At current global warming rates, the sea levels are rising because the ice caps are melting. But once the ice caps are all melted, the sea would stay the same.

In my world, humanity's money revolves around natural gases and other fossil fuels, and most money comes from that. Because of this, climate change is greatly accelerated. At the rate that the earth is heating up, say 10 times faster than it is today, about how long would it take for all the water in the oceans to evaporate?

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    $\begingroup$ Before losing water, Earth should go through a "steambath" phase, which would last millions of years. $\endgroup$ – Alexander Jan 28 at 2:59
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    $\begingroup$ what would the steambath phase look like? $\endgroup$ – HaveProblemsEveryday Jan 28 at 3:29
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    $\begingroup$ Increased warming would lead to massive evaporation - climate would get hot and humid. Only then water vapor would be lost to space. During that phase, it may feel like "Turkish bath" for the people who would still live on Earth. $\endgroup$ – Alexander Jan 28 at 5:02
  • $\begingroup$ Aircon 101: yes unlike boiling evaporation can take place at any temperature but it will take super longer time when water vapour in the air is saturated, since it is a surface phenomenon you would want to scoop the ocean first before posting this question. It is a good question no doubt ;D $\endgroup$ – user6760 Jan 28 at 6:13

For a rough estimation look at Venus and its atmosphere

Studies have suggested that billions of years ago, Venus' atmosphere could have been much more like the one surrounding Earth, and that there may have been substantial quantities of liquid water on the surface, but after a period of 600 million to several billion years, a runaway greenhouse effect was caused by the evaporation of that original water, which generated a critical level of greenhouse gases in its atmosphere.

Given that water vapor is a stronger greenhouse gas than CO2, I think that once the trigger is pulled water evaporation would dominate over anthropogenic gases. Thus you would fall in the Venus scenario and timeline.


I think the title is a bit weird, rather skewed towards a different scenario than the one discussed in text. Reading it, I was first thinking at Mars, where because of the loss of its internal geomagnetic field, water sank out to space. But your text only refers to evaporation, which is one part of the present-day oceanic-atmospheric cycle of water, the other being rain.

On Earth, there is another water cycle with a much much longer timescale, which is an interior-surface cycle. Four cycles in fact :

  • water in sediments and altered oceanic crust returns back to the mantle, some of which goes along within the internal convection, and then mostly outgases at ridges, and
  • some of which takes the short circuit of subduction zones (much more intense, but shorter term). The quantity numbers of these fluxes are still much in debate, but there is a big lot of assumption but the amount of water inside the mantle is larger than what is present at Earth surface, with a range from an equivalent amount up to sort-of five times (not an order of magnitude more, but rather a significant amount).

In terms of characteristics duration, the subduction cycle takes a few tens of million years, while the cycling through the upper mantle convection is in orders of a very few (one to three ?) half-billion years.

  • There is a deeper cycle, supposedly much longer, which comes from the potential reinjection of hydrated material down to the core-mantle boundary ("CMB"), the so-called D'' layered zone (pronounced "dee-double-prime") ; it's a thin "layer" laying at CMB, not thicker than 100 km, heterogenous in properties, accumulating some of the oceanic slabs material that might have come down though the whole mantle (about 3000 km thick !), not detected to be present all around the core, and it is the origin from which big hot plumes rise, as seems to be the case for Hawaii hotspot. As far as water is concerned, the effectiveness of this very deep cycling process is still in debate.
  • Finally, it seems that there still exists some pristine material inside the lower mantle (between 570 km and the CMB, accreted at time of Earth formation, and which still has kept it primary load of volatiles (shortly said : geochemical observation of xenon isotopic anomalies in Loihi seamount lava). Therefore not a cycle, but a proper source, a spring !

These last two very deep potential sources for water, either pristine or recycled, would have characteristics durations in orders of magnitude of some billion years…

Therefore, the discussion of water cycles and water exchanges between internal Earth reservoirs and the atmosphere-hydrospere, at geological time scales, say durations between the one million years beat up to the four and a half billion years of Earth being, is quite different than the one for the meteorological and climatic cycles. No need to say that drying this Earth, its interior the mantle, will last much longer than will humanity :-).

This to say that the comparison of the hydrated fate of the Earth interior, with some well documented past situations of the surface Earth (recorded as the geological history of climate, no longer than, being large, a pair of hundredth million years), is not that simple.

And for the Venus case, whom so little is known except that it does not seem to house a large-scale internal convection, rather "only" a plume/hot-spot one…, we still lack many fondamental informations.

In conclusion, drying up the Earth (as in the title question) is a totally different question to that of evaporating the oceans (as in the question content).

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    $\begingroup$ What does "hour texter" mean? A fork? To me it's unclear if this answers the question or not because the way it's written, it's unclear what you are saying. Please edit to create paragraphs and to clear-up the spelling and very strange language. $\endgroup$ – A Rogue Ant. Jan 28 at 6:58
  • $\begingroup$ @Tantalus'touch. Sorry for this curious "hour texter" that i miss when rereading my answer. I guess it might come from some automatic correction, or… Really I don't know. I'll edit it. Another point : "very strange language" is not an absolute qualification. There are many different ways of expressing the same thing, as well as there are different flavours of english. If there is some point that you don't understand, please, do flag it, or question in a comment, so that I see what I can improve. All my best regards -- ÉLw $\endgroup$ – ELw38fr Feb 2 at 5:44
  • $\begingroup$ After re-reading my comment I've realized that "strange language" might have sounded like a bit of a personal criticism. My apologies, I intended no offense. I've turned off my auto-correct for that reason, it kept generating garbled text and didn't seem to possess the right vocabulary at all sometimes. I look forward to reading your edited answer. $\endgroup$ – A Rogue Ant. Feb 2 at 7:33
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    $\begingroup$ I see that you are a scientist, very informative answer. What I perhaps should have said first was "welcome to worldbuilding", I'm glad you've not been put off. Welcome to worldbuilding, enjoy the site. $\endgroup$ – A Rogue Ant. Feb 2 at 7:43
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    $\begingroup$ Since there is no shortcut way (read "icon :thumb-up:" nor ":heart thank:" to click), a few more bytes here. First no need to apologize: english being de facto the international language, every one-to-one meeting has a high chance to near 2 strangers (foreigners is more correct, I guess). As much as I can, benevolence & positiveness guideline my understanding. Conversely my expression may not necessarily be without criticisms. I accept them when explained. Whatever, some of my edits didn't make it. Paragraphing requires more than one CR apparently…And thanks for your welcome. Best regards $\endgroup$ – ELw38fr Feb 3 at 13:29

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