A recent set of posts at Anthony Watt’s blog, particularly this one has sparked some interest over the internet as of late. From a quick glance, it looks like negative trends in specific humidity over the last half a century. Readers were quick to pick up on the connection to water vapor feedback, which is expected to at least double the sensitivity of climate to external perturbations (e.g., by human released CO2).

The accepted theory of water vapor feedback in climate change is that in a warming world the global relative humidity will not change much, and an increase in temperature with little change in relative humidity means an increase in specific humidity. So any increase in temperature caused by something (maybe CO2, increased solar irradiance, etc) increases the saturation vapor pressure which allows water vapor concentration to go up, which further amplifies the greenhouse effect since H₂O is also a strong greenhouse gas being the most important gaseous source of infrared opacity in the atmosphere. Most of the water vapor feedback relevant for global warming occurs in the upper layers of the atmosphere, which are considerably drier than the boundary layer. Only about 10% of the water vapor feedback is from below 800 mb.

So what do the plots in Anthony Watts blog show? Well, they show specific humidity as a function of time, with multiple graphs corresponding to different altitudes in the atmosphere. For example, at 700 mb

600 mb

and so on…

The figures come from plotting annual specific humidity at global coverage from this site. Now where is this data coming from and how exactly does it relate to reality? The constructed timeseries is from the NCEP Reanalysis Dataset. The goal of the NCEP/NCAR reanalysis project is to “produce new atmospheric analyses using historical data (1948 onwards) and as well to produce analyses of the current atmospheric state.” Application has been used to process multi-decadal sequences of past observations using modern data assimilation techniques, which brings its share of observational and model problems (coverages and bias varying over time, biases in background forecasts which are combined with observations over a short time period to get an analysis of the state of the atmosphere, etc). Radiosondes provide water vapor information in the atmosphere since the 1940’s, but earlier products had a lot of biases, and since then changes in instrumentation have taken place which may lead to discontinuities in the data, and problems arose especially for upper atmospheric data. Reanalysis products contain discontinuities from changes in observational data available, changes in error characteristics of data, changes in sampling, better assimilation techniques, and other things. These make them virtually unusable for examining trends and low-frequency variability. Reanalysis products are not reliable sources for trends on water vapor, precipitation, clouds, etc though estimates other climatic variables like temperature do well after the satellite era. Here is a quote from Soden et al (2005),

“Although an international network of weather
balloons has carried water vapor sensors for
more than half a century, changes in instrumentation
and poor calibration make such
sensors unsuitable for detecting trends in
upper tropospheric water vapor (27). Similarly,
global reanalysis products also suffer
from spurious variability and trends related to
changes in data quality and data coverage (24).”

Satellites are a nice tool though. By measuring the upwelling radiance in different spectral bands which water vapor absorbs, you can obtain measurements of water vapor concentrations in various parts of the atmosphere. The Soden paper, for example, uses satellites to detect upper tropospheric moistening from 1982 to 2004 as evidenced by changing emission levels in T12 (the High Resolution Infrared radiation sounder channel 12) because of increased opacity to water vapor. As the IPCC AR4 report discusses in Chapter 3, interannual variability is not often captured well by reanalysis techniques, even after the satellite era. Probably the best paper discussing upper atmospheric trends is the above paper, and IPCC AR4 (Chapter 3) also summarizes the literature and supports the conclusion of no detectable changes in relative humidity, but trends in increased specific humidity.

Putting aside the data and model conclusions, from a purely theoretical framework, a lack of water vapor response to global warming (especially in the upper troposphere) would mean a very insensitive climate system, as the discussion here (see final figure as well) goes over. The water vapor effect also works in sync with other feedback effects. For example, more water vapor means more warming which means more of an ice-albedo effect, and that in turn means more warming. If climate sensitivity were very low (they would be on the low end of the IPCC scale, or lower if the WV feedback effect was not substantial) then we would not be able to explain the variability over the paleoclimatic record, or the 20th century rise. But as a lot of research has shown (see empirical evidence by James Annan for instance) there is unlikely to be anything wrong with the estimates of 2 to 4.5 C per doubling of CO2. Overall, I’ve not been convinced that there is anything significantly wrong with our understanding of water vapor feedback, or that (as some of Watts’ readers proclaim) that this is some nail in the coffin for AGW.

Although global temperature rise is widely discussed concerning the severity of climate change, a more societally relevant concern is how weather and climate will vary at the local and regional level. Temperature rises over very large spatial scales (e.g., a hemisphere or the globe) do not imply uniform changes of various climatic variables (hurricanes, droughts, storms, etc) but we should expect global inhomogenities in climate as greenhouse gases build up in the atmosphere. For example, changes in global mean precipitation (or evaporation) are not incredibly large in a warmer world; models tend to agree that there is a less than 2% increase per degree C global mean warming. However, changes in horizontal transport and increased precipitation gradients (drier areas getting drier, wetter areas getting wetter, droughts in areas, flooding in others, etc) are a big reason for concern. What’s more, people will inevitably be concerned about the likelihood of extremes, such as the possibility of more anomalous events like the European heatwave of 2003.

The first federal review of research on how global warming may affect extreme climate events in North America is available here. Regions of focus include North America, Hawaii, Caribbean, and U.S. Pacific Islands. A summary of findings below:

– Over most land areas, the last 10 years had lower numbers of severe cold events than any other 10-year period.

