Occasional Thoughts on Climate Change

[donsutherland1]

9 minutes ago, LibertyBell said:

The question is why the Northern Pacific specifically and not the Northern Atlantic too?

 

The North Atlantic has a deep overturning circulation (AMOC) that pushes surface heat below resulting in a much deeper mixed layer than the North Pacific. The melting of the Greenland ice sheet has also been dumping lighter freshwater into the North Atlantic weakening the AMOC but creating a persistent area of cool SSTAs, often referred to as a 'warming hole." 

So, even as positive cloud feedbacks and reduction in aerosols have increased incoming solar radiation, these differences mitigate the extent of North Atlantic warming relative to the North Pacific.

[LibertyBell]

1 hour ago, donsutherland1 said:

The North Atlantic has a deep overturning circulation (AMOC) that pushes surface heat below resulting in a much deeper mixed layer than the North Pacific. The melting of the Greenland ice sheet has also been dumping lighter freshwater into the North Atlantic weakening the AMOC but creating a persistent area of cool SSTAs, often referred to as a 'warming hole." 

So, even as positive cloud feedbacks and reduction in aerosols have increased incoming solar radiation, these differences mitigate the extent of North Atlantic warming relative to the North Pacific.

and the Atlantic is also smaller than the Pacific so melting polar ice would have more of an effect on the Atlantic I would guess.

[Typhoon Tip]

1 hour ago, LibertyBell said:

and the Atlantic is also smaller than the Pacific so melting polar ice would have more of an effect on the Atlantic I would guess.

You have to consider the total geology of Earth in the model/differences comparing the two oceanic basins.

The NE Pacific arc is blocked off from the arctic by Alaska and the continental rise - identified by Aleutian archipelago of islands. The arctic waters are prevented from intermingling. Additionally, the NW Pacific blocks the arctic due to NE Siberia. There is a gap between, but it is very shallow - the Bering Straight. In fact, ...over the last ice advance cycle of the greater Pleistocene epoch, it is theorized that the ocean levels, having fallen crucial distance, exposed a 'land bridge' that assisted animal migrations between Asia and North America.  Many ancient native America human populations are believed to have arrived via the land bridge route during these lower oceanic level time spans.. 

Anyway, that sub-surface geology blocks the Pacific from establishing an "AMOC" of its own.  Compared to the N Atlantic Basin, where deep oceanic floor abruptly abuts the Greenland landmass.  Very cold water due to intermingling with the Arctic happens there, where it really can't happen in the far N Pacific Basin.  The cold water is heavy ... it falls to the bottom of the ocean - organized in 'chimneys', these tubes of very cold water plummet to the ocean floor.  The falling motion pulls the surface water into replace, due to conservation of mass; and since their is less obstacle to fluid flow, S, that encourages a surface motion that is preferential from the Equator toward the N.  The ongoing pattern of wind stress and Coriolis then organizes the large scaled anti-cyclonic motion of the Basin.  The Gulf Stream and the Japan currents of either Basin are artifacts of the same wind stressing and Coriolis balancing, but the Atlantic has this AMOC machinery that the Pacific does not.   

Because of all this... the Pacific distribution of upper oceanic heat content is shallower, thus .. can be thermally modulated faster.  Might be a little counter-intuitive when knowing that the Pacific is larger than the Atlantic by a several factors of total mass and surface area, but AMOC has a vastly deeper Z-coordinate in the total integral.  

[TheClimateChanger]

 

[TheClimateChanger]

With this incredible global warming increase, I think we could see average mean temperatures climbing near or above existing annual records by mid-century here in the mid latitudes. As I would expect 1-1.5F/decade of warming most likely, if the global rate is near +.7F/decade.