Sam Carana
“RISE IN GREENHOUSE GASES ACCELERATES
Carbon dioxide concentration at Mauna Loa was 420.52 ppm on January 26, 2022. The annual peak for CO₂ is expected to occur about May 2022, so it will still go up a lot higher than this over the next few months.
Even more terrifying is the rise in methane in the Arctic. The second image shows monthly average in situ methane measurements recorded at Barrow, Alaska, with high averages showing up for recent months.
Why again is this growth in methane so terrifying?
The MetOp-B satellite recorded a mean methane level of 1958 ppb on October 25, 2021 am at 295 mb, and when using a 1-year GWP of 200, this translates into 391.6 ppm CO₂e. Together with the above CO₂, that's 391.6 + 420.52 = 812.12 ppm CO₂e.
Now add an additional 5 Gt of methane from an abrupt eruption of the seafloor, which is only 10% of the 50 Gt that Natalia Shakhova et al. warned about long ago, while 50 Gt is in turn only a small fraction of all the methane contained in sediments in the Arctic. On its own, such an eruption of seafloor methane could raise the global mean methane concentration by almost 2000 ppb which, at a 1-year GWP of 200, would translate into 400 ppm CO₂.
So, that would abruptly cause the joint CO₂e of just two greenhouse gases, i.e. methane and CO₂, to cross the 1200 ppm clouds tipping point, triggering a further 8°C global temperature rise, due to the clouds feedback.
From the post 'Terrifying Arctic greenhouse gas levels continue', at:”
2015-04-30 176aaa
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