Of note: “Unlike Earth, which has a thick, moist atmosphere that produces a strong greenhouse effect, Mars’ atmosphere is too thin and dry to produce as strong a greenhouse effect as Earth’s, even when you double its carbon-dioxide content.”
NASA Orbiter Reveals Big Changes in Mars’ Atmosphere
PASADENA, Calif. — NASA’s Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet’s axis varies. This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms.
Researchers using the orbiter’s ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet’s south pole. The scientists suspect that much of this carbon dioxide enters the planet’s atmosphere and swells the atmosphere’s mass when Mars’ tilt increases. The findings are published in this week’s issue of the journal Science.
The newly found deposit has a volume similar to Lake Superior’s nearly 3,000 cubic miles (about 12,000 cubic kilometers). The deposit holds up to 80 percent as much carbon dioxide as today’s Martian atmosphere. Collapse pits caused by dry ice sublimation and other clues suggest the deposit is in a dissipating phase, adding gas to the atmosphere each year. Mars’ atmosphere is about 95 percent carbon dioxide, in contrast to Earth’s much thicker atmosphere, which is less than .04 percent carbon dioxide.
“We already knew there is a small perennial cap of carbon-dioxide ice on top of the water ice there, but this buried deposit has about 30 times more dry ice than previously estimated,” said Roger Phillips of Southwest Research Institute in Boulder, Colo. Phillips is deputy team leader for the Mars Reconnaissance Orbiter’s Shallow Radar instrument and lead author of the report.
“We identified the deposit as dry ice by determining the radar signature fit the radio-wave transmission characteristics of frozen carbon dioxide far better than the characteristics of frozen water,” said Roberto Seu of Sapienza University of Rome, team leader for the Shallow Radar and a co-author of the new report. Additional evidence came from correlating the deposit to visible sublimation features typical of dry ice.
“When you include this buried deposit, Martian carbon dioxide right now is roughly half frozen and half in the atmosphere, but at other times it can be nearly all frozen or nearly all in the atmosphere,” Phillips said.
An occasional increase in the atmosphere would strengthen winds, lofting more dust and leading to more frequent and more intense dust storms. Another result is an expanded area on the planet’s surface where liquid water could persist without boiling. Modeling based on known variation in the tilt of Mars’ axis suggests several-fold changes in the total mass of the planet’s atmosphere can happen on time frames of 100,000 years or less.
The changes in atmospheric density caused by the carbon-dioxide increase also would amplify some effects of the changes caused by the tilt. Researchers plugged the mass of the buried carbon-dioxide deposit into climate models for the period when Mars’ tilt and orbital properties maximize the amount of summer sunshine hitting the south pole. They found at such times, global, year-round average air pressure is approximately 75 percent greater than the current level.
“A tilted Mars with a thicker carbon-dioxide atmosphere causes a greenhouse effect that tries to warm the Martian surface, while thicker and longer-lived polar ice caps try to cool it,” said co-author Robert Haberle, a planetary scientist at NASA’s Ames Research Center in Moffett Field, Calif. “Our simulations show the polar caps cool more than the greenhouse warms. Unlike Earth, which has a thick, moist atmosphere that produces a strong greenhouse effect, Mars’ atmosphere is too thin and dry to produce as strong a greenhouse effect as Earth’s, even when you double its carbon-dioxide content.”
The Shallow Radar, one of the Mars Reconnaissance Orbiter’s six instruments, was provided by the Italian Space Agency, and its operations are led by the Department of Information Engineering, Electronics and Telecommunications at Sapienza University of Rome. NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter project for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. Lockheed Martin Space Systems in Denver built the spacecraft.
h/t to WUWT reader Dennis
source: http://www.nasa.gov/mission_pages/MRO/news/mro20110421.html
Since they are so very good at modeling Earth’c climate, what confidence do we have in this? I would take their consideration of CO2’s effects with lots of grains of NaCl. I would start with their definition of a greenhouse and then see if they are using the IPCC’s constants for CO2’s thermodynamics or the real values.
