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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."

19 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, Interesting

      This is the point most deniers seem to miss when they bring up past periods of climate change. Scientists have never said it didn't happen in the past. What they say is the rate of change is faster than they have seen and may be faster than species can adapt and humans are most likely the cause of the current change.

      --
      Well, there's spam egg sausage and spam, that's not got much spam in it.
    2. Re:More to the point... by gmuslera · · Score: 4, Interesting

      More than life, civilization, most of mankind and big cities are near sea level, and at coasts. And the crops that feeds most of them are not so far. Maybe if sea rises 20 meters in a century or two we could cope with that, but if time is much shorter it will be pretty bad. Also not sure how it would impact ocean's salinity and life that much water if happens fast, but if is affected you are cutting also sea food to that people.

    3. Re:More to the point... by i+kan+reed · · Score: 4, Funny

      Actually, it's not the rate of change, it's the rate of change of the rate of change that's scary.

    4. Re:More to the point... by Anonymous Coward · · Score: 5, Funny

      what a jerk

    5. Re:More to the point... by CrimsonAvenger · · Score: 4, Interesting

      Let's see....

      According to Google, Antarctica is ~14 million square km, and has an average of about 1.6 km of ice on top of it.

      So, call it 22.4 million cubic km of ice. With a density of about 0.92 g/cm^3. So ~20.6 million cubic km of water tied up in that ice sheet.

      Surface area of the planet is ~510 milllion square km.

      Which gives us ~40 meters of sea level rise as a MINIMUM if the entire ice sheet melts.

      Of course, it's not all expected to melt, but hey....

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    6. Re:More to the point... by danbob999 · · Score: 4, Interesting

      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.

      Life isn't threatened by anthropogenic global warming. Even the human specie, as a whole, isn't threatened. There is also a scientific consensus on the fact that global warming is happening and that we are responsible for it.

      The real question is whether the costs of reducing greenhouse gases emissions outweigh the costs of global warming. The answer is that it's globally cheaper to reduce greenhouse gases, however every single country or individual, by being selfish, has interest to let the others pay the bill.

    7. Re:More to the point... by catchblue22 · · Score: 5, Interesting

      A couple of important points: Firstly, 5 million years ago, there weren't 7 billion people living on Earth, people whose food supply was dependent on an agricultural system tightly adapted to today's particular climatic conditons. I will always remember a lecture given by one of my geology professors. He drew a graph on the board, initially without a scale. On the left, the graph fluctuated wildly up and down, going from extreme highs to extreme lows. Then suddenly, the graph settled down to mild up and down variations, and became basically horizontal, continuing to the right. Then he labelled the axes. The vertical axis was local temperature for an area where most humans lived. The horizontal axis was time. The time when the temperature settled down to a relatively constant pattern was about 10 000 years ago, the time when the last ice age ended. Then he asked us what other important event occurred around 8000 to 10000 years ago. Of course, the answer was the dawn of human civilization. Human civilization appeared about 8000 years ago. Civilization can only exist because of agriculture. People begin to plant crops in one area. They grow more food than they can eat, so they can have more children. Not all members of society have to spend time farming; individuals can afford to spend time doing other things like making pottery to store extra food, building better houses, or posting on Slashdot.

      The problem for cities comes when the conditions that allowed successful agriculture change. Three or four years of failed crops caused by drought or heat or cold or surplus precipitation will exhaust all stored food. The residents of the cities will have to abandon their cities to begin hunting and gathering again, thus largely shattering any nascent civilization. The lesson from this is that human civilization was not simply the result of the triumph of human intelligence over nature. Civilization appeared 8000 years ago because the climate conditions favored it. During the last ice age, the conditions did not favor the development of cities. Even in areas that were not covered in ice, the climate conditions would have been highly variable thanks to the huge persistent ice sheets to the north. One day the air would come from the warm south, another day, the air would come from the cold northern ice sheets. These unstable conditions would have made sustained agriculture impossible.

      My second point is that the well known fact that the climate in the past has shifted from warm to cold to warm should not be comforting to us. In fact, it should be the opposite. The fact that the Earth's climate has shifted in the past indicates that our climate is highly sensitive to relatively small forcings. Tiny changes in the Earth's orbit that cause periodically the Northern hemisphere to get more sunlight, and then tens of thousands of years later less sunlight are thought to have forced the Earth into and then out of ice ages (Milankovic Cycles). The slow collision of the Indian sub-continent with Asia, and its resulting volcanism is thought to have caused a large spike in carbon dioxide concentrations, resulting in a climate where the conditions in the north were near tropical.

      The fact that the climate has shifted in the past due to relatively small changes indicates that "relatively small" changes wrought by humans, such as the removal of carbon from under the ground and the dumping of it into the atmosphere are capable of pushing our climate into a very different state, one that is likely to reduce human agricultural output by enough to make our current large scale civilization a dubious proposition.

      --
      This and no other is the root from which a tyrant springs; when first he appears as a protector - Plato (423 to 327 BC)
    8. 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.
    9. Re:More to the point... by MightyYar · · Score: 5, Funny

      I find your humor quite derivative.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    10. Re:More to the point... by ColdWetDog · · Score: 4, Funny

      That comment is certainly integral to this discussion.

      --
      Faster! Faster! Faster would be better!
    11. Re:More to the point... by Anonymous Coward · · Score: 4, Funny

      So what is so fucking wrong with the rate of change. I for one will be glad when I can finally grow oranges in Antarctica. Seriously world is a harsh inhospitable place. This planet has been giving us earth quakes, and hurricanes for a long time. I am glad humanity is finally striking back. Fuck the planet earth.

      I want to see the bitch in pain. Lets burn the land and boil the sea. Every last inch of the planet should be raped and plundered. Why is it when some alleged middle eastern terrorist kill a few new yorkers, the USA wants to go to war with the middle east and kill every single arab. Yet when mother earth sends Katrina our way we do nothing. I say it is about time we started holding the planet accountable for all the suffering it has given us.

    12. Re:More to the point... by cusco · · Score: 4, Insightful

      The problem is that "facts" and "science" generally support the liberal and progressive points of view. Pollution was a liberal hippy issue, until the Cuyahoga River caught fire. The link between smoking and cancer was just a liberal conspiracy to bankrupt tobacco companies. Overuse of antibiotics was a liberal attack on upstanding pharmaceutical companies, until MRSA appeared. And of course conservatives said that all of our financial woes in the 1980s could be solved by simply deregulating everything, while liberals pointed at every single prior case of financial deregulation leading to chaos in a desperate attempt to prevent today's economy.

      --
      "Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin
  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. Re:Who was burning fossil fuels then? by Robear · · Score: 4, Insightful

    Because there can't be both natural and man-made causes for warming and cooling? Really? That seems arbitrary, especially if it's just the argument from disbelief.

    We've got very good evidence that there are climate cycles, and very good evidence that we should be cooling right now, but we're not. We have very good evidence that we're warming specifically because of our own actions, and that's overwhelming the natural cycles, both in speed of change and intensity.

    If you are comfortable with natural cycles, then the physics of artificial change should not faze you, because the physics behind them is the same. If something can be changed by natural forces, then it can be affected by artificial ones of sufficient scale and intensity. Excluding the latter is simply ignoring evidence.

    --
    French - The lingua franca of Europe!
  4. Re:And what most folks are missing... by matfud · · Score: 5, Insightful

    The interglacial periods coincide with variations in the earths orbit.
    eccentricity, tilt and precession all interacting. So yes it is pretty well understood why glaciation occurs. Yes it has been taken into account. No it does no account for the current changes being seen.

  5. Climates change, then and now by sqrt(2) · · Score: 4, Insightful

    Before anyone smugly proclaims that this proves humans aren't responsible for climate change, remember that it's possible for some phenomenon to have multiple causes. It's entirely possible for there to be both natural and man-made causes for variations in climate. Giving examples of natural causes doesn't do anything to weaken the argument against anthropogenic climate change in this epoch.

    If climate change is currently man-made, or partially man-made, or being made worse by human activity, then it's still worth bending every effort to slow or reverse it.

    --
    If you build it, nerds will come. Soylentnews.org
  6. Re:Right, so... by Art+Challenor · · Score: 4, Insightful

    It's idiocy like this that causes software to suck so badly. Faced with a bug report that has the same symptoms as a previous solved bug, the issue is marked as "resolved".

    It is possible to have events with broadly the same symptoms that actually have different underlying causes. (Although as others point out the timescale of the symptoms is massively different).

  7. 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.