New Curiosity data leaves scientists baffled about past evidence of water

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The uncertainty of science: Despite substantial evidence by Curiosity that Gale Crater once had running water and even lakes, the rover has also found no evidence that the atmosphere ever had enough carbon dioxide in its atmosphere to warm the climate enough to allow that water to flow as a liquid.

Mars scientists are wrestling with a problem. Ample evidence says ancient Mars was sometimes wet, with water flowing and pooling on the planet’s surface. Yet, the ancient sun was about one-third less warm and climate modelers struggle to produce scenarios that get the surface of Mars warm enough for keeping water unfrozen.

A leading theory is to have a thicker carbon-dioxide atmosphere forming a greenhouse-gas blanket, helping to warm the surface of ancient Mars. However, according to a new analysis of data from NASA’s Mars rover Curiosity, Mars had far too little carbon dioxide about 3.5 billion years ago to provide enough greenhouse-effect warming to thaw water ice.

The same Martian bedrock in which Curiosity found sediments from an ancient lake where microbes could have thrived is the source of the evidence adding to the quandary about how such a lake could have existed. Curiosity detected no carbonate minerals in the samples of the bedrock it analyzed. The new analysis concludes that the dearth of carbonates in that bedrock means Mars’ atmosphere when the lake existed — about 3.5 billion years ago — could not have held much carbon dioxide.

Does anyone but me see the faulty scientific reasoning here? Basically, these scientists appear to be assuming that the only global warming atmospheric molecule that exists is carbon dioxide. And because Mars has little carbonates in its surface, meaning it had little past CO2 in its atmosphere, there thus no way Mars’ atmosphere could have been warmed enough to allow water to flow as a liquid.

Balderdash! On Earth, the most important global warming component in the atmosphere is water, not carbon dioxide. Moreover, there are other atmospheric components, such as methane, that are also more important than CO2 in warming the climate. In fact, carbon dioxide as a trace gas in the atmosphere plays only a tiny global warming role. On Mars it is just as likely that other atmospheric components, such as water and methane, provided the necessary warming. To assume it has to be carbon dioxide suggests to me that these scientists have become so caught up with the human-caused global warming scare here on Earth that they have lost the ability to consider other possibilities on Mars.

Nonetheless, this remains the fundamental scientific mystery of Mars. We have found enormous evidence on Mars that water once flowed on its surface. We have also found no explanation so far that would explain how that was possible.



  • diane wilson

    No, you weren’t the only one who noticed. Of course, it’s possible that even with widespread liquid water on the surface, there was no evaporation and therefore no water vapor in the atmosphere. Yes, if you wave your hands just right, that might be possible.

    It’s also interesting that carbon dioxide is about the only gas left from Mars’ original atmosphere. It’s heavier than any other likely early gasses, and so less likely to escape. Perhaps MAVEN’s instruments will tell us more.

    I don’t generally quote Ayn Rand, but one useful point she made is that when you think you’ve found a contradiction, examine your premises. One of them is wrong.

  • wayne

    diane wilson-
    Very nicely stated!

  • m d mill

    “…as a trace gas in the atmosphere plays only a tiny global warming role.”

    You may go too far in your understandable questioning of the validity of AGW alarmism.
    Don’t understate the role of CO2 in the earth atmosphere . Even though it is a trace gas, the earth would be a “snowball” without that trace amount. The role of CO2 is not trivial, it is even vital to a comfortable earth. I believe this is acknowledged by reputable “skeptics” of AGW alarmism (e.g. Lindzen and Curry). This is separate from the question of current temperature sensitivity to CO2, which the IPCC admits is highly questionable [they won’t even give a “most likely” number these days!]

  • m d mill: You might be right, but the one fact I have learned about CO2 that makes me doubtful about its importance to global warming is that scientists have found that consistently past temperature rises always happen first. Only after does the amount of CO2 increase in the atmosphere. The evidence therefore suggests that it is temperature rise that causes an increase in CO2, not the other way around.

