An important consideration in evaluating a threat is whether it is more likely to do its damage through uncertainty or by bringing about instability. Uncertainty is bad for an economy, but instability is a killer. In uncertain times people worry about whether to postpone a vacation, while businesses put off hiring decisions and reduce spending. In unstable times, people stockpile food or hit the road as refugees, while businesses shutter. Uncertainty focuses on worries about what the future might bring, while instability has to do with upheavals in the here and now.
Fears of terrorism and disease have already pummeled world economies, but, at least for the moment, the damage wrought by these threats comes more from their attendant uncertainties than their direct affects. So what might bring about actual instability? The endless winter in the northeast, for instance, may be a signal that an abrupt change in climate lies right around the corner. If so, large parts of the world might face ice age that's right, ice age conditions with virtually incalculable consequences for agriculture and travel, much less ordinary commerce.
The key to this threat is a recently discovered vulnerability of the Gulf Stream. The current, dubbed the Blue God by author William MacLeisch, warms much of Europe and eastern North America by bringing enormous amounts of tropical water northward as part of the "great ocean conveyor" that distributes heat around the world. As this warm water moves north, evaporation makes it saltier and heavier. By the time the stream has reached the far northern waters between Norway and Greenland it has given up most of its heat, and this salty, heavy water plunges into the abyss, pulling more water behind it.
This is where our warming globe can screw things up, according to scientists such as Robert Gagosian, president and director of the Woods Hole Oceanographic Institution in Massachusetts. The melting of glaciers and increased precipitation in the north has poured fresh water into the Atlantic, in some places leaving a ten foot thick layer on the ocean surface, according to Terence Joyce, also of Woods Hole. As the lighter fresh water slows the sinking of the Gulf Stream as it hits these northern latitudes it reduces the pull that brings warm water northward. Scientists estimate that the speed of the conveyor in the far north has diminished by 20% since the 1970s. Coincidence? Perhaps, but the synchronous freshening of the North Atlantic, a less vigorous Gulf Stream, and a cold snowy Northeast when the rest of the world is baking (last year was the second warmest year on record), may be conveying an urgent message. Something like this happened 12,700 years ago when a post-ice age warming suddenly reversed and in just a few years plunged much of the North Atlantic region into a 1,300 year deep freeze.
If this signals the beginning of an abrupt change in climate, instabilities that dwarf the threat of terrorism lie in our future. If these great ocean currents are interrupted, temperatures in the Northeast might drop 10 degrees F (this winter represented a drop of about 2.5 degrees F) in less than a decade. Naturally, one winter does not an ice age make, and maybe our cold winter represents nothing more than a byproduct of regularly recurring cycles such as the North Atlantic Oscillation and El Nino. At the moment we don't know.
But maybe we should try to find out. As recently as the 1980s, a cold winter was a curiosity, an outbreak of a new disease, a problem for the third world, and, while the Soviets had many nuclear weapons, they knew better than to use them. Today's tightly connected globe means that uncertain times create a petri dish in which destabilizing fears multiply. Worse, if climate change does come about and those fears become real, the damage will be far greater if we're not prepared.
Such uncertainties will be with us for the foreseeable future, dampening spending and investment, and leaving regions prone to sporadic panics. The last thing the public needs right now is another threat on people's minds, but a little more attention to rapid climate change is in order. In an uncertain world, the first order of business is to know what to worry about.
Eugene Linden is the author of "The Future in Plain Sight: Nine Clues to the Coming Instability." His website is eugenelinden.com