– In North America, the 1930’s remain the most severe in terms of unusually hot spells, but there is an increasing trend since mid-century. The ’30s in the U.S. were a very extreme regional warming event, and we’ve not yet approached a point where the global pattern exceeds such extremes, but we’re approaching them. In Mexico, the 1950s and 1994-present were the driest periods.

–Extreme precipitation episodes have become more frequent and more intense in recent decades than at any other time in the historical record

– For increases in area affected by drought, there is no overall average change for North America, but regional changes are evident.

– The observed relationship between increased intensity of Tropical Cyclones and rising ocean temperatures is robust. In terms of the focus of this report, increases are substantial since about 1970 in association with rising Atlantic SST’s. Increasing tendency in West Pacific and decreasing tendency in East Pacific (Mexico West Coast) since 1980.

– Decreased snow cover in United States. Decrease in snowstorms in the South and lower Midwest of the United States, and an increase in snowstorms in the upper Midwest and Northeast.

– It is very likely (IPCC standards) that there will be warmer extreme cold days and nights and fewer frosts, warmer nights (and probably further decrease in the diurnal temperature gradient), more frequent and intense heavy downpours, more frequent heat waves and warm spells, increases in area affected by drought (particularly in the Southwest), and possibly increases in hurricane intensity due to rising SST’s. Changes in precipitation extremes will be pronounced, and more evaporation leading to droughts in other areas.

– In terms of attribution, anthropogenic warming has likely caused much of the average temperature increase in North America over the past 50 years effecting temperature extremes, very likely caused increases in Atlantic SST’s, and also are responsible for increases in water vapor concentration.

Concerning extremes, there may be some benefits, but the report says “But on balance, because systems have adapted to their historical range of extremes, the majority of events outside this range have primarily negative impacts.”

“Actions that lessen the risk from small or moderate events in the short-term, such as construction of levees, can lead to increases in vulnerability to larger extremes in the long-term.”

Same crap, different year, different number. Arthur Robinson and co. strike again. At first, it was the 19,000 signatories for the Oregon Institute of Science and Medicine (OISM), and now they’ve jacked the number up to over 31,000 “scientists” who signed a petition against the AGW consensus. The phone book is cute, but personally I’d prefer one person with real science and data, as opposed to 31,000 people supporting scientific hogwash. The science in their “peer-reviewed” publication is easy enough to invalidate, and carries its share of looking at regional temperature (as opposed to global), throwing up strawman attacks (no one expects global temperatures to follow hydrocarbon emissions), and refuting themselves in the process (like their solar radiative forcing graph, which would be converted into a temperature anomaly that is negligible). But, surely Chris doesn’t know more than all of these 31,000 scientists, right? Well I did a quick survery of these “scientists” and report as follows:

Of 60 samples (including 54 phD’s), there were a grand total of zero publications behind the sampled signatories that were relevant to climate or climate change. None has specific background in meteorology, climatology, oceanography, etc and just two with a geology background (including one who is now deceased).

My subsample was the first 10 people of the petition, and the first two of each subsequent letter (ten from A, two from B, two from C…two from Z). I actually did a bit of cherry picking, but only to help out there side a bit more, so starting from “B,” I chose the first two people who were listed as phD’s. I looked at their publication records by the criteria of typing their name in the “search by author” box in Google Scholar. So, here we go
A

1) Earl M.J. Aagaard - Professor of Biology

Research Interests:
Intelligent design (we’re off to a great start), Relation of Man to his environment

No publications relevant to climate

2) Charles W. Aami
Can’t find him anywhere on google, with a few different terms.
Charles W. Aami
“Charles W. Aami”
“Charles Aami”
Apparently no publications, nor anything relevant to climate

3) Roger L. Aamodt
Looks like someone from the National Cancer Institute
Here and Here
No publications relevant to climate

4) Wilbur A. Aanes
Veterinary /Large Animal Surgery
No publications relevant to climate change

5) Robert Aaron (now deceased)

Electrical Engineer/Telecommunications
Here and Here
No publications relevant to climate

6) Ralph F. Abate

in the area of bridge design, and also runs student bridge contests (which I’m sure allows him to make judgments on the errors in the scientific community on climate change)
Here and Here
No publications relevant to climate

7) Hamed K. Abbas
Research Plant Pathologist, food safety
No publications relevant to climate

8, Paul Abbett
Can’t find much on google, with a couple of search terms
“Paul Abbett”
Paul Abbett AND climate
No publications relevant to climate

9) Wyatt E. Abbitt III
Same thing,
and zero publications

10) Ursula K. Abbott
In Avian Wildlife/Avian Genetics
No publications relevant to climate

Remember, everyone from here on out has (or should have) phD’s.

B

1) Dirk Den Baars
Looks like the guy is now deceased for several years, but specialized in exploration and mining of copper, precious metals, and industrial minerals, from here and here. Looks like he has some interesting World War 2 stories though.
No publications relevant to climate

2) Ronald R. Bach
Medical (health) Field / Oncology

No publications relevant to climate

C

3) Fernando Cadena- Civil Engineering
No publications relevant to climate

4) Fernando Cadena, C (different guy I suppose)

Inventor , and looks like he is looking to remove arsenic from water

No relevant publications to climate

D

5) Hugo C. da Silva

There is a Hugo C Da Silva Jr who recently graduated in nuclear engineering. But there is no “Jr.” in the petition, so it could be Hugo C. da Silva the sales associate/real estate guy. Doesn’t look like a phD though, but no matter which guy you want, no publications on climate

6) John W. Dabbs

Another strange search…I’ll let you take your pick.
You can have John W. Dabbs the guy who died in 1919, the family genealogy guy , or the medical guy. The last guy might be the more impressive choice (Though that is an M.D., not a phD) but regardless, none of them have any publications on climate

E

7) Joseph Jackson Eachus-
Couldn’t find much , but I think some poor guy is trying to get some information on him on one of them ancestry sites. In any case, no publications relevant to climate

8, Robert John Eagan

Not a lot of luck either, a search search with just his name gave no results- Played around with the name a bit (Robert J. Eagan) and I found a guy in nuclear power, a guy for Southwestern Electrical cooperative and one lawyer. I found no phD’s, but I also found no publications in climate

F

9) Michael William Fabian
Can’t find him, but he might be involved in OSU’s biological department. No publications relevant to climate

10) Thomas John Fabish

Looks like a bandconductor. The band guy seems to be the more famous one, but if you don’t like him, there is the guy from the Paint and Coating Resource Center. No publications in climate.

G

11) Steven Alexander Gaal- Involved in the mathematics geneaology project. Looks like a guy from back in the 1940’s, and no publications relevant to climate

12) P. S. Gaal
Looks like the guy is involved in the advancement of the transport properties of materials. Deals with thermal conductivity in materials, thermal diffusivity, etc. No publications relevant to climate

H
13) Gottfried Haacke
Looks like an inventor. Has patents on narrow band radiation films. Perhaps worked on windows that absorbed solar heat (on greenhouses for instance). No publications relevant to climate

14) Ronald L. Haaland
In agronomy and deals with plants/soil. Or he could be a real estate agent. No publications relevant to climate

I

15) Michael John Iatropoulos
Department of Pathology, expertise in toxicology. No publications relevant to climate

16) Icko Iben, Jr
Professor at Universtiy of Illinois (Dept. of Astronomy) with expertise in the structure and evolution of stars . A good publication record, but nothing on climate

J

17) Robert B. Jacko
Professor of civil engineering. Research interests are air pollution management and control, transportation noise problems, environmental occupational safety and health. Looks like he has some background in environmental problems ( I spot one publication on ozone modeling), but nothing on climate/climate change

18, Harold Jackson

founder and president of The JacksonHeath Group Inc., (I quote). “an international communications and management consulting agency established in 1990 that has provided strategic counsel to corporate CEOs, government officials, college presidents and dignitaries across the country and abroad.” No publications relevant to climate

K

19) Robert Kabel

Kabel does consulting work, and represents clients before Congress, Executive Branch departments and agencies, independent agencies and the White House. There is also a Robert L. Kabel who is in chemical engineering, though no publications anytime recent. All around, no climate expertise.

20) T. Theodore Kadota
Some different guys here. Possibly one in Spatial Statistics and Digital Image Analysis, another guy in Mathematical and Algorithmic Sciences Research Center from 1966-1994. Maybe the same guy, who knows.
No one with publications pertaining to climate

L

21) Peter La Celle
Department of Dermatology, member of Cancer Center at University of Rochester. From his publications linked inside, nothing to do with climate.

22) Timothy La Farge
This guy seemed interesting. If it’s the same guy in these publications, then he seems like he is into forestry (no work on climate). He has a couple of writeups in some obscure sources (and supporting some obscure material like geocraft.com, and Lindzen’s wall street journal article) on global warming, which are far from impressive.

M

23) Robert P. Ma
Sorry, couldn’t find anything on this guy. Certainly nothing relevant to climate.

24) Tso-Ping Ma
Department of Electrical engineering . Interested in technological issues related to semiconductor devices. No publications relevant to climate

N

25) Misac Nabighian
I suppose this is as close as we get to a goody. Dr. Misac Nabighian is a senior researcher in the department of geophysics at Colorado School of Mines. Research interests are Potential and electromagnetic fields in Geophysics: theory, data processing and interpretation. No publications relevant to climate.

26) Robert E. Nabours
Consulting Electrical Engineers. No publications relevant to climate.

O

27) Robert Quincy Oaks Jr
Couldn’t find anything on him here. I tried a few different search terms, but the guy doesn’t seem too popular. I get no publications relevant to climate (or anything)

28, Deborah O’Bannon
A civil engineering proferssor. She was also awarded the “Fellow Grade of the Society of Women Engineers for her empowerment of women in engineering.” No publications relevant to climate.

P

29) J. Pace

Hard to do much without a first name, but I googled J. Pace AND climate and got nothing. Miraculously, this guy seems to be another nobody. If anyone knows Dr. Pace, I’d love to hear it.

30) Gilbert E. Pacey
Professor at Miami University in the Center for Nanotechnology, Department of Chemistry and Biochemistry. No publications relevant to climate.

Q

31) Forrest W. Quackenbush
Into biochemsitry. Looks like a lot of work in biology and chemistry involving genetics, cellular level stuff, etc, but nothing on climate

32) James R. Qualey
The guy looks like he knows his stuff about smoke detectors, and appears to be a principal systems engineer. Unless the fire alarms have something to do with more forest fires in a warming world (maybe he’s preparing us all), he doesn’t seem to have any involvement with anything pertaining to climate

R

33) Bernard Raab
Couldn’t find anything really. He had a reply to a post about finding intelligent life in the universe where he says he’s a retired physicist. I don’t see anything of a publication record, let alone anything to do with climate.

34) F. H. Raab
Works with amplifiers and Transmitters. Cited in work on electronics, radio engineering, wireless communications, etc. No publications relevant to climate

S

35) Patrick Saatzer
Received his phD in Chemistry. Some publications on photochemistry of saturated molecules, but nothing on climate.

36) Burns Roy Sabey
Looks like he’s involved in soil science, and has am Introductory Experimental Soil Science book. No found publications on climate

T

37) Widen Tabakoff
Professor of Aerospace Engineering & Engineering Mechanics . No relevant publications (on his page) to climate.

38, Ronald Dwight Tabler
Check out Tabler and associates involved in engineering for snow, sand, dust, and wind control. No publications relevant to climate. Though, he has some work on the effects of snow fences on crashes, controlling blowing snow with fences, etc…maybe it’ll come in handy with climate change…who knows.

U

39) Herbert M S Uberall
Knowledge in scattering of soundwaves and acoustics. Now a retired professor, as they announced in The Journal of the Acoustical Society of America . No publications relevant to climate.

40) Waheed Uddin
Professional in research and instruction, design, construction, maintenance management of highways and airports, sustainable development, and related areas of transportation engineering. Degrees in engineering. Publications in infrastructure management, but nothing to do with climate .

V

41) James P. Vacik
In Pharmaceutical area, here and from a college of pharmacy. To me astonishment, he has no publications relevant to climate

42) Juris Vagners
Retired professor in Aeronautics and Astronautics department. Degrees and teaching in engineering disciplines. Of course, no publications relevant to climate

W

43) William R. Wachtler
Patent of a Liquid processing and sorting system…interesting. Publications relevant to climate: zero

44) William Howard Wade
Couldn’t find anything scientific related. Some stuff on that family history and genealogy stuff. No publications relevant to climate

45) Ning Xi
degree in Systems Science and Mathematics, an M.S. in Computer Science, and background in engineering. Research interests include robotics, manufacturing automation, micro/nano systems, and intelligent control and systems. From his publications page (inside), nothing relevant to climate.

46) Y. Xie
A hard search term, and I got a few things, none of which was relevant to climate. Best bet is in biology.

Y

47) Dmeter Yablonsky
Mathematics professor for Pace University. No publications relevant to climate

48, Richard Howard Yahner
If it’s the same guy, Professor of Wildlife Conservation and Assistant Director for Outreach. Interests are in Wildlife ecology and conservation biology in forested and human-induced landscapes and ecosystems. Has publications in ecosystems, but not climate.

Z

49) Robert V. Zackroff- Microbiologist
Massachusetts College of Pharmacy and Health Sciences. No relevant publications on climate

50) Daniel J. Zaffarano (retired)
Involved in physics (Science Education K-12, retired Dean of Graduate College and Vice President, Research). Looks like some interesting stuff on Beta and Gamma Rays, but no publications relevant to climate.

Update- Apparently there is a Robert Quincy Oaks Jr. here and at least some papers in stratigraphy (back in the 1960’s, he’s retired now).

The IPCC AR4 report has concluded that atmospheric carbon dioxide has reached levels that are higher than anytime during the past 650,000 years. That was a recent update to the literature just several years ago which only went back 420,000 years. These results are supported by ice cores from Antarctica which trap bubbles of ancient atmosphere and allow for confident reconstructions of ancient climates. In the latest issue of Nature, members of the European Project for Ice Coring in Antarctica (EPICA) present the latest, and longest, record from ice cores which extend to 800,000 years. The glacial-interglacial, carbon dioxide, and methane cyclicity remain similar to the previous reconstructions, and the correlation of greenhouse gases to temperature also remains very firm. The latest graph on this is below, from Lüthi et al 2008 (click for enlarged image).

_{Roman numbers and Italic numbers represent glacial terminations and Marine Isotopic Stages}

Of interest here, is the unusually low levels of carbon dioxide during the two earliest glacial–interglacial cycles. The authors seem confident that they have the CO2 levels right, which extends the pre-industrial CO2 range from about 172–300 ppmv. There could be a long-term CO2 increase by about 25 ppmv from 800 to 400 kya BP, and a long-term decrease of 15 ppmv during the past four glacial cycles, which the authors suggest may be indicative of long-term variations in the carbon cycle on orders of hundreds of thousands of years. CO2 may have reached an absolute minima at 667 BP, though there is slight discrepancy between CO2 concentration measured at University of Bern (172 ppmv) and Grenoble (178 ppmv).

In the recent literature, as well as in the supplementary information in this paper, the infamous “CO2 lag” may be overestimated by some hundreds of years, so the 800 year lag at Termination V may be something like 300 years. In interesting case is during MIS 14.2 (~550 kyr BP), CO2 preceded temperature by about by a little over 1,000 years. Like many other of the ice core record papers which are blown out of context, the authors emphasize the role of CO2 as a positive feedback on temperatures supporting its greenhouse role.

Meanwhile, methane (See Loulergue et al) has fluctuated between around 350 and 800 parts per billion by volume (ppbv) over glacial-interglacial cycles, but over 1,770 ppbv during present day. Interestingly, methane seemed to follow the eccentricity signal more during the earlier cycles, but the methane levels appear more precession-paced since ~400 kya, which is likely due to changes in wetlands, monsoon systems, and ITCZ.

