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NASA Space Science

Big Drop In Solar Activity Could Cool Earth 569

coondoggie writes "Scientists say the Sun, which roils with flares and electromagnetic energy every 11 years or so, could go into virtual hibernation after the current cycle of high activity, reducing temperatures on Earth. As the current sunspot cycle, Cycle 24, begins to ramp up toward maximum, scientists from the National Solar Observatory and the Air Force Research Laboratory independently found that the Sun's interior, visible surface, and corona indicate the next 11-year solar sunspot cycle, Cycle 25, will be greatly reduced or may not happen at all."
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Big Drop In Solar Activity Could Cool Earth

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  • by Anonymous Coward on Tuesday June 14, 2011 @05:14PM (#36441966)

    How does the sun know how much greenhouse gas I'm generating to heat or cool the planet?

  • Better article (Score:4, Informative)

    by dogmatixpsych ( 786818 ) on Tuesday June 14, 2011 @05:22PM (#36442132) Journal
    The networkworld (why are we posting a solar/space article from there?) article links to a much better Cosmic Log article: http://cosmiclog.msnbc.msn.com/_news/2011/06/14/6857473-solar-forecast-hints-at-a-big-chill [msn.com]
  • by cwebster ( 100824 ) on Tuesday June 14, 2011 @05:39PM (#36442402)

    Decreased solar output will have an impact on global temperatures, but it will take time.

    Greenhouse gasses (Water, CO2, CH4, etc) do not directly interact with incoming shortwave radiation from the sun. Rather, they interact with the longwave radiation coming from the surface of the Earth. With no greenhouse gasses, the Earth would radiate (based on its temperature) and this radiation would be lost to space. What greenhouse gasses do is absorb the emitted longwave which adds energy to the molecule absorbing it. The excited state either results in a temperature increase of the molecule, or the emission of radiation. Some of this re-emitted radiation is directed downward, toward the Earth. The net result is that some energy that would be lost to space is absorbed by molecules in the atmosphere, warming it, and some is redirected back to the Earth, increasing the net incoming radiation.

    The effect can be directly observed. If you look at the measured longwave radiation emitted at the top of our atmosphere, the global average temperature you would calculate would not support life as we know it (much too cold). The difference from that and our directly observed average surface temperatures are due to the greenhouse effect (the energy based on those temperatures is not making it to the top of the atmosphere).

    Decreasing solar input would change part of the energy budget, but the greenhouse effect will act as a buffer (from absorbing and re-emitting longwave radiation) that would cause a delayed response.

    Note that I am not a climate scientist, just a regular meteorologist who has taken a few classes in radiative transfer.

  • by peter303 ( 12292 ) on Tuesday June 14, 2011 @05:41PM (#36442412)
    Slight changes in Earths orbit over the Millennia have the best correlation of any factor. These are called the Milankovitch Cycles [wikipedia.org]. This does not rule out a co-factor like a series of large eruptions pushing the climate over the edge. There is about 20K years until the next Milankovitch susceptibility.
  • Re:Starvation (Score:5, Informative)

    by riverat1 ( 1048260 ) on Tuesday June 14, 2011 @05:48PM (#36442534)

    Solar activity had nothing to do with "The Year Without a Summer". It was the eruption of Tambora that caused that.

  • by Nemyst ( 1383049 ) on Tuesday June 14, 2011 @05:50PM (#36442564) Homepage

    Never did he say that those were man-made issues, he simply used them to illustrate how fickle and changing nature can be, which is entirely appropriate and not up to questioning.

    You should read what it is you're replying to, it helps.

  • by Mindcontrolled ( 1388007 ) on Tuesday June 14, 2011 @05:58PM (#36442694)
    Well, to be honest, we are not that exceptional in this regard. Many a species has created its own version of the great pacific garbage patch. Growing to your limits and then crashing seems to be a biological imperative. Only we do it on a global scale - well, you might hold that one to the early photosynthesizing algae, which poisoned the reducing atmosphere of early earth with oxygen. What sets us apart is only the fact that we are blessed (?) with sentience, and should be able to look into the future, at least a little bit.
  • Re:Oh good... (Score:5, Informative)

    by riverat1 ( 1048260 ) on Tuesday June 14, 2011 @05:59PM (#36442710)

    And they're going to be sorely disappointed when the warming continues despite reduced solar output.

