Co2 Acquittal

[Chris C]

If it were wrong, it would only take one

Regarding the opening post and the argument therein, it's really just an extended regurgetation of the "CO2 lags temperature" argument. You will note isotopic signatures which verify today's CO2 fossil fuel source, and the fact you cannot get 100 ppmv feedback with less than 1 C rise.

This blog post (from me) may help
chriscolose.wordpress.com/2007/12/18/the-scientific-basis-for-anthropogenic-climate-change/

(throw in the http stuff before, I couldn't post the full link since I'm under 10 posts)

[InfiniteNow]

Originally Posted by Chris C

If it were wrong, it would only take one

Regarding the opening post and the argument therein, it's really just an extended regurgetation of the "CO2 lags temperature" argument. You will note isotopic signatures which verify today's CO2 fossil fuel source, and the fact you cannot get 100 ppmv feedback with less than 1 C rise.

This blog post (from me) may help
chriscolose.wordpress.com/2007/12/18/the-scientific-basis-for-anthropogenic-climate-change/

(throw in the http stuff before, I couldn't post the full link since I'm under 10 posts)

Nice job on the blog, Chris. You've done a fantastic job supporting your points and making them approachable to everyone. You have a noticably solid understanding of these issues, and you communicate that understanding better than many I've seen. Bravo.



The Scientific Basis for Anthropogenic Climate Change « Climate Change

[pmaust]

Okay guys, sorry for the long delays in my replies lots of stuff going on and to add insult to injury, I am having to type one handed since I have a cast on the other hand.

Why is so much of the focus on Co2 when water vapor is a much more potent GH gas and there are thousands of times more of it put into the atmosphere every day? According to one source I found, there is over 20,000 times more. Here for example ===> Roy W. Spencer: Global Warming and Nature's Thermostat

Here are two additional links that I found to be interesting. One is a policy discussion.

http://icecap.us/images/uploads/US_T...since_1895.pdf



http://icecap.us/images/uploads/mcka...astrophism.pdf

[InfiniteNow]

Originally Posted by pmaust

Why is so much of the focus on Co2 when water vapor is a much more potent GH gas and there are thousands of times more of it put into the atmosphere every day?

The answer to your question is that water vapor is a feedback, not a forcing. CO₂, however, is a forcing.




This link goes into pretty good detail, and also helps raise your understanding on the issue quickly:

RealClimate » Water vapour: feedback or forcing?

While water vapour is indeed the most important greenhouse gas, the issue that makes it a feedback (rather than a forcing) is the relatively short residence time for water in the atmosphere (around 10 days).

<...>

Compared to the residence time for perturbations to CO₂ (decades to centuries) or CH₄ (a decade), this is a really short time.

When surface temperatures change (whether from CO₂ or solar forcing or volcanos etc.), you can therefore expect water vapour to adjust quickly to reflect that. To first approximation, the water vapour adjusts to maintain constant relative humidity. It's important to point out that this is a result of the models, not a built-in assumption. Since approximately constant relative humidity implies an increase in specific humidity for an increase in air temperatures, the total amount of water vapour will increase adding to the greenhouse trapping of long-wave radiation. This is the famed 'water vapour feedback'.

RealClimate » Water Vapour Feedback

One important difference between water vapour and other greenhouse gases such as CO₂ is that the moisture spends only a short time in the atmosphere before being precipitated out, whereas the life time of CO₂ in the atmosphere may be longer than 100 years.

Stoat: Water vapour is not the dominant greenhouse gas

So: adding CO₂ to the atmosphere warms it a bit and ends up with more [water vapor] WV. Adding WV does nothing much and the atmos returns to equilibrium. This is why WV is not the *dominant* [green house gas] GHG; its more like a submissive GHG.

Sorry to hear about your hand. Maybe you can learn to type with your toes?


All the best.

[InfiniteNow]

Originally Posted by pmaust

http://icecap.us/images/uploads/US_T...since_1895.pdf

This article closes by stating the following:

Clearly the US annul temperatures over the last century have correlated far better with cycles in the sun and oceans than carbon dioxide.

Please recall though that correlation does not mean causation. The carrying of umbrellas is very highly correlated with rainy days, but that does not mean that people carrying umbrellas causes it to rain.

[pmaust]

Originally Posted by InfiniteNow

The answer to your question is that water vapor is a feedback, not a forcing. CO₂, however, is a forcing.




This link goes into pretty good detail, and also helps raise your understanding on the issue quickly:

RealClimate » Water vapour: feedback or forcing?

Interesting discussion about feedbacks and forcings. Thanks. It also appears that the cloud feedback issue is undergoing further study as well. See discussion here ==> Climate Science: Roger Pielke Sr. Research Group News » Positive Feedback: Have We Been Fooling Ourselves? by Roy Spencer

And here===> http://cires.colorado.edu/science/gr...oc7500/sun.pdf

[InfiniteNow]

Originally Posted by pmaust

See discussion here ==> Climate Science: Roger Pielke Sr. Research Group News » Positive Feedback: Have We Been Fooling Ourselves? by Roy Spencer

Ah yes... good ole Rog Pielke. I have encountered his name before in another GW debate thread where he said the following in conclusion to the link I provided:

Climate Science: Roger Pielke Sr. Research Group News » NOAA Cover Up Of US Historical Climate Network Surface Station Photographs

This is clearly a procedure to avoid making these photographs available. Indeed, in the papers that have been published with photographs of these HCN sites, care was taken to not publish the address or name of the observer.

<...>

The new NOAA policy is a deliberate attempt to avoid presenting this information for scrutiny.

The references, IMO, don't warrant that conclusion, and I am inclined to agree with and accept the response Roger Pielke Sr received via email from NOAA which stated the following:

Originally Posted by Email from NOAA to Roger Pielke, Sr.

The policy is an attempt to protect volounteers from harrassment by the kind of conspiracy nuts that Surface Stations is likely to inspire.

There's also this (fancy that... he's a political scientist, not a climatologist):

Roger Pielke Jr - SourceWatch.

During congressional hearings on political interference with government scientists by members of the Bush Administration, Pielke testified that Bush's actions are not different from prior administrations. It was later revealed that his testimony had been sought by Republicans on the committee.

<...>

Pielke is regularly cited by conservative activists to undercut the science on global warming and policies that might mitigate climate change.

<...>

A study he published in the journal Proceedings of the Philosophical Transactions of the Royal Society contains numerous references that were not peer-reviewed.

The main citation for the paper is a study that Pielke published in the skeptic journal Energy and Environment which not carried in the ISI listing of peer-reviewed journals. A review of the paper finds that Pielke cites the Energy and Environment study four different times in his latest paper.

<...>

At the 2007 Fall meeting of the American Geophysical Union, Pielke Jr. gave a joint presentation on hurricanes and climate change with global warming skeptic Stephen McIntyre.

McIntyre's is another name favored by skeptics and thoroughly debunked by experts in the field. However, to his credit, he did find an error in a data point regarding temperature in the early 20th century and he contacted NASA to have it corrected. The rest of his work, unfortunately, is wrought with falsehoods and misrepresentations.

Originally Posted by pmaust

And here===> http://cires.colorado.edu/science/gr...oc7500/sun.pdf

You'll notice that this was never published in a peer reviewed journal. That should be your first clue to it's validity (or lack thereof).


Cheers.

[Chris C]

Hello pmaust, I don't have much time but let me respond briefly to your comments and links

To say water vapor is not a dominant greenhouse gas is incorrect (the name of one of Infinite's links). In fact, if you remove all the water vapor you can easily simulate a snowball earth, and taking it away results in a reduction of around 60% of the longwave absorbed. (See table 3 Earth’s Annual Global Mean Energy Budget)

However, "greenhouse gas," or "greenhouse effect," and "global warming" are two different things. "Feedback not a forcing" is a good simple answer, and is indicative of water vapor's strong impact on the temperature, but it does not provide any answer for the "change in" temperature observed over the last century. Global warming is about the change. And water vapor follows along with any temperature change, amplifying that change in the way it was going. Just to advertise my blog again, see my post at "Basic Radiative models/Earth’s climate system analysis Pt. 2"

There, I talk a bit about the radiative physics of the greenhouse effect, and the relationship of water vapor to temperature, and its role in climate change. If you have any comments, criticisms, questions, let me know.

Regarding the first icecap reference by Joseph D’Aleo, this link actually does not discuss the global mean temperature, but the United States mean temperature (tricky, eh). However, the third graph in that link refutes the basic premise of the post (the article is clearly not intended for those familair with radiative physics, but people who just like to see lines going up together). Note the Y axis for the TSI. At most, I would say you can get 2 W/m^2 of a change in TSI (total solar irradiance) from the pre-industrial time. To convert this into a radiative forcing on Earth, you need to divide by 4 (for the geometry of the Earth), and multiply by 0.69 to account for the albedo of the Earth. Ideally, you'd still need to account for efficacy, and the UV radiation absorbed at the stratosphere which would further lower the number, but this is typically not done in the primary literature: So you end up with around .35 W/m^2 of radiative forcing, compared to the 1.66 W/m^2 from just CO2. This is past the high end in the IPCC document, because IPCC is relative to 1750, and the ΔTSI of 2 W/m^2 is probably high. Here is the IPCC forcings chart


Regarding Spencer's post, there are much better sources out there. The first points on water vapor are addressed in my blog, and if you want more reliable sources than me, I can reference you to several from the peer review that refute the "Water vapor overwhelms CO2" nonsense. There are a lot of other claims in his post- some true, some false. The literature does not support his point on the medieval warm period, and that really has nothing to do with what is causing it today. The post itself seems to come down to his view on feedbacks. Spencer ( I think) notes somewhere in there that the temperature change is about 1 degree with just 2x CO2 increase (1.2 C actually). That part is basic physics. What is more uncertain is feedbacks, notably cloud responses. There are many cloud feedbacks, on amount, height, optical thickness, etc., and different for different cloud types and at different latitudes. Overall, today's models produce cloud feedbacks ranging from approximately neutral to strongly positive. There could be an overall negative cloud feedback but it couldn't be very strong, because we have data that show that overall low clouds, which control the albedo more than any other kind, get thinner when it gets warmer.

There are several academic sources which go over this,

Pubs.GISS: Abstract of Bony et al. 2006
http://www.gfdl.noaa.gov/reference/b...06/bjs0601.pdf

and the free,online book from the NAtional Academies
Understanding Climate Change Feedbacks

Ch. 8 in the AR4 is also a good place to start.

There is no question that cloud feedbacks are uncertain and that modeling them is hard -- I don't think that anyone has ever seriously claimed otherwise. Another thing is that to argue for the 3 C rise per 2x CO2 by the IPCC, you do need to argue for a positive cloud feedback (the range is 2-4.5 C, and real world observations are putting confidence in this rather than wishful thinking). Putting faith in Spencer's rather contrarian view that we will be saved by a hypothetical strong negative feedback (also pushed by Lindzen) is not much better.

chris
And sorry for the link format, still a few more posts to go (Moderator note: per suggestion, made url references into links)

[InfiniteNow]

Originally Posted by Chris C

And sorry for the link format, still a few more posts to go

Maybe a moderator or admin would be willing to edit your post and put proper links in on your behalf? (Moderator note: good suggestion - did it)

[Turtle]

Mary, Mary,quite contrary,
how does your garden grow?
With silver bells, and cockle shells,
And pretty maids all in a row.

CO2 acquital is, as CO2 acquital does.

Global Warming: A closer look at the numbers

Just how much of the "Greenhouse Effect" is caused by human activity?

It is about 0.28%, if water vapor is taken into account-- about 5.53%, if not.

This point is so crucial to the debate over global warming that how water vapor is or isn't factored into an analysis of Earth's greenhouse gases makes the difference between describing a significant human contribution to the greenhouse effect, or a negligible one.
...
The Kyoto Protocol calls for mandatory carbon dioxide reductions of 30% from developed countries like the U.S. Reducing man-made CO2 emissions this much would have an undetectable effect on climate while having a devastating effect on the U.S. economy. Can you drive your car 30% less, reduce your winter heating 30%? Pay 20-50% more for everything from automobiles to zippers? And that is just a down payment, with more sacrifices to come later.

Such drastic measures, even if imposed equally on all countries around the world, would reduce total human greenhouse contributions from CO2 by about 0.035%.

This is much less than the natural variability of Earth's climate system! ...