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Menopausal Mother Nature

News about Climate Change and our Planet

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Methane keeps rising

Methane keeps rising. The image below shows methane flask measurements at Mauna Loa, Hawaii, since 2001. 

A recently-published article points out that prudent risk management requires consideration of bad-to-worst-case scenarios.

There is the danger that, as methane keeps rising, the clouds tipping point could be crossed. This danger is rarely discussed. How bad could it be? 

The MetOp-B satellite recorded a mean methane level of 1981 ppb at 393 mb on October 2, 2022 am, while plenty of methane was present over the Arctic Ocean at the three altitudes, as the compilation image below shows. 

This supports the possibility that large amounts of methane are getting released from the Arctic Ocean, with even more to follow. 

This 1981 ppb mean methane level translates into 396.2 ppm CO₂e at a 1-year GWP of 200. Destabilization of sediments at the seafloor of the Arctic Ocean could cause a large abrupt burst of methane to enter the atmosphere over the Arctic Ocean.

A doubling of the mean methane level could push up the mean methane level to twice as much, to 792.4 ppm CO₂e, which is only 407.6 ppm CO₂ away from the 1200 ppm CO₂e clouds tipping point that on its own could push up the temperature by some 8°C globally.

This gap of 407.6 ppm CO₂ could be more than covered by the current carbon dioxide level. The September 2022 carbon dioxide level at Mauna Loa was higher than that, at 415.96 ppm. Since the carbon dioxide level at Mauna Loa in September typically is at its lowest point for the year, this implies that a large abrupt burst of methane could cause the the clouds tipping point to be instantly crossed due to methane and carbon dioxide alone.

Since there are further forcers, such as nitrous oxide and CFCs, while further events and developments could additionally speed up the temperature rise, this means that the clouds tipping point could be instantly crossed with a burst of methane that is far smaller in size than the methane already in the atmosphere. 

That’s not even the worst-case scenario. In the above calculation, global mean methane levels are used. However, there is a possibility that low-lying clouds could at first break up and vanish abruptly at one specific point, due to a high methane peak, and that this could lead to break-up of neighboring clouds, propagating break-up across the globe and thus pushing up the temperature rise virtually instantly by some 8°C globally. 

The MetOp satellite recorded a peak methane level of 3644 ppb and a mean level of 1944 ppb at 367 mb on November 21, 2021, pm, as discussed in an earlier post. This 3644 ppb translates into 728.8 ppm CO₂e, again at a 1-year GWP of 200. This is 471.2 ppm CO₂e away from the clouds tipping point and that 471.2 ppm CO₂e could be covered by the carbon dioxide, nitrous oxide and CFCs currently in the atmosphere.

There are further scenarios that could cause the clouds tipping point to be crossed soon, e.g. if the rise in methane kept following a trend such as depicted in the image below. 

The situation is dire and the right thing to do now is to help avoid or delay the worst from happening, through action as described in the Climate Plan.
• NOAA – Global Monitoring Laboratory

• Climate Endgame: Exploring catastrophic climate change scenarios – by Luke Kemp et al.
https://www.pnas.org/doi/full/10.1073/pnas.2108146119
• The Clouds Feedback and the Clouds Tipping Point
https://arctic-news.blogspot.com/p/clouds-feedback.html

• NOAA – MetOp satellite
https://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi

• The Importance of Methane in Climate Change
https://arctic-news.blogspot.com/p/the-importance-of-methane-in-climate.html

• Overshoot or Omnicide?
https://arctic-news.blogspot.com/2021/03/overshoot-or-omnicide.html

• Human Extinction by 2022?• Cataclysmic Alignment
• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

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