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It's that most wonderful time of the year! Christmas decorations are going up all over America. Those colorful little strings of twinkling lights racing down eaves and winding artfully around tree trunks can do more than paint pretty holiday vistas. We can use them as an intuitive probe to look at our nearest neighbor in space and speculate on earth's distant, or not so distant, future.

A typical Christmas tree light puts out about one watt of heat and light energy. That's not a lot but it does the job. On that same scale, the incident solar radiation, or insolation, received by earth when all wavelengths are taken into account works to about 250 watts per square meter1 (usually referred to as just "watts") when averaged over the entire surface, light and dark, from poles to equator. Some of it is reflected back, the rest is absorbed.

If you take an introductory planetary astronomy course you'll hear the usual spiel that the earth is in the solar system's Goldilocks zone, not too hot like our sister planet Venus, not too cold like our smaller cousin Mars. It's actually more complicated than that. At 250 watts, the earth is a little too far away, a little too cold, for our liking. By the laws of simple thermodynamics our lovely blue-green planet should boast an average temperature well below the freezing point of water. And the sun is very slowly heating up, roughly 5 to 10 percent per billion years, so ancient insolation was even less long ago than it is now. The earth should have started out frozen solid right down to the deep ocean trenches and it would be a brilliant iceball hanging in space like a snow-white ornament to this day. What's kept that grim fate at bay for billions of years are greenhouses gases (GHGs).

If you compare GHGs like  carbon dioxide (CO2), water vapor (H2O), and ozone (O3), to non GHGs in our atmosphere like oxygen (O2) or nitrogen (N2), one of the first things you notice is that the GHGs have more than two atoms. That's not a coincidence. The physical arrangement of atoms that make up GHGs allows them to absorb a lot more heat than the simpler compounds. They act on our planet just like windows in your car; they let light through but retain heat, so when you come back to your SUV in a sunny parking after holiday shopping, it's noticeably warmer inside.

The Greenhouse Effect saved earth from turning into a snowball and made our world a haven for life, but the same phenomenon pulled Venus into the fiery pit of hell. Billions of years ago, lovely Venus was true to her mythological name, hospitable, inviting, and probably much more like earth. Evidence suggests she had warm liquid oceans and everything else a heat loving anaerobic microbe could want. But proximity to the sun and relentless solar heating evaporated more and more water. Water vapor is a potent heat trapping gas. The temperature rose further evaporating more water, the process fed back, viciously, and eventually the oceans boiled off completely cloaking the planet in thick steam. High in the atmosphere, under the influence of harsh solar UV, hydrogen atoms escaped their watery embrace with oxygen and bled into space. The oxygen combined with left over nitrogen to form clouds of acid. Nearer the now broiling surface, carbon was baked out of the rock and combined with oxygen to form CO2, trapping even more heat. The picture of the surface below taken by a Russian probe (Venera 13) gives an idea of what Venus is like now (Click on any image to enlarge offsite). The horizon is off in the upper right corner.

It's every bit as hot as it looks. Today Venus is as dry as a bone under a smothering atmosphere ninety times denser than ours and the planet roasts at 850 F. So hot it snows metal, so hot you wouldn't need a light in a Venusian cave because the walls glow red. Some scientist speculate that if Venus had a robust microbiology early on, microbes might still eek out a living high in the clouds. But any life that resembled even the hardiest terrestrial thermophiles on or near the surface was charred to a cinder.

Planetary astronomers don't know for sure when this happened. But it most likely occurred at least 500 million years ago, because that's the last time the entire surface melted and re-solidified in the tortured Hadaean tableau we see now. It may have periodically melted, several times, which means the climate on Venus may have spun out of control over two or three billion years ago when the insolation was not much greater than it is on earth today

That brings up a chilling question, no pun intended: could the same thing happen to earth? Yes, and it's not a matter of if, it's a matter of when. The sun will continue to slowly heat up until our world is forced into a similar greenhouse loop. It may take hundreds of million of years, but it probably won't take much more than a billion. And with a little help, say if a huge source of greenhouses gases were suddenly released, it might happen more quickly than we could ever dream up in our worst nightmare.

Climate scientists have found that at the current solar luminosity and continental configuration, the earth is amazingly sensitive to small perturbations in climate. The difference between the warm period we're in now and enough cooling to trigger an ice age is one, tiny twinkling little Christmas tree bulb over each square meter of the earth's surface for several centuries. If the lack of a single miniature decorative light could trigger ice sheets marching down into Indiana, imagine the warming that might ensue if 5 or 10 of them were added? Next week we'll look at the most recent work from the man who is arguably the world's foremost expert in climate science. He worries that, under some of the grimmer assumptions, we may embark on a whirl-wind journey to join our sister planet, in more ways than size and mass, a lot earlier than we think.

Originally posted to Daily Kos on Sun Nov 29, 2009 at 07:58 AM PST.

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Comment Preferences

    •  Yet Mars (0+ / 0-)

      experienced apparent global cooling and there is no liquid on the planet.  Seems an equally possible future for earth.

