Direct Radiative Forcing Scenarios

That article started off in error, so it probably isn't worht looking into further. "Carbon dioxide remains the undisputed king of recent climate change," is just false. CO2 is barely a greenhouse gas at all. The molecule can't hold much energy in a way that cn reradiate in the infrared part of the spectrum unile water vapor, methan, and some other gasses.

Maxx said:

It would be a fine thing if you were right, though I don't know what the side effects on the physics of molecules would be. Anyway, I attach a standard exposition of the standard view of the effects of CO2 in the atmosphere:

http://www.aip.org/history/climate/co2.htm

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For a gas to have greenhouse effects, it must have a dipole moment, and CO2 is no a dipole, but it can absorb a small amount of infrared, because it sometimes vibrates in a way that allows it to absorb some infrared.
http://www.ocf.berkeley.edu/~lan/globalwarming/greenhouse.pdf
http://en.wikipedia.org/wiki/Greenhouse_gas

http://en.wikipedia.org/wiki/Molecular_dipole_moment#Molecular_dipoles
The figures below are the real numbers for how much of a greenhouse gas those gasses are. In many places there are assertions that CO2 is a powerful greenhouse gas because it lasts a long time in the atmosphere, but the annual variation in the amount of CO2 suggests that CO2 typically lremains in the atmosphere for a year or two. But regardless of how long it remains, it is essentially incapable of holding infrared energy.
Typical gas phase values of some chemical compounds in debye units:[6]

• carbon dioxide: 0
• carbon monoxide: 0.112
• ozone: 0.53
• phosgene: 1.17
• water vapor: 1.85
• hydrogen cyanide: 2.98
• cyanamide: 4.27
• potassium bromide: 10.41

Maxx said:

It doesn't have to hold the energy, it just has to absorb it and re-radiate it.

As this thingy suggests:

http://wattsupwiththat.com/2011/03/29/visualizing-the-greenhouse-effect-molecules-and-photons/

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It can't absorb and re-emit, because it can't absorb the infrared.

I don't understand why people keep claiming that CO2 is a powerful greenhouse gas when it isn't. It simply does not absorb a significant amount of radiation that can be re-emitted in the infrared.

Snick said:

I don't understand why people keep claiming that CO2 is a powerful greenhouse gas when it isn't. It simply does not absorb a significant amount of radiation that can be re-emitted in the infrared.

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So what frequency does CO2 re-emit if it were in the right state to capture the energy from an errant photon? How long does it hold that energy before re-emitting it?

The information in the links suggest that CO2 does capture some amount of radiated energy in the frequencies produced by the surface. If it has a dipole of 0, how can that happen? What are the chances of a CO2 molecule being in the right state to take on heat? How does it get into the right state?

This is the stuff that the links provided seem to gloss over. One link says CO2 captures energy because of dipole differences, yet another says that CO2 is not dipole at all. That's a major incongruity.

I believe that if you look carefully at Snick's reference links, especially this one (page 25), it shows that CO[sub]2[/sub] has dipole properties that qualify it as a significant re-radiator of thermal energy.

But I don't know...I just read the thing.

This might be of interest.

http://www.mdpi.com/2072-4292/3/8/1603/pdf

Snick said:

CO2 is barely a greenhouse gas at all. The molecule can't hold much energy in a way that cn reradiate in the infrared part of the spectrum unile water vapor, methan, and some other gasses.

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Umm -- you really don't understand the science of it.

The sentence you gave makes zero sense - it is like saying "Leaving kids in a car with the windows up on a hot day isn't a problem because the windows are clear - glass doesn't hold much energy that can reradiate in the infrared part of the spectrum."

Are you seriously saying that glass can't be used to make a greenhouse because it doesn't have a dipole moment? It makes no difference!

You really don't understand how glasshouses work - or what the glasshouse effect is actually about.
The glass in a glasshouse (or the CO2) doesn't need to absorb and then re-emit it .. it simply needs to be transparent in one part of the spectrum but not in another.

So the infra-red put out by the sun is at one wavelength (because it is very hot) and is sent through the atmosphere to the ground. The ground heats up.
The ground gives of infrared radiation of it's own ... but it is at a different wavelength - because it is basically black body radiation instead of a sun.

Here's a graph of the data: http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png
If the atmosphere passed (or blocked) both wavelengths equally then there wouldn't be a greenhouse effect.

So you can see that your understanding of the science is totally wrong.

I don't understand why people keep claiming that CO2 is a powerful greenhouse gas when it isn't. It simply does not absorb a significant amount of radiation that can be re-emitted in the infrared.

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That's nothing to be embarrassed about not understanding this - science is hard. You can start the learning by reading the very light-on-science magazines like New Scientist etc - they should give you a good start.

This bit is particularly interesting - if you look at the graph of Atmospheric transmission above it isn't immediately clear that CO2 should be particularly significant.

But - when you don't understand a bit of science you need to consider two options:
1. There is a massive worldwide conspiracy among all the scientists to hide the truth -or-
2. Science is a bit harder than you think .. and you don't understand it very well

The simple version of the answer is pretty easy. Yes - water vapour is a bigger greenhouse gas than CO2. However the water vapour in the atmosphere hasn't really changed much over the hundred years or so .. and CO2 concentration has gone up by about 38% (not percentage points) since the 1950s.

It's like saying that I'm eating more now - I've been eating 38% more Pasta in the last year. When someone points out that I'm getting fatter I could argue that it isn't likely to be the pasta .. since chocolate has more calories and I haven't eaten more chocolate over the last year. Clearly it is illogical .. but it is the equivalent of someone saying "I can't see how Pasta is a 'put on weight' food compared to chocolate". Yes - logically it isn't (compared to Chocolate!!) .. but it is still probably the reason I've gotten so fat over the last year.

You also made a bizarre claim that that CO2 isn't accumulating in the atmosphere because there is an annual variation in it.
Seriously? Have you ever looked at a graph of CO2 in the atmosphere over the last 50 years? How can you make that claim? It's one of the most famous graphs in climate science!

In case you want the facts - here's the graph: http://eoimages.gsfc.nasa.gov/images/imagerecords/5000/5620/maunaloa_2004.pdf

Good luck - I hope you take the time to learn more about science. It really is fascinating.

Mac

Mac H. said:

You really don't understand how glasshouses work - or what the glasshouse effect is actually about.
The glass in a glasshouse (or the CO2) doesn't need to absorb and then re-emit it .. it simply needs to be transparent in one part of the spectrum but not in another.

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You could be a little less condescending in your posts. You'd be taken more seriously that way.

From what I've read on the subject, and the links provided by the other folks here, indicate that a greenhouse and the "greenhouse effect" talked about with regards to global warming are two different things. I've even heard climate folks say that they wished the greenhouse analogy was never used because the principles at work are completely different.

The linked materials do clearly show absorption and re-emission of the energy as a requirement for global warming.

CO2 may have increased by 38% since 1950, although that graph shows a roughly 16% increase since 1960, but nobody can say for sure what that means from an environment position. That's roughly a 0.004% increase over that time in the atmosphere. So, It's pretty easy to throw numbers around and it's pretty easy to say A increased and B increased, therefore the increase in A caused the increase in B, but that doesn't make it a fact. Yes, it takes a highly trained expert to understand all of this and again, that's part of the problem. Peer review of a lot of this work has been downright negligent, in some cases criminal. What's a layman to do?

The big problem here is that it is immensely complicated and it isn't a closed system and never will be. It's extremely difficult to study and it's impossible to model accurately. Looking at one aspect of the environment and declaring it is the root of all evil is like calling water evil because somebody drown in it.

Anyway, I'd still be interested in any answers to the questions I posted earlier.

Hallen said:

The linked materials do clearly show absorption and re-emission of the energy as a requirement for global warming.

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Absolutely - but the CO2 isn't what is re-emitting the energy.

This is a classic example of not understanding the subject - people hear the phrase 'reemitting' & 'CO2' .. and when they realise that CO2 doesn't re-emit the energy what do they do? Instead of believing that they misunderstood the science they believe that there is a vast conspiracy of every single climate scientist on the planet!

You could be a little less condescending in your posts. You'd be taken more seriously that way.

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I used to think so too.

But there are tens of thousands of climate scientists out there explaining this in detail. They are experts. They understand it.

Yet some people are still ignorant. They are ignoring the thousands of climate scientists who are experts.

Why are they doing that?

Since those ignorant deniers are ignoring the thousands of experts who are explaining things without condescension - why would you believe that the deniers would listen to me if I acted just like the other people they are ignoring?

It doesn't make sense - these ignorant deniers are ignoring thousand expert voices already.

This is a serious question - how should I communicate to make the deniers understand that they are, indeed, ignorant ?

It is not insulting to be called ignorant. Ignorant just means 'unknowing'. I am 100% ignorant on the mating habits of fleas. I am 99% ignorant on popular culture. I am 95% ignorant on our planet. I am 99.99999% ignorant on our universe as a whole.

Given the vast amount of information of our world, and the puny three score and ten we have available to learn - we are all ignorant on almost everything. The surprising thing is that people don't seem to understand this - they simply don't listen to others who have spent decades studying subjects, and instead seem to tend towards conspiracy theories.

Yes - I'm deliberately trying condescension as a communication technique. It's an experiment. I know it's an annoying experiment.

Mac

PS: To answer your questions:

So, It's pretty easy to throw numbers around and it's pretty easy to say A increased and B increased, therefore the increase in A caused the increase in B, but that doesn't make it a fact.

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That's a misunderstanding right there.

Climate scientists are not saying 'CO2 increased and temperature increased - therefore CO2 increase caused the increased temperature'. (Although you will see that argument used in laymen media articles)

Climate scientists are saying that basic physics means that increased CO2 will lead to increased temperatures - and when we look at the data of the past we see the correlation .. confirming that our model based on basic physics is likely to be correct.

It's extremely difficult to study and it's impossible to model accurately.

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You might think that it is impossible to model accurately.

Yet our models ARE accurate. Look at how well the climate model matches the predictions made back a couple of decades ago. To want 99.999% accuracy is impossible - but it models incredibly well.

Don't believe me? Look at what happened when Mount Pinatubo erupted. We did a climate model based on how that would affect the environment and it turned out amazingly accurate.

It's shown nicely in this graph:
http://www.skepticalscience.com/images/SLR_models_obs.gif
(The volcano perturbation is the bump)

So even though deniers say things like 'it is impossible to model accurately' - the weight of evidence indicates that their statement is wrong - the models do look pretty damn accurate.

Looking at one aspect of the environment and declaring it is the root of all evil is like calling water evil because somebody drown in it.

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It would be silly to say that it is the root of all evil. CO2 also has an amazingly good affect in many cases. For a start, it increases acidification in the sea which means that big chunks of Australia's Great Barrier reef will be dissolved over the next century or so. That sounds bad - but only for tourism. It will open up the area for shipping .. which is good. Climate change has also opened up more shipping lanes in the Arctic .. which is also good.

The downsides are largely because we've gotten used to our planet in a certain way and get surprised when it changes. So, for example, we built a city and planned a water catchment area to provide water for the city. Now, because of climate change, we expect that over the next 30 years or so the rainfall will mainly occur outside our water catchment area.

From the planet's point of view it is a minuscule difference - only a couple of hundred kilometres.

For our point of view - it will cost us hundreds of millions of dollars .. for that one fairly small city.

And yet there are studies like this http://www.sciencedaily.com/releases/2009/11/091110141842.htm (ScienceDaily (Nov. 11, 2009) — New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of carbon dioxide having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.)
are glossed over. The point is that the science is far from settled, regardless of what is presented in the media. I will also point out that this article states that the important part of this study is that it is from data alone and does not rely on predictive models that have generally assumed that the absorption rate would decrease over time. A real scientist is a skeptic and asks questions. That's what a lot of laymen are doing too. The answers given are condescending and contradictory. Therefore, yes, people don't accept and with good reason, apparently. Science is about study and experimentation and questioning -- except in climate science where it appears that if you question, you're a heretic.

Hallen said:

-- except in climate science where it appears that if you question, you're a heretic.

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And that's on both sides of the argument, too, hm?

Pthom said:

And that's on both sides of the argument, too, hm?

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LOL, yep, most people do prefer their own position over the other. That's all good. Reasoned discourse is good. Scientific study is good.

Hallen said:

And yet there are studies like this http://www.sciencedaily.com/releases/2009/11/091110141842.htm (ScienceDaily (Nov. 11, 2009) — New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of carbon dioxide having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.)

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Umm - you do realise that the study is simply announcing that the model used for the Copenhagen Emissions conference is ACCURATE.

Yes - accurate.

It amazes me that the article seems to be simply a reprint of the original press-release .. but somehow mangling the basic fact that it confirms the model used for the conference!

Here's the original press release:

http://www.bris.ac.uk/news/2009/6649.html

To quote the press-release:

This work is extremely important for climate change policy, because emission targets to be negotiated at the United Nations Climate Change Conference in Copenhagen early next month have been based on projections [of an unchanged carbon sink]. ...

Some researchers have cautioned against this approach, pointing at evidence that suggests the sink has already started to decrease.

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How could the media misinterpret this study so badly?

It seems that the climate-denier network seems to look for studies that use phrases like 'carbon dioxide' & 'unchanged' ... without looking to see what they are actually talking about.

Yes - the study confirms exactly what we already knew - that environment absorbs a proportion of the emitted CO2. We know that.

That is why coral reefs will face extinction - because the CO2 absorbed means that the coral can't build up the calcium anymore.

We all agree that the CO2 in the atmosphere has been going up - we've been measuring it and it is indisputable.

The concern is the future - whether the ratio will stay constant or whether some of the factors absorbing it will saturate.

This study showed that the ratio has been constant in the past while the CO2 has been increasing.

That's great. We expect the ratio won't be constant in the future, though, because we know that there is a limit to how much certain items can absorb. The standard model of ocean CO2 absorption (published 9 years before the report you quote) predicted that it would be largely linear up until 2050.

It is wonderful that this study 100% agrees with the model.

It is a terrible shame that the denier websites are claiming that studies like these are somehow supporting their claims.

Mac

It's also worth noting that CO2, while not a powerful greenhouse gas, still makes a significant greenhouse contribution because of the length of time it persists in the atmosphere. Releasing water vapor or methane into the atmosphere does little to increase greenhouse warming, even though they're far more potent greenhouse gases, simply because they persist in an imbalanced state for such a short length of time. The carbon cycle, however, is much more ponderous, giving CO2 significantly more time to "do its thing" with regard to trapping heat.

It's like the difference between ion and chemical rocket engines. The one that goes farther beats the one that goes (initially) faster.