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I'm not talking a single-biome sand-world. Of course I want the classic large sand seas, but I also want steppes, mesas and buttes, floodplains, salt pans, hamadas, and canyons, both hot and not so hot, and regions with unique weather patterns. You know, like earth, but overall a lot drier and with way less dense vegetation.

This planet needs to still support indigenous complex life with an earth-like atmospheric composition. I'm not against large bodies of water to help regulate extreme temperatures and produce seasonal precipitation, but I don't want regions that are hydrated year-round. I like the idea of savannas that are dry for most of the year and then water-logged for a few months, or Atacama-like deserts with heavy fog banks.

Would it work to alter the planet's atmosphere so that fog, rain, and snow are possible, but where shallow water evaporates very quickly? Or might I need to alter the composition of the soil itself so that it doesn't retain water? Might there be other ways to achieve this?

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  • $\begingroup$ Ever read Dune? $\endgroup$ – tonysdg May 27 '17 at 18:23
  • $\begingroup$ You do realize at least half the features you mentioned are caused directly by water. You need to describe what makes your earth different from our earth, becasue it sounds like you should just use an earth like planet and use a normal desert as the setting. $\endgroup$ – John May 28 '17 at 6:50
  • $\begingroup$ I do realize these are water-formed features (though wind also contributes to weathering), and I'm not proposing that water be eliminated altogether, just a lot more scarce. What I do not want is areas like rainforests that are drenched in water year-round. Ideally there would be no region more hydrated than a savanna. $\endgroup$ – RLuebke May 28 '17 at 23:29
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There are two basic ways to make a world almost exactly like Earth but drier:

  • Have a little less water. Water is essentially indestructible, the ultimate recyclable material; Earth has about the same amount of water it always had. (Some little amount is lost to space, some little amount is gained from comets and such, but those are small.) The less water the planet has the smaller the oceans are and the larger the dry land masses; less evaporation would mean that arid areas would occupy more land, proportionally.

  • Have all the continents bunched up, like Earth had from the late Carboniferous to the early Jurassic (abour 335 to 175 million years ago). The inner areas of large continents are usually arid because rain comes mainly from the oceans and in the middle of large continents all rain which was to fall down has already fallen somewhere closer to the sea; for example, the middle of the large Eurasian continent on Earth is pretty much all a huge desert -- think Kazakhstan, Turkmenistan, Afghanistan, Tajikistan, Uzbekistan, and western China.

P.S. Sandy areas are quite rare in deserts. Most desert area is rocky. Large rocks, mid-size rocks and small rocks over thousands of miles.

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  • $\begingroup$ the continent position is a good one, you can't really make an earth that has so little water it affects the planet's climate and still have anything like earth. But you can move the continents around to make bigger deserts. $\endgroup$ – John May 28 '17 at 6:55
  • $\begingroup$ @John: It doesn't have to have very little water. Most of Earth's water is in the deep parts of the oceans; decreasing the amount of water by about 10% would lower the sea level considerably. $\endgroup$ – AlexP May 28 '17 at 6:57
  • $\begingroup$ And would not affect the deserts of earth by any significant amount. As long as there is a large water reservoir (oceans) the Air will continue to reach saturation thus the hydro cycle will continue to create wide spread rain. Because of the continental shelf drastically shrinking the oceans size would require removing a large percentage of the water. You were right that putting all the continents together is the best way to deny a larger portion of the land rain. $\endgroup$ – John May 28 '17 at 13:51
  • $\begingroup$ The problem with the idea of a supercontinent (which I'm planning on anyway) is that you still have areas with pretty high precipitation around the coasts, and I'd like to have as little non-arid land as possible. $\endgroup$ – RLuebke May 28 '17 at 23:34
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Please consider that climate is very complicated and even the experts can't make a prediction that goes beyond 3 days into the future. Changing certain parameters (take for example temperature, when Antartica wasn't at the South Pole reflecting sun light, as far as I know earth was hotter but not drier as you described it - feel free to correct me if I'm mistaken here) might not give you the results you wish and any answer is pure speculation. As a writer, you have freedom here and your typical reader will not complain.

AlexP has already given you a very good approach with his super continent (I do not agree with his less water idea for several reasons, but who cares). Here is another one:

Be aware that wind is your best friend if you want water to evaporate quickly. Trees are great if you want your area to be kept sheltered from wind, cold and humid. So have no or few tree-like plants. Several parts of this world became deserts because they had no trees or lost their trees.

I also advice you to google "desertification".

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