No Mediterranean

[Zirojtan]

What would that be like?


After I've had enough fun with the timeline that I'm currently working on, whose PoD is in the Saalian Glacial Period and doesn't involve anything geologic, I was thinking about doing something that involved the Messinian Salinity Crisis, which temporarily closed the Mediterranean some 5.9 million years ago never ending.


Off the top of my head, I can certainly ascertain that Europe, and probably Eurasia in general would be a much drier place, and that the Sahara Desert might not have had as many lovely little pluvial periods during the Pliocene and Pleistocene. I also think that there would be a lot more shared fauna between Africa and Europe than there was and is in our own timeline, since they've had to travel through the Saharan Pump (up the Nile and through the Levant) to enter Eurasia.


But I'm sure that the Mediterranean Sea is a lot more important globally than just that, and I'm no climatologist... What do you guys think that this could do to the global climate during interglacial periods?

[Borgholio]

Not sure about the climate, but it does raise an interesting question about changes to Human history.

Civilization would be vastly different. Many ancient empires such as the Greeks and Romans relied on the Mediterranean to help supply and defend their territories. Imagine if Xerxes had been able to march on Greece without worrying about the Athenian navy, or if Hannibal had been able to drive straight to Rome without having to take the back way over the Alps?

Egypt might have been an even larger empire, since the Nile would have continued a greater distance instead of terminating at the delta that we know about today. Cyprus and Minoa wouldn't have existed at all.

[Zirojtan]

Civilization would be vastly different.

I agree, as would the story of human evolution. One must wonder, with the vast barrier that the Sahara would present though, would humans have left Africa sooner, or later? Perhaps the Atlantic coast of Africa would be green enough to allow hominid expansion into Spain? Idk, that's a question for the climatologists here.

Imagine if Xerxes had been able to march on Greece without worrying about the Athenian navy, or if Hannibal had been able to drive straight to Rome without having to take the back way over the Alps?

I imagine that crossing the vast salt flat that would exist in place of the Mediterranean would still present a significant barrier, especially considering that any rivers running into it would be hyperhaline marshlands at best where only the most extreme plants and arthropods would survive. Although they might be ideal places for flamingos. In fact you'd probably sea a more northerly species of flamingo developing because of this.

Egypt might have been an even larger empire, since the Nile would have continued a greater distance instead of terminating at the delta that we know about today. Cyprus and Minoa wouldn't have existed at all.

The Nile, if it existed at all, cuz I believe that it's only a couple of million years old, would probably end in a giant hyperhaline lake many times the size of the Great Salt Lake, providing more habitat for flamingos and migratory birds, but not good for humans.


I agree that Cyprus and Minoa would never have existed though, as the Mediterranean "islands" would be turned into ecological refugia in a non-analogous barren landscape, probably with only the highlands of these islands being suitable really suitable for vertebrate life.

[Mr. G]

Before the invention of railroad transportation by sea was the only cheap way to carry bulk goods like grain. Thus all the most economically sophisticated pre-industrial societies grew around sea lanes, such as Classical Athens, other city states such as Alexandria, Syracuse, Ephesus, The Roman Empire was essentially a network of cities connected by the Mediterranean trade, in the late middle ages, the Italian cities such as Venice and Genoa, everything connected to Mediterranean trade.

The Mediterranean sea was essentially the cradle of western civilization so removing it from history would be extremely radical.

[Grandmaster Jogurt]

Wouldn't the entire Mediterranean area be almost a desert? From my understanding, the empty basin would be hot, saline, and dead, and without a marine influence the climate around it would be dry as hell.

[Borgholio]

That latitude tends to spawn anywhere from arid to semi-arid. That is the same latitude as the Great Plains in the US, so it's possible it may have a similar climate with grasslands. Looking at the opposite latitude going south, you have the Serengeti in Africa. Same basic idea. So I doubt it'd be a wasteland, but certainly not as mild as it currently is.

[Zirojtan]

The basin would definitely be a wasteland, I'm pretty sure anyways. I mean, yes, you would think that 5.9 million years of rain would serve to at least lay some kind of a layer of sediment, however thin over the salt, but who says that rain is really going to penetrate that far inland often enough to do that?


I'm inclined to think that it would be like the American Great Basin on steroids. A huge, salty bowl where water from the Alps and surrounding mountains drains and evaporates. It probably wouldn't be all that hospitable to much else than... brine shrimp, maybe some really extreme species of algae/seaweed, and flamingos. Lots and lots and lots of flamingos would congregate there.


But I'm more interested in the REST of the world. Does the Mediterranean Sea have any important effect on global climate? If it does, what is it? And what would Eurasia and North Africa be like? I mean, a lot drier I'm sure, but just how dry? And how would precipitation be redistributed? I'm inclined to think that Europe's west coast would get most of the rain, leaving the interior very dry and continental until you get over to the coast of the Black Sea, which I'm fairly sure would still exist as a giant lake at least.


