A few years ago geologist Carlos Jaramillo stood in a man-made canyon in Panama staring at rocks he knew to be 20 million years old, and shook his head in confusion. According to conventional geologic theory, the Panamanian Isthmus didn't emerge from the sea until just a few million years ago. So what was a 20 million-year-old fossilized tree doing there?

A new body of data emerging from such questions threatens to upend what geologists thought they knew about our planet. The Isthmus of Panama plays an outsized role in ocean circulation and may be a reason that our planet currently undergoes ice ages, so the new theory could rewrite not just the history of continents and biology, but also global climate.

Science owes this research to an unlikely source: a public works project. Panama is expanding its namesake canal, which has required monumental excavations to accommodate the world's growing fleet of ships that are too large for the original channels. Those digs have exposed an abundance of ancient rocks across a land normally choked by jungle. Jaramillo, a staff geologist at the Smithsonian Tropical Research Institute in Panama City, is leading a team of about 40 scientists who are taking advantage of this brief opportunity to study the rocks before they again surrender to plants or water.

Until recently, scientific theory has dictated that up to about three million years ago, the Atlantic and Pacific formed a single wide and deep sea between the American continents. As continental plates collided, a chain of islands between the two rose up, forming the Isthmus of Panama and ending what preeminent 20th-century paleontologist George Gaylord Simpson famously described as South America's "splendid isolation."

But Jaramillo and his colleagues have proposed a new model: most of Panama existed as it does today 12 million years ago, with shallow, narrow channels connecting the two oceans periodically after that. The results are detailed in a recent issue of the Geological Society of America Bulletin (pdf), with more details in press in the Journal of Geophysical Research (pdf).

The discrepancy between the two theories is no small matter. The three-million-year time frame neatly accounted for an important sequence of events that began about the same time. The current global cycle of glaciation dates to this period and might have been triggered by a transformation of the world's ocean currents, which a slender rib of land separating Atlantic and Pacific would naturally explain. New currents began carrying warmth to northern Europe and precipitation to the Arctic. The Atlantic grew saltier and warmer; the Pacific grew more nutrient-rich. Flora and fauna began traipsing between the two American continents, often extinguishing each other. In Africa a savanna formed, which may have nudged forward the evolution of our species.

So if the new theory is right, and the oceans were separated much earlier—then what triggered all of those epochal events?

"This is the most interesting for me, because if you tell somebody living in Nepal that the isthmus rises three million years ago versus 10 million—who cares?" Jaramillo says. "But think about this: having ice in the Arctic is the reason we're in the climate we are right now, and we still don't have a clear mechanism for it. That's very interesting, no? How can we even think about modeling the climate of the next 100 years if we cannot model how to produce such a big feature of our climate today?"

Climatologists will have to begin taking seriously alternative theories about why the ice ages began, says geologist Peter Molnar of University of Colorado at Boulder's Cooperative Institute for Research in Environmental Sciences. His favored alternative theory involves precipitation in Indonesia. "I think this will turn the field on its head," Molnar says.

9 Comments

1. 1. jtdwyer 10:31 AM 6/15/12

   Jaramillo says:
   "But think about this: having ice in the Arctic is the reason we're in the climate we are right now, and we still don't have a clear mechanism for it. That's very interesting, no? How can we even think about modeling the climate of the next 100 years if we cannot model how to produce such a big feature of our climate today?"
   
   Oh, noooo!

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2. 2. Ralf123 in reply to jtdwyer 11:46 AM 6/15/12

   Just my thought. Cue the climate change deniers: "See, we have no clue about the future climate!!!1!!!"
   Wrong. We may not know enough to predict the distribution of ice, precipitation or deserts under climate change, but the average heat content of the planet with certain greenhouse gas concentrations is basic physics.

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3. 3. 1oldsarg 12:54 PM 6/15/12

   The more we learn the less we understand. All the climate models for the next century are just that, models. If the data going in is faulty, the data coming out won't be accurate, basic physics or not. So we need more data and while we're collecting it, cleaning up the air and water is a good idea in any case.

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4. 4. reussere in reply to 1oldsarg 05:29 PM 6/15/12

   I completely agree. Cleaning up the air and water is crucial to increasing the carrying capacity of the planet for more humans and other species.
   
   I think fossil fuels should not be used to power our society primarily because in centuries to come they will find much more important uses than burning them up for transportation. We will need them for chemical feed-stocks for our petro-checmical industustries, lubricants, etc. Burning most of them up now just insures that they will cost 1000 dollars a barrel or more when finally do stop burning them.

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5. 5. reussere in reply to jtdwyer 05:34 PM 6/15/12

   It doesn't actually matter to deniers. They haven't a clue how models work, just that its a dirty word. For example, the fact that a scientist published a report warning of some sorts of weakness's in climate models and had no trouble publishing it, is solid evidence that people are not discouraged from disseminating whatever evidence is out there. I would bet anyone that not a single denier will acknowledge that however, continuing to claim that its a global conspiracy and dissenting reports are being squashed somehow. Its like talking to children.

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6. 6. Basemento 07:52 AM 6/16/12

   Maybe it's time to re-read Fred Hoyle's Book _ Ice. Published by Hutchinson in 1981 it has some interesting comments regarding ice ages and glaciation.

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7. 7. lowndesw 06:35 PM 6/17/12

   I'm not a geologist but I understand that layers of sedimentary rock (strata) sometimes travel substantial distances laterally (horizontally) in relation to the strata directly below. As evidence, you sometimes find a "polished" surface between layers, or strata that is extensively fractured above a layer but not below. Maybe more research is called for here to determine if that is the case here.

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8. 8. Steve D in reply to 1oldsarg 03:45 PM 6/19/12

   And the models that predict economic disaster if we try to halt global warming are orders of magnitude less reliable than climate models.

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9. 9. gnagy 04:58 PM 6/20/12

   Sorry to wake you up but consider this info below:
   
   Never underestimate the power of human imagination run wild. They can even make monkeys out of us.
   
   On December 9, 2010 in The New York Times science writer Nicolas Wade wrote: "Anthropologists have been thrown into turmoil about the nature and future of their profession after a decision by the American Anthropological Association at its recent annual meeting to strip the word “science” from a statement of its long-range plan.?
   
   A NY Times (March 12, 1961) article, “There Are Neanderthals Among Us” that discussed fossil skeletons found in La Chapelle in Europe that turned out to be those of contemporaries who were bent over from bone disease.
   
   In pro-evolutionist Bill Bryson’s best seller, “A Short History of Nearly Everything” he writes about “The American Museum of Natural History Hall of Human Biology and Evolution in New York that has an absorbing diorama that depicts life-sized creations of a male and female walking side by side across the ancient African plain. The tableau is presented with such conviction that it is easy to overlook the consideration that virtually everything above the footprints is imaginary.”
   
   He asked the curator of the museum and paleoanthropologist, Ian Tattersall, if “he was troubled about the amount of artistic license that was taken in reconstructing the figures,? Tattersall replied, “It’s always a problem in making recreations. You wouldn’t believe how much discussion can go into deciding details like whether Neanderthals had eyebrows or not…We simply can’t know the details of what they looked like… If I had to do it again, I think I might have made them slightly more apelike and less human.”
   
   In 2004 National Geographic tested four paleoartists by giving them the same fossil bones at different times without telling them other paleoartist would be creating drawings from the fossils. The results were that not one of the drawings looked like the others and none of them had any body hair on them!
   
   This whole field has proven again and again that many of these researchers have lied and continue to lie. The most brazen and unfounded theories are proclaimed only to find the research was faked or non-existent.
   
   This is chicanery not science.
   This is imagination run wild not science.
   This is absolute fraud.
   
   Talk about honesty in the "sciences."
   

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