Runaway Greenhouse on Earth

[newtron]

Greetings all!<br /><br />I have a few questions concerning the event of a runaway greenhouse on Earth.<br /><br />First, is Earth more mountainous than Venus, and does this play a big role in effecting greenhouse gases?<br /><br />Secondly, I would assume Earth's present orbit would play a big role in determining how long and how strong a runaway greenhouse effect would be. Would Earth's present orbit keep it from becoming a permanent fireball like Venus?<br /><br />Thirdly, How does the Ozone factor into all this (if at all)? Would Earth's atmosphere be too weak to keep the supposed large amount of water vapor from evaporating into space?<br /><br />Fourthly, Does the large amount of water in comparison to that of Venus necessarily mean that it would be worse? Is it possible that something else might happen concerning all that water?<br /><br />Bonus: What might a meteor or asteroid strike do to the conditions to a planet like Venus or the supposed-runaway, greenhouse Earth? Would it alleviate or contribute to the problem?<br /><br />Thank you for even reading, in advance.

 

[yevaud]

<i>I have a few questions concerning the event of a runaway greenhouse on Earth.<br /><br />First, is Earth more mountainous than Venus, and does this play a big role in effecting greenhouse gases?</i><br /><br />No, Earth and Venus are quite close in mass. Mountains have no real effect in the way you mean.<br /><br /><i>Secondly, I would assume Earth's present orbit would play a big role in determining how long and how strong a runaway greenhouse effect would be. Would Earth's present orbit keep it from becoming a permanent fireball like Venus?</i><br /><br />Depends. Our orbit is deep within the "sweet spot" (habitable zone) that allows liquid H2O to exist. It would take something severe, Climatologically, to create a runaway - and the current "Climate Change" isn't even remotely there.<br /><br /><i>Thirdly, How does the Ozone factor into all this (if at all)? Would Earth's atmosphere be too weak to keep the supposed large amount of water vapor from evaporating into space?</i><br /><br />Nothing to do with it whatsoever. The Ozone layer blocks UV and only that. (though it has a minor effect in atmospheric heating)<br /><br /><i>Fourthly, Does the large amount of water in comparison to that of Venus necessarily mean that it would be worse? Is it possible that something else might happen concerning all that water?</i><br /><br />Venus has <i>no</i> H2O worth mentioning.<br /><br /><i>Bonus: What might a meteor or asteroid strike do to the conditions to a planet like Venus or the supposed-runaway, greenhouse Earth? Would it alleviate or contribute to the problem?</i><br /><br />Far too generic a question. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[brellis]

<font color="yellow">Bonus: What might a meteor or asteroid strike do to the conditions to a planet like Venus or the supposed-runaway, greenhouse Earth? Would it alleviate or contribute to the problem?</font><br /><br />This thread and this thread have some posts speculating on redirecting asteroids or comets towards Venus. <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

Venus extreme slow rotation (Once each 225 or 243 days IIRC) plays a big role in its runaway greenhouse state. If earth were this slow in rotation, I would think we'd already be frying. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[logicize]

It might be worth trying to create a nuclear winter on Venus while at the same time disposing of our extra nuclear weapons. The lack of spin on Venus, does create a problem, the heat will just return unless we can figure out a way to get it spinning. Perhaps when aim the nukes so they hit at an angle. <img src="/images/icons/smile.gif" />

 

[yevaud]

Sorry. I meant to be a bit more informative, pressed for time lately.<br /><br />1. Mountains have an effect on the atmosphere, but not really in any meaningful way with respect to a runaway greenhouse effect. More in a way of steering the atmospheric jets and/or blocking weather systems, etc. That sort of thing.<br /><br />2. As I mentioned, there is a region stretching from approximately the orbit of Venus out a bit past Mars, which is known as the "Habitable Zone" or the "Life Zone." Within this, H2O can freely exist on the surface, such as here.<br /><br />The problem is, Venus is damned near at the inner edge of this zone, so the ability for the natural synergistic properties of a planetary atmosphere to recover from aberrations, such as an early runaway greenhouse effect, are precarious. <br /><br />Venus also has a very weak and spotty magnetic field, which plays a major part in retaining an atmosphere as some of it escapes, or tries to.<br /><br />And of course, it would receive more intense solar insolation, being closer to our primary.<br /><br />So, it begins to lose atmosphere, lighter elements onwards, and as it does, the properties (composition) of the atmosphere begins to change. And the change isn't good, assisting further atmospheric species to escape.<br /><br />E.g.: Planet loses lots of Hydrogen at first = less H20, more Co2 and other species = more heat trapped = easier for heavier species to escape = vicious cycle.<br /><br />So yes, our orbit is deeper within the Life Zone, meaning we have a much greater leeway before some critical point is crossed.<br /><br />3. Ozone is 03, and is pretty stable, except in the presence of catalysts such as CFCs or Methane. It mainly blocks shorter wavelength components of solar insolation from reaching the surface, which is a really good thing. Otherwise, we'd be bathed in UV all day long, and develop cataracts, cancers, DNA defects, sterility, etc. Enough and it will kill you.<br /><br />However, there would be some <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[fingle]

Re: This thread and this thread have some posts speculating on redirecting asteroids or comets towards Venus.<br /><br /><img src="/images/icons/shocked.gif" /> Don't waste those resources on Venus. Send them to Mars instead. Or better yet, as someone suggested in one of those threads. Shepard the comets and asteroids to a place where humans can exploit them more directly for the resources needed to build space stations and stuff. <br /><br /><br />fingle<br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[newtron]

Thank you for the responses.<br /><br />I haven't read through everything yet, but the info is definitely appreciated.<br /><br />To elaborate on the meteor/asteroid impact question, I meant for it to be that open, I wanted to see what you guys would say about different sizes, compositions, velocities and impact angles.<br /><br />Since it is extremely open ended, and I don't have time at the moment to draw out specific scenarios, you can ignore the question or draw out whatever scenario you like.<br /><br />Also, the nuclear winter idea sounds interesting, i'll have to look into it. How would nuclear contamination factor in? And would astro-environmentalists (if thats a term) have an issue with it?

 

[brellis]

hi newtron<br /><br /><font color="yellow">would astro-environmentalists (if thats a term) have an issue with it?</font><br /><br />I started this thread to open discussion of ethical and environmental issues as we expand the human presence further across the solar system. Check it out, and I'd like to hear your opinions, too! <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

logicize:<br />It might be worth trying to create a nuclear winter on Venus while at the same time disposing of our extra nuclear weapons.<br /><br />Me:<br />At this point, we have a long way to go technologically before we can do anything like that. Beleive it or not, there are not enough nukes on earth to speed up a planet the size of earth to anything more than miniscule levels if even that.<br /><br />We'd have to build many more bombs. In addition, much of the arsenal consists of average yield weapons. The largest nuclear device ever detonated was the Russian test called Tsar Bomba, at 57 megatons. The shockwave from that blast was detected by our intel community. The shockwave circled the earth three times according to the Guiness Book of World Records. Bombs of that megatonnage are nonexistent. 25 megatons is about the next largest that have been built and again, Russian. And again, not that many.<br /><br />Maybe one day there will be a way to do something like that. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>