The greenhouse effect is real. If there were no greenhouse gases in the atmosphere, earth would be a cold place. Compare Mars versus Venus – Mars has minimal greenhouse gas molecules in its’ atmosphere due to low atmospheric pressure, and is cold. By contrast, Venus has a lot of greenhouse gas molecules in its’ atmosphere, and is very hot. Temperature increases as greenhouse gas concentration increases. These are undisputed facts.
outgoing radiation = incoming radiation – changes in oceanic heat content
The image below from AER Research explains the radiative balance.
http://www.aer.com/scienceResearch/rc/rc.html
About 30% of the incoming shortwave radiation (SW) is reflected by clouds and from the earth’s surface. 20% is absorbed by clouds and re-emitted back into space as longwave (LW) radiation. The other 50% reaches the earth’s surface and warms us. All of that 50% eventually makes it back out into space as LW radiation, through intermediate processes of convection, conduction or radiation. As greenhouse gas concentration increases, the total number of collisions with GHG molecules increases. This makes it more difficult for LW radiation to escape. In order to maintain equilibrium, the temperature has to increase. Higher temperatures mean higher energies, which in turn increase the frequency of emission events. Thus the incoming/outgoing balance is maintained.
Click for larger image
http://www.aer.com/scienceResearch/rc/m-proj/lbl_clrt_mls.html
The important greenhouse gases are: H2O, CO2, O3, N2O, CO and CH4. The reason why the desert can get very cold at night is because of a lack of water vapor. The same is true for Antarctica. The extreme cold in Antarctica is due to high albedo and a lack of water vapor and clouds in the atmosphere, which results in almost all of the incoming radiation returning immediately to space.
An earth with no CO2 would be very cold. The first few tens of PPM produce a strong warming effect, and increases after that are incremental. It is widely agreed that a doubling of CO2 will increase atmospheric temperatures by about 1.2C, before feedbacks. So the debate is not about the greenhouse effect, it is about the feedbacks.
Suppose that the amount of reflected SW from clouds increases from 20% to 21%? That would cause a significant cooling effect. Thus the ability of GCM models to model future temperatures is largely dependent on the ability to model future clouds. Cloud modeling is acknowledged to be currently one of the weakest links in the GCMs. Given the sensitivity to clouds, it is perhaps surprising that some high profile climate scientists are willing to claim that 6C+ temperature rises are established science.
So the bottom line is that the greenhouse effect is real. Increasing CO2 will increase temperatures. If you want to make a knowledgeable argument, learn about the feedbacks. That is where the disagreement lies.
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Steven Goddard:
“If the atmosphere is warmer over the ocean, then less heat flows out of the ocean into the atmosphere, and the ocean warms up.”
No it doesn’t. If less heat flows out of the ocean, it COOLS LESS.
Also an important effect of warm cloudy night is the reduction of convection by the denser clouds of water vapour ( The REAL greenhouse effect).
If you only consider CO2, and historical surface data for the last 100 years in a model, then you get a +6C rise.
If you factor in cosmic rays, Earths relative distance from the sun, Suns relative position in the galaxy, Ocean current fluctuation, humidity, etc. You come to an answer of ???
Then you have 90% of surface stations with significant human growth and building development near them, and the data you gather is tainted, and all conclusions based on the data is suspect or outright wrong.
Will the real scientist please stand up!
jae
Why are deserts so hot?
The cooling effect of evaporation is key.
The AER chart does show convection as “sensible heat.”
http://en.wikipedia.org/wiki/Sensible_heat
Sensible heat is potential energy in the form of thermal energy or heat. The thermal body must have a temperature higher than its surroundings (see also latent heat). The thermal energy can be transported via conduction, convection, radiation or by a combination thereof.
Ich denke, dass das Umweltbewusstsein langsam besser wird. Außerdem wird die Marktlücke Umweltschutz immer grösser, da ja auch der Bedarf steigt. So nimmt die Entwicklung auch langsam einen positiven Verlauf. Desweiteren sollte man auch die Wirtschaftskriese als Chance sehen, denn wenn alte Strukturen vernichtet werden, werden neue Strukturen wachsen. Wie die Natur so will wenn etwas Neues entsteht kann um weiten besser und moderner sein. Lass die Politik nur machen, die wollen alle nur Ihr Geldwelt retten und nicht unsere Umwelt. In der Politik geht’s nur um Macht und nicht um Idealismus.