      "Just because I don't care doesn't mean I don't understand" -- Homer Simpson

      by USAFguy on Sun Nov 29, 2009 at 09:50:36 AM PST

      [ Parent ]

      •  Mars (4+ / 0-)
        Recommended by:
        lotlizard, adrianrf, Robobagpiper, yaque
        1. experienced some very localized cooling during a planet wide dust storm.
        1. we have barely taken Mars' temperature cmpared to the scrutiny given earth. We can estimate its average temp to within a degree or so, we have measurements frm a few spots at various times of the year, we have little data on long term trends and nothing like the thousands of stations on land, sea, and orbit we have for earth over decades.

        This is a common item used by warming skeptics to misinform, the dust storm part is usually not included, nor is the fact that we know earth's temperature and trends to within a hundredth of a degree from direct examination so it doesn't really matter what Mars is doing.

        •  Over geologic time, Mars lost its differentiated (3+ / 0-)
          Recommended by:
          DarkSyde, Tennessee Dave, yaque

          core and hence its planetary magnetic field, then much of its atmosphere.

          So yeah, it's cooled since the days it had an ocean.

          •  Yeah (2+ / 0-)
            Recommended by:
            Robobagpiper, yaque

            not sure where that was coming form though, it looks like a gabled version of a common skeptic chestnut. I believe the current thinking is that Mars cooled off very early on because it lost most of it's atmosphere, which if present signs and traces are any indication included water vapor and a lot of CO2.

            •  Indeed; and though I mainly (2+ / 0-)
              Recommended by:
              DarkSyde, yaque

              hear mechanisms for the loss like solar wind scavenging and the like, I'm personally wondering what role impact played.

              The lack of crustal magnetism in the northern hemisphere, with its considerable presence in the southern (except notably in Hellas), speaks to massive resurfacing of the north some time after the planetary dynamo shut down.

              I've heard a couple people mention a massive impact event in the northern hemisphere as a cause for it, but no mention of what impact that would have on the atmosphere. I suspect it would be catastrophic.

  •  Excellent essay. I didn't know much about (10+ / 0-)

    Venus. A prominent clown Senator in Oklahoma might find this useful.

  •  Some corrections ... (16+ / 0-)
    1. Total solar irradiance, corrected for orbital distance, averages about 1365 Watts per square meter above the atmosphere. Spreading that over the surface gives mean insolation of 341.25 Watts per square meter, a lot more than the 250 you quote.
    1. Greenhouse gas molecules have more than two atoms.

    If you don't stand for something, you'll stand for anything.

    by Keith Pickering on Sun Nov 29, 2009 at 08:03:54 AM PST

  •  Love your essays DarkSyde. (4+ / 0-)

    I'll hotlist yet another one.

    A society grows great when old men plant trees in whose shade they know they shall never sit. -Greek proverb

    by marleycat on Sun Nov 29, 2009 at 08:04:53 AM PST

  •  500 million years (5+ / 0-)

    That's the number I've heard for the point where solar luminosity heats the earth to the point where life goes bye bye.  If true it suggests that solar system only had time to create one species of intelligent life.  Or put another way, if we wipe ourselves out a second chance is unlikely.

    We'll, there's always Europa.

    Die energie der Welt ist constant; die Entropie der welt strebt einem Maximum zu. - Rudolf Clausius, 1865

    by xgy2 on Sun Nov 29, 2009 at 08:06:24 AM PST

  •  Inhofe is right! It's all natural cycles! (3+ / 0-)
    Recommended by:
    B Amer, happymisanthropy, Karl Rover

    Sunspots!  Plants breathe CO2! (the latest denier skeptic twit line) The glaciers hacked the emails!

  •  I've always said... (7+ / 0-)

    that the issue of climate change wasn't about "killing the earth," especially since many deniers turn first to the "it was much warmer in the past" argument.  It's about destroying us, wrecking our society to the point where our whole civilization is in doubt.

    Turns out that I was wrong.  We could really tip it over.

    We seem intent on acting out some kind of nightmarish event from a Hal Clement novel.

    •  The (7+ / 0-)

      way Hansen puts it is something like "If we burn every last drop of oil, gas, and shovelful of coal in the next century, the syndrome becomes a possibility. If we add in tar sands, shale, and maybe some methane hydrate in the same period, it's a dead certainty." The latter is a big factor though, there's way more tar and hydrate than traditional fossil fuels even counting coal. It's also the speed of adding it that tips it. Done over thousands of years, like in the Paleocene-Eocene Thermal Maximum, natural, dampening feedbacks might have time to set up.

    •  Isn't the earth doomed in the long run? (1+ / 0-)
      Recommended by:

      As the sun will become a red giant that will expand and engulf the earth, before it implodes and dies?

      "We have always known that heedless self-interest was bad morals, now we know that it is bad economics." Franklin Delano Roosevelt, Jan. 20, 1937

      by Navy Vet Terp on Sun Nov 29, 2009 at 09:01:15 AM PST

      [ Parent ]

  •  Wow! Snowing metal (6+ / 0-)

    So hot it snows metal...

    That was some great cognitive dissonance there -- thanks for this, Darksyde, and for all your science fabulousness.

    Now what I want to know is: what metal(s) are snowing on Venus?


  •  Give a little credit to a nuclear furnace and (0+ / 0-)

    vulcanism.  It ain't all in the air.

    Free speech? Yeah, I've heard of that. Have you?

    by dinotrac on Sun Nov 29, 2009 at 08:17:21 AM PST

    •  Venus doesn't have any active vulcanism (2+ / 0-)
      Recommended by:
      dinotrac, yaque

      that anyone can tell.

      Indeed, the lack of any significant planetary (or crustal) magnetic field raises the question of how geologically active the planet is at all.

      •  but the earth does nt (0+ / 0-)

        Free speech? Yeah, I've heard of that. Have you?

        by dinotrac on Sun Nov 29, 2009 at 10:10:53 AM PST

        [ Parent ]

        •  The the energy budget of vulcanism and (2+ / 0-)
          Recommended by:
          dinotrac, yaque

          geothermal heat through the surface of the Earth is minute compared the insolation.

          Except for secondary effects (like particulates and GHGs from volcanos) and the planetary magnetic field, the actual heat budget from below the crust is not a noteworthy climate forcer.

          •  Today, in my basement, it's not. (4+ / 0-)
            Recommended by:
            DarkSyde, adrianrf, Tennessee Dave, yaque

            And, as you pointed out, there is a difference in the amount of solar energy that reaches the vicinity of the earth and that which makes it to the ground.

            Millions and billions of years ago, vulcanism was a much bigger factor than it is today, but we still get lots of geothermal energy and major eruptions can still cool the planet a smidge.

            Free speech? Yeah, I've heard of that. Have you?

            by dinotrac on Sun Nov 29, 2009 at 10:34:48 AM PST

            [ Parent ]

            •  Your basement is not reflecting the (5+ / 0-)
              Recommended by:
              DarkSyde, alefnot, adrianrf, dinotrac, yaque

              planetary average.

              Insolation puts 250 W/m^2 into the climate, averaged over the planet. Geothermal puts 0.06 W/m^2 into the climate, averaged over the planet.

              That's almost five orders of magnitude difference.

              Geothermal energy per se is a negligible factor. Stratospheric aerosols and particulates from volcanoes on the cooling side, and GHGs from volcanoes on the heating side are not negligible.

  •  I used to play around with feedback algorithms (4+ / 0-)
    Recommended by:
    DarkSyde, se portland, adrianrf, fernan47

    on Microsoft Excel, back in the 1990s when so-called chaos theory was in vogue.

    I found, for example, that if I set sin(x) = output, and x = r x output, I could get to the point where just a teeny, tiny change in r would create a "catastrophic" change in my plot of output.

    Same, I guess, for planet Earth.

  •  I'd read an interesting chapter in a book on (7+ / 0-)

    Venus and why we aren't likely to go that route. Something about some bad combination of factors, including being 30 million miles closer to the sun, and a bit smaller than EArth, meaning that Venus just couldn't manage to keep its oceans from boiling off. Also, something about there not being any subduction on Venus because there's something different about the make-up of its innards. It may be something also about there being no moon, so that the lack of a lunar gravitational pull doesn't work on Venus in the same beneficial manner that it does on Earth. REally interesting read, including something about Venus leaking off its hydrogen pretty early in the game, becase being a little smaller and a little hotter made it that much easier for hydrogen to make it to escape velocity.

  •  Meteorites (5+ / 0-)

    A bit off topic, but your observation that the Earth is actually in a rather chilly zone reminded me of a myth.

    The myth, that almost everyone I talk to believes, is that meteorites are red hot when then hit the ground.

    But it is not true.  A meteorite is just as likely to be cold as hot, depending on the path it takes to get here. If it hits at something close to a 90 degree angle, then yes it will be hot. But if it hits at a more oblique angle then it can be quite frosty because it will have spent more time in the very cold upper atmosphere.

    Of course large ones, even if they where cold when they hit, will get hot when the energy of the impact is converted to heat. But, you might be able to walk over to a little one, pick it up, and put it in your pocket a second after it hits.

    Four out five sock puppets agree

    by se portland on Sun Nov 29, 2009 at 08:18:55 AM PST

    •  The Earth -- (2+ / 0-)
      Recommended by:
      se portland, Tennessee Dave

      is much closer to the hotter end of the zone of habitable planets around the Sun than it is to the cold end.

      "The greatest purveyor of violence in the world today -- my own government." -- Martin Luther King Jr.

      by Cassiodorus on Sun Nov 29, 2009 at 08:22:00 AM PST

      [ Parent ]

    •  meteorites after falling to Earth (0+ / 0-)

      The reason meteorites are likely to be red hot when they fall to Earth is because they have travelled through the atmosphere and have experienced friction. The friction is hot enough to usually make the meteorites explode even before they hit the surface. So it doesn't matter of they are coming in at a right angle to the surface or not, they will travel through the atmosphere and get red hot.

  •  Let's hope IPCC is right and 80%/2050 works. (4+ / 0-)
    Recommended by:
    Dauphin, adrianrf, jfromga, yaque

    80% reduction in human generated greenhouse gases by 2050 is theInternational Panel on Climate Change's goal for keeping global warming from getting out of control and having consequences that human civilization cannot adapt to.

    Obama and Democrats are on board. Europe is on board. China, India, Japan, Korea, Brazil are on board.

    The battle is really going to be in the US where the Christian fanatics and corporate sharks who control the GOP will fight to keep the worlds No. 1 polluter and producer of greenhouse gases from fixing the problem.

    •  The IPCC is wrong. (3+ / 0-)
      Recommended by:
      adrianrf, Tennessee Dave, yaque

      Their predictions as to the extent of abrupt climate change are lowballing it past the point of credibility -- Joseph Romm has already pointed this out in detail.  I have already argued that they have underestimated the problem by a factor of three or four.

      "The greatest purveyor of violence in the world today -- my own government." -- Martin Luther King Jr.

      by Cassiodorus on Sun Nov 29, 2009 at 08:36:11 AM PST

      [ Parent ]

    •  There were recently two papers in "Nature" (5+ / 0-)

      that indicated that we shouldn't be looking at emissions reductions by a certain year.  It's the cumulative impact of all of the greenhouse gases that matter.  That means that if we slowly reach some target, things will be a whole lot worse than if we reduce emissions sooner.

      The other part of this is that the total concentration of greenhouse gases must be below some critical amount, which is currently not known for sure.  However, the best analysis available suggests that we've already passed that amount.

      Reducing emissions is not enough.  We have to reduce the current atmospheric concentration of GHGs.

      The conclusion that I draw is that unless we reach some good tipping points in lifestyles with lower carbon footprints and in technologies that reduce emissions and in technologies that allow us to reduce atmospheric GHGs, we're not going to do well.

      We're passed the point where talking is enough.

      "Trust only those who doubt" Lu Xun

      by LookingUp on Sun Nov 29, 2009 at 09:17:16 AM PST

      [ Parent ]

      •  IPCC is the science spot. Gotta go with science. (0+ / 0-)

        Versus anonymous internet bloggers interpretation of something they read.

        •  Actually peer reviewed journals, such as (4+ / 0-)

          Nature, are where the science is.

          The IPCC is a quasi-scientific organization.  It includes political representatives from all nations involved, and they often keep the scientists from going with the science 100%.  It works reasonably well, but the stronger the claim, even when backed up by good science, the less likely it will get into print.

          To go with the science, read the journals and talk to other scientists.  That's what I do.

          Of course anything written in here is opinion, but that can be a starting point for forming additional perspectives.  If you choose in advance to ignore what is written by "anonymous internet bloggers," there's not a lot of point in reading here.

          "Trust only those who doubt" Lu Xun

          by LookingUp on Sun Nov 29, 2009 at 09:56:24 AM PST

          [ Parent ]

  •  I'll bet the skiing sucks on Venus. (7+ / 0-)

    But I am amazed that the Russians landed a probe that was able to send back data for an entire hour before it was smelted into nothing.

    Once in a while you get shown the light, in the strangest of places if you look at it right.

    by darthstar on Sun Nov 29, 2009 at 08:26:52 AM PST

  •  LED lights and non-carbon energy sources (3+ / 0-)
    Recommended by:
    adrianrf, Tennessee Dave, fernan47

    And if the nations of the world could truly cooperate (starting with dismissing our US-ian denial-ists) we could regulate our greenhouse gases in much the same way we regulate pH in a fish tank.

    Just on a much larger scale.

    Governing well shall be the best revenge

    by Bill White on Sun Nov 29, 2009 at 08:28:51 AM PST

    •  I think we need LSD lights. (5+ / 0-)

      Wouldn't that be great! ;)

      "The greatest purveyor of violence in the world today -- my own government." -- Martin Luther King Jr.

      by Cassiodorus on Sun Nov 29, 2009 at 08:37:05 AM PST

      [ Parent ]

    •  hmmmm (0+ / 0-)

      commercial products - tube fluorescents with high efficiency ballasts still beat white LEDs, as do metal-halide lamps.  There are higher efficiency LEDs in the labs and as prototypes, some of the most recent LED products claim to have reached higher efficiencies than those other two, but those claims have been disputed as being distortions. Certainly there is a tendency to report the efficiency of the LED, without including losses in the support electronics, while the fluorescents and metal-halide lamps are evaluated as the complete system.

      You also need to consider that LEDs are directional sources, while the other two types are area illuminators; that adds extra materials resources to a LED-based replacement.

      If you notice commercial establishments have been using fluorescents and metal-halide lighting for some years; it's more efficient and thus saves money.  It's the residential users that are lagging.

      There is also increasing evidence that the wavelength of the actual LED in a white LED can be harmful to the eye. If so the white LED story gets reset using LEDs in the deep blue to near UV.

      But if you are really serious about efficiency, you'd move to low pressure sodium vapor lighting as it can be 130% more efficient than the best that white LEDs have reached.

  •  I've been away (3+ / 0-)
    Recommended by:
    adrianrf, LookingUp, yaque

    from this subject for awhile, but it seems the deniers have become more shrill in their comments and insults toward similar articles written in mainstream papers like the WaPo.  I suspect it's partially because of some encouragement from the 'climategaters', but it probably has more to do with the approaching consensus expected at Copenhagen.  

    Subtlety: The art of saying what you think and getting out of the way before it is understood.

    by ccallure on Sun Nov 29, 2009 at 08:29:33 AM PST

  •  Given that the IPCC predictions (1+ / 0-)
    Recommended by:

    are off by a scale of three to four, it would probably be wisest for the human race to do an inventory of existing fossil fuels to decide which are to be burned and which are to be left in the ground.

    Is anyone going to propose this at Copenhagen?  And, if not, why not?

    "The greatest purveyor of violence in the world today -- my own government." -- Martin Luther King Jr.

    by Cassiodorus on Sun Nov 29, 2009 at 08:31:24 AM PST

  •  Positive feedback & exponential growth. (5+ / 0-)

    proximity to the sun and relentless solar heating evaporated more and more water. Water vapor is a potent heat trapping gas. The temperature rose further evaporating more water, the process fed back, viciously, and eventually the oceans boiled off completely cloaking the planet in thick steam. High in the atmosphere, under the influence of harsh solar UV, hydrogen atoms escaped their watery embrace with oxygen and bled into space. The oxygen combined with left over nitrogen to form clouds of acid. Nearer the now broiling surface, carbon was baked out of the rock and combined with oxygen to form CO2, trapping even more heat

    These kind of reactions always seem to accelerate exponentially. We can fairly easily imagine linear growth, but the speed with which exp growth "takes-off" is really hard to understand.

    -- We are just regular people informed on issues

    by mike101 on Sun Nov 29, 2009 at 08:31:40 AM PST

  •  Permanent runaway greenhouse effect unlikely (0+ / 0-)

    "[there] is no possibility of [Venus's] runaway greenhouse conditions occurring on the Earth", John Houghton.

    If apes evolved from humans, why are there still humans?

    by Bobs Telecaster on Sun Nov 29, 2009 at 08:43:58 AM PST

  •  Recent evidence (2+ / 0-)
    Recommended by:
    Ignacio Magaloni, yaque

    suggests that 2 billion years ago, Earth was indeed a 'snowball Earth', only retreating from that state as a result of native volcanic acitivity

    images here:

    And further, it happened at least twice, the more recent event 700 million years ago, IIRC


    "Never trust a computer too big to throw out a window" -Steve Wozniak

    by Four of Nine on Sun Nov 29, 2009 at 08:45:44 AM PST

    •  Further (3+ / 0-)
      Recommended by:
      Ignacio Magaloni, adrianrf, yaque

      The Earth may be on the verge of a massive, cascading release of methane similar to one that caused a global warming that ended the last “snowball” ice age, according to a team of California scientists.
      Writing in the journal Nature, lead researcher Martin J. Kennedy of UC Riverside suggests the same kind of warming could be about to occur, not over thousands of years, but within a human lifetime.

      Methane is 25 times more potent as a greenhouse gas as carbon dioxide (CO2), and 10,000 gigatons of frozen methane are currently stored in the world’s oceans and permafrost.

      The current trend of accelerated permafrost melting as the Arctic warms faster than other areas of the planet could release vast amounts of methane into the atmosphere, triggering rapid climate change.

      Kennedy worries that rising CO2 levels could drive enough warming to destabilize the Earth's stored methane reserves.

      “Unzippering the methane reservoir could potentially warm the Earth tens of degrees, and the mechanism could be geologically very rapid.” Kennedy wrote


      More at the link:

      "Never trust a computer too big to throw out a window" -Steve Wozniak

      by Four of Nine on Sun Nov 29, 2009 at 08:47:53 AM PST

      [ Parent ]

  •  umbrella (1+ / 0-)
    Recommended by:

    It's becoming painfully obvious that the world's leaders will not stop global warming--it's bad local politics, especially during a recession.  Even if they saw the light, some warming seems unavoidable, unless we shield the sun light.  Whenever a big volcano erupts, we are told the earth gets temporarily cooled, could we do this artificially?  I know there could/would be unintended consequences, but things seem to be heating up rapidly, and we should be getting desperate.  At least this should be carefully studied.  Please--I have children.

  •  Mercury is half the distance to the Sun as Venus (7+ / 0-)

    and about half as hot. That shows you the power of an extreme greenhouse atmosphere.

  •  I wonder how far the parallel goes between Earth (9+ / 0-)

    and Venus....

    I wonder if at one time Venus didn't also have it's own round the clock climate change-denial tv news network???

