#Clathrate
To stay stable, clathrates require pressure. Ocean depths of >350m provide enough pressure.
The top map shows ocean depths as white which are shallower than 280m.
The bottom map shows known clathrate reservoirs in brown.
Puzzling difference: many ocean regions near costs are white but appear to have clathrate? Eg., north of Siberia and Alaska, South of Indonesia, West of Ireland.
One of my sources must be wrong. Which one?
Anyway. +1ºC in 500m depth breaks the ice cap and WAM.
Got suspicious of the bottom map for clathrate due to the supposed Indonesia deposits. So looked for a better source in AR6-WG1 where I found https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GB005011#
This doesn't have hydrates for Indonesia's coastal ocean so I trust it more.
But it is also only a model, ie., not from actual mapping of deposits. I think, they weren't mapped, yet.
So once I know the warming at bottom water near Ireland and north of Alaska (ordered data from NCEI), I can faint for fear of the "clathrate bomb"😁
So far, I don't fear a clathrate bomb. My reasoning being that in the interglacial 420ky ago clathrates had lotsa time to melt and didn't.
Or in the Pliocene, too, when it was 2ºC warmer than today. But they didn't thaw then or we would have found sudden warmings outside the normal envelope of Milankovitch cycles.
Maybe, tho, sea level was rising and falling in sync with each warming cycle and kept the pressure lid on CH4 hydrates. Whereas today, warming is faster than sea level rise= lid off.
https://www.science.org/doi/full/10.1126/sciadv.aaz1346
Miller et al 2020 charted 65million years of #sealevel with CO2 and temperature. The Pliocene at the very top and the blue curve in the centre chart shows that sea level in the Pliocene undulated between 30m and -40m.
Noteworthy is also that sea level was never lower than in the last #IceAge with -120m. I wonder what that means for #clathrate #hydrate on continental shelves – and for potential fossil CH4 gas pockets beneath them I mentioned elsewhere. Hm. Hm.🤔
Read 2 papers about what happens to CH4 in the water column. One from onsite inspection after #DeepWaterHorizon. But that's in 800-1200m. Needless to say, CH4 doesn't make it to the surface. Bacteria eat methane, CH4 is oxidised to CO2 (which acidifies the ocean. Bad!).
The other paper is about CH4 seeps in 240m from thawed (!) #clathrate
https://www.sciencedirect.com/science/article/pii/S0278434313002604
Winter currents may drive some CH4 up to the atmo but summer stratification def-o holds CH4 down.
Take away: don't fret💃🏼 much😁
anlomedad