The situation: A planet largely composed of water, with land masses being island chains scattered planet-wide. At all times there is precipitation of some sort, whether it be snow or rain based on regional climate. At times it can be light, and other times it can be extremely severe, but the average tends toward what would be considered a "steady" amount like that of a "typical" storm, not dangerous but certainly enough to have an effect on many facets of life. We'll assume that, as the planet has been like this, the water cycle is stable and therefore there's no concern of rising water levels encroaching on limited land resources.

The question: How would a population of human or humanesque people most likely adapt/overcome this sort of situation, and what would most likely be their biggest choke-point in doing so (i.e. resources, manpower, etc, assuming there is such a choke-point in your solution).

  • 3
    $\begingroup$ Real-life case study: Seattle. $\endgroup$
    – Wingman4l7
    Dec 23, 2015 at 23:06
  • 1
    $\begingroup$ @Wingman4l7 Sorry to disagree with you but the climate of Seattle is not that rainy, compared to other places. I've found one with high precipitation all year long: Quibdó (Colombia). Receive 8 time more rain and unlike Seattle, there is no dry season. Mawsynram and all of NE India receive more rain overall but there is a dry season. Aside from that, Hawaii has the Guinness record for the most rainy days: 350 guinnessworldrecords.com/world-records/most-rainy-days $\endgroup$
    – Vincent
    Dec 24, 2015 at 5:10
  • 1
    $\begingroup$ Is adaptation restricted to biology or would a technology solution also fit? I mean presumably constant damp and wet nearly exactly describes some early Earth history theories. Also the humanesqe people are intelligent by our standard? Waterworld explores some of these ramifications. $\endgroup$ Dec 24, 2015 at 5:42
  • 1
    $\begingroup$ When you say island chains, are you talking Bahamas style small islands or Britain/Ireland/New Zealand sized? You're going to need some good sized rocky islands to develop any heavy industry. $\endgroup$
    – Separatrix
    Dec 24, 2015 at 12:36
  • 1
    $\begingroup$ Does constant literally mean 24x7 or rains every day or something else? $\endgroup$ Dec 24, 2015 at 13:01

2 Answers 2


This is one lousy planet for humanoids.

I think we need determine how can you get continuous precipitation on an earth-like planet. Clearly you need a lot of water entering the atmosphere in its water cycle. So, hot oceans are required.

Next, you need air capable of carrying lots of moisture. Air can contain over 10 times as much water at 40 C as is does at 0 C, so again, hot atmosphere. You also need cool upper air to squeeze out the moisture in the air as well as dust particles to encourage droplet formation.

Though you have mentioned mostly oceans, some island chains instead of land masses, this is an absolute requirement, as any significant land masses would likely result in at least occasional gaps of rain.

So, steamy, jungle-like conditions, on steroids. Snow is not generally compatible with such an environment, so no cold polar regions. High mountains could get snow, but are bad because the air uplift squeezes out to much water, leaving desert conditions on the leeward side. So, snow should be very rare on your world.

How do you manage to have all the necessary conditions simultaneously? Because of the continuous rain, you have continuous down-draft that bring lower temperatures down to the surface with the rain. If you make the solar flux very large to compensate, you get much thicker cloud layers reflecting the sun and I believe kill off the temperature driven atmospheric uplift required. The continuous downdraft from the rain contraindicates the thermal uplift required to cause the rain in the first place too.

The only way I can envision making this world is to make the oceans hot due to very large heat movement coming from the core, making the oceans hot compared to the upper atmosphere at all times. So in addition to the rain, you necessarily will have high vulcanism and earthquakes. I think that constant rain is like impossible even under these conditions.

Earth style photosynthesis will be torturous at best due to the thick cloud deck reducing available light, so you need a brighter sun, but not too bright. So marginal plant growth at best. Soil erosion is going to be an awful problem too.

Food sources will be very limited, probably impossible to support a large and varied biome like Earth. Much worse than you might otherwise expect.

Thick clouds, constant rain, earthquakes and volcanoes and the food is not very good either. This place is going to have lousy tourism; so there is little hope of bringing in off-planet resources that way either.

Forgot one important thing, tsunamis - lots of them. Those are really bad for small islands in the middle of deep water. Most people remember the 2 largest tsunamis of the 21st century, the Christmas 2006 tsunami (Dec 26) in Sumatra and the northern Japan tsunami that triggered the Fukushima meltdown in 2011 (Mar 11).

  • 2
    $\begingroup$ The planet would most likely have developed a pretty diverse aquatic biome, and any animals that come up on land will probably be at least semi-aquatic. The plants might not rely as heavily on photosynthesis, but could make use of thermal energy and very nutrient rich water, like would be found around volcanic vents. Not like earth plants at all. $\endgroup$
    – AndyD273
    Dec 24, 2015 at 15:33
  • $\begingroup$ Also, it might be a miserable planet for humans, but the humanoid aquatic fish people of Dagon IV couldn't picture living anywhere else :) $\endgroup$
    – AndyD273
    Dec 24, 2015 at 16:10
  • $\begingroup$ @AndyD273 - Sure, there could be a relatively rich and abundant set of chemosynthetic lifeforms, IMO these should not be expected to supply nearly enough food to replace the equivalent food missing due to the paucity of working photosynthesis, as conditions needed to form nutrient rich underwater vents are fairly rare on this planet - you need water seeping down into hot zones, picking up nutrients and being forced back up. Probably should have mention this in my original answer +1. $\endgroup$ Dec 24, 2015 at 16:17

Food would be an obvious one, where plants would need to be able to grow in low light levels. Precipitation means clouds, which means lower solar energy reaching the ground.
This isn't really a problem since any plants developing there are going to be adapted to the environment.
Most earth based plants are going to have a problem growing in overly wet, constant low light conditions.

Next is industry. Metal and water react to each other, causing corrosion. Electricity and fire both get along poorly with water.
A technological system like earth developed is going to have a hard time of it. But they could still have something. Biotech though selective breeding would still be doable, which could develop into a lot of areas.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .