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Climate and Alpine Ecosystem Changes in Glacier National Park
Klasner, F.L. and Fagre, D.B. 2002. A half century of change in alpine treeline patterns at Glacier National Park, Montana, U.S.A. Arctic, Antarctic, and Alpine Research 34: 49-56.

What was done
The authors studied summer temperatures and spring snowpack over the period 1927-1991 in the McDonald Creek drainage basin of Glacier National Park (Montana, USA), as well as altitudinal and areal changes in subalpine fir forests between 1945 and 1991 at six 40-hectare sites located between elevations of 1900 and 2200 meters.

What was learned
In spite of periodic climate-alarmist warnings of highly-negative global-warming-induced impacts on Glacier National Park, the authors' data revealed no net change in spring snowpack from the beginning to the end of the record. Likewise, there was no net change in summer minimum temperature; but in the case of summer maximum temperature, there was a change: a net drop of about 0.7C from the beginning to the end of the study period. Hence, it should come as no surprise that, in the words of the authors, "altitudinal changes in the location of alpine treeline ecotone were not observed." However, and in spite of the drop in summer maximum temperature, there was a 3.4% increase in the area of tree coverage from 1945 to 1991, as well as an increase in the density of trees.

What it means
The authors report that ecotones - or ecosystem gradients (as from tundra to krummholz to patch-forest to continuous-canopy forest) resulting from environmental gradients - "are hypothesized to be sensitive indicators of climate change." Hence, in light of the highly-hyped melting of glaciers in Glacier National Park, one would have expected to have seen trees moving upward in altitude over the half-century study period. Such, however, was not the case; nor was there any indication of warming in the meteorological record. What was observed, however, was an increasing aerial coverage and density of trees, as would be expected to result from the ongoing rise in the air's CO2 content over the study period. It would appear, therefore, that dreaded global warming is not only not affecting the ecosystems of Glacier National Park, it is not even occurring there.

Reviewed 5 June 2002