Alaska simmered in summer

October 11, 2007

Courtesy of  Far North Science
By Doug O'Harra

Source: Alaska Climate Research Center

These relatively sizzling temps - partly generated by regional high pressure and clear skies - contributed to the all-time record loss of summer sea ice. Vast stretches of the Arctic Ocean became ice free for the first time since humans developed technology, stunning scientists and offering a dismal harbinger for the fate of polar bears.

The details can be found at the Alaska Climate Research Center, highlighted in the center's new climate blog.

This is a site worth checking often. Call it a reality check.

One of the outstanding features produced by the climate center - and linked to by the blog - tracks the temperature change across Alaska over the past 50 years, a time when concentrations of CO2 in the atmosphere reached levels not seen in 650,000 years.

Source: Alaska Climate Research Center Indeed, the rise in temps between 1949 and 2006, as reflected by average readings at Alaska's 19 official "first order" weather stations, is stunning. Alaska's annual average rose 3.4 °F during the past half century, more than three times the global rise. Some some winter increases rocketed up more than 8 and 9 °F, the equivalent of moving south a couple thousand miles.

Did Alaska prove global warming or not? Case closed.

Not so fast.

Almost all of the increase occurred in the single 1976-77 season, when the ocean off Alaska's southern and western coasts suddenly warmed.

Source: Alaska Climate Research Center

In a ecological sea-change that anthropologists have seen in ancient Aleutian middens, a marine world once dominated by crustaceans like crab and shrimp, and forage fish like herring and capelin, shifted to one dominated by pollock, flatfish and salmon. It's what scientists call "the regime shift."

If you realign the temperature change chart so that it begins in 1977, after the regime shift, and ends in 2006, the rise in annual temperatures for Alaska's land mass becomes almost negligible, only about half a degree.

Some places actually grew cooler. Like Anchorage, Fairbanks and Nome.

Think this through. During the era of the most pronounced global warming, when levels of CO2 and other greenhouse gases soared, Alaska remained flat. 2007 data might change the trend. We'll have to check the center blog in January.

While this bit of data doesn't disprove global trends, it is a sobering antidote for the poison of jumping to conclusions based on teeny geographic zones (like Alaska) and recent weather patterns. It suggests that both the deniers and the doomsayers need to submit to the data and take the long view.