In other news, and going far away from the ice core record to the Paleocene-Eocene boundary around 55 million years ago, δ¹⁸O records show an abrupt spike when temperatures soared by 8° to 10°C in high-latitude sea surface temperatures, and 4° to 5°C in bottom water temperatures and tropical SST’s (Zachos et al., 2003). A major negative carbon-13 isotope bump also shows up in proxy records, signifying a massive release of isotopically light carbon, which gives clues to the cause of the dramatic temperature anomaly. Possible sources could have been from methane (decomposition of clathrates on the sea floor), CO2 outgassing from volcanoes, among other things. The mass extinction of benthic species at the time was probably a combination of thermal stress and ocean acidfication. In this latest paper by Panchuk, Ridwell, and Kump, the authors suggest that methane alone could not have caused the calcium carbonate dissolution in the oceans estimated from sediment layers, so a large external forcing from CO2 (perhaps a carbon pulse of ~6800 gigatons) helped out. This would enhance the greenhouse effect significantly, but a lot of that carbon would be removed by the oceans within a thousand years reducing the effect, but data suggests that the PETM lasted perhaps 200,000 years. A very large impulse of carbon would have been needed to sustain the warming over millennial timescales given that ~80% of it would be removed by the oceans in around 1,000 years.

Interesting week. Not too much to be excited about though as we keep burning fossil fuels, and nothing new for policy makers to hear.

So it appears that Florida has now decided to actually teach science in their science classrooms. After a February 19th vote, the United States science curriculum made the improvement from worse to bad, now allowing the young padawans to learn evolution in class. The infamous motto of “Teach the controversy” (like gravity and cell theory) won 4-3, but of course with the scientific caveat that “it’s just a theory.”; my guess is that lecture begins right after discussing “hypothesis,” “theory,” “law” definitions in chapter 1. Now, reading this new Nature article, it looks like the Institute for Creation Research wants to grant online master’s degrees in science education in Texas. But I loved the next line, which reads, “The ICR accepts the Bible as literal truth on all topics. According to its website, the palaeoclimatology class covers “climates before and after the Genesis Flood”". Maybe someone like Paul Reiter can moan about the IPCC not covering creation paleoclimates in the report…too bias I suppose.

Chris Colose even finds a book here. There you go, now we don’t need to hear about “CO2 lagging temperature” anymore. From our interpretation of the “young ice cores” the CO2 levels and temperatures fluctuated significantly over just a few thousand years…we’ve even gone through several ice ages since the global flood. Aside from the obvious climate pitfalls of a young ice sheet hypothesis, the other argument reads like “there were WW2 planes found deep in the ice sheet” so it must be a young ice sheet, but this discounts the fundamental fact that glaciers flow and so ice at the bottom is much more compacted than ice at the top. This means one meter of ice core at the bottom represents a much longer amount of time than one meter of core near the top.

So what about that global flood?

As far as I know, the leading creation hypothesis for a global flood (or the source of water for that flood) is a canopy of water in the atmosphere. What kind of climate implications would this vapor canopy have?

First of all, the atmospheric pressure caused by the amount of vapor in the atmosphere needed to flood the Earth would by far and away overwhelm that of even Venus, and would be similar to that of the deep ocean. This would have made a pancake out of Noah and company. Modern day air pressure is roughly 1 bar. It only takes a few centimeters of precipitable water to saturate a column of air at Earthlike temperatures, and much less to saturate air aloft, because of the adiabatic lapse rate cooling with altitude. It would take kilometers to create the waterworld of Noah.

There would be many effects on temperature. For the greenhouse effect, water vapor in the mid to upper troposphere is more important than water vapor near the ground. Low clouds or vapor have a modest longwave effect because the temperature is similar to the surface. In contrast, high clouds and upper level water vapor has a considerable longwave effect. If you’re to add a cloud in the boundary layer, from the perspective of the top of the atmosphere (TOA) there is very little change on the planet because the temperature of the lower clouds is basically that of the surface, and since from the TOA perspective, the planet is in energy balance you don’t need to get warming. The low level stuff “looks” just like the surface, and only wavelengths through the “atmospheric window” get by the lower levels. Because they look radiatively like the surface, the energy out changes little (in fact the large influence from a low cloud is on the incoming side, from the albedo effect).  High stuff has much more of a longwave effect because the temperature is considerably colder, and you start to introduce water vapor where there was none.  In the case of clouds, they will block some IR that comes from all lower layers of the atmosphere.  The water vapor canopy would need to extend to the upper atmosphere, and in doing so would create an extremely large greenhouse effect.  However, it would also have a cooling component by increasing the planetary albedo from sunlight reflection. The net effect would surely be to warm, but no large climate jumps are apparent in the proxy records, and no evidence for any global flood. At sufficiently high pressures, the diatomic gases will also act as greenhouse agents from collision-induced absorption.

If there are no other greenhouse gases, then the OLR for a dry case (zero relative humidity) is just σT_g^4. But, at larger RH, the curve of the OLR (T) begins to flatten at high temperatures, making the climate much more sensitive to radiative perturbations (reminder of the Kombayashi-Ingersoll limit in Greenhouse effect part 2. Not exactly a runaway effect, but much hotter. Further, when vapor condenses into water, it releases the same amount of heat which originally turned it into vapor. The water vapor canopy would release enough latent heat to burn up the guys on the ark, and the millions of animals with them. The temperature changes at the surface would be a competition between latent heat of vaporization and increased longwave absorption, and reduced sunlight at the surface.

A further question for the vapor canopy assuming a habitable Earth is how enough water got there? Because of the Clausius-Clapeyron relationship, with relationship between vapor pressure and temperature being

ln P₁/P₂ = dH_vap/R [ (T₁ - T₂)/T₁T₂]

where P is the vapor pressure. Essentially, for the amount of vapor needed to flood the world, the temperature would need to be much, much hotter (not habitable) to prevent condensation, since the saturation vapor pressure increases nearly exponentially with T. At Earth temperatures and pressures, water diminishes rapidly with height because of temperature drop, and saturation in the atmosphere quickly leads to a cloud, and precipitation.