100,000 year cycle?
Oh, yes, an Ice Age cycle.
Not at all ‘unlike Earth’.
Hmmmm……..messages from the Red Planet.
If Percival Lowell were alive today, he’d be ROFL.
“A tilted Mars with a thicker carbon-dioxide atmosphere causes a greenhouse effect that tries to warm the Martian surface, while thicker and longer-lived polar ice caps try to cool it,” said co-author Robert Haberle, a planetary scientist at NASA’s Ames Research Center in Moffett Field, Calif.
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Anything else to report??
Your statement is old news, some say the science is well understood and a consensus has been reached.
Not even a flicker of something new, anything, I assume we are still exploring?
With the Mars Orbiter taking high quality pictures, we should be able to round up the SUVs causing this problem in short order.
OMG they model on Mars, too. Who-da thunk it.
“Another result is an expanded area on the planet’s surface where liquid water could persist without boiling. ”
Fascinating! How much does the axial tilt change and which way is the ’tilt’ progressing currently? To greater exposure of the south pole or lesser? When might the atmospheric pressure be sufficient to sustain water without ‘boiling’?
Since H2O is the only effective GHG, they’d do better to track water-ice transitions.
😉
Mars’s atmospheric pressure is ~1% of Earth and its CO2 content is ~96%. Earth’s atmosphere is ~0.04% CO2. Thus Mars has about 25 times as much CO2 in its atmosphere than Earth. That is, there are around 25 molecules intercepting IR for each molecule in Earth’s atmosphere. Assuming my arithmetic is correct.
So how does the “thinness” Mars’s atmosphere reduce the magnitude of the greenhouse effect when compared to Earth? I’m not saying it should necessarily be 25 times greater, just that seems it should be greater, rather than less.
The earth also has a very thin CO2 atmosphere. Almost none at all, measured in the parts per million.
The temperature of Venus, Earth and Mars shows much better correlation with the thickness of the atmosphere than with CO2 concentration.
Both Venus and Mars are mostly CO2 atmosphere, one is hot, the other cold. Earth with very little CO2 is in the middle. Where is the correlation?
Venus with a thick atmosphere is hot, Mars with a thin atmosphere is cold, and Earth with an atmosphere in the middle has a temperature in the middle. Much better correlation, even when adjusted for distance from the sun.
[[[Of note: “Unlike Earth, which has a thick, moist atmosphere that produces a strong greenhouse effect, Mars’ atmosphere is too thin and dry to produce as strong a greenhouse effect as Earth’s, even when you double its carbon-dioxide content.”]]]
These statements seem to be pulled out of thin dry air and fail to have any strong greening effect on me….
The location of these deposits near the south pole of Mars may tie in with the southern location of magnetic fields claimed to be as strong as on earth that would protect these deposits from solar wind erosion.
http://science.nasa.gov/science-news/science-at-nasa/2001/ast31jan_1/
ferd berple said @ur momisugly April 21, 2011 at 10:27 pm
“Venus with a thick atmosphere is hot, Mars with a thin atmosphere is cold, and Earth with an atmosphere in the middle has a temperature in the middle. Much better correlation, even when adjusted for distance from the sun.”
Which is what I believe to be the case. But I am told by ever so many radiative physicists that the relative temperature of Earth’s atmosphere is not due to the lapse rate; it’s the CO2. And it still seems to me that 25 molecules of CO2 ought to be absorbing and reradiating 25 times as many photons as one molecule.
I seem to be missing something. Perhaps it’s because I’m cognitively dysfunctional 😉
That is the proof, that Aliens live on mars and produce CO2!
Gosh.
These “scientists” know as much about the effects of CO2 on climate on Mars as they do about the effects of CO2 on climate on Earth.
Y’know? I reckon that’s about right!
“even when you double its carbon-dioxide content.”
As Mars has an atmopshere comprised of 95% CO2, doubling it might be a problem?
How does an atmosphere of 95% carbon dioxide “double”?
