https://www.nature.com/articles/s41586-022-05447-w
Published December 2022:

in 2020, the lockdown year, the #OHsink, which breaks up #methane in the atmo, shrunk because NOx emissions from -fossil fuel- combustion were reduced due to lockdowns. #NOx is a precurser for tropospheric #ozone from which very short-lived OH-radicals are born and immediately bomb methane molecules to bits.
At the same time, #CH4 emissions rose to a new high (already surpassed by 2021 but the paper only looks at 2020).
The authors assume wetlands as source for more CH4 emissions, and the reason: a warmer, moister year.
Okay. Our ecoclimateclusterfuck increases "warm and moist" every year. So we can expect more natural CH4 every year. At the same time, we reduce to zero our fossil fuel combustion. Which means less and less NOx and OH-radicals, meaning, more CH4 is left in the atmo = more heat.
This is inevitable.

But what's missing in the paper: they ignore that less fossil gas demand let many US companies go bust who left their abandoned wells unplugged. And like what Russia did in 2022 with gas that wasn't bought by EU: lower demand in 2020 meant more incomplete flaring.
Both increased methane emissions. But the authors don't quantify this. They claim but don't "prove" that anthropogenic CH4 was lower in 2020 than in 2019.

@DrEvanGowan
What did you have in mind was the affect on the climate when #Arctic #megafauna went extinct 13,500 years ago?

From the PNAS paper, I'd assume it was the spread of woody flora once the herbivores were gone. Which increased the landsink.

But I do like more the trampling hooves, this heavy megafaunal machinery that used to keep the thawing top soil from turning into bogs, one to two 8t mammoths per km2.
Once the number of animals fell, peat bogs spread and #methane levels rose – while no additional source for #NOx as #OHsink meant that the peaty #CH4 accumulated its heat-trapping for longer than it does today, triggering other feedbacks.

I am maths dyslexic and need #help

The update to the 2019 IPCC Special Report on Ocean and Cryosphere https://iccinet.org/statecryo2022/ chapter 4 states that CO2e from permafrost at current policy scenario requires removal per century of 400Gt CO2.
(Yes, permafrost is officially thawing and it is officially now requiring CO2 removal.)

The report doesn't say but I assume they use the official GWP by UNEP, 25 over 100 years.

How do I back-calculate those 400Gt CO2e to see how much methane it is that's going to be released per decade?

My calculation ends in a crazy warming of 1.6ºC per decade from permafrost thaw. Can you point me to where my mistake is?

It goes like this:
400Gt CO2e / 25 = 16Gt? If true, then CH4 from permafrost per decade is 1.6Gt. If true, and if the OH-sink stays the same, it'd mean 1.6ºC warming each decade.

Why 1.6ºC/decade:
*because #AR6-WG1 states that 2010-2019, methane caused 0.51ºC warming.
*from the Global Methane Project's top down view, we know that ~600Mt were released/yr
* and from NOAA, we know that the concentration was Ø 1830ppb in that decade.

It follows that in the decade 2010-2019, with the particular capacity of the OH-sink in that decade, 1Mt CH4 emissions resulted in 3.111 ppb and 0.001 ºC.

If these conditions stay the same, and if my back-calculation is correct for CO2e==>CH4, then the scientists are saying we're going to make permafrost thaw release 1.6Gt CH4 per decade which results in an immediate warming of 1.6ºC / decade, and to the weather and social chaos from this warming.

But I reckon, I must have omitted a zero somewhere. 0.16ºC feels more logical to me. I just don't know where I went wrong.

#Help #MathsDyslexia
#CO2e #GWP #CH4 #Permafrost #SROC #OHSink