Did CLOUD Just Rain on the Global Warming Parade?

Today in Forbes, I have an article bringing the layman up to speed on Henrik Svensmark and this theory of cosmic ray cloud seeding.  Since his theory helped explain some 20th century warming via natural effects rather than anthropogenic ones, he and fellow researchers have face an uphill climb even getting funding to test his hypothesis.  But today, CERN in Geneva has released study results confirming most of Svensmark's hypothesis, though crucially, it is impossible to infer from this work how much of 20th century temperature changes can be traced to the effect (this is the same problem global warming alarmists face -- CO2 greenhouse warming can be demonstrated in a lab, but its hard to figure out its actual effect in a complex climate system).

From the article:

Much of the debate revolves around the  role of the sun, and though holding opposing positions, both skeptics and alarmists have had good points in the debate.  Skeptics have argued that it is absurd to downplay the role of the sun, as it is the energy source driving the entire climate system.  Michael Mann notwithstanding, there is good evidence that unusually cold periods have been recorded in times of reduced solar activity, and that the warming of the second half of the 20th century has coincided with a series of unusually strong solar cycles.

Global warming advocates have responded, in turn, that while the sun has indeed been more active in the last half of the century, the actual percentage change in solar irradiance is tiny, and hardly seems large enough to explain measured increases in temperatures and ocean heat content.

And thus the debate stood, until a Danish scientist named Henrik Svensmark suggested something outrageous -- that cosmic rays might seed cloud formation.  The implications, if true, had potentially enormous implications for the debate about natural causes of warming.

When the sun is very active, it can be thought of as pushing away cosmic rays from the Earth, reducing their incidence.  When the sun is less active, we see more cosmic rays.  This is fairly well understood.  But if Svensmark was correct, it would mean that periods of high solar output should coincide with reduced cloud formation (due to reduced cosmic race incidence), which in turn would have a warming effect on the Earth, since less sunlight would be reflected back into space before hitting the Earth.

Here was a theory, then, that would increase the theoretical impact on climate of an active sun, and better explain why solar irradiance changes might be underestimating the effect of solar output changes on climate and temperatures.

I go on to discuss the recent CERN CLOUD study and what it has apparently found.

  • dearieme

    "Global warming advocates have responded, in turn, that while the sun has indeed been more active in the last half of the century, the actual percentage change in solar irradiance is tiny, and hardly seems large enough to explain measured increases in temperatures and ocean heat content." The first time I heard that from them I guffawed. Their own model relies entirely on inserting an amplifier to act on the direct effect of CO2; to deny their opponents the possibility of an amplifier is just dishonest.

  • RandomReal[]

    Just a particle shower :-)

  • Gil

    What does the Sun or water vapour have to do with anything as they're both pretty much stable? If anything the 18th century was cooler due to volcanic activity. The problem is supposed to be that of more and more CO2 is being released in the atmosphere causing the Earth to warm up because the atmosphere is capable of storing more of the Sun's heat. Likewise, if hydrogen fuel cells became all the rage and long-trapped hydrogen was being extracted which in turn caused more and more water vapour to enter the atmosphere then that would be bad news too.

  • Mark

    @Gil, CO2 is very weak greenhouse gas. The entire theory is that somehow the CO2 will cause extra H2O be in the atmosphere which will cause the actual warming. And the effect is suppose to cascade.

    It is a really bizarre theory once you read a bit about it.

    Not sure what good Hydrogen fuel cells will do. Hydrogen is not a fuel source, it is a store, like a battery.

  • Dan

    I'm no scientist, but this theory about cosmic rays affecting cloud formation on earth sounds kind of bizarre. I'm willing to hear more, but it's not accepted by most scientists and I wouldn't put too much stock in it.

    Basically, to embrace what you're saying, I'd have to believe that exploding stars billions of light years away can change the earth's climate, but that a dramatic rise in the level of carbon dioxide in the atmosphere over the last 150 years can't change the climate.

    It's easy to see that in order to avoid facing the inconvenient (to industry) explanation of global warming, you're resorting to fantastic explanations that wouldn't require us to make any changes that might affect the economy.

    I'm not even saying I believe we need to make such changes or that climate change is an urgent issue. I'm undecided. But your motivations are pretty transparent when you cite research like this.

  • tomw

    Dan said:
    Basically, to embrace what you’re saying, I’d have to believe that exploding stars billions of light years away can change the earth’s climate, but that a dramatic rise in the level of carbon dioxide in the atmosphere over the last 150 years can’t change the climate.

    Dramatic? If you have a LCD computer monitor with 1024 X 1024 resolution, you have a megapixel display. Man's DRAMATIC contribution to GW is 3.5 of those pixels. Hardly dramatic.
    Even if all of the 'suggestions' to curtail CO2 emissions, or reduce them were acted upon, the effect on the concentration of CO2 in the atmosphere would be what exactly? The .5 ppm? How much would the 'warming' be reduced? Show the rest of us how DRAMATIC the mathematical proof is, or the dynamic model that can produce the historical measured values of the recent past.
    They can't. None of the models used even take into account cloud formation, and even ignore the most powerful greenhouse gas of all, water vapor. Instead, they zeroed in on the most insignificant of all greenhouse gases, CO2. Why? Because it is MAN MADE. Except for volcanoes, forest fires and natural decay of anything made from Carbon.

  • Dan

    TomW,

    I agree with you that other factors besides CO2 should be taken into account to explain the recent warming. I'm just saying don't ignore CO2, or else you're selectively removing the one element you don't like from the equation. Science means looking at all possible factors, not removing one because it might not support the conclusion you're attempting to draw.

  • Gil

    Uh oh! You're willing to admit CO2 is a Greenhouse Gas! CO2 is weak per se but it is the primary GHG that humans are pouring into the atmosphere. (It's the same one termite won't destroy a person's house but a whole nest of them will.) Since it's heavier than air it accumulates around the surface of the Earth and thus the heat that is trapped is the ground level. There's also the possibility of large amounts of methane trapped under Arctic ice which would help to accelerate Global Warming if released. The real kicker is that methane breaks down into other molecules one of which is CO2 - a rather stable molecule.

    P.S. I was imagining a scenario in which hydrogen could be produced en masse from a lot trapped source for little energy (thus making hydrogen a energy source) which in turn meant humans went from pouring CO2 into the air to the more potent GHG, water vapour, into the air.