    Even if the Sun went into a new Maunder Minimum Global Warming will continue because the forcing from increased GHG's (primarily CO2) overwhelms the change in insolation. There is a peer reviewed paper on the subject here: On the Effect of a New Grand Minimum of Solar Activity on the Future Climate on Earth (Feulner & Rahmstorf 2010) [agu.org].

    So what will the "naysayers" response be to continued warming despite reduced insolation?

  • by CyberBill ( 526285 ) on Tuesday June 14, 2011 @05:59PM (#36442716)

    Local solar astronomer here - Current global warming trend is definitely not Sun driven. We went through a prolonged period of solar inactivity over the last 5 years and what do you know, temperatures kept going up. We also monitor the Sun in every conceivable wavelength and from multiple angles, so it would be pretty hard to have some significant amount of energy hitting us that we don't know about.

  • by Mindcontrolled ( 1388007 ) on Tuesday June 14, 2011 @06:16PM (#36443032)
    Criticism usually includes putting forth an alternative model. Not just shouting "NO! NO! NO!". The basic forcing by CO2 is a simple physical fact - every 2nd semester student can do the math. The effect is measurable, just take a spectrum. Did that myself, ages ago in a physical chemistry lab session. Measuring the increase in atmospheric CO2 is trivial. Proving that the increase is anthropogenic is trivial - just look at the isotope ratio. Measuring solar input is trivial. These are the basic forcings. Now, the feedbacks and the amount of their contribution is open, I give you that - but the basic fact of warming due to CO2 is simply not open to debate any more.
  • Re:Oh good... (Score:4, Informative)

    by Jeremy Erwin ( 2054 ) on Tuesday June 14, 2011 @07:57PM (#36444194) Journal

    That link requires AGU membership. For non-members: Feulner and Rahmstorf's paper (pdf) [pik-potsdam.de]

  • Re:Oh good... (Score:4, Informative)

    by SETIGuy ( 33768 ) * on Tuesday June 14, 2011 @08:34PM (#36444540) Homepage

    I'll go away as soon as you explain the difference between the 1990 IPCC predictions for and the actual measured temperatures reported in HadCRUT for 1990-2011.

    No you wont, because the temperatures are well within the prediction envelope. As is sea level rise. Sea level rise stands a chance of breaking through the top of the prediction envelope soon.

    A slight reduction in insolation can only be good. But it's temporary reduction and therefore not a solution to the problem.

    Are you going away?

  • Re:Oh good... (Score:4, Informative)

    by SETIGuy ( 33768 ) * on Tuesday June 14, 2011 @08:44PM (#36444610) Homepage

    Yep, as long as you don't look at the real data we've been steadily cooling since 1998. My weather girl says it's colder now then it's been since God created weather. She's pretty and blond, so she must be smart.

    But if you actually look at the temperature record, last year was the warmest on record and the one before was the third warmest and we've been on a steady warming trend for 40 years.

  • Re:Oh good... (Score:4, Informative)

    by riverat1 ( 1048260 ) on Tuesday June 14, 2011 @11:25PM (#36445710)

    Except for the fact we've been cooling for the last 13 years, ...

    Yes, if you cherry pick 1998 as your starting point you can contrive to make it look like maybe there's been a little cooling. But seriously, who uses 13 years periods for something like this? Climatologists generally use 30 year periods. CO2 is like the rising carrier signal that the natural variability noise signal sits on. Rising CO2 levels don't lead to a monotonic rise in temperatures, just a bias toward higher temperatures. Natural variability can overcome that bias over periods of less than 15 or 20 years.

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