as 2845ppb

Methane levels as high as 2845 parts per billion (ppb) were recorded on April 25, 2015, as illustrated by the image below.

This is an extremely high peak. The average daily peak in 2015 until May 1 was 2371 ppb, while the highest daily mean ranged from 1807 ppb (January 10) to 1829 ppb (April 22). Daily peaks and daily highest mean levels in 2015 are shown on the image below.

These peaks are much higher than they were in previous years, as illustrated by the image below, from an earlier post and showing the average highest peak readings in 2013 and 2014 at selected altitudes..

Peak readings in above image are averages over April 2013 and April 2014. On specific days, peak readings could be much higher, e.g. on April 28, 2014, methane levels were recorded as high as 2551 ppb at 469 mb. As said, methane levels as high as 2845 ppb were recorded on April 25, 2015, while the average peak for the first four months of 2015 was 2371 ppb, and this average was calculated from peaks across altitudes.

The table below shows the altitude equivalents in mb (millibar) and feet.

56,925 ft	44,689 ft	36,850 ft	30,569 ft	25,543 ft	19,819 ft	14,383 ft	8,367 ft	1,916 ft
74 mb	147 mb	218 mb	293 mb	367 mb	469 mb	586 mb	742 mb	945 mb

Peak levels in April appear to be rising strongly each year, following higher peak readings during previous months, especially at higher altitudes, i.e. especially the Arctic Ocean. It appears that much of the additional methane originating from the higher latitudes of the Northern Hemisphere has moved closer to the equator over the past few months, and is now accumulating at higher altitudes over the continents on the Northern Hemisphere, i.e. Asia, Europe, North America and north Africa.

Further analysis of the rise in global mean methane levels appears to confirm the above. The image below shows methane levels on April 22, over three years. While there appears to be little or no rise in mean methane levels at low altitudes, the rise is quite profound at higher altitudes.  

[ click on image to enlarge ]

Things look set to get worse. As shown by the image below, from an earlier post, global methane levels have risen sharply from a low of 723 ppb in 1755. Mean methane levels were as high as 1839 ppb in 2014. That's a rise of more than 254%.

As that post concluded a year ago, it appears that the rise of methane in the atmosphere is accelerating. What can we expect? As temperatures can be expected to continue to rise and as feedbacks start to kick in, this may well constitute a non-linear trend. The image below shows a polynomial trend that is contained in IPCC AR5 data from 1955 to 2011, pointing at methane reaching mean global levels higher than 3000 ppb by the year 2030. If methane starts to erupt in large quantities from clathrates underneath the seafloor of the Arctic Ocean, this may well be where we are heading. 

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

The 2845 ppb recorded on April 25, 2015, is an extremely high peak. The average daily peak in 2015 until now was 2372...
Posted by Sam Carana on Monday, April 27, 2015

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Warm waters threaten to trigger huge methane eruptions from Arctic Ocean seafloor

The evidence of abrupt high methane releases in the Arctic Ocean is accumulating. The graph below shows in situ methane measurements taken at the Barrow Observatory, including recent levels as high as close to 2200 parts per billion (ppb).

Satellite data picture a similarly dire situation. Global mean methane levels as high as 1831 ppb were recorded on the morning of July 30, 2014, while peak methane levels as high as 2330 ppb were recorded that morning. More recently, peak methane levels as high as 2522 ppb were recorded (on August 2, 2014).

IPCC/NOAA figures suggest that methane levels were rising by some 5 to 6 ppb annually, reaching 1814 ppb in 2013. While methane levels at lower altitudes have indeed shown little rise, much larger rises have been recorded at higher altitudes, as illustrated by the image below.

These high methane levels recorded at higher altitudes appear to be caused by the huge quantities of methane released from the seafloor of the Arctic Ocean during the period from end 2013 to early 2014. This methane has meanwhile risen to higher altitudes, while also descending to lower latitudes, wreaking havoc on weather patterns around latitude 60° North.

The releases of methane from the seafloor of the Arctic Ocean were caused by water that had warmed up strongly off the east coast of North America from June 2013. It took some months for this warm water to be carried by the Gulf Stream into the Arctic Ocean.

Meanwhile, very high sea surface temperatures are recorded in the Arctic Ocean, as above image shows, while warm water is carried into the Arctic Ocean by the Gulf Stream, as illustrated by the image below.

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

Post by Sam Carana.

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Methane buildup in the atmosphere

Levels of carbon dioxide (CO2) in the atmosphere are now firmly above the 400 parts per million (ppm) level, as illustrated by the graph below, from keelingcurve.ucsd.edu.

As above graph shows, levels of CO2 go up and down with the seasons. Even higher levels are expected to be reached in May 2014. Importantly, 400 ppm is 143% its pre-industrial peak levels of 280 ppm.

Levels of methane (CH4) in the atmosphere are rising even faster. According to IPCC AR5, methane levels were 1798 ppb in 2010 and 1803 ppb for 2011. A graph included in an earlier post shows historic levels of CH4, CO2 and N2O levels, highlighting methane's steep rise (now some 250% its pre-industrial level). The graph below, based on a plot by NOAA, shows the rise of methane over the past few decades and also shows that methane levels similarly go up and down with the seasons.

Globally, IPCC/NOAA figures suggest that abundance of methane in the atmosphere did reach 1814 ppb in 2013 and is rising with some 5 to 6 ppb annually. IASI data show that - at the hight of the northern summer, in August 2013 - mean methane levels rose strongly, to levels well above 1800 ppb, as also discussed in posts such as this one.

Next to seasonal variations, methane levels also differ depending on altitude. Often, when mean methane values are given, readings at 14,383 feet altitude are used, as methane typically reaches its highest levels at this altitude.

The image on the right compares methane levels for 2013 and 2014 at this altitude over six recent days, with a.m readings and p.m. readings for each day.

Around this time of year in 2013, as the graph shows, methane levels went through the 1800 ppb mark. The same thing occurred this year, while levels have meanwhile increased with a few ppb, so at first glance methane's rise appears to continue as anticipated by the IPCC.

While the above is very worrying, the situation may be even more dire than this. The graph below compares methane levels in 2013 and in 2014, averaged over the same six-day period (April 5 through to April 10) and at six different altitudes.

Above image indicates that, while the difference between 2013 and 2014 at lower altitudes (8,367 feet and 14,383 feet) may seem relatively small, increases at higher altitudes may be much stronger. In other words, rather than rising in a similar way across all altitudes, methane may in fact be building up much more strongly at higher altitudes.

This frightening possibility was raised a few times at this blog, such as in the altitude analysis in January 2014 and in the post Quantifying Arctic Methane, which noted that IPCC-estimates of global methane levels may rely too much on low-altitude data collected over the past few decades. Indeed, the total methane burden may already be rising much more rapidly than the IPCC is anticipating, also because methane is rising in the atmosphere, increasing the burden especially at higher altitudes, as evidenced by increasing occurence of noctilucent clouds.

The above analysis uses a limited dataset, just like the previous one, but if verified by further analysis, it could be that a dramatic rise in the presence of methane in the atmosphere is occuring without showing up at lower altitudes. This could also explain how earlier releases of methane from hydrates could have been ignored by many, i.e. relatively small increases in methane levels at relatively low altitudes may have given a false reassurance that such releases were not adding much methane to the atmosphere. Further analysis, comparing satellite data at different altitudes over the years, could give more clarity on these points.

Post by Sam Carana.

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