If the Zanclean Flood never happened, I wonder how the ice ages in the Pleistocene might have been different as well, or if they would've been at all.

[Zwinmar]

Just pointing out that your assuming that the Sahara as a desert would still be there when historically it was not always a desert.

[Zirojtan]

Just pointing out that your assuming that the Sahara as a desert would still be there when historically it was not always a desert.

Not, it wasn't. In fact as recently as 6,000 years ago it was a fertile savanna for the most part during what's called a "pluvial" or "Green Sahara" period. However, I tend to think that the Mediterranean Sea would be important in providing the necessary precipitation for it to become fertile.

[Zwinmar]

my mistake then, was how I read it.

[Guardsman Bass]

The Nile starts farther south in Africa and is primarily fed by Lake Victoria and other tributaries, so it might still be around even if the Mediterranean was a gigantic salt flat with the occasional salty lake (I tend to think it would be like the Atacama Desert on steroids, with only the occasional island/mountain getting cooler weather). It would flow out through Egypt and into what is now the continental shelf, before quickly dropping off in the basin. Probably a very cool waterfall.

But I'm more interested in the REST of the world. Does the Mediterranean Sea have any important effect on global climate? If it does, what is it? And what would Eurasia and North Africa be like? I mean, a lot drier I'm sure, but just how dry? And how would precipitation be redistributed? I'm inclined to think that Europe's west coast would get most of the rain, leaving the interior very dry and continental until you get over to the coast of the Black Sea, which I'm fairly sure would still exist as a giant lake at least.

The North Atlantic Current would still be dumping warm waters (and rain) on western and northern Europe, so those might be okay (particularly if the Alps help to keep hot air coming off the Mediterranean Desert out). From what it seems like, the Messinian Salinity Crisis didn't negatively impact climate outside of the areas bordering the Mediterranean, which became much drier.

[madd0ct0r]

Done a rough bit of map overlay - looking at precipitation and climate:

http://imgur.com/a/Hq7bA#0

I've not taken into account mountains, so that would significantly effect things, but you should certainly expect rain fall in the west half of the basin and a rain shadow beyond - looking at the current eastern edge of the med and beyond seems to confirm that.

[madd0ct0r]

Double post.

[Simon_Jester]

That latitude tends to spawn anywhere from arid to semi-arid. That is the same latitude as the Great Plains in the US, so it's possible it may have a similar climate with grasslands. Looking at the opposite latitude going south, you have the Serengeti in Africa. Same basic idea. So I doubt it'd be a wasteland, but certainly not as mild as it currently is.

The catch is that the dry Mediterranean basin would be having minerals dumped into it, and the water evaporating off- bodies of water there would be landlocked seas.

When we look at landlocked seas in real life, they tend to be extremely saline (Great Salt Lake, Dead Sea). When we look at the basins where such a sea has evaporated, we get even more saline ground conditions, because when the billions of tons of water evaporate away, they don't take the salt with them. That is why you'd expect to see a huge, extremely hostile salt flat at the bottom of the Mediterranean. It's below sea level, at a latitude where it gets a lot of sunlight, and what water there is is going to be ridiculously salty and bad for living things.

Of course, you'd get very different results if the Med simply didn't exist, if there was no basin there. I'm talking about what geographic and climate conditions in Europe and Africa would be like if the Mediterranean were closed, at the straits of Gibraltar, and allowed to evaporate away without a connection to the overall world ocean.

[Ziggy Stardust]

It seems unlikely that the basin would remain simply a large featureless salt flat. After all, the sea floor of the Mediterranean isn't exactly flat.

During the salinity crisis, before the Atlantic reflooded the basin, the climate in the Mediterranean basis was humid and subtropical. In fact, the climate supported laurel forests (there are still relicts of these forests in parts of Spain and Morocco). Before the Zanclean flood, the salinity of many of the water pockets was diminished to something akin to the brackish waters of the Caspian Sea. The basin is simply too large, with too many potential sources of fresh water coming down out of the mountains formed by the coast, for it to stay completely dry and hypersaline. Perhaps the Eastern Mediterranean (where the sea floor is deeper and more mountainous) would retain large Dead Sea-like bodies of water. However, if the Atlantic never refloods the basin, fresh water would continue to infuse the area.

Erosion would carve out huge canyon systems in the Western Mediterranean, though most would likely be colonized by subtropical flora/fauna. Here is a poster for an interesting recent study on the subject. The Eastern Mediterranean would be a network of brackish and saline lakes. It would likely resemble the sabkhas and khors of the modern Persian Gulf region, on a larger scale (that is, a network of salt flats and lagoons and Dead Sea-like lakes).