There are some other theories for the source of water, like runaway subduction and bursting from the crust. None stand up well, but it is also neat to see the “what ifs” in climate and other geological thought experiments.

FICTION ATMOSPHERES IN THE MOVIES

Just as ridiculous as the overhanging vapor canopy, are some other neat climates presented on television. Of course, at the top of the list is The Day After Tomorrow. In this movie, there is a “shutdown” of the North Atlantic circulation (to their credit, they didn’t say Gulf Stream). This is not unreasonable, but what follows is an overnight freeze down to at least the middle of the United States. What can we say about the THC shutdown often discussed on the internet? A rapid, large reduction in north Atlantic circulation appears very unlikely (10% chance, according to IPCC) but surely not impossible (it happened before). Unfortunately, putting an exact number on the freshwater flux required for a shutdown is not possible right now; although the broad picture of deepwater formation is known and modeled, the details are not, and such details are required to get quantitatively accurate numbers. There is a decline though over time in models (maybe next century for a shutdown); what happens with a shutdown depends on when the shutdown is, because if you got one tomorrow, then there would be cooling in certain places of the North Atlantic (not global), but if you get one next century, then that is likely to be overwhelmed by the increased CO2. In any event, it would most certainly not cause an ice age. Because ocean circulation transports heat from the warm tropics to the cooler high latitudes, a reduction of that transport would cause anomalous cooling in certain areas (more snowblowers in Europe from harsher winters), but not glacial conditions. Moreover, because of the immense volume of the water and the time it takes to gain/lose heat, as well as the response time of ice, it would take a minimum of decades to get abrupt climate changes. Even if the sun shut off, you don’t get “The Day After Tomorrow” tomorrow. “Abrupt” is a word compared to geologic changes. If I recall right, there were also hurricanes forming in the arctic…that just doesn’t happen because of the low SST’s.

One interesting planet is in Star Wars Episode 2, where our cloner friends, Jango Fett, and Obi Wan enjoy a planet which I get the impression is covered in water, and is characterized by constant rainfall. There is no silicate weathering, no volcanoes, so depending on the solar conditions, the planet will swing into a runaway greenhouse or a snowball planet in a geologically short period of time. As I mentioned with the water vapor canopy, there is not that much water in a column of air, and at a habitable range of temperatures you cannot get never-ending rainfall. To sustain evaporation would require solar input of thousands of W/m2 which would bring the planet into a runaway greenhouse state.

The very dry but habitable planets such as Tatooine (Luke’s home) or in the movie Dune are also good for a short time. Because of the very high albedo of sand, the planet must be greenhouse-enriched or close to the sun (or two suns in Tatooine’s case). Unfortunately, with no water on the surface, the silicate weathering processes that remove CO2 from the atmosphere will not occur. When CO2 dissolves in water it forms a weak acid which reacts with silicate minerals to form carbonate minerals (e.g. limestone), but with no water, CO2 will just accumulate in the atmosphere until it is all lost from the interior…this will soon make the planet too hot for life. It might seem like a good idea then that Muad’Dib comes along and fulfills the prophecy of bringing water to Arrakis, but introducing an ocean to an already habitable planet is likely to be even more catastrophic. On Earth, if it were not for the greenhouse effect from water vapor, we would surely be locked in a snowball world; creating a much more sensitive planet by bringing in a water vapor effect to the Dune-situation would likely bring the planet into a runaway state.

Luckily, only one of these states of affairs claims not to be fiction.

Much noise has been made over the internets about “sea ice recovery” this year, along with a list of other noisy distractions, like “Global Warming stopped in January 2008″ (after it stopped in 1998).  But does that mean it has recovered? Most definitely not.  The ice covering the Arctic Ocean is much younger and thinner than normal, and 2008 might in fact be a new record low.  The previous record low was 2007 which beat out 2005 (lucky #2) by the size of California and Texas combined. 

The colors are ice age, with green and purple being older ice, 5 and 6 years old. The older ice is rapidly being lost.

Meanwhile, Colorado researchers say there is a 3 in 5 chance that 2008 will have a new record low. Mr. Atmoz also has a post on this.

It is my non-quantified opinion that we’ve hit one of the first “tipping points” as far as global warming is concerned, or at least we will over the next few years– a commitment to seasonal loss of arctic sea ice regardless of what we do to CO2 emissions. We’ll be able to see by autumn if summer ice hit a new low, so stay tuned.

This was an interesting article.

Whether or not the oceans are net sources or sinks of CO2 is very important, since right now, atmospheric CO₂ increases at only about one half the rate of human-induced CO₂ emissions, because quite a bit is taken up by the oceans. The study back in 2007 by Le Quere et al on the decline of the Southern Ocean as a sink still looks like it is holding.

The planetary albedo (the percentage of the incoming solar radiation that is reflected back to space) plays a large role in the Earth’s radiative balance. The planet currently reflects about 30% of the incoming radiation back to space (clouds, particles in the atmosphere, ice sheets). If the albedo of the planet were 0 (all of it were absorbed) the planet would be over 20 degrees C hotter.

It is very difficult to quantify the effect that aerosols (acting as Cloud Condensation Nuclei) have on cloud albedo. Increased CCN should “brighten” clouds, that is, increase their albedo (for more on the importance of CCN see my last post). Fewer CCN means optically thinner, lower-albedo, and shorter-lived clouds, which should warm the planet by decreasing the amount of incoming sunlight that is immediately reflected back to space before it can interact thermodynamically with the climate system.

