Saturday, April 12, 2008

The missing continent

kw: book reviews, nonfiction, exploring

It would be quite convenient if there were an Arctic continent, it really would. Suppose the Asian landmass went right over the pole to attach to North America. Wouldn't that be nice? One could pass overland right from Winnipeg to Moscow or Novosibirsk. Of course, with the much different deep ocean currents that scenario would entail, both Winnipeg and Moscow might be under a mile or three of ice. Or they might be in the midst of great corn belts. How are we to know?

The truth is, we have no way to know (today) just what might eventuate. The climate models and ocean circulation models upon which our long-term projections are based are so poorly coupled together that such a large-scale simulation would be little better than guesswork.

Twenty-five years ago, I was given an assignment, along with a dozen fellow students in a Tectonics class, to write about the process by which I would go about determining if there had been plate tectonics (continental motions) in the earliest Precambrian, say a quarter billion years after the crust first formed. Being a Computer-oriented Geologist (or more of a Geology-oriented Computer scientist, truth be told), I proposed a simulation of earth dynamics to cover the first one or two billion years of planetary evolution. Should we posit half a dozen initial scenarios, and run the simulation for each, we'd have a good parameter space from which to draw conclusions about what is needed for plate tectonics to get going some 3.5 billion years ago. Of course I already had a sneaking suspicion that the continents and oceanic crust of that time, being warmer and with a higher water content, were fairly ripping along compared to their sedate pace at present.

I outlined the range of parameters—a billion-fold range of rock strength, an equally great range of fluid compositions, and perhaps an incompletely segregated core with the deep mantle still disgorging dollops of liquid iron downward. I outlined the number of layers and cells per layer needed to render the came to a few billion finite elements. Then it would have to run in steps of several millennia each, perhaps shorter, perhaps longer. Anyway, on the fastest supercomputer in existence (in 1982), running one of the six models would take several thousand years. I invoked Moore's Law and stated that in twenty years' time, such a model could be run in about a week, so I proposed we busy ourselves about other matters in the meantime. I got a poor grade.

What is the situation with global modeling today? The twenty years ended half a decade ago. Models of such a size and complexity can indeed be run in a week or two now. Do they tell us what we need to know? Not at all. And here is why: We don't know nearly enough, not even a hundredth of a percent of enough, about what is actually going on RIGHT NOW, as input to start the model, and to test its predictions. This is true whether we are modeling earth dynamics, ocean currents, or the climate. After twenty-five years, Geologists still debate whether the force that moves the continents around is "ridge push" more than "trench pull", or vice versa. And a case has been made that continental directions are significantly influenced by coriolis effects! As to the climate, we were more worried about another ice age in 1982 than about global warming, or whatever one wishes to call it.

We've just got to the point that we can predict the circulation of the ice in the North Polar cap with enough precision, so that Nansen could have known which piece of ice to attach the Fram to so as to cross within a mile or so of the Pole. In The Ends of the Earth: An Anthology of the Finest Writing on The Arctic, edited by Elizabeth Kolbert, we read a portion of Nansen's account of coming within 3.75 degrees (about 260 miles or 420 km) of the Pole in the icebound Fram. But this was almost happenstance, it seemed, because for much of the journey they sidled southward, slipping northward somewhat as an afterthought.

The book is the in-volume, back-to-back companion of ...Finest Writing on the Antarctic, about which I posted a few days ago. The singular distinction between the two sets of writings is that the Arctic writings are almost exclusively about human interactions between explorers or scientists and the native Arctic peoples. There are no Southern natives, other than penguins. Curiously, much of the writing is about Greenlanders. Perhaps they were more hospitable, at least to folks who could write well...

The Arctic has been known to written (i.e. European) history for much longer than the Antarctic, so this volume covers more than 180 years, beginning with an excerpt from John Franklin's 1923 "The Extreme Misery of the Whole Party". Franklin and more than 120 others died the following year, and a significantly larger number died in later years while looking for survivors!

A theme I picked up, perhaps witting by the editor, is the great tendency of all "visitors" to northern lands to take great advantage of the skills of native guides, but to learn nearly nothing from them, until very recent times. A singular exception to this trend was Gontran De Poncins, who wrote Kabloona (Inuit for "white man") about his experiences living among the Inuit in their igloos in and after 1938. He consciously learned what he could of their culture and skills, and experienced a great shift of his own cultural orientation. He did not "go native", but did come to understand what lay beneath a veneer that Europeans (as he had) found quite repugnant.

The most recent few articles focus on changes in the Arctic realms because of climatic warming over the past couple of centuries. The climate has warmed steadily since the end of the "Little Ice Age" in about 1850, and continues to do so, perhaps abetted by the extra greenhouse gases our technological society produces. The warming is most evident in the far North, which is much easier to melt off than the far south: tens of feet of Northern ice cap compared to ten thousand feet in the South. As warming (and the invention of fertilizer and tractors) has produced increased farm productivity in temperate climes, the productivity in the far North, at least that available to humans, has decreased. This plus well-meant but misguided Missionary practices has led to a near-total disappearance of Northern cultures. They all have snowmobiles and rifles now, but are catching fewer seals, whales, and bears.

This book, and its companion, both end on an ambiguous note. We don't know what we don't know, and we know the Polar regions less than the rest, and little enough of that, at best.

No comments: