Ozone hole may disappear by 2050

[taks]

no kidding #2.

we're debating about our agreement now. someone should link to something about silliness.

 

taks

[SteveThaiBinh]

What's happened - and is happening - about the hole in the ozone layer is indicative of two important things. Firstly, man and his activities can have a significant impact on the environment, and in ways that are potentially very dangerous for human health (skin cancer and so on). Secondly, action taken together by individuals, corporations and governments can turn such situations around.

 

Let's see the same for CO2 emissions and global warming, please.

[astr0creep]

Maybe I missed something(through the off-topic silliness no doubt) but isn't the closing of the ozone layer a good thing? Wasn't the hole itself a bad thing?

 

 

Oh I know! I should Wikify it!

 

EDIT: Ok so it's bad at low altitude, which it is both involved in the formation and removal of smog, but all fine and dandy in the stratosphere.

Edited May 24, 2006 by astr0creep

[213374U]

What's happened - and is happening - about the hole in the ozone layer is indicative of two important things.  Firstly, man and his activities can have a significant impact on the environment, and in ways that are potentially very dangerous for human health (skin cancer and so on).  Secondly, action taken together by individuals, corporations and governments can turn such situations around.

 

Let's see the same for CO2 emissions and global warming, please.

Or at least that's the impression we've got. We can curb CO2 emissions alright, since those are our emissions. But freely claiming we can stop a cyclical event from happening as it's the case with global temperature changes, is akin to saying we can prevent tsunamis or earthquakes.

[astr0creep]

Let's see the same for CO2 emissions and global warming, please. :)Or at least that's the impression we've got. We can curb CO2 emissions alright, since those are our emissions. But freely claiming we can stop a cyclical event from happening as it's the case with global temperature changes, is akin to saying we can prevent tsunamis or earthquakes.

<{POST_SNAPBACK}>

 

But we can!

All we need to do is ask God!

[taks]

Or at least that's the impression we've got. We can curb CO2 emissions alright, since those are our emissions. But freely claiming we can stop a cyclical event from happening as it's the case with global temperature changes, is akin to saying we can prevent tsunamis or earthquakes.

<{POST_SNAPBACK}>

yup.

 

several problems with the whole CO2 argument, btw. first, CO2 increases typically follow temperature rise. i.e. rising CO2 is an effect, not a cause. second, even if we were to attribute warming to CO2 increases, there is a limit. the primary mechanism attributed to CO2 in the atmosphere is absorption of otherwise re-radiated heat - at very specific wavelengths, btw - from the sun (you know, the big yellow ball in the sky where we get all that heat from in the first place). well, hate to blow the lid off this one, but that process has a limit. once you absorb all those wavelengths completely, no matter how much more CO2 you add to the atmosphere, you can't absorb any more than 100%. this function is logarithmic, and we're already near the peak. it becomes very difficult to claim increased CO2 will continue to cause warming when it is already near its full impact anyway.

 

w.r.t. ozone,

Firstly, man and his activities can have a significant impact on the environment

nobody has ever claimed man cannot impact the environment. however, equating one influence with equal relevance to another, unrelated influence is disingenuous (i'm not saying SteveThaiBinh did, just in general). such discoveries are often hailed as "see, man can influence the environment therefore XXX must also be true!" such is not always (or ever) the case.

 

taks

[Surreptishus]

What about Global Dimming?

[kirottu]

What about Global Dimming?

<{POST_SNAPBACK}>

 

I saw a document about that once... It was scary.

[alanschu]

attributed to CO2 in the atmosphere is absorption of otherwise re-radiated heat - at very specific wavelengths, btw - from the sun (you know, the big yellow ball in the sky where we get all that heat from in the first place). well, hate to blow the lid off this one, but that process has a limit. once you absorb all those wavelengths completely, no matter how much more CO2 you add to the atmosphere, you can't absorb any more than 100%. this function is logarithmic, and we're already near the peak.

 

Why would it be logarithmic? It would seem that an increase in CO2 molecules would result in a linear increase in how much absorption could go on.

[taks]

Why would it be logarithmic?  It would seem that an increase in CO2 molecules would result in a linear increase in how much absorption could go on.

<{POST_SNAPBACK}>

as you approach the limit, you need more and more CO2 to get that last bit. the example provided by junkscience is a window shade. pull one shade, and you block half the light coming into a room. pull a similar shade over the top and you will not block the rest, only half again. keep doing this repeatedly and the light in the room decreases logarithmically. the same analogy can be used with sound from a speaker. put a 3dB attenuator (power, not voltage) in the line and you lose half of your power. put another in there and you don't lose all of your remaining power, you lose half again even though it is the same size attenuator.

 

in other words, CO2 is sort of an attenuator on re-radiated heat (well, wavelengths which happen to correspond to heat). double it and you absorb half of what you have...

 

capiche?

 

taks

[Judge Hades]

I hate this whole save the planet bull****. That is exactly what it is. Bull****. The planet has been around for 5 billion years and had gone through hell. The planet wil survive for another 5 billion years. The people on is F***ed but that is okay with me.

[alanschu]

Why would it be logarithmic?  It would seem that an increase in CO2 molecules would result in a linear increase in how much absorption could go on.

<{POST_SNAPBACK}>

as you approach the limit, you need more and more CO2 to get that last bit. the example provided by junkscience is a window shade. pull one shade, and you block half the light coming into a room. pull a similar shade over the top and you will not block the rest, only half again. keep doing this repeatedly and the light in the room decreases logarithmically. the same analogy can be used with sound from a speaker. put a 3dB attenuator (power, not voltage) in the line and you lose half of your power. put another in there and you don't lose all of your remaining power, you lose half again even though it is the same size attenuator.

 

in other words, CO2 is sort of an attenuator on re-radiated heat (well, wavelengths which happen to correspond to heat). double it and you absorb half of what you have...

 

capiche?

 

taks

<{POST_SNAPBACK}>

 

Where have you heard that the reflected solar energy is already near 100% absorption? The number I remember in my astronomy class (which briefly covered it, since it was discussed when covering Venus) was 75%.

 

How would this explain the runaway greenhouse effect that was believed to occur on Venus?

Edited May 25, 2006 by alanschu

[astr0creep]

as you approach the limit, you need more and more CO2 to get that last bit.  the example provided by junkscience is a window shade.  pull one shade, and you block half the light coming into a room.  pull a similar shade over the top and you will not block the rest, only half again.  keep doing this repeatedly and the light in the room decreases logarithmically.  the same analogy can be used with sound from a speaker.  put a 3dB attenuator (power, not voltage) in the line and you lose half of your power.  put another in there and you don't lose all of your remaining power, you lose half again even though it is the same size attenuator.

 

taks

<{POST_SNAPBACK}>

 

So it's like casting Demi in Final Fantasy?

[taks]

Where have you heard that the reflected solar energy is already near 100% absorption?

uh, i did not say it was AT 100%, i said "near its peak" and, 75% is near the peak in terms of what i was saying. at least, 75% of the specific wavelength is being trapped which is an overwhelming majority, i.e. their ain't much more to trap.

 

How would this explain the runaway greenhouse effect that was believed to occur on Venus?

<{POST_SNAPBACK}>

it reached the peak, and its atmosphere is 96% CO2. ours is 0.038%. biiiiiiig difference. venus also has a much denser atmosphere to begin with.

 

taks

[taks]

So it's like casting Demi in Final Fantasy?

<{POST_SNAPBACK}>

?

 

taks

[taks]

oh, i must apologize, btw, i incorrectly referred to ozone as O, it is not. ozone is O3.

 

taks

[astr0creep]

So it's like casting Demi in Final Fantasy?

<{POST_SNAPBACK}>

?

 

taks

<{POST_SNAPBACK}>

 

 

When Demi connects in FFs the enemy's hit points are reduced by half but never to zero.

[alanschu]

Where have you heard that the reflected solar energy is already near 100% absorption?

uh, i did not say it was AT 100%, i said "near its peak" and, 75% is near the peak in terms of what i was saying. at least, 75% of the specific wavelength is being trapped which is an overwhelming majority, i.e. their ain't much more to trap.

 

Err, just a clarification...what exactly do you mean when you say "specific" wavelength. Are you implying that only 1 specific wavelength gets absorbed?

 

Also, are you taking into consideration that anything that doesn't get absorbed, gets reflected (think back to your example with the blinds. Much of the light is reflected back)?

 

I also disagree that 75% is near it's peak, especially consider that that number is an absolute value.

 

How would this explain the runaway greenhouse effect that was believed to occur on Venus?

<{POST_SNAPBACK}>

it reached the peak, and its atmosphere is 96% CO2. ours is 0.038%. biiiiiiig difference. venus also has a much denser atmosphere to begin with.

 

taks

<{POST_SNAPBACK}>

 

I'm confused here, why is reaching the peak in Venus result in the runaway greenhouse effect, whereas ours won't? Not sure what citing the CO2 values means anyways, as the theory is that, with a runaway greenhouse effect, your CO2 values will explode. Not all that shocking that after it occurs, the atmosphere is 96%.

 

This of course overlooks the fact that water vapour played a key role in Venus, as well as the fact that water vapour is the primary contributor to Earth's greenhouse effect.

[Fenghuang]

Also it's overlooking the fact that Venus is freaking weird!

 

Last I checked we still haven't figured out how the damn rock hasn't asploded from internal pressures, much less how it ended up the way it did.

[alanschu]

Outside of the distance to the sun (which is likely very significant), Venus and Earth are believed to be similar when created.

 

Though it does rotate slower, and IIRC it actually rotates "backwards." It is bizarro.

 

 

A quick check at Wikipedia indicates that it likely lost most of its water due to solar wind, which is an important thing to consider with respect to Earth. Water is an important carbon sink, and it sound like Venus was at a disadvantage from that point.

 

It's high temperature also prevents liquid water period, making sure that water vapour stays water vapour (and is an important principle of the runaway greenhouse effect). Though it seems as though most of the water was probably gonzo due to the lack of protection from the solar wind. For some reason I remembered water vapour being important on Venus, but wiki says otherwise. It has been a few years since I took astronomy :">

 

 

Oh well, we have water on Earth. Go go water!

Edited May 26, 2006 by alanschu

[Fenghuang]

Not only does it rotate backwards, it also has no tectonic plates. The thing has to have a molten core because of it's size, but no apparent way to exchange the heat.

[alanschu]

Isn't there quite the history of volcanic activity? I don't think they are too active right now, but IIRC they have two gigantic peaks that were believed to be volcanoes.

 

EDIT: That's Mars, though Venus still has a geology that displays a prevalence of shield volcanoes.

Edited May 26, 2006 by alanschu

[Fenghuang]

Not according to the Nova documentary I watched!

[alanschu]

Yeah, I had an edit.

 

The Volcanoes are on Mars.

 

Since Google searches like wiki:

 

http://en.wikipedia.org/wiki/Geology_of_Venus

 

The surface of Venus is dominated by volcanism. Although Venus is superficially similar to Earth, it seems that the tectonic plates so active in Earth's geology do not exist on Venus. About 80% of the planet consists of a mosaic of volcanic lava plains, dotted with more than a hundred large isolated shield volcanoes, and many hundreds of smaller volcanoes and volcanic constructs such as coronae. These are geological features believed to be unique to Venus: huge, ring-shaped structures 100

Edited May 26, 2006 by alanschu

[Fenghuang]

In the documentary I watched two theories were proposed as to how Venus expels heat the first was that it has lots of vents or volcanoes that constantly burn it away, this seems to have been proven somewhat recently if Wiki is to be believed.

 

The second, regarded as spurious by some scientists, is that the crust sheds itself every so often when the pressure gets too high and the stuff underneath cools and makes more. I liked that one better just because the idea of a planet shedding it's crust was cool.