Methane levels keep rising rapidly

Global methane levels keep rising rapidly. Earlier this month, the post Methane as high as 2303 ppb quickly became outdated and was updated with the post Methane as high as 2349 ppb. Meanwhile, though, the most recent data show that the highest level reached on August 5, 2013, was 2442 ppb.

This recent peak level is only slightly below the highest peak level this year, which was a level of 2475 ppb reached on April 26, 2013, which at the time was considered a one-off local peak.

These recent high peak levels do seem to be more than just local peaks, given that high levels of methane are suddenly recorded over much of the globe, as described in the earlier post Methane as high as 2349 ppb.

The image on the right (added later, editor) also shows that not only have peak levels greater than 2300 ppb appeared since late June 2013, but also have the highest daily mean methane levels suddenly increased by about 20 ppb recently.

The image below shows over how many square kilometers methane was present at over 1950 ppb globally over the past few days.

The numbers also feature in the image on the left and they illustrate the huge jump that took place somewhere between July 31 and August 1, 2013.

It may be that there has indeed been a huge sudden increase in methane.

On the other hand, it could also be that EuMetSat implemented a re-calibration on July 31. After all, EuMetSat announced recently that IASI Level 2 products from Metop-B had been declared operational and would be available on GTS from 31 July.

Such a re-calibration (if it did indeed take place) does appear to make sense, given the discrepancy between IASI's mean methane levels and the levels recorded at stations. Below are measurements taken at Mauna Loa, Hawaii, which given the station's location close to the equator are often taken as global averages (flasks on the left, and hourly average in situ measurements on the right).

[ click on image to enlarge ]
from: http://www.esrl.noaa.gov/gmd/dv/iadv/index.php

Mauna Loa methane levels are often quoted to be about 1830 ppb, whereas the highest IASI mean levels did barely cross the 1800 ppb mark earlier this year. Since the jump, the highest IASI mean levels have suddenly been significantly higher (20 ppb more, at around 1820 ppb).

Even so, the current situation is very worrying. High levels of methane are present not only on the Northern Hemisphere, but also on Antarctica and over the oceans on the Southern Hemisphere, as shown in a recent post. And of course, the situation remains most threatening in the East Siberian Arctic Shelf (ESAS), as described at the Methane-hydrates blog and and at Arctic Methane FAQ.

Methane as high as 2349 ppb

Earth is undergoing one of the largest climate changes in the past 65 million years, Stanford climate scientists Noah Diffenbaugh and Chris Field report, and it's on pace to occur at a rate 10 times faster than any change in that period.

“We know from past changes that ecosystems have responded to a few degrees of global temperature change over thousands of years,” said Diffenbaugh. “But the unprecedented trajectory that we're on now is forcing that change to occur over decades.”

Some of the strongest evidence for how the global climate system responds to high levels of carbon dioxide comes from paleoclimate studies. Fifty-five million years ago, carbon dioxide in the atmosphere was elevated to a level comparable to today. The Arctic Ocean did not have ice in the summer, and nearby land was warm enough to support alligators and palm trees. But apart from the rate of change, Diffenbaugh adds, another key difference is that “today there are multiple human stressors that were not present 55 million years ago, such as urbanization and air and water pollution.”

By the end of the century, should the current emissions of greenhouse gases remain unchecked, temperatures over the northern hemisphere will tip 5-6 degrees C warmer than today's averages. In this case, the hottest summer of the last 20 years becomes the new annual norm.

The situation looks to be even more dire than that, argues Sam Carana. In addition to carbon dioxide, there are further pollutants driving global warming. Moreover, as pictured below, feedbacks can dramatically accelerate the rise in temperature locally, particularly in the Arctic.

Image 21. For more details on feedbacks, see extended version of this image and discussion at

arctic-news.blogspot.com/2012/08/diagram-of-doom.html

The level of methane in the atmosphere has already been rising even faster than the level of carbon dioxide, as illustrated by the image below. Moreover, there's the threat that large additional amounts of methane will suddenly be released, in particular from the Arctic seabed.

In August 2013, methane were recorded as high as 2349 ppb, as illustrated by the graph on below (added later, editor), showing that in early August, the world's mean methane level suddenly increased with at least 10 ppb compared to mean levels over the past few months.

To get an idea just how much methane has entered the atmosphere, have a look at the image below, covering several days from the start of August 2013.

[ click on image to enlarge ]

This is further illustrated by the two images below. The image directly below shows where the highest methane levels (i.e. over 1950 ppb, in yellow) were recorded on August 2, 2013.

[ click on image to enlarge ]

The image below shows the presence of methane on August 2, 2013, for a number of ranges, including at levels over 1950 ppb (this time in red).

[ click on image to enlarge ]

The methane threat is further described in the post Methane hydrates, which also features the image below.

Methane as high as 2303 ppb

This post has been updated as Methane as high as 2349 ppb.

Where does the methane come from?

[ image July 29, 2013. Click on image to enlarge ]

Wildfires are still raging, sending huge amounts of smoke into the sky. Worryingly, much black carbon that comes with this smoke gets deposited at high latitudes, discoloring snow and ice, and thus speeding up the melt.

A lot of methane has been emitted over the last few days, and much appears to be due to wildfires, as illustrated by the image below, picturing the situation on July 31, 2013, p.m.

[ click on image to enlarge ]

Above image shows some methane on the right, over the Atlantic Ocean, which appears to originate from these wildfires and is visible in that location due to the Coriolis effect. The image below, picturing the situation on August 1, 2013, p.m., shows a lot of methane over Russia and elsewhere in Europe and Asia. Again, the methane on the left of Europe appears to originate from wildfires in North America.

[ click on image to enlarge ]

High levels of methane are recorded in many places on the Northern Hemisphere, and there is also a lot over the Southern Hemisphere, as illustrated by the image below.

[ click on image to enlarge ]

Where did the methane over the oceans on the Southern Hemisphere come from? It appears that it originates from hydrates under the ocean floor. For more about methane hydrates, also see the methane-hydrates blog.