Slashdot Mirror

← Back to Stories (view on slashdot.org)

Global Warming 5 Million Years Ago In Antarctic Drastically Raised Sea Levels

Posted by samzenpus on from the how-deeps-the-water-momma? dept.

An anonymous reader writes "As temperatures rise, scientists continue to worry about the effects of melting Antarctic ice, which threatens to raise sea levels and swamp coastal communities. This event, though, isn't unprecedented. Researchers have uncovered evidence that reveals global warming five million years ago may have caused parts of Antarctica's ice sheets to melt, causing sea levels to rise by about 20 meters."

10 of 437 comments (clear)

  1. More to the point... by Extremus · · Score: 4, Informative

    It is well known that sea levels have been going up and down throughout the ages. The question now is whether or not we are acelerating these variations and whether life can adapt to them fast enough.

    1. Re:More to the point... by UnknowingFool · · Score: 4, Informative

      I call them deniers because despite the overwhelming scientific evidence, they still hold onto ideas based not on science. Same thing with the anti-evolutionists, birthers, and truthers. At some point you have to realize it doesn't matter what proof, what reasoned arguments you have, some people will believe what they want to believe.

      --
      Well, there's spam egg sausage and spam, that's not got much spam in it.
    2. Re:More to the point... by kedmison · · Score: 3, Informative
      Think in 3D, not 2D.
      This article appears to reference a decent study http://www.bbc.co.uk/news/science-environment-21692423 According to it, the average depth of ice in the Antarctic is around 2126m, (~6975ft, or ~1.3 miles!) At that depth, it would take the ice contained under a 1 square yard area to cover a football field with over a foot of ice. (6875*3*3 = 62275 cubic ft, 360*160*1=57600 cubic feet)

      Oh yeah: that 2.1km average: it's apparently over a 12.295 million square kilometer area. 26.54 million cubic _kilometers_ of ice. while we're at it: surface area of the planet: 510,072,000 sq km (wikipedia).

      So. simple math from there: 26,540,000/510,072,000 = 0.052km... or about 52m (170ft) for the planet if all ice in Antarctica melts. The article actually says potential equivalent of 58m, so an exercise to the reader to determine where the extra 6m comes from.. and how many cities that would affect.

      BTW: Highly recommend seeing the movie Chasing Ice http://www.chasingice.com/ for a view of how fast the glaciers are changing. Netflix carries it.

    3. Re:More to the point... by gtall · · Score: 3, Informative

      Errr... the dino's farted out about 65 million years ago. My guess is their farts would have dissipated by 5 millions years ago seeing as methane has about a net lifetime of 8.4 years in the atmosphere.

      Don't let science blind you, just continue to use whatever you are using.

  2. FUD title by argStyopa · · Score: 4, Informative

    Or, we COULD say "Middle Miocene ice age 15 million years ago drastically lowered temperatures, lowered sea level 20m" as well, couldn't we?

    Then it warmed, and melted, and sea levels rose. (The subject of the OP.)

    Then it froze again, and sea levels dropped, since the last ice age ended only about 11,000 yrs ago.

    It's almost like this shit is cyclic.

    --
    -Styopa
  3. Who was burning fossil fuels then? by bobbied · · Score: 3, Informative

    That was a long time before the bronze age.. Nobody was burning fossil fuels and dumping CO2 into the air. SO.... How does something like this happen? Can you believe there is some kind of natural process that we don't yet understand going on?

    Problem with all of this is that if the process cycles are in the millions of years, it's going to be impossible to really know if your models are accurate because you only have a few thousand years of recorded history to validate your models with. Plus, you don't know if the system has been disturbed by some outside forces, say a meteor strike (think meteor crater) or volcanic eruption.

    Interesting evidence guys, please keep looking into this..

    --
    "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    1. Re:Who was burning fossil fuels then? by Anonymous Coward · · Score: 1, Informative

      You are the first person I have ever heard implying that man is THE ONLY possible cause for a gloval warming.
      No scientist defends a position like that.
      However, we now have overwhelming evidence to support that the PRESENT period of global warming is man-made, which makes it very different from earlier ones.
      You didn't know that, did you ?

    2. Re:Who was burning fossil fuels then? by Anonymous Coward · · Score: 3, Informative

      It's still surprising to me that no one has ever heard of Milankovitch cycles. There are three cycles that all work to change the overall climate. There are meters of ice in various spots around the world, and they all have layers of trapped gas bubbles that are used as indicators for what the atmosphere must have been like during that time period. The problem is that as things get older, the ice is thinner and thinner, so the further back you look the less certainty you have. Overall though, it's still pretty good, and certainly not impossible.

      • Axial Precession - ~26k years. The earth is like a top spinning about it's axis, and this is the tilt of that north pole toward/away from the sun as it spins.
      • Axial Tilt - ~40k years. This is the no-kidding tilt of the axis.
      • Orbital shape - ~100k years. This is the eccentricity of the earths orbit.

      With all these things there are changes in CO2 levels in the geologic record (i.e. layers of ice in greenland) that serve as indicators to overall global temperature. Looking back, we can see that the world got much warmer, waters much higher, greenhouse gasses much higher. Then the earth was not able to support the high temperature, more gasses got trapped in the ocean, then froze, and we went into another ice age.

      Any paleoclimatologists out there can feel free to correct/add, I'm just going from memory of a couple classes I had as an undergrad...

  4. Jesus. Get a grip. by Jane+Q.+Public · · Score: 5, Informative

    According to IPCC's WORST-CASE estimates (from which they have recently backed off), sea levels were not projected to rise by more than about a meter over the next 100 years.

    I daresay we can adapt fast enough to that.

  5. As temperatures rise, scientists continue to... by Anonymous Coward · · Score: 2, Informative

    As temperatures rise

    Temperature isn't rising.

    scientists continue to worry about the effects of melting Antarctic ice

    Scientists are presently worried about the credibility of their models, because reality has failed to comply.