Soll kein Spam sein. Ich finde diese Seiten nur interessant.
Hier ist auch ein Tipp für euch zum Posten NEUER Rekord bei Kohlendioxidausstoß Umweltschutz im Bog
Mit nachhaltigem Gruß
Heinz
weatherag “Dr. Hanson argument that heating the atmosphere will heat the ocean is wrong. You have to ask yourself, how you boil water. You don’t blow hot air over the surface; you heat the water from below.”
Yes and no. It is more efficient to heat from below, warm water rises heating the whole of the basin relatively evenly, but heating from above will also work but slower and less efficient.
The main problem with “heating the ocean” argument I find is time. The oceans volume is so large, and local, or recent environmental change will not be felt for hundreds of years. Much of the oceans liquid volume is in the same “mode” as the little ice age, and not the modern warming period.
Some theories about the little ice age is that the ocean caused us to leave it, more than the sun did. This is yet another area we do not know enough about.
Anyone know of a study about the movement in the magnetic poles and global volcanic activity? The magnetic core moving or changing it’s axis slightly or slightly more cause magma fluctuation resulting in more activity?? and can you localize where the resulting activity will be centralized due to the waves? Have we even gotten a good image of the planets core, it’s shape, etc?
Volcanic activity would also help us predict warming and cooling periods since it is a major cooling factor as well.. Just an idea.
Nice post Steve,
As others have noted, greenhouse theory and the very greenhouse formulae themselves are incomplete because they are missing the “Time” dimension.
There never really is an energy balance between the energy coming and the energy leaving. Time is a crucial element in the system.
341 W / m2 comes in from the Sun for an average 12 hour period and during the next 12 hour period, 170 W / m2 is either reflected back to space or escapes back to space overnight.
How long does additional GHGs delay the time period that those photons of light / EM radiation stay in the Earth system before they escape to space.
The average energy held in the Earth system is only 170 W / m2 or a delay of 12 hours and increased CO2 could only delay that for a period of minutes or one hour at the outside.
As the summer season warms, perhaps an additional 0.5 W /m2 is absorbed per day and then the opposite occurs during the winter season.
As the deep oceans warm up to catch up with surface temps (which can take 800 to 1,500 years) perhaps an additional 0.1 W / m2 is absorbed per day.
Greenhouse theory needs to incorporate the Time element and we are talking about the speed of light and particle physics types of timelines here.
And the physics show that Temperatures are 0.2C to 0.3C per W / m2, not the 0.75C / W / m2 that Hansen like to quote. [that formula alone invalidates global warming theory and even GISS’ Model E incorporates only 0.32C / W / m2 in its hindcast to match the temperature record.]
The way that I heard this is that when the insulating effects first became understood, there was an intellectual proposal that a greenhouse could be constructed without the need for glass to make it work. Before this was tried, someone interjected the proposition that without the glass convection would release all of the gas and that it wouldn’t work. So it was never tried. When the unexpected the high temperature of Venus was discovered (it had been thought to be warm and moist like primeval earth) an explanation was needed. 3 scientists (headed by Carl Sagan) were allowed to propose that this constituted a “Runaway Greeen House effect”. Venus is hotter at its north pole than elsewhere and radiates more heat than it receives from the sun. No one knows WHY Venus is so hot. It has no glass shell around it and neither does earth.
“Science” comes from the Latin scio “I Know”–scientists only WISH that they knew–but want to convince others that they actually do.
Steve,
My understanding of the skeptic argument regarding saturation is this: At current CO2 concentrations, all of the available IR in the relevant bands (2.7, 4.3 and 15 µm) is already captured. This is about 8% of the whole IR spectrum, which means that 92% of the IR passes right through without being absorbed by CO2. If the entire atmosphere were composed of nothing but CO2, it would still only be able to absorb 8% of the radiant heat. So if all of the available IR in that spectrum is being captured at current concentrations or lower, then adding more CO2 to the atmosphere won’t matter a bit. Don’t claim to be expert here. This is not my field.