Much of the basin would be hot and dry, with the highlands around, say, modern day Malta would be cool and wet. African fauna and some European species would thrive, but most likely it would more closely resemble Africa in terms of flora/fauna. River like the Nile would carve HUGE canyons (in fact, the remains of one of those canyons still exists under Cairo!) as they wound their way into the basin.

As for how it would affect world climate? There are a couple of things to think about.

1) All the water that would otherwise be in the Mediterranean is in the rest of the world ocean's. This raises the global sea level (in the real timeline, by as much as 10 feet before it was refolded). However, the salt deposited in the basin would result in a salinity decrease, and with that a raised freezing point, which would affect glaciation events and the season cycles of the poles. This would have massive effects on a global scale. It changes the shape of coastlines, and likely allows for ice-free portages in more northerly waters.

2) The Iberian peninsula and Western Maghreb would not be affected overly much climatically, as they would still be receiving moisture from the Atlantic. However, further inland, the area around the Alps, the Balkans, and the Levant would be much drier. It is hard to say exactly how far reaching this effects would be, but it could result in cooling and drying of regions even further to the east into Central Asia (due to the action of the Westerlies). It is unlikely to directly impact anything in southern Africa or the Americas, but the ramifications of the sea levels rising and not freezing certainly would.

[Ziggy Stardust]

When we look at landlocked seas in real life, they tend to be extremely saline (Great Salt Lake, Dead Sea). When we look at the basins where such a sea has evaporated, we get even more saline ground conditions, because when the billions of tons of water evaporate away, they don't take the salt with them. That is why you'd expect to see a huge, extremely hostile salt flat at the bottom of the Mediterranean. It's below sea level, at a latitude where it gets a lot of sunlight, and what water there is is going to be ridiculously salty and bad for living things.

On the other hand, the Mediterranean is on a MUCH larger scale than either of these examples, and it seems extremely unlikely that such a delicate microclimate could prevail over such a wide and varied topography as the Mediterranean basis. In real life, before being reflooded by the Atlantic, only a few pockets of the basin were still hypersaline, most of it had already been infused with fresh water. You would expect this process to continue, and over a geological time scale, only parts of the basin would be this inhospitable. It would still be hot and dry, but with pockets of cooler wetlands, and it would have the most amazing network of river valleys in the world, as waterways like the Nile spill over into the basin.

[Zirojtan]

I can definitely imagine a much closer link between Eurasia and African fauna coming from this, however which species win out and where would be interesting to look into.


How do you think that this would effect the Sahara Desert? Does it dry out like I thought it would, or does that just depend on other factors that are directly affecting the global climate?

1) All the water that would otherwise be in the Mediterranean is in the rest of the world ocean's. This raises the global sea level (in the real timeline, by as much as 10 feet before it was refolded). However, the salt deposited in the basin would result in a salinity decrease, and with that a raised freezing point, which would affect glaciation events and the season cycles of the poles. This would have massive effects on a global scale. It changes the shape of coastlines, and likely allows for ice-free portages in more northerly waters.

Wait, so, freshwater has a higher freezing point than salt water? I didn't know that...


I wonder, does this make the ice ages of the Pleistocene significantly less icy?

[Simon_Jester]

Salt water freezes at considerably lower temperatures- this is why when you go to the seaside in winter, there will usually NOT be pack ice covering the surface of the ocean, even if air temperatures are freezing or below. You only get freezing over of the ocean in unusually cold climates, i.e. polar regions and places like Russia.

[Zirojtan]

Oh... semantics. lol


"Raise the freezing temperature", I get it now. So because it takes significantly lower temperatures to freeze saltwater, the decreased salinity of the Atlantic Ocean would in theory make it more easily frozen then? So... even more icy ice ages then?

[madd0ct0r]

2) The Iberian peninsula and Western Maghreb would not be affected overly much climatically, as they would still be receiving moisture from the Atlantic. However, further inland, the area around the Alps, the Balkans, and the Levant would be much drier. It is hard to say exactly how far reaching this effects would be, but it could result in cooling and drying of regions even further to the east into Central Asia (due to the action of the Westerlies). It is unlikely to directly impact anything in southern Africa or the Americas, but the ramifications of the sea levels rising and not freezing certainly would.

I'm not so sure. It was my first guess as well, but look at the precipitation maps for the USA- after the intial rain at the west coast, the air rushes over the first half of the continent, only starting to rain in the 2nd half, after it's been cooled by being forced high by the mountains.
It's the complete opposite of the rain shadow affect I'd expect, but I guess it's becuase we're looking at a much larger area than usual?