    I also disagree with you when you say “the earth would be ‘snowball’ without” carbon dioxide. This is not true. It is water that produces most of the Earth’s global warming, raising the climate’s temperature somewhere between 10 to 20 degrees Fahrenheit. CO2 might help, but without water this would be a very cold planet indeed.

  • Tom Billings

    “I also disagree with you when you say “the earth would be ‘snowball’ without” carbon dioxide. This is not true. It is water that produces most of the Earth’s global warming, raising the climate’s temperature somewhere between 10 to 20 degrees Fahrenheit. CO2 might help, but without water this would be a very cold planet indeed.”

    Indeed, the *average* CO2 level of the *Cryogenian* Era was 1,300ppm, over 4 times what it is today! That includes both the Sturtian and Maurinoan glaciations, the second of which was what gave us a “Snowball Earth”.

  • wodun

    I hope their analysis included atmospheric pressure.

  • diane wilsond

    CO2 is indeed a lagging indicator of temperature change, and the mechanism isn’t exactly a secret. CO2 exists in solution in the oceans, but warming ocean temperatures cause dissolved CO2 to come out of solution… and into the atmosphere. Atmospheric CO2 also leads to increased photosynthesis, providing a negative feedback loop to help moderate CO2 levels.

    Runaway CO2 greenhouse isn’t about to happen. Some increase in CO2 will increase food supplies, helping to feed the global population.

    Somebody is making stuff up.

  • m d mill

    After further review I admit the “snowball” remark was probably an exaggeration. (I do that sometimes)
    Using the MODTRAN radiation calculator (see
    I believe it can be shown (by direct calculation of reflected (greenhouse effect) infrared radiation) that a removal of all CO2 would result in a temperature reduction of roughly 10 C. for the USA. This assumes an unchanged relative humidity as temperature changes…which seems reasonable to me (otherwise the temperature decrease is only 7 C). This is 18 F cooling, which is more than significant…the world would be a very different place! My point is this…just because CO2 is a “trace” gas does not prove anything in itself, either way.

    FYI:the MODTRAN website above is a great tool to play with…thanks uchigago

  • m d mill

    more MODTRAN direct calculation results:

    If all water vapor was removed (CO2 unchanged) the USA could expect a 14C cooling (25F).
    If all CO2 and water vapor were removed, the USA could expect 21C cooling (38F).

    However, all these results exclude the effects of temperature and water vapor on cloud formation, and thus solar visible radiation reflection…which could be a positive or negative feedback on temperature!!

  • BSJ

    When they make their predictions, do they assume that Mars has always been in the orbit it is now?

    Could it have been closer to the Sun and since moved to where it is now, within the timeframe when there was liquid water?

  • BSJ: Mars’ orbit and inclination goes through significant changes. All models have to include this, as it is a significant factor in its climate.

  • pzatchok

    Could Mars at one point had a significant amount of water locked up in the soil frozen and a very short term period of increased solar output have pushed it into thawing enough to create the flow patterns and lake like effects? Only a week or so of increased temps would be needed.

    Something like a huge Solar flare that hit Mars while it was in opposition to Earth. Thus protecting us and not Mars.

    Once water is exposed on the surface could it sublimate over time (a million years) and then be swept away with the rest of Mars atmosphere?

  • wayne

    100 years of John Carter
    ERB Centennial
    -includes some great vintage animation

  • ken anthony

    but… but… the science is settled!? (How to identify a moron.)

  • Rick Shelby

    What I see is solid evidence of ‘flow.’ While the most reasonable agent would appear to be water it is not the only mechanism to make ‘flow’ marks under various conditions. However, making the case for water, I would not discard the water vapor warming effect (a “two for” given the volcanic state of Mars billions of years ago) over the missing CO2.
    I find it most interesting (ironic, perhaps not applicable) that here we are debating the nature of the canals on Barsoom a hundred years later.

    [also to K.A, as a certified AceOfSpades Moron, I resemble that]

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