September 30, 2005

Arctic Ice Declines: A few things that got left out

Filed under: Arctic, Climate Changes, Polar

As shown on the front page of the September 29 New York Times, NASA has pronounced that the September, 2005 coverage of Arctic sea ice is the lowest since their satellite record began in 1979.

We offer a more measured reaction: ho-hum. Summer (that’s when ice melts) Arctic temperatures in the late 1970s were at their lowest levels since the mid-1920’s. Since then, they have risen to slightly exceed the previous 100-year high point of the late 1930s.

Read that again. From roughly 1925 through 1940, a 15 year period, Arctic summer temperatures rose just about as much as they have from 1979 through 2005, a 25 year period. If sea-ice wasn’t near or at its end-of-summer lows this year, something would be wrong with a very basic physical theory: warm temperatures melt ice.

This generated headlines elsewhere than in the Times:

“Arctic ice ‘disappearing fast’” [BBC News]

“Arctic ice melts faster as it gets warmer” [USA Today] and

“Arctic meltdown just decades away, scientists warn” [Sydney Morning Herald]

This arctic ice story is now an annual event, reminding us of the annual release of the global average temperature. This always occurs in early December (rather than at the end of the year) because research groups are competing to see who can get it out first that we are setting, or just missing, a new record. But the great El Nino of 1997-1998 put the kibosh on this annual media event, jacking up temperatures to heights that went far beyond the previous record. None has been set since. (Funny, no one notices that, even in a warming world, it takes nearly a decade to establish a new record!).

So now, it is the record low Arctic ice announcement that makes the headlines. And it’s a better poster child for global warming than rising temperatures. One only needs to ignore the inconvenient fact that the amount of ice at the other pole is growing.

But, the fact of the matter is that these annual announcements really represent just another example of telling less than the whole story in an attempt to tell a particular story. As a refresher, here are a host of things that were left out of the press reports:

Temperatures and no doubt ice conditions fluctuate in the Arctic and have likely been as warm or warmer (and thus as ice free or more so) at various times since the end of the last ice age. For instance, researchers Overland and Wood examined overwintering logs from ships taking part in Arctic expeditions from 1818 through 1910. They found that “climate indicators such as navigability, the distribution and thickness of annual sea ice, monthly surface air temperatures, and the onset of melt and freeze were within the present range of variability.”

In a sweeping review of conditions in the Western Arctic, Kaufman et al. summarized “The spatio-temporal pattern of peak Holocene warmth (Holocene thermal maximum, HTM) is traced over 140 sites across the Western Hemisphere of the Arctic (0–180W; north of 60N). Paleoclimate inferences based on a wide variety of proxy indicators provide clear evidence for warmer-than-present conditions at 120 of these sites.”

And, it is a well-established scientific fact (see MacCracken and Luther, 1985) that summer temperatures in the high arctic averaged about 1-2°C warmer than today’s for several millennia, centered about 6,000 year ago. That’s right—for a good 30-40% of the last 7,000-8,000 years, summers were warmer (see here for another example). Which, of course, means that the late summer ice was much less (or even non-existent). Where was the ecological tragedy? Inuit culture flourished.

For a synopsis of more on Arctic ice, check our posts

here, here, and here.

And, for a summary of the findings about ice conditions in Antarctica, visit here and here.

After spending a bit of time looking through the above links, we think that you’ll realize that we’ve seen yet another “predictable distortion” on global warming, this time about polar ice.

References:

Kaufman, D.S., et al., 2004. Holocene thermal maximum in the western Arctic (0-180ºW), Quaternary Science Reviews, 23, 529-560.

MacCracken, M.C., Luther, F.M, (eds), 1985. Projecting the climatic effects of increasing carbon dioxide. DOE/ER-0237, United States Department of Energy, Washington D.C., pp. 381.

Overland, J.E., and Wood, K., 2003. Accounts from 19th-century Canadian Arctic Explorers’ Logs Reflect Present Climate Conditions, EOS Transactions of the American Geophysical Union, 84.




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