What Keeps Earth From Being Like Venus?

Venus is very hot, because it has a thick, high pressure CO2 atmosphere. The only reason why Earth is not like Venus, is because we have oceans. The oceans absorb CO2 emitted from volcanoes and convert it into limestone. Without these limestone beds, earth would have a very thick, high pressure atmosphere and would be hot like Venus.

ScreenHunter_4745 Nov. 20 09.25

Proximity to the Sun is not the cause of high temperature on Venus. It has a thick cloud layer which reflects 70% of sunlight back into space, which is why Venus appears so bright. The surface of Venus receives much less sunlight than Earth’s surface.


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59 Responses to What Keeps Earth From Being Like Venus?

  1. annieoakley says:

    Makes perfect sense to me. I love geology.

    • Baa Humbug says:

      Well now I really am confused.

      On the one hand, GHGs (mainly H2O) keeps us warmer than we would otherwise be. It’s the Greenhouse Effect you see, just like putting on a coat or blanket.

      On the other hand, the same H2O keeps our planet from becoming a fiery inferno like Venus by sequestering the other main GHG gas CO2.

      So we are warmer by 33K thanx to GHGs, but cooler by 400+K thanx to GHGs.


      </scratches head

      • Water has many properties. Being a GHG is just one of them.

        • Baa Humbug says:

          Just so I undertood you. H2O is not a contributor to the GHE in some of its properties.
          Is that what you’re saying?

        • I wouldn’t consider sea ice to be a greenhouse gas.

        • Baa Humbug says:

          OK it’s clear now thnx.

          Science is about describing realities, and the reality is water in all its forms are coupled to the Earth atmosphere system.
          Decoupling bodies of water (oceans etc) and ice from the system is not reality therefore is just a thought experiment.

          IMHO your recent posts and comments about this ‘unreal’ system may well be right, but they don’t describe the ‘real’ system therefore they don’t provide answers about the ‘real’ system.

      • Robert Austin says:

        Think of the properties of water beyond its quality as the most significant greenhouse gas in our atmosphere. It exists in three phases and has high latent heat properties. In other words, it is an efficient “refrigerant” in our atmosphere transferring heat from the surface / lower atmosphere to the upper troposphere from whence greenhouse gases can readily dump the heat to space.

      • Herve D says:

        Please consider these facts: On Earth, CO² and water vapour are transparent to visible solar irradiance. But when some clouds occur, their water droplets diffuse light in every direction, returning to space vacuum sometimes 70% of irradiance. As cloud coverage is never 100%, lot of solar irradiance nevertheless reaches ground. On Venus, which ground has never be optically seen from space, clouds (essentially sulfuric acid clouds at 50km altitude) covering 100% of it, play the same role with full efficiency. On top of this, earth oceans can partially evaporate, massively transporting (by “heat pipe effect”) extra energy towards the beginning of transparent stratosphere, allowing this energy excess to be released to space vacuum by thermal radiation: This effect does not exist on Venus as no known chemical compoud can play same thermal evaporation role as water on Earth.
        This why the article is correct.

  2. emsnews says:

    The biggest reasons are two: Venus is very much closer to the sun and…it barely rotates. A ‘day’ there lasts nearly a year here.

    • No.
      High albedo at the top of venus atmosphere keeps the surface much darker than earth’s surface. The heat on Venus is due to the pressure of the atmosphere. Nights are months long and the temperature never drops.

      • See - owe to Rich says:

        Hooray, you finally said it: “pressure”. Venus is hot because of a much higher atmospheric pressure and the existence of some greenhouse gases (doesn’t much matter which).


        • nielszoo says:

          If Venus had an atmosphere like Earth at 90 bar it would be even warmer. CO2’s gas constant value is lower than that of mixed air.

  3. elmer says:

    Why do they call it Limestone then? Shouldn’t it be CO2 stone?

  4. darkobutina says:

    It is very simple, Venus atmosphere consists of 97% of CO2 while our atmosphere consists of 99% N2 and O2. So to explain Venus atmosphere one has to understand physicochemical properties of CO2 while on our planet physicochemical properties of N2 and O2 explain behavior of our atmosphere. N2 and O2 are as relevant to Venus’ atmosphere as CO2 is to Earth’s.

    • The composition of the atmosphere has very little to do with it. The lapse rate on Venus is similar to earth.

    • Steve Case says:

      Mars has an atmosphere that’s about 97% CO2 and it’s so cold there it snows dry ice.

      • cptwayne says:

        Mars atmosphere is cold because there is little moisture in the atmosphere, if not none at all. On Venus, if one adjusts the temperature based the enormous pressure and then then calculate what the temperature should be due to its distance from the sun, bingo, the math comes out right. Nothing to do with the GHE or CO2. It’s the pressure and the proximity distance to the Sun. Both of these demonstrate that CO2 has little effect.

  5. Paul says:

    What makes Venus hot is Venus atmosphere pressure (93 bars) – thanks to gravity (the real greenhouse engine), and its proximity to the sun. CO2 has nothing to do since sunlight does not even reach the surface.

    • Proximity to the sun is not important. Venus atmosphere has very high albedo and reflects 70% of sunlight back into space.

      • For information purposes only, Earth has an albedo of 30%

      • Cornelius says:

        Maybe we should consider our wording here. I do understand that you’re reinforcing the fact that atmospheric pressure is key to Venusian temperature. Proximity to the sun, though, is certainly a contributing factor. Do you believe that Venus would have the same temperature if its mean distance from the sun were that of Neptune? Or if there were no sun at all? Of course not. It appears that you’re attempting to dispel the common fallacy that the disparity between temperature on Earth and Venus is primarily due to proximity to the sun. Definitely a worthwhile endeavor. Might be confusing, though, to make statements which could be construed as claiming that proximity to the sun has zero impact on planetary temperature.

        • pinroot says:

          Distance from the sun isn’t necessarily the only determining factor. Mercury is closer to the sun than Venus, but Venus is hotter.

          I like to point out to alarmists that the atmospheres of both Mars and Venus are ~96% CO2, and then ask why Mars hasn’t had a “runaway greenhouse event”. They always point out that Venus is closer to the sun. I like to watch them sputter after I point out that Mercury is closer than Venus, but not as hot as Venus, ruling out proximity as THE reason for the differences.

        • cptwayne says:

          Pinpot, you have to correct for the atmospheric pressure and then adjust for the closer distance to the sun. The calculations work out very nicely to explain Venus’s atmospheric temperature.

      • davidswuk says:

        First came the planet and then its atmosphere…………..

      • cptwayne says:

        That sounds like backward logic. That much reflection back into space should cool the planet, don’t you think? A Venus day is about 265 Earth days. Yet, there is little temperature difference between the long dark atmospheric and the correspondingly long sunlit atmosphere as Venus slowly rotates. If the GHE was at play, this would not be the case. Venus can’t radiate heat into space as freely as other planets, so it heats up. Nothing to do with CO2. If the atmosphere were pure nitrogen, it would still be very hot at its high atmospheric pressure. Matter of fact, Venus has 4 times the quantity of nitrogen as planet Earth.

  6. philjourdan says:

    Thank you for saying what I have been saying for years.

  7. Robertv says:

    Is this the reason that while it is the same amount of solar energy reaching the top of mount Kilimanjaro and the streets of Nairobi one place is always cold and the other one is always warm ?

    • Robertv says:

      Is Venus today not like how Earth was billions of years ago ?

      • The oceans never would have formed if it was hot like that.

      • Hell_Is_Like_Newark says:

        That has been a head scratcher for me: Why doesn’t Venus have water? What happened that made the formation of Venus different than earth? It also doesn’t appears to have subduction zones (also theorized due to the fact there are no oceans), yet has evidence of lots of volcanic activity.

        • Louis Hooffstetter says:

          The Earth is the only planet in our solar system with plate tectonics. The atmosphere, oceans, and continents are all products of approximately 4 billion years of plate subduction, partial melting of oceanic crust, and volcanic activity. The light volcanic gasses became our atmosphere, the condensable water vapor formed our oceans, and the lighter silica rich magma became the continents. Continents are predominantly made of relatively light granitic rock that ‘floats’ on/in the heavier mantle. Current theory holds that two proto-planets likely formed in (or very near) our Earth’s orbit and later collided to form the Earth and moon. Had this collision not occurred and triggered the subduction process, the Earth would likely resemble the other rocky planets, Mercury, Venus, and Mars.