[Ziggy Stardust]

How do you think that this would effect the Sahara Desert? Does it dry out like I thought it would, or does that just depend on other factors that are directly affecting the global climate?

I would expect it to dry out on a larger scale, and the mid and Eastern regions would be even drier than in real life. The northern coast (Tunisia, Libya) would be significantly more arid than they are now. The Nile Delta would no longer exist, replaced instead by essentially a new Grand Canyon. The Sahara may even be contiguous up into the Levant and the Arabian Peninsula.

I wonder, does this make the ice ages of the Pleistocene significantly less icy?

I would think so, though it is hard for me to guess whether or not the changes in water composition would be enough to significantly off-set the glaciation.

I'm not so sure. It was my first guess as well, but look at the precipitation maps for the USA- after the intial rain at the west coast, the air rushes over the first half of the continent, only starting to rain in the 2nd half, after it's been cooled by being forced high by the mountains.
It's the complete opposite of the rain shadow affect I'd expect, but I guess it's becuase we're looking at a much larger area than usual?

The geography of this hypothetical dry Mediterranean would be too different to be really comparable to the US. In the US, wind comes up from the south-west and hits the mountains, the rain shadow creating the Great American Desert. However, there is also the interaction of the westerlies with weather patterns coming in from Canada and with the trade winds in the southeast. Look at a wind map:



There is a great rain shadow to the rockies. When you look at the other parts of the US where rain begins to fall, you will see it is where the cool winds coming high over the deserts meet the other weather patterns. Around the Great Lakes (which are infamous for their storms), and in the southeast, where the trade winds and the westerlies hit ANOTHER range of mountains.

Unfortunately I cannot find a comparable map to Europe. But the wind patterns are different. Most of southern Europe's climate is shaped by the winds that blow off of the Med. If there's no sea there, most of those winds actually wouldn't even exist anymore - instead, the westerlies would blow more from west to east. There would be a massive weather system that moves across the Mediterranean basin and into the Balkans/Turkey/Levant, consisting mostly of cool, dry air. I just don't expect it would pick up enough moisture traveling over the basin to create any significant rainfall in those reaches of Europe and the midEast. What little rain-fall there is would fall where it hits the mountains - so there may be a narrow strip along the Alps, pockets of the Balkans, and Turkey that is relatively green, but it certainly wouldn't be to the extent it is in the real timeline.

[madd0ct0r]

I can't find a decent map either. so far identified - large storms coming down from the artic in the NW, and hot winds coming up from africa during the summer. Labrador current raises temp along west coast areas higher than it should be.

[Zirojtan]

I would expect it to dry out on a larger scale, and the mid and Eastern regions would be even drier than in real life. The northern coast (Tunisia, Libya) would be significantly more arid than they are now. The Nile Delta would no longer exist, replaced instead by essentially a new Grand Canyon. The Sahara may even be contiguous up into the Levant and the Arabian Peninsula.

I wonder what kind of effects this would have on faunal exchange between Africa and Eurasia? When the Messinian Salinity Crisis happened, I know that there was exchange of some bovids, hippopotamids, and camelids (Paracamelus I believe). Would the climate of the Sahara be too extreme for further exchange of species between the two continents, say, between Sub-Saharan Africa and Eurasia? How do you think this might effect the pluvial periods that occasionally allowed for the expansion of certain grassland species OTL? Would they even be happening at all without the Med to facilitate precipitation, or did the Med have much of a roll to play?


I can certainly see Europe having a more diverse bovid fauna because of this, and the saiga is one species that in particular that I can see making good use of the considerably drier grasslands of Eastern Europe, maybe even evolving a larger subspecies/species?

I would think so, though it is hard for me to guess whether or not the changes in water composition would be enough to significantly off-set the glaciation.

Wait a second; if saltwater freezes at a lower temperature than freshwater, and we decrease the salinity (by how much, do you think?), thus raising the freezing temperature, doesn't that mean that it's then easier for glaciation to occur? Or am I confusing myself again?

What little rain-fall there is would fall where it hits the mountains - so there may be a narrow strip along the Alps, pockets of the Balkans, and Turkey that is relatively green, but it certainly wouldn't be to the extent it is in the real timeline.

I imagine then some seasonal dry forests? Maybe an expansion of acacia?

I can't find a decent map either. so far identified - large storms coming down from the artic in the NW, and hot winds coming up from africa during the summer. Labrador current raises temp along west coast areas higher than it should be.

So, are we saying that Western Europe is largely unaffected by this? Does the decrease in salinity affect the Gulf Stream current in any way? I've been reading a little bit about ocean currents, and wouldn't a decrease in the salinity of the water of the Atlantic mean that the North Atlantic current that is fed by the warm water of the Gulf Stream would eventually cool down faster, resulting in a less temperate climate for Western Europe?