Greenland--Not So Green Anymore

Question

Back home, there are three factors to consider:

1. Mont Forel, Greenland's tallest peak, can be found in coordinates 66.9333° North and 36.8167° West
2. The Arctic Ocean's average depth is 3406 feet, 17,880 feet maximum
3. The maximum width of the Atlantic Ocean is 4,000 miles

We're talking about a planet that has a median surface temperature of 58.3 degrees Fahrenheit.

In this alternate scenario, these three factors have changed.

1. Greenland has been rearranged to the extent that Mont Forel can now be found at coordinates 90 degrees North and 0 degrees West--the North Geographic Pole.
2. The proportion and ratio between the Arctic Ocean's average and maximum depths is the same as back home, but the average has now become 1652 meters, 5420 feet.
3. The Atlantic's maximum width has now become 5350 miles, creating a landbridge that connects Asia to North America, erasing the Bering Strait off the map and shrinking the Bering Sea. To that extent, it would be like turning the Russian urban locality of Egvekinot (66.3205 degrees North and 179.1184 degrees West) the next-door neighbor of Teller, Alaska.

Remember, our median surface temperature is currently 58.3 degrees Fahrenheit. Would these three changes listed above lower the median surface temperature, or would it be the same?

Answer 1

This change in the position of Greenland is actually relatively minor and will have no significant impact on the geographic origin of the world's surface temperature, or the wind-driven equatorial and temperate gyres that distribute heat via ocean currents, or prevailing winds doing the same. The North Atlantic current would continue to warm western and northern Europe, the Labrador current would remain in place, and the Beaufort Gyre's equivalent would exist somewhere off the Russian or Scandinavian coast (Barents Sea?).

An aside — Why it won't specifically result in a colder Europe:

Models of the thermohaline cycle being shut down or disrupted, resulting in a drop in temperature in Europe, have nothing to do with overall water temperatures and everything to do with salinity. The disruption is caused by lighter-than-sea-water fresh water (stored as ice in the Arctic in places like Greenland) diluting the warmer (and therefore slightly lighter-than-cold-sea-water) water coming up from the equator and decreasing overall salinity, preventing colder denser waters from sinking.

Without Greenland there is no source of this fresh water disruption; a more polar Greenland would store fresh water out of reach of warm sea/air currents, thus stabilizing salinity.

Answer 2

The change in greenland won't do much, but you make a bigger change. Here's a little scientific article on closing the bering strait.

https://staff.ucar.edu/browse/people/13028/OSGC-000-000-000-158

Here we use a fully coupled climate model to show that the transport of relatively fresh Pacific water into the North Atlantic Ocean was limited when lower sea level restricted or closed the Bering Strait, resulting in saltier North Atlantic surface waters. This invigorated deep convection in the North Atlantic Ocean, strengthening meridional overturning circulation and northward heat transport in our model, which consequently promoted melting of ice sheets in North America and Europe. Our simulations show that the associated sea-level rise led to a reopening of the Bering Strait; the flux of relatively fresh water into the North Atlantic Ocean muted meridional overturning circulation and led to cooling and ice-sheet advance in the Northern Hemisphere. We conclude that the repetition of this cycle could produce the sea-level changes that have been observed throughout the last glacial cycle.

(just a quick edit here...the article is saying that by closing the bearing strait, you lose the fresh pacific water entering the Atlantic and the Atlantic becomes saltier. This salt concentration increases the strength of the thermohaline circulation, ultimately driving more warm water into the northern Atlantic and warming the arctic.)

It does appear that if you close the bearing straight, you are going to cause an arctic warming cycle that will continue until the bearing straight once again floods over and allows this circulation to continue and once again cool off the north. The change in the depths that you make might also contribute to the strength of this system, causing the warming to be a bit more pronounced.

So summary:

• Yes likely a warmer greenland and potentially warmer surface temps worldwide (not by much, but measurable). Not to do with the moving of greenland, everything to do with the closing of the bering strait.

• Likely far less land and sea ice on and around Greenland

• This cycle appears to continue until the bering strait refloods and will enter a cooling phase once that occurs.