    If cats could blog.... they wouldn't.

    by crystal eyes on Sun Nov 29, 2009 at 08:56:22 AM PST

  •  Faint Young Sun (1+ / 0-)
    Recommended by:

    That's all well and good, but if the Sun was a little bit colder in the past and the climate is so sensitive, how come our planet wasn't a snowball for most of its history?  I don't really buy the possibility of a runaway greenhouse in the near term.  We've had plenty of warmer times -- the Paleocene-Eocene Thermal Maximum springs to mind -- that did not result in a runaway greenhouse, and to this day, our models still can't predict the temperatures then as "observed" (from paleorecords).  I'm sure it'll turn out that humanity is very sensitive to small changes in global average temperature, but the climate itself is quite far from such an apocalypse.  (That's not to say that more reasonable climate apocalypses aren't coming -- rising oceans, etc. -- just not something that will turn us into Venus in the next few hundred years.)

    •  Evidence (2+ / 0-)
      Recommended by:
      adrianrf, yaque

      is the earth did indeed go through periodic snowball events. Early on, the planet is thought to have had a thicker atmosphere or at least much higher ghg levls which would have kept the oceans liquid. But later, especially after photosynthetic bacteria evolved, the CO2 levels crashed and the world became very cold, perhaps thick ice at the poles and slush or thin ice even at the equator. But ice doesn't stop volcanic outgassing, and with little or no precip and other processes to remove them, ghgs would build up over five to ten million years and bail us out of the total snowball every time.

    •  The sun was much cooler billions of years ago, (5+ / 0-)

      but during most of that time the CO2 concentration in the atmosphere was also a lot higher.  There is little doubt of either of these statements, and this shows how large an affect greenhouse gases can produce.  It also, along with the case of Venus, shows that the old claim that the effects of GHGs have reacher saturation is completely ruled out by objective evidence.  It's also ruled out by the theory behind spectroscopy.

      100 million years ago the sun was about 1% cooler than it is now, but the Earth was significantly warmer.  The difference is mostly accounted for by differences in CO2 concentration.

      We happen to be in a time of unusually low atmospheric CO2 concentration.  Speculation is that this is due to a combination of unusually low volcanic activity over the last 100 million years or so along with the exposure of minerals from the plate collision that is building the Himalayas.  These minerals slowly take CO2 out of the atmosphere through weathering processes.

      Much of life now on Earth, including us, has adapted to these conditions.  We are now rapidly changing them, and evolution isn't keeping up.  This is an experiment that I'd rather not continue.

      "Trust only those who doubt" Lu Xun

      by LookingUp on Sun Nov 29, 2009 at 09:32:23 AM PST

      [ Parent ]

  •  No, it can't happen here. (1+ / 0-)
    Recommended by:

    OK, I'm not an expert, but everything I have seen indicates that the Earth is simply too far from the sun for the same thing to happen as Venus.  There simply is not enough energy to keep the water from raining out again. I get the thing about maybe in a billion years the sun might warm up enough.  Maybe, especially right before it explodes, but I'm not going to worry about that just yet.

    I'm all for Cap and Trade and putting the deniers in their place, and I have never put up Christmas lights.  But I am also for science.  I am against any attempts to suppress dissent, as the infamous folks at CRU may or MAY NOT have been doing.  And I am against telling people that the Earth will be destroyed if they put up too many Christmas lights. There are good reasons to save energy short of that.

    "I beseech you,... think it possible you may be mistaken." -- Cromwell/Bronowski

    by jockyoung on Sun Nov 29, 2009 at 08:59:11 AM PST

  •  Storms of My Grandchildren.. (1+ / 0-)
    Recommended by:

    Thanks for the link to the Amazon page on this forthcoming book. I searched its contents for "nuclear" and it appears he has a lot to say on the subject of nuclear energy, including why we aren't using more of it now. As my sig might suggest, I am very interested to read more on this subject when the book comes out, along with what he has to say about climate change.

    Moderation in most things. Except Reactors. IFR forever!

    by billmosby on Sun Nov 29, 2009 at 09:01:46 AM PST

  •  GOP from Venus. Democrats from Mars. (2+ / 0-)
    Recommended by:
    DarkSyde, dotalbon

    The melted slag heap or the cool planet we could survive on with fusion power.

    Humanity could terraform and migrate to Mars but Venus holds no hope.

  •  I can't understand (9+ / 0-)

    why some folks fret about imaginary Muslims hiding under the bed while we're messing with the fate of the whole damn planet. Excellent diary.

  •  P.S. Thanks DarkSyde (2+ / 0-)
    Recommended by:
    DarkSyde, dotalbon

    Lest anyone get grumpy, I should point out that I love the science stuff DarkSyde gives us. And I do not claim that my research is better than his.  I'm sure it is not. But I still have my opinions!

    "I beseech you,... think it possible you may be mistaken." -- Cromwell/Bronowski

    by jockyoung on Sun Nov 29, 2009 at 09:06:16 AM PST

  •  Fascinating diary, DarkSyde (0+ / 0-)

    It continually amazes me, the slender line that separates life from non-life.  In the case of Earth, that line is more slender than we'd thought.  Conditions had to be just right and stay right for life to begin, and flourish.

