Exploring the Impact of Ocean Depths on Global Climate

[JohnWDailey]

Back home, the average depths of the world's oceans--and the Mediterranean Sea--are as follows:

Atlantic--3926 meters
Pacific--4028 meters
Indian--3963 meters
Arctic--1205 meters
Southern--4500 meters
Mediterranean--1500 meters

In this alternate Earth, the average depths are as follows:

Atlantic--4679 meters
Pacific--6896 meters
Indian--3295 meters
Arctic--3460 meters
Southern--2735 meters
Mediterranean--3767 metersHow would these changes in depth affect the world's climate and ocean currents?

 

[DaveC426913]

Difference:
Atlantic: +700 meters
Pacific: +2800 meters
Indian: -700 meters
Arctic: +2200 meters
Southern: -1800 meters
Mediterranean +2200 meters

Unless this alternate Earth has a truly spectacular set of kilometres-high, globe-spanning dams, I dare say there are a few other differences between this and alternate Earth.

 

[JohnWDailey]

I don't follow you.

 

[DaveC426913]

On our Earth, all Oceans and ocean-adjacent seas are at the same water level.
On Alt-Earth:
- There is a 2.5 kilometre drop in water level from Atlantic Ocean to Southern Ocean - along a 2000 kilometre stretch of water from Cape Horn to Tierra Del Fuego.
- The Mediterranean Sea has a waterfall at Gibraltar that is a 1.5 kilometer drop to the Atlantic.
- Somewhere around New Guinea and New Zealand is a waterfall about 2000 kilometers across, and 3.5 kilometres high.
Etc.

 

[JohnWDailey]

I still don't follow you. What do these have to do with climate and ocean currents?

 

[DaveC426913]

Alt Earth doesn't make sense, as described. The ocean levels vary by several kilometers between each other. This is not possible.

There are more differences between Earth and Alt Earth than merely ocean levels. There must be.

Is it possible that what are you envisioning is that some ocean bottoms have risen while others have fallen?
eg.: Indian ocean bottom has risen by 700 meters, whereas Pacific ocean bottom has dropped by 2.8 kilometers?

This is a bigger question about the structure of Alt-Earth as compared to Earth, than is belied by mere ocean depths. We need to understand those other differences.

 

[JohnWDailey]

Other differences, definitely. But I'm doing this one at a time.

 

[DaveC426913]

Was this Alt-Earth constructed to generally resemble Earth?

 

[Bandersnatch]

@DaveC426913 : all the bodies of water from the OP are on the same surface level, it's just where their bottom floor is varies.

@JohnWDailey : I can't help you much here. All I can think of is more water volume means a better heatsink, and more CO2 from the atmosphere can be absorbed.

 

[JohnWDailey]

I can't help you much here. All I can think of is more water volume means a better heatsink, and more CO2 from the atmosphere can be absorbed.

Is that a good thing or a bad thing?

 

[rootone]

It will alter the chemistry of the oceans and the thermal dynamics of both the oceans and the atmosphere.
That could result in evolution taking very different paths to what happened for Earth 1.
No doubt whatever life forms arise, (if they are sentient), would consider the prevailing environment to be a good thing.

 

[JohnWDailey]

It will alter the chemistry of the oceans and the thermal dynamics of both the oceans and the atmosphere.

Alter them how?

 

[rootone]

If more CO2 is being absorbed there will be more carbon dissolved in seawater, and that extra carbon could lead to all manners of complex organic chemistry.
Less CO2 in the atmosphere would mean an overall cooler climate, and less water vapour in the atmosphere, so there should be less rain, so less rivers and other inland water.

 

[Loren]

On our Earth, all Oceans and ocean-adjacent seas are at the same water level.

Not true! That is why there are locks in the Panama canal.

Try sailing around the southern tip of South America.

The sea levels are not isotropic. For one thing, the specific gravity is different between oceans.

 

[DrStupid]

That is why there are locks in the Panama canal.

There are locks because the Panama canal is above sea level.

The sea levels are not isotropic. For one thing, the specific gravity is different between oceans.

That depends on how you define "sea level". If you define it relative to the gravitational potential than it is almost equal around the world.

 

[Loren]

There are locks because the Panama canal is above sea level.
That depends on how you define "sea level". If you define it relative to the gravitational potential than it is almost equal around the world.

The Atlantic and Pacific oceans are not at the same height or level as measured from the center of the Earth.

The Pacific is higher mostly due to the Atlantic being a higher salt concentration.

 

[DrStupid]

The Atlantic and Pacific oceans are not at the same height or level as measured from the center of the Earth.

± 20 cm is almost equal

 

[DaveC426913]

@Loren :

On our Earth, all Oceans and ocean-adjacent seas are at essentially the same water level.

Is that acceptable?

The point is, they are not hundreds of metres to several kilometres different.

 

[Loren]

@Loren :

Is that acceptable?

The point is, they are not hundreds of metres to several kilometres different.

Yes, I am good with that. It was the way it was originally written that made it sound like sea level is really the same everywhere.

 

[meBigGuy]

I think it safe to assume the original post was indicating that the sea floors were different, and that sea level was "essentially" equal all over earth.
Are you assuming the same total mass or the same geometry as "real earth". If it is the same geometry, then the mass would be different, so gravity would be different.

If it is the same mass, then the size of Earth would be different.

Do you have the same ratio of sea surface to land surface?
Are you assuming the salinity of the Oceans are also the same? (big ecological consequences)
Same ratio of Ice and water? Or same amount of Ice as now? (affects fresh water impact on deep ocean currents)
Same global energy? (for example, some say global warming is adding energy to the system as Ice melts, so variance produces more violent weather events)

It would be very difficult to predict the effects on Ocean Currents. Especially since we understand so little now (like the subtlties of the Antarctic conveyer)
http://oceanservice.noaa.gov/education/kits/currents/06conveyor2.html

You could probably make up whatever scenario fits your needs.