During the Cretaceous (~100 mya) temperatures were considerably hotter than today, being around 35 C (nearly 100 F) in the tropics, and the polar latitudes featured well above-freezing winters. Warm climates like that of the Cretaceous tend to have smaller pole-equator temperature gradients than the present, while colder climates like that of the LGM have much larger temperature gradients, what many call ‘polar amplification.’ It is fairly well known that a warming climate (such as one we are getting as we approach a doubling of carbon dioxide) features the poles warming more than the low latitudes. It is believed that CO2 levels were around 4 times what they are today during the supergreenhouse of the Cretaceous, a time when palm trees were in Canada, and crocodiles on Hudson Bay, and at least one published estimate of Arctic waters over 20 C. For those who argue that negative feedbacks are going to save us from an increase in CO2 in modern times, the Cretaceous is not a supporting paleoclimatic example. In fact, temperatures from proxy records are even higher than one would expect from a quadrupling of carbon dioxide. There is still a lot of confusion that the Cretaceous causes amongst scientists today. The very low temperature gradient is one example.

More question marks arose by a paper by André Bornemann and others suggesting that there in fact was some Antarctic ice during the Cretaceous time based on excellently preserved fossils showing that the geochemistry of the ocean had changed in the same way as it should if large scale glaciation takes place. Ray Pierrehumbert has good insight into some of the questions and interesting points going on during this time period, here. But no doubt it was very hot (and we also can’t talk about the Cretaceous as having just one set of conditions since it represents some 60 million years of geological time). Now, in the latest edition of Science, Kump and Pollard provide more insight that can assist CO2 in explaining the steamy conditions– albedo change from decreased CCN caused by biological impacts.

According to the study, reduction in Cretaceous cloud cover stemmed from a drop in cloud condensation nuclei which further amplified temperatures. If CO2-induced warming during the supergreenhouse reduced global biological productivity by temperature stress, and fewer nutrients to rise up to feed algae in the warm surface waters, then this could have resulted in less CCN and clouds, and thus a lower planetary albedo. Kump and Pollard use a GCM to explore the hypothesis, increasing CO2 from 1x to 4x preindustrial atmospheric level and both fail to account for the dramatic warmth (fig 1 a and b below) while 4x CO2 and increases in Cloud droplet radii and precipitation efficiency (leading to fig 1 c) would reduce planetary albedo from about 0.3 to 0.24, substantially enhancing temperatures, and a bit more in line with proxy evidence for paleotemperatures at the time.

_{Kump and Pollard, Science 2008}

Naturally occurring or anthropogenically induced particles that promote condensation or deposition are called nuclei, and those greater than about a micron favor condensation/deposition of water vapor. Once condensation/deposition starts they become comparably sized cloud droplets, or ice crystals. With about 10 to 100-fold global reductions in past aerosol (and so CCN amounts) large increases of droplet radii (to 17 microns maybe) are possible. Decreases of aerosol concentration should lead to fewer and larger droplets, and increased rate at which cloud water is converted to precipitation (larger cloud droplets means faster conversion to precipitation and reduced lifetime of the cloud). In contrast, increases in aerosol concentrations increase the amount of low-level cloudiness through a reduction in drizzle, which regulates the liquid water content and the energetics of shallow marine clouds, and produce brighter clouds that are less efficient at releasing precipitation. This is because large concentrations of small CCN nucleate many small droplets, which coalesce inefficiently into raindrops.

The Cretaceous cloud-to-precipitation conversion rate Kump and Pollard used in the GCM was P_e ~ r_e³ (precip. efficiency and cloud droplet radii), with a ~30% increase in r_e, and an increase in P_e by about 2.2x.

In the SOM is a sensitivity experiment for radiative versus precipitation efficiency effects in the modern world. Here, r_e effects cloud radiative properties (squares) and radiative properties and precipitation efficiency (triangles), and the circle is a modern GCM control with no changes to r_e.

A 10% reduction in cloud cover, from the decreased CCN concentrations, was caused by the biological impacts from the very high CO2 concentrations. Andreae (2007) explored the sources of CCN before the human era. There are many factors involved in CCN including primary biogenic aerosols (plant particles, spores, microbes, etc.), sources from sea spray and fires, and secondary organic aerosols (from natural hydrocarbons), as shown in the below diagram

_{Andreae 2007}

Humans play a large role in aerosol concentrations in modern times, but in the prehuman days concentrations ranged from a few tens per cm³ in biogenically inactive regions or seasons to a few hundreds per cm³ under biologically active conditions, with similar conditions over the continents and the oceans. If biological productivity of CCN goes down, as Kump and Pollard suggest happened in the high CO2 world, there may have been less CCN and so changes in cloud cover.

Implications for modern times

In modern times, we know that anthropogenic emissions of aerosols have a strong cooling effect (by reflecting solar radiation back to space) and have acted to offset some of the greenhouse warming (Global Dimming), and aerosol rise was partially responsible for a slight cooling trend between 1940-1970 when CO2 was not yet high enough to overwhelm that influence, and environmental regulations in the seventies caused a decline in emissions. Aerosols also modify clouds, and potentially this indirect aerosol effect is much greater than the direct effect of inhibiting solar radiation to reach the surface.