Also, the “ocean effect” is pure heat storage (as is some of the atmospheric effect), and has very little to do with ghgs. Water is quite transparent to visible light, so the energy does get “trapped” by the water. Another BIG reason you cannot compare Venus and Mars to Earth. I think that most of the so-called “greenhouse effect” is simply a heat storage effect. The IR radiation is the “result” of this, not any “cause.” LTE requires that the 98% of the atmosphere that doesn’t absorb/radiate IR must be thermalized. This represents stored kinetic and potential energy. Too many folks are overly-hung up on radiation cartoons.
Has there ever been a study that involved a bunch of greenhouses where each had different amounts of CO2 (all other factors equal) and all subjected to the same amount of sunlight to see how the different CO2 levels affect temperature?
I hold no scientific credentials so my apologies if my questions seem overly simple.
I’ve been led to understand that the CO2 released by man-made activities represents about 3% of the atmospheric CO2. Can anyone attest to the accuracy of that claim?
Is there something different about man-made CO2 that gives that 3% more impact in Steve’s model?
Thanks,
Peter
tmtis free 00:39:45
You stated earlier: “As an analogy, if you use a blind over a window on a sunny day, adding more blinds will not make the room any darker”
I like your analogy, however I partially disagree and suggest an improvement . Think of the gases in the atmosphere as if the “shade” was cut into narrow strips. Pulling these strips down individually would block particular segments of the incoming light. The more strips you brought down the darker the room would become. Some strips would overlap while others would still allow light into the room through gaps between each other. To completely block light from coming into the room you would need to add multiple layers of shading to eliminate all of these “gaps”.
Thanks
Edward
Here is an interesting site. The author attempts to determine an upper level for global warming caused by co2 by simply observing the warming for the 20th century, assuming it was all caused by co2 increase, and projecting additional warming into the future using log functions. Since forcings are ignored as a cause they are “in” the future calculations of an upper limit.
I’m sorry, I have read this primer several times but it doesn’t work for me.
The basic problem I have is that in the real world heat is not trapped in the atmosphere, it escapes, and as a result you cannot transfer heat from a colder atmosphere to a warmer surface without the application of work. Where is the AGW engine that heats up the planet?
The image below shows GHG absorption by altitude and wavenumber. As you can see, there is a strong absorption band of CO2 at 600/cm. That is what makes CO2 an important greenhouse gas.
This is incorrect, the Clough & Iacono graph is of Radiational cooling, i.e. emission.
jae,
Phoenix is an urban heat island. I’ve driven south on I-10 out of Phoenix in the summer when the temperature dropped 20 degrees between Tempe and McCormick Ranch. That was before McCormick Ranch was part of the UHI. Southern Arizona also gets very high humidities in July and August. I remember once when the dew point was 80F after a thunderstorm.
I have read all of the earlier posts on this thread.
Would someone please explain to me how the absorption of carbon dioxide in the oceans is affected by
1) ocean surface temperature;
2) ocean saturation;
3) incident light levels (cloudy or not);
4) microorganism carbon dioxide uptake (plants in the ocean) as a function of carbon dioxide level, salinity, pollution, and other factors;
5) quantity of carbon dioxide currently sequestered in the ocean and in subsea deposits;
6) atmospheric (surface) concentration of carbon dioxide;
7) other ocean/air boundary effects?
What should be glaringly obvious is that we are not well-informed on the overall (intake versus output) carbon dioxide budget. I have not mentioned volcanic activity: how do you assess the contributions of volcanoes to atmospheric carbon dioxide?
The Elephant in the Room is the widely known and equally widely ignored propensity of all plant life to use carbon dioxide in metabolism.
AGW proponents propose a positive feedback phenomenon.
What if the feedback is negative and self-correcting?
You are describing the Urban Heat Island effect (UHI).
I lived in Las Vegas for a few years. The microclimate in the Las Vegas valley differs from that of the surrounding desert. The relative humidity in the valley is much higher because of all the non-native plants, swimming pools, outdoor watering, etc., etc., that occurs in the metro area.