Since the Greenhouse Effect violates the Laws of Thermodynamics let us look at the real reason for part of atmospheric heating, apart from solar. This is adiabatic which relies on atmospheric density. Since the atmosphere of Mars has a density far lower than Earth’s the adiabatic heating effect is far lower.
Planetary heating has nothing to do with the GHG effect of CO2. Jupiter has a warm atmosphere, similar to Earth at the 1000mbar level and there are no so called greenhouse gasses on Jupiter at all. That atmosphere is mainly hydrogen.
We are told Long Wave Radiation passes through most of the atmosphere only to be trapped by GHGs. Therefore we must conclude that non-GHGs are irrelevant to the so called greenhouse effect and that only GHGs matter.
If the above is true, then Mars, with so much more CO2 in it’s atmosphere must demonstrate a stronger greenhouse effect. Whether non-GHG gasses are present or not is irrlevant because they are “invisible” to radiation.
If Mars doesn’t demonstrate a strong greenhouse effect, the proponents of the greenhouse theort need to explain why not.
If someone is wiling to explain it, I’m willing to learn.
I seem to recall Mars South Pole was melting back in 2004. NASA had time lapsed picture of this event. Later NASA said that “dust storms” was causing the melting. I guess now it’s do to tilted Mars. Well it the time several other planets were experiencing warming including our planet. What I’m I to think? All the planets either tilted their axis or they all had massive dust storms at the same time. Of course the the Sun had nothing to do with it. Then again, it could be, driving SUVs over heated the whole system. Evil SUV drivers.
Mars does have dust devils, so one presumes that there is convectional activity going on, which means the atmosphere must have a troposphere that exists at the adiabatic lapse rate. So convection would represent a significant method of heat loss, as it does on earth. This means that temperature would be a function of the simple thickness of the atmosphere.
Why would the presence of moisture in the martian atmosphere matter? The atmosphere is already warmed to the adiabatic lapse rate, so adding more GHG is irrelevant surely.
Louis Hissink says:
April 22, 2011 at 1:59 am
and
H.R. says:
April 22, 2011 at 2:16 am
An atmosphere of 95% carbon dioxide “double” can be shown in the following example:
Assume the Martian atmosphere consists of 100 “parts”. There are 95 parts of CO2, and 5 parts “other”, where other is the sum total of nitrogen (2.7 parts), argon (1.6 parts), oxygen (0.13 parts), and traces of additional gases. Now, if we hold the “other” parts constant at 5, but double the CO2, the atmosphere consists of 190 parts CO2 and 5 parts “other”, for a total of 195 parts. We’ve doubled the CO2 parts (95 to 190), but the percentage of of CO2 has changed from 95% to 97.4% (190/195).
However, if your question is really about how to add CO2 to the Martian atmosphere, I’ll gladly volunteer to drive an ‘evil’ CO2-spewing SUV on Mars, if someone will cover the interplanetary travel expenses. 🙂
1) The “doubling of CO2 content” they refer to is the melting of the dry ice cap, which they estimate to contain almost as much CO2 as the atmosphere itself.
2) There is a word for the carbon hysteria that leads people to claim that CO2 drives temperature more strongly than distance from the sun or atmospheric mass, but it would be impolite to use it. Let’s just say it’s a byproduct of equestrian pursuits.
@Louis Hessink:
Nicely spotted, Louis! Heh heh – ‘“even when you double its carbon-dioxide content.”
Of course, the scientist who wrote that really meant “double its carbon-dioxide quantity”. But, heck, why would we expect a scientist to use scientifically correct language, eh? If they did that, we might also expect them to use the scientific method…
Pompous Git says: April 21, 2011 at 11:22 pm
And it still seems to me that 25 molecules of CO2 ought to be absorbing and reradiating 25 times as many photons as one molecule.
The amount of sunlight at mars’ orbit is much less than here, I believe it diminishes by the square of the distance from the source. So while there is much more relative CO2, there is much less light to play with, and no mass to hold the heat.