Would an Earth-analog dominated by land, rather than oceans, be habitable?

[szputnyik]

About 2/3 of Earth is dominated by water. During the Permian, this 1/3 of land was concentrated in one supercontinent, and only the coastal areas of this continent were habitable, while the inlands resembled Martian deserts.

If there existed a planet homologous to Earth, except containing only 1/3 of water, distributed among large seas, sort of like the moon Titan, would it be habitable outside the seashores? Or would everything far from the sea turn into something like the Sahara desert?

Edited April 23, 2014 by szputnyik

[NERVAfan]

Hmmm. Interesting question. I would think it would have huge deserts, yes.

I think it's an overstatement to say the interior of Pangaea was like a "Martian desert" though... apparently it's more complicated than "moist coastlines, totally dead desert interior". Some parts were desert, yes, but probably not all the interior. Apparently Pangaea had a really extreme monsoon climate ("megamonsoon") so some parts of the interior got lots of rain at certain seasons... but were dry other times... while other areas were always desert. Very seasonal and very "continental" (hot summers/cold winters), with defined latitude zones, including apparently a moist equatorial belt.

http://onlinelibrary.wiley.com/doi/10.1029/JD094iD03p03341/abstract

http://www.pnas.org/content/108/22/8972

EDIT: I see references to huge amounts of evaporites though so there were major deserts in some parts... but do you have a source for them being basically lifeless? I mean, the Sahara and the Rub al'Khali are extreme deserts but have significant life... it's really only the absolute driest like parts of the Atacama, or salt flats, which approach lifelessness.

Edited April 24, 2014 by NERVAfan

[Seret]

It might be broadly habitable, but it wouldn't be exactly like the Earth. Things like the balance of gases in the atmosphere depend on cycles that include release and sequestration of gases by geology and the sea. It's a complex system, change the parameters too much and you can tip over into wildly different equilibria than our current one.

So the planet could be habitable in terms of things like gravity and radiation, but I'd be surprised if the atmosphere was healthy for us to breathe.

[Moar Boosters]

It might not be healthy for us to breathe, but I expect something could. In much of earths geological history our planet was covered in life but we wouldn't survive long breathing the atmosphere.

As long as there's an active water cycle, water can be distributed to other parts of the landmass other than the coast. Just like on earth some areas have the conditions that make the clouds release their rain, and other areas rarely even see clouds. As long as the conditions exist to allow the clouds to pass beyond the coast, then other areas are likely to see rainfall. This will then form rivers and lakes which would likely be hospitable for life.

[Seret]

It might not be healthy for us to breathe, but I expect something could.

Sure, the OP wasn't really specific about their definition of "habitable". Technically a world consisting entirely of seabed covered in black smokers is habitable, but I'm not sure that's what they were getting at.

[szputnyik]

What I meant by "habitable" is whether there would be tolerable temperatures and enough arable land to farm, and how big of a population could live on a planet like this.

[Nuke]

we know on earth that the oceans are a major heat conveyer. so if you had a few small, non contiguous bodies of water, i would think that you would have a lot of hot spots that take up heat with no way to get rid of it, and a lot of cold spots that cant get heat from the warm spots. so i can imagine less dynamic weather, but wider differences in climate from biome to biome.

[Moar Boosters]

It was the primitive forms of life on earth that created the atmosphere which allowed more advanced life to develop. It's extremely unlikely another planet would have an atmosphere that we could breathe as even tiny changes can make it inhospitable for us, but that doesn't mean equivalent life-forms couldn't evolve.

[Fingal]

Surrounded by such a large water mass, a supercontinent could find itself inundated with massive hurricanes on a regular basis. That could bring a lot of water inland and any higher ground inland would continue to produce precipitation.

[Seret]

What I meant by "habitable" is whether there would be tolerable temperatures and enough arable land to farm, and how big of a population could live on a planet like this.

Population of what? If you mean normal unmodified Earth humans, plants and livestock then no I don't think it would be habitable. If the mix of atmospheric gases is different then crops won't thrive and people can't breathe properly. I am however not a planetary scientist so this is a bit of a guess.