The urban heat island effect is primarily caused by all the concrete and asphalt which retain heat and electric motors, internal combustion engines and air conditioning exhaust which produce heat.
Your comparisons to other cities with the same latitude as Phoenix are also incorrect. Atlanta is not in a desert and does not have the same day-time highs as Phoenix.
Steve …
As I understand it, much of the LW energy absorbed by CO2 is transformed in the collision process to different wavelengths. Thus, the LW energy at 600 cm will not remain a constant, but will degrade over distance, and as such, the re-emittance will not necessarily be in a band relevant to further concentrations of CO2.
Thoughts??
“The other 50% reaches the earth’s surface and warms us.”
Where does this 341 W/m^2 come from? We are constantly told 1360 is the value.
“As Dr. Hansen has correctly argued, increases in atmospheric temperature cause the ocean to warm up.”
Help me out. By raising the temp of precip and by increased KE in conduction? What is the consequence of increased temp over 70% of the surface?
Two quick questions
1. Does increased CO2 also decrease the LW radiation coming from the sun from reaching the surface?
2. Does radiation absorbed at a particular frequency by a greenhouse gas get converted to heat (meaning vibrational motion at the molecular level), get reradiated or a combination of the two?
Fails due to omissions
Steve Goddard
Compliments on an impressive tutorial on conventional wisdom and your efforts to support it.
Unfortunately it fails due to all the major parameters that it leaves out. For starters consider:
1) Differing Reflection Feedback
The Cloud reflection feedback differs between short and long wave radiation.
See: Roy Spencer What About the Clouds, Andy?
2) Cosmic ray variations modulate clouds
See discussion about Svensmark
Center for Sun-Climate Research
“Cosmic rays” And “cosmoclimatology”
See efforts by:
Nir Shaviv
Shaviv, N. J. (2008), Using the oceans as a calorimeter to quantify the solar radiative forcing, J. Geophys. Res., 113, A11101, doi:10.1029/2007JA012989.
3) Feedback Causation
Spencer & Braswell point to a critical flaw of causation in feedback analysis.
Potential Biases in Feedback Diagnosis from Observational Data: A Simple Model Demonstration
Roy W. Spencer and William D. Braswell, Journal of Climate, Volume 21, Issue 21 (November 2008)pp. 5624–5628
3) Convection
The temperature in the troposphere is dominated by convection with a strong change in the temperature lapse rate with altitude above and below the tropospause.
As kevendick noted, Miskolczi is a world expert on radiation modeling. He has developed alternative climate theory to explain the major errors in IPCC models not fitting the temperature lapse rate data.
<a href=”http://www.landshape.org/dokuwiki/doku.php?id=introductionThe new climate theory of Dr. Ferenc Miskolczi
See also discussion on Miskolczi
at Niche Modeling
4) Precipitation
The Prof. Emeritus William Alexander shows actual precipitation trends are actually linked to sunspot cycles which IPCC models ignore. See:
Linkages between solar activity, climate predictability and water resource development
JOURNAL OF THE SOUTH AFRICAN INSTITUTION OF CIVIL ENGINEERING
Vol 49 No 2, June 2007, Pages 32–44, Paper 659
5) Ocean Cycles ENSO, PDO
Ocean cycles cause major changes in atmospheric temperature. By excluding these in climate modeling, they have been missinterpreted warming as due primarily to CO2.
E.g. see articles on PDO at ICECAP.US
And on PDO and Clouds Roy Spencer
etc.
Look forward to your incorporating these effects into your tutorial.
warming on other planets, a short overview…
http://motls.blogspot.com/2006/05/global-warming-on-jupiter.html
It seems that we could melt metals down (except, of course, mercury and gallium) using “the green house effect”!!. You forget that the volumetric heat capacity of air is 3,227 times less than that of water, in case of air convection takes all heat to stratosphere and there dissipates and in the case of water you have a limit: it evaporates( Remember?: The “water cycle”). Atmosphere has its limits also, then you can not suppose it having an infinite height.Have you experienced a total solar eclipse? Temperature drops inmediately.