However, separating “natural” from human-induced aerosol amounts is not trivial. The radiative effects of aerosols are complicated because of the direct, and indirect impacts as well as there complicated vertical changes. The “single scattering albedo” is the fraction of energy that a particle scatters compared to the amount that it both scatters and absorbs. For single scattering albedo greater than ~0.89 the aerosol particles will cool at top-of-atmosphere and below 0.89, warm. Any single scattering below 1 means that they warm at the level they reside. Aerosol always cool the surface (Black Carbon has a warming effect though), warm (if they absorb) at the altitude where they reside, and either cool or warm at the TOA.

For potential implications of this paper to modern times, we’re interested in how cloud cover changes in a warming climate, and how biological production of CCN might change. Climate models and observations suggest that cloud feedbacks may be neutral to strongly positive, and if they are negative it won’t be very strong, because observations indicate that low level clouds (which control the albedo more than any other kind) decline in a warmer climate. This is due to various physical processes like increases in precipitation efficiency or decreases in cloud physical extent with temperature. The effects of changes in CCN from changes in aerosol emissions would play a role (if aerosols decline, so should the negative radiative forcing in their direct/indirect impacts). Changes in CCN from responses in land/marine organic life are another interesting factor, and I don’t know of much work that has examined this. If the “background” CCN changes, than so should albedo because of changing cloud cover.

Speaking purely on speculation and non-expert opinion, I do not think the changes in ecology would play a very influential role in the planet’s radiative balance, at least until much different CO2 levels beyond a doubling or even tripling. The responses that shape the carbon cycle would probably play a larger role in determining the rate of change of CO2 concentration in the atmosphere. But, this needs to be further investigated, and the role of all feedbacks into models. I think the main story from the Cretaceous is that there may be some substantial positive feedback lurking in the climate system, from both physical and biological responses. It may not be wise to be playing experiments with greenhouse gases and aerosols.

The March 2008 temperature data is available now.  While some sources like Anthony Watts blog made a big deal out of anomalous January 2008 cooling (largely due to La Nina), and a DailyTech article went as far as to say that January 2008 cooling “cancelled out” a century of global warming. March 2008 recovered, but also jumped much higher than expected.

The past year (2007) witnessed a transition from a weak El Nino to a strong La Nina, with the latter now beginning to moderate as evidenced by the warming waters off of the coast of Peru. There seems to be more going on that just a dissipating La Nina (I would expect a shorter jump), and there are clearly anomalous conditions recently over Asia…not exactly sure what is going on. These 3 GISS maps show anomalies of Jan 08, Feb 08, and March 08 relative to the standard GISS base period.

Also of note is missing data in Africa which would effect what is going on. SkepticalScience also shows us this graph with the SOI index, so it appears La Nina is at least partially responsible.

_{SkepticalScience, http://www.skepticalscience.com/La-Nina-watch-March-update.html}

The Southern Oscillation Index is a measure of La Nina, with a more positive SOI meaning La Nina( El Nino would have a more negative SOI). The U.K Met Office says that 2008 will probably still be a top 10 year, but a bit cooler than recent years because of the cold januray and february (next skeptic line: Global Warming Stopped in 2008!!!). But the point is that January did not cancel out any global warming, and there’s nothing unusual about La Nina. I predict that 2008 will be a top 10 year (certainly above the 1951-80 baseline), but will not break any records.

Aside from the total solar irradiance changes, changes in cosmic rays might be the next skeptic alternative to increases in greenhouse gases and other anthropogenic activities as the cause of modern global warming. It is an idea being investiaged a lot, though some like Henrik Svensmark and Nir Shaviv are very confident that they have overturned the CO2 paradigm and found a link between cosmic rays and low level cloud cover.

A simple soda bottle experiment can demonstrate the idea…fill a 2-liter plastic bottle 1/3 full of some warm water and close the cap and swish it around such that the inside is saturated, and then squeeze the bottle in and out. Given a saturation state, you’d think you might get fog-like residue on the side. You probably won’t. Clouds need condensation nuclei to build off of, so by adding particles you enhance the water condensation process. If you light a match and let it burn for a few seconds, blow it out, and then drop it in the bottle quickly and close the cap, the smoke now can serve as a foundation for which a cloud can form. Now if you squeeze the bottle in and out, you should see some cloudiness around the sides of the bottle.

The idea behind cosmic rays is that they effect cloud condensation nuclei (CCN) and thus when you get more cosmic rays, you can get more low clouds. A decrease in CR intensity should cause a decrease in Low Cloud Cover (LCC). Changes in clouds effect the albedo of the planet.

In a new paper, by Sloan and Wolfendale, the authors investigated the link by looking for periods in time/places on the planet which had documented various cosmic ray arrivals, and seeing if that affected the cloudiness.  The authors looked at solar cycles 22 and 23 especially. The conclusion by the paper is that the there is a weak correlation over the first cycle, and the upper limit percentage (less than 1/4 due to CC variability) is incompatible with a large part of the change in the LCC during solar cycle 22 being produced by changes in ionization. No correlation is found in solar cycle 23. During Forbush decreases (small decreases in CC intensity), and the causal connection would imply a decrease in LCC over a Forbush decrease, and on timescales of days and shorter. From this paper, it is statistically improbable that there is a correlation during Forbush decreases between changes in LCC and ionization.

This is a subject that needs further investigation, but no corroboration of the hypothesis of a causal connection between the changes in ionization from cosmic rays and LCC could be made in this paper. Other papers such as Benestad 2005 and Lockwood and Frohlich 2007 find no explanatory trend in cosmic rays to be causing the observed temperature rise.