        • nielszoo says:

          Venus does have water but it would be a gas at the temps and pressures at the surface.

  8. SunSword says:

    My best guess: BEFORE Venus formed its thick heavy atmosphere, it didn’t have such a high albedo. So the oceans gradually evaporated because:
    (1) it was closer to the sun, received more sunlight, and was therefore hotter and atmospheric molecules including the H2O molecules were carried high up in the atmosphere of Venus and were lost to space.
    (2) Venus slightly lower gravity helped with this.
    (3) Also the fact that Venus lacks a magnetic field helps with this because the solar wind blows the molecules at the top of the atmosphere away.

    Once oceans on Venus were gone, the CO2 began to accumulate. CO2 on Venus also escapes to space BUT due to the volcanic activity it is emitted faster than it escapes. Thus over time the atmospheric pressure kept rising until it reached current state.

    • davidswuk says:

      Venus got toasted and not spit-roasted (like sister Earth)

    • Robertv says:

      But why is it rotating in a different direction as the rest of the planets ? (and slowing down)

      Pero ¿por qué está girando en una dirección diferente que el resto de los planetas? (y desacelerando ) (helping the warming refugee voters)

      • It’s not really rotating, It’s wobbling. Mercury and Venus are closest to the sun and are subject to the strongest tidal forces with it….they probably rotated a lot billions of years ago but are getting into tidal lock with the sun. Like the moon is with earth. Soon, Venus will face one side towards the sun forever. The reason Venus is spinning the wrong way is because, right before tidal lock, planets spin slowly one way, stop, then slowly the other way, then it stops, until it’s locked in.

        • Hell_Is_Like_Newark says:

          I have read theories that Venus might have gotten smacked by something big early on its formation, causing it to spin really slow and didn’t form a moon like with Earth.

        • Olaf Koenders says:

          I think you’ll find tidal locking doesn’t take millions of years of spinning one way then the other for millions, it pretty much grinds to a halt. Venus was struck by something in its past.

  9. petavs says:

    Nope… It’s because Venus is a Goddess and CO2 is an elemental. And Venus is HOT!!

  10. inMAGICn says:

    What would happen if we placed Earth in Venus’s orbit and vice versa?

  11. Libro Vore says:

    My understanding is that our moon pulls atmosphere into space, which keeps the pressure down and the temperature correspondingly low (Boyle’s Law). Because tectonic movement releases gases, including Oxygen, CO2, and others, we’d have a very thick atmosphere otherwise. As noted above, Venus’ temperature is the result of pressure, not the ratio of CO2 in the atmosphere.

  12. rishrac says:

    That’s not what keeps Venus so hot. What emf penetrates clouds? And what does earth currently have that Venus doesn’t (Venus did have water, rule out water )? What happened to it and why?

  13. emsnews says:

    Yes, atmosphere does create warmer climates than naked planets or moons. Mercury is like the moon only closer to the sun.

    Venus is more like say…Jupiter only smaller and much closer to the sun and with a lot less rotation. The core of Jupiter below the atmosphere is how hot? We don’t know. The guess is, it is so hot, there is no ‘surface’ but rather it is a broiling caldron.

    The core is hotter than the sun. So yes, gasses can cause enough compression to create hot planetary surfaces. The earth has little in the way of gasses and when seen from afar, the clouds show up but otherwise, like only with Mars and Mercury, we can see the surface.

    All the other planets are like Venus, totally shrouded by huge coverings of various gases, it doesn’t matter which mix it is, it is the density.

  14. emsnews says:

    Earth has a moderately thin atmosphere and Mars has a very thin atmosphere.

    Even so, just below the surface of the land masses lurks broiling hot lava. 90%+ of the planet is hot enough to melt steel, too. Mars isn’t. Why this is so is a very interesting topic seldom really understood, we can guess about it.

    • Louis Hooffstetter says:

      Since we are guessing…
      the internal heat of our planet is generated by radioactive decay. My guess is that Mars formed with a much lower percentage of radioactive elements.

  15. jamzwj says:

    If Venus had Earth’s atmosphere it would still be torrid by day but for other reasons. How hot would Earth get in the orbit of Venus?

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