Saturday, November 8, 2008
Last weekend we decided to travel towards the Arctic Circle to see migrating polar bears. Although we had had such a vague plan for a long time, we finally pushed the button on it after hearing alarmist reports about these largest land carnivores were becoming endangered species.
It all made sense. After all, polar bears do not prey on land creatures, but mostly depend on ice cover to hunt ringed seals and bearded seals, which must surface through breathing holes. The bears’ extraordinary sense of smell helps them detect the doomed pinnipedia. Their massive forward paws have evolved to make ice breaking look easy. But if there is no more ice, then the bears will be in trouble, forced to swim over large distances between isolated ice floes in the hope of catching the faster and more agile marine mammals. Or so the story goes…
The locals quickly disabused us. People who have been watching bears for decades are quick to laugh off the naiveté of the somewhat uniformist reports. Apparently, bears migrate through the region as they always have, and in large numbers. Watching these white giants stomp, face off, encroach on each other’s territory, fight, wrestle, play and frolic, as we did, it was difficult to think about them as a population in distress. Granted, such casual observations of ecological health are anecdotal at best and carry no statistical validity. The enthralling tundra safari experience, as well as locals’ elucidating comments, focuses only on one of some 20 polar bear populations that inhabit the deep north of our globe but interbreed very rarely. But it is the population in question – the Hudson Bay bears –that has, after only a few years of warmer climes developed an astounding level of adaptation to the changing conditions.
To be fair, these bears still favor the yummy staple of ringed seal fat and will slip adorably on the first ice, through which they are led by the irresistible olfactive call. But the relative unreliability of the freezing seasons has turned these animals to seek substitutes. Woe to caribous. Woe to rodents. Woe to the arctic fox. On land, the fluffy, round giant is able to bolt at incredible speed of a hunting feline. So, who knows? Should winters remain warm, within several years we could even expect to watch exciting NHK, BBC or Discovery Channel documentaries, showing the white beasts charging through petrified caribou herds in a way lions poach wildebeest in East Africa.
Or may be, we will not.
Once in the tundra, north of the tree line, you have enough time to ponder the non-linear enigmas of the climate change. Hudson Bay folks still shudder at the thought of the winter’07/08, the coldest in recent memory since 1993. Indeed, last year the northern hemisphere suffered in an unprecedented way, with deep frost gripping most of Eurasia. Villagers froze in Iran and in Afghanistan. Homebound holidaymakers in China got stuck for days at railroad stations. Power distribution systems broke down. This year’s winter in the southern hemisphere was also unusually cold. Was the whole brouhaha about global warming somewhat premature?
There is no satisfying answer to it as there is no easy explanation for the cold snap in 2007/08. It is possible that Western Europe’s temperatures suffered from increased melting rates of the Arctic ice cap. This mass of lighter, fresh water pumped from the northern latitudes into the Atlantic may have pushed the warm Gulf Stream lower or off its course, depriving Europe’s coast of its moderating role.
As I am writing it, we are already hearing reports about another cool La Niña system approaching America’s shores from the Pacific. Such a phenomenon could mean another dry spell in the Andes, and colder weather in the northern hemisphere, especially in America’s northwest and Asia’s northeast. If this turned out to be true, Southeast Asia and south-western Pacific should brace for another season of floods, with potentially considerable impact on several key agricultural and coal markets.
And yet, if there is anything we can learn from a chaotic system, such as weather, is that no year resembles exactly the previous one. Like in the securities markets, changes make sense only in hindsight and only in the longer term. Not surprisingly, humans are fascinated by what they cannot fathom. Multifactor models do not exhibit monotone relations. Unfortunately, this is what happens when you plug in all the modifications in albedo, Arctic, Greenland and West Antarctic ice sheets, southern oscillation (el Niño and la Niña), Atlantic Thermohaline Circulation, Indian summer monsoons, West African monsoons, the impact of Amazon and Southeast Asian rainforests, Boreal forests, sun flares, cosmic rays, changes to magnetic poles, Greenhouse Gas emissions and the effects of crop overfertilization. Good luck modeling!
But there are certain things we do know. Holocene is bound to be climatically unstable. With the end of the last glacial period some 12000 years ago, temperature anomalies have been commonplace, at least for as much as we can learn from the ice accumulated in polar regions (data from lower latitudes are spotty). But there has been a striking regularity since at least the so-called Maunder Minimum, which lasted for about 200 years and has been often labeled as “little ice age”. This period, immortalized in wintertime canvases of Dutch painters, ended in early 19th century. Since then, a fairly regular succession of 11-year long sunspot cycles provided for a fairly predictable guide to longer term solar activity. Although no scientific proof exists, high sunspot activity has been associated by most casual observers with warmer weather.
But somehow the measurements of recent sunspot activity do not quite fit the cycle predictions. For one, the unprecedented solar flares during the stormy 2005 were not supposed to happen in a cycle that was expected to bottom out in 2006. Nor should the late 2008 qualify, a priori, for a solar activity of low intensity as observed at the moment. The proton storms usually travel from the sun to earth within about two days, causing engrossing auroras in the polar regions. But I caution against travel plans to the frigid Arctic this winter. If you expect to see spectacular celestial displays, you could be sorely disappointed.
What surprises sunwatchers in this uneasy solar lull is that it breaks the regularity of a relatively high sun flare activity that had prevailed during the postwar period. Modern, industrial agriculture has been built around the assumption of consistent temperature and rainfall cycles, but this stability appears unwarranted if longer historical periods are taken into consideration. Some observers even believe that the period of the last 60 years was a climatic anomaly. The problem is that, historically, sudden shifts in sunspot activity seem to have been correlated with dramatic dislocations in food production, as evinced by the starving Chinese cannibals in the 1700s. Conversely, the period following the First Millennium was, apparently, associated with high solar activity. It underwrote sufficient safety in food production to favor pre-industrial exploration (New Foundland), long distance travel (Iceland) and a colonization drive (Greenland) that remained unmatched until the Portuguese ventures five centuries later. Encouragingly, all of these examples point to increased human activity in the higher latitudes, where warming temperatures are mostly beneficial. But should sunspot inactivity truly break away from its predictable 11-year cycles, lower temperatures in tropical regions could, in fact, increase the soil’s capacity to store water and nutrients.
This is not to say that alarmed polar bear fans should not worry about human impact on climate change and long term implications of eventual, higher temperatures. But, like in the markets, the near term weather misbehavior could be the exact opposite of long term consequences. This is what October snowfalls from London to Idaho could signal. The American prairies are now (early November) lying under 2ft snow. And before we realize, our favorite bears could show some mettle and catch the cattle.