Global temperature patterns and predictions about warming or cooling are experiencing a sort of schizophrenia lately, with warming enthusiasts suggesting the oceans may rise even more than IPCC predictions, and cooling enthusiasts - supported by the weather - arguing that human-caused emissions are only a small part of the equation, in which the sun's activity (or lack of it, as now) plays the major role.
In the former camp, proponents argue that the earth is indeed warming due to human activity, and cite Arctic ice melting at a record rate as proof. They are backed by scientific evidence, which shows the ice between Canada and Greenland is melting at a rate not seen since the Medieval Warm Period of 800-1200 A.D, when Norse sailors dodged ice floes to arrive in the New World. This warming also occurred during the Late Boreal Period, between 8,000 and 5,000 BP, at a time when humans weren't recording temperature but tree-ring growth was.
Researchers can't agree on how this current melting will affect sea levels worldwide, but scientists at the University of Wisconsin and Columbia University's Center for Climate Systems Research are using data from that period - collected via tree rings, carbon dating and rock formations - to estimate the damages.
Based on the melting of the Laurentide Ice Sheet, which occurred during the Boreal, they have extrapolated that sea levels can rise very rapidly when ice sheets go south, so to speak. Their study, to be published online in Nature Geoscience, suggests that sea levels may rise as much as 8.85 feet per year.
The latter camp, which favors cooling, cites the fact that the winter of 2007-08 was the coolest on record in both the United States and elsewhere. In fact, the entire year so far has been at least one-tenth of a degree cooler than at any time since 2000, a fact which leads global cooling advocates like geophysicist Phil Chapman (an Australian astronaut with NASA) to conclude we may be facing another ice age.
Chapman is quick to note that we are in an extended solar minimum (no spots on the sun) which began in 2005 and has not yet reversed itself, with the exception of a few spots so tiny they can only be seen with a high-powered telescope. In fact, the sun has reached a milestone, namely that an entire month has passed without a visible sunspot, a situation not seen since 1910. Even more significant, the first seven months of the year recorded only three sunspots, with none in August - a decline in activity that has taken astronomers by surprise.
This lack of activity, which has only three precedents over the last 1000 years (the Dalton, Maunder, and Spörer Minimums) have all resulted in rapid cooling. The last, occurring from 1790-1830, was severe enough to earn the title, "Mini Ice Age". If another one were to occur now, with the world already in crisis, the loss of crops would ensure starvation for at least a quarter of earth's inhabitants.
Unfortunately for Chapman and his cohorts, global warming has been trumpeted as the cause du jour for so long and so loudly that the idea has found a certain resonance in the modern psyche. If one believes in anything, it is global warming. Thus, most of the world looks at Chapman and his associates as modern-day Cassandras; an analogy that doesn't quite work, since Cassandra knew her revelations would be rejected. The ice age enthusiasts are dismayed that no one sees the truth of their proclamations. We should be buying firewood, they insist. Instead, we're building dikes.
Their opponents argue that sunspots have little to do with earth's weather, which is dependent on ocean currents. Last winter's chill was, they say, the result of a La Nina in the Pacific Ocean. La Nina is an ocean current that produces unusually cold water temperatures; the temperature is transmitted to global winds that cool the planet, particularly in North America.
Although La Nina is currently inactive, and El Nino has yet to make an appearance, a cool phase in the eastern Pacific Ocean, called the Pacific Decadal Oscillation, is still causing cooler temperatures from the Pacific Northwest to the Midwest. Here in Minnesota, September 3 finds us wearing sweaters during a 50-degree afternoon. According to Frank Roylance, June and July in Anchorage both averaged 2.5 to 3 degrees below the long-term temperature averages. Fairbanks had a pretty normal June, but after a sizzling July 4th of 85 degrees (same as Baltimore on the same day), the temperatures fell off a cliff. July in Fairbanks averaged 60.6 degrees, almost two degrees below normal. And August is averaging 51.4 degrees, a whopping 7.7 degrees below the long-term norms.
Even so, scientists say 2008 is likely to be the 10th warmest year since 1850, and predict temperatures will go up again as soon as the Pacific Decadal Oscillation cools its heels and El Nino takes up where his sister left off. The last time the PDO shifted into a cool phase was in 1947. And it stayed there until 1976, bringing cooler, cloudier summers.
A new computer model developed by German researchers, reported in the journal Nature, suggests the cooling will counter greenhouse warming. However, temperatures will again be rising quickly by about 2020, they say. Other climate scientists have welcomed the research, saying it may help societies plan better for the future. The key to the new prediction is the natural cycle of ocean temperatures called the Atlantic Multidecadal Oscillation (AMO), which is closely related to the warm currents that bring heat from the tropics to the shores of Europe. The cause of the oscillation is not well understood, but the cycle appears to come round about every 60 to 70 years.
The Environmental Protection Agency, (EPA) is hedging its bets, but says that human activities are changing the composition of earth's atmosphere, creating a burden of gases that will persist for decades, perhaps centuries, and that these gases ‘tend' to warm the planet. To add some spice to that phlegmatic warning, on September 3rd climatologists noted that three Arctic ice shelves are currently either losing mass or adrift in the ocean. NewScientist echoes the warning, and environmental scientist James Lovelock, who created the Gaia Theory - a sort of unified field theory for earth - suggests we may have to engage in planet-wide geoengineering to reverse our mistakes and excesses because warming is proceeding even faster than anticipated. The UK Telegraph added its own sense of alarm by noting that the past decade has been the hottest in 1,300 years, at least in the Northern Hemisphere.
A lot of people are going to be caught unprepared if the next few years grow progressively colder. It may be vindication for Chapman, but for the rest of us, such unexpected cooling will lead to unaffordable heating bills in a world where energy prices are already getting out of hand.
Since we can't all move south, expect a colder world to again divide populations into have and have-nots. This time, the division will occur in developed nations, where the fortunate live south of the 35th parallel and the rest burn their furniture to keep from freezing to death.