    I wonder if it's so far-fetched to believe that our form of life may be a unique phenomenon.  Yes, there are literally billions of planets in the universe, and some of those must be close to our own Earth conditions.  

    But think of the odds, for instance, against any one of US having been born at all. Given the number of events that had to happen just one way, those odds are truly staggering.   And perhaps that's the way it is with carbon-based life itself.

    I can't understand why people are frightened of new ideas. I'm frightened of the old ones. (John Cage)

    by dotalbon on Sun Nov 29, 2009 at 09:08:43 AM PST

  •  "So hot it snows metal..." (1+ / 0-)
    Recommended by:

    Wow, talk about an attention grabber.

    They only call it Class War when we fight back.

    by lineatus on Sun Nov 29, 2009 at 09:13:01 AM PST

  •  Venus has an extremely slow rotation (1+ / 0-)
    Recommended by:

    I thought that played a large role in it's current state.

    big badda boom : GRB 080913

    by squarewheel on Sun Nov 29, 2009 at 09:13:39 AM PST

  •  Some clarification on Greenhouse effect (3+ / 0-)
    Recommended by:
    adrianrf, smellybeast, yaque

    The chemical constituents in the atmosphere absorb very little of the incoming solar (shortwave) radiation. So it gets through to the earth.  The earth absorbs it, and re-radiates in the infrared (longwave). The GHG intercept this longwave radiation emitted by the earth (terrestrial radiation) because as you say they absorb in the IR - these are quantum vibrational transitions. Anyhow, this terrestrial radiation (which is just the earth trying to cool) is then not all lost to space, but is absorbed by GHG and some of it is re-radiated back to the earth's surface, warming the surface relative to the case where the terrestrial radiation escapes to space. The amazing thing is that the earth emits at a IR wavelength of a few microns and this wavelength happens to be matched to the quantum vibrational transitions of CO2 (and other GHG).  So in a sense,  the physics at the microscopic QM level are driving change on the planetary scale. Deep thought for the day.

  •  DarkSyde your presentation of knowledge is .... (1+ / 0-)
    Recommended by:

    ..... delicious, digestible and nourishing.

    I have lots of empty space inside where all the science can fit comfortably.

    Emptiness ... is always bigger ... than you remembered.

    by abarefootboy on Sun Nov 29, 2009 at 09:50:01 AM PST

  •  Insolation vs internal heating (0+ / 0-)

    Insolation is not the only way Earth receives warmth. While the sun is busy producing heat by nuclear fusion, the core of the Earth is producing heat by nuclear fission -- this is why (if I am not horribly mistaken) if you dig a big hole, the ground will reach a fairly constant temperature rather quickly, and the reason there is lava and magma and all that good stuff. What I don't know, and I'm curious if anyone does, is what is the ratio of incident heat between insolation and the Earth's internal nuclear source?

    •  you want to look at something like (3+ / 0-)
      Recommended by:
      alefnot, adrianrf, yaque


      solar radiation (99.978%, or nearly 174 petawatts; or about 340 W m-2)

      geothermal energy (0.013%, or about 23 terawatts; or about 0.045 W m-2)

      tidal energy (0.002%, or about 3 terawatts; or about 0.0059 W m-2)

      This, BTW, is why the ground sourced heat pumps for building heating are misnamed why referred to as geothermal heating. At a fraction of a watt per square meter, you're not going to get much heating from geothermal sources. What those systems do is extract stored solar energy from the ground, and that's why they are less attractive in the northern Midwest as they can mine out the summer's heat before the end of winter.

      •  The planetary component not (2+ / 0-)
        Recommended by:
        wondering if, adrianrf

        known with great precision, partly because of the sparsity and difficulty of measurements in the deep ocean, Antarctic, etc. I've seen estimates for the globally averaged quantity range from 30 mW/m^2 (probably too low) to over 100 mW/m^2. But even that factor of 3+ is noise compared to the solar term.

        •  Antartctica, being a standard continental plate (0+ / 0-)

          shouldn't be much different than any other major land mass, and it isn't all that large so even a factor of two wouldn't affect the total that much.

          Ocean beds are more of an issue, around ridges and in particular regarding vents.  The numbers you gave aren't out of bounds, but as you said - greater than 3 nines comes from the sun.

          •  Getting to this late ... (0+ / 0-)

            Antarctica has a fair amount of variability for a land mass (I've a figure here) -- West Antarctica is quite different from East. But there's a lot more interpolation there than in the US, eg. And in the end, of course, that variation is still just noise compared to the solar term.

  •  Carbon Sequesteration...Oil (2+ / 0-)
    Recommended by:
    adrianrf, Calamity Jean

    There is evidence that the existence of billions and billions of tons of unrotted and stored trees, grass, algae, animals, ferns, and bacteria mats have created the oxygen surplus, kept the majority of carbon molecules out of the atmosphere, moderating temperatures since the atmosphere is mostly nitrogen, a simple element, and not the complex energy-storing molecules of carbon and carbon compounds were more abundant.

    The issue we face is the unique situation of Earth, however it evolved. We have billions of tons of stored carbon in the crust, in coal, oil, natural gas, frozen methane at the bottom of the oceans, and its all rather "recent", within the last half billion years or 1/10th billion years or so. If we have used about 20 to 30 percent of that stored carbon, or even 10 to 20 percent of recoverable carbon, we have made a measureable dent in the composition of the atmosphere within which all mammals, flowering plants, and atmospheric feedback loops have evolved in the last 1/10 billion years.  

    It goes almost without saying that we cannot allow ourselves the freedom to screw that up, however much we value unrestricted freedom.  We can think of much better ways to express our freedoms.  

    Figures don't lie, but liars do figure-Mark Twain

    by OregonOak on Sun Nov 29, 2009 at 10:23:59 AM PST

  •  This is why I laugh at (1+ / 0-)
    Recommended by:

    climate change deniers. These pea-brained idiots couldn't tell you what happens to carbon dioxide.

  •  "At 250 watts the earth is a little too far away" (0+ / 0-)

    I think you meant 93 million miles, DS.

  •  Question (0+ / 0-)

    What's the insolation on the surface of Venus compared to that of Earth?

    (It's an easy calculation, but you'll get a range of answers because there's a range of estimates for albedo; the answer may surprise you.)

  •  It all makes me amazed and thankful to be here (1+ / 0-)
    Recommended by:

    on planet earth at this time in its history.


  •  Just a quibbly correction... (2+ / 0-)
    Recommended by:
    lotlizard, adrianrf

    According to the link you provided, Venera 13 was not a Russian probe, but rather, a Soviet probe.

    Credit where due :-)

    Those 47 million uninsured Americans? I am one of them.

    by Immigrant Punk on Sun Nov 29, 2009 at 05:55:49 PM PST

  •  God I hate science. (0+ / 0-)

    My eyes roll to the back of my head as soon as I see anything remotefully science related. But, thank God somebody loves it. And, no, I didn't read this diary.

    •  LOL (0+ / 0-)

      I am alone in a house full of engineers - from husband to children.  I'm the only one who reads novels.  And finding science diaries on kos is jarring sometimes, I'll give you that!  It's sure not why I come here.  But then again, there is always something new to be learned.  I now have dinner conversation with the geeks I've raised!

      Dancing Tom Delay - "That guy must have watched a lot of porn!" - Jon Stewart

      by Meggie on Mon Nov 30, 2009 at 06:21:52 AM PST

      [ Parent ]

  •  That Russian pict of Venus looks like the (0+ / 0-)

    pict from the diver's camera in Jaws, just tinted red this time.  Sorry Russia, gotta do better than that!

    Dancing Tom Delay - "That guy must have watched a lot of porn!" - Jon Stewart

    by Meggie on Mon Nov 30, 2009 at 06:18:48 AM PST

  •  Granite... (0+ / 0-)

    will tell the tale. If Venus has granite, then it has or had plate tectonics and oceans.

  •  Venus & Mars are not good Earths (0+ / 0-)

    There is plenty wrong with trying to compare Earth to either Venus or Mars. Mars wasn't massive enough to hold on to its atmosphere through gravity, while neither Mars nor Venus have magnetic fields that can divert the Solar winds & protect their atmospheres from it. Also, Earth has a massive moon, that stabilizes its rotational tilt, which neither Venus nor Mars have. Mars has two tiny moons, which are just glorified asteroids really, so tiny they could be moons or our own Moon.

    And another important factor why Earth can't be compared to Venus or Mars is that on Earth, life has firmly taken root. A lot of the chemistry of Earth's atmosphere was produced by its lifeforms entirely, including Oxygen & C02. So the life on Earth not only adapts itself to the changing climate on Earth, it also regulates it by varying the amounts of each type of gas getting released. Species going extinct is just the natural selection at work, where new species take their place that can survive better in the new environment. So a species of plant that might go extinct might be replaced by a species that absorbs more CO2, if CO2 levels are getting higher.

  •  The life on Earth regulates its own climate (0+ / 0-)

    As noted in the article, the Earth is a bit too far away from the Sun for real comfort. Also it's been noted that the Sun is going to be about 10% hotter in a billion years than it is now; it also true that the Sun was 10% cooler a billion years ago than it is now, and it was 40% cooler when the Solar system was created about 4.5 billion years ago. Yet life took hold on this planet despite the relative cold. That was because the life itself created the greenhouse gases that kept the Earth warm in a cold zone. As the Sun heats up, the greenhouse gases are going down to compensate.

    They often say that the Earth exists inside a Goldilocks Zone, where it is neither too hot nor too cold. That's not totally true, the Earth was in a good general location, and then life on Earth evolved and took over management of the climate and made it a Goldilocks planet. The Earth's climate is not teetering on a knife-edge where slight changes will kill all life forevermore. The Earth reaches new equilibriums from time to time, and the life on Earth evolves and adapts to it.

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