(Are you slipping, Rio? That's actually an interesting question!) Well, let's start by "assuming" both planets were otherwise extremely similar - they have the same mass, same orbital distance & insolation, start with the same climate and mix of species, etc. What they would not have if the climates started out the same - within limits, which I'll get to - is the same amount of greenhouse gases in atmosphere. Let's call this planet E2. Because the ocean is significantly smaller, to have the same general climate, E2 would have a lot less greenhouse gas in atmosphere to have the same temps. The oceans are a gigantic heat sink, and an ocean 1/3 the size would nor be as adequate a heat sink - it couldn't hold as much heat as Earth (E). Therefore, if the CO2 increased there (E2) 50% - 100%, the land surface temperatures would go up noticeably higher than we experience. I think - okay, guess - that would be the first major effect.
Now down to some details. E2 would necessarily have more deserts, because the available "moisture pool" is much smaller. These deserts would be far drier in their interiors, and far more extensive than those on E. You would get far greater temperature swings and extremes on E2 than on E. I would suspect the general (life) carrying capacity of E2 would be less than E, because most life and much of our oxygen is generated in the oceans.
If plate tectonics operated about the same, you would get multiple inland mountain ranges shielding even more moisture from the interior deserts. Hm, more inland volcanoes and fewer ocean floor volcanoes would put more CO2 (etc) directly into atmosphere, causing bigger climate swings, I would think.
Less life and more desert would affect the albedo of E2, probably holding it to a somewhat narrower range, since a much larger fraction of land would be relatively unchanging in albedo, I would think. Ocean placement would probably be very important here. If the oceans were primarily equatorial, that would tend to flatten the albedo range over the year. If the oceans were concentrated closer to one pole, that would cause a noticeably larger swing in albedo over the year, I would think. A lot more rocky surface being renewed by vulcanism would expose more rock to weathering, and so reduce atmospheric CO2 faster, at a guess. Again, this would lead to greater swings in climate.
I have no clue how ice caps would work. Clouds would possibly be less than on E, less moisture giving less cloud production, and more desert wringing any moisture out of atmosphere. Equatorial interior deserts would be very bad places to be. I suspect all these factors would push both total species and total living things well down in numbers, compared to E. I would not say there would be no life, but compared to our planet, it would certainly be impoverished.
Thanks for the chance to spin a little science fiction out.
Probably not stable. Earth would become too hot or too to support life. If you see a world with no oceans in a science fiction movie, don't believe that such a world would be be able to support life in this Universe.
<28% is a fairly large ocean. Why would you make the assumption that there wasn't one?>
Yeah! 28% is very different from no ocean. Sorry for the misunderstanding. A planet with 28% ocean would be more stable than a planet with no ocean, but less stable than a planet with 60% ocean.
C
I think this question is about a hypothetical planet, not Earth
So much would count on where the water was, if it was just one ocean, it would be pretty bad for Earth because nearly all the land mass would be hot dry desert, and only areas around the ocean would be habitable,
Ignore Joe Joyce greenhouse gases have little effect, the biggest GHG is water vapor and that would be in short supply, it would definitely be hotter in summer, colder in winter, with hot days and cold nights
The Earth probably wouldn't have become habitable. The ocean(s) would be extremely salty, and most of the land would be desert.
If we keep pumping out CO2 as we have been, the oceans would still rise and the planet would continue to warm
hot and cold
I think a good starting point would be 1:1, but then I'm not a climatologist. Nor do I expect absolute answers.Just inverse logic.
