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Global Warming Non-Effects on a Subalpine Ecosystem
Price, M.V. and Waser, N.M.  2000.  Responses of subalpine meadow vegetation to four years of experimental warming.  Ecological Applications 10: 811-823.

According to the authors, "ecosystems at high elevations may be especially sensitive to global warming, because productivity is limited to a snow-free growing season, and warming is expected to cause earlier snowmelt."  Hence, they devised an experimental protocol for investigating this possibility.

What was done
On the slope of a small glacial moraine at the Rocky Mountain Biological Laboratory in west-central Colorado, the authors marked out ten replicate plots.  Above half of the plots, they suspended electric heaters that warmed the surface of the soil beneath them by approximately the same amount that is predicted by state-of-the-art GCMs to result from a doubling of the air's CO2 content.  Then, for the next five years, they observed what happened to the portions of the subalpine meadow ecosystem that were located within these two sets of plots.

What was learned
Earlier snowmelt caused by the radiant heaters induced earlier flowering and fruiting in ten representative forb species, but it changed little else.  The experimental warming did not extend the duration of reproduction, nor did it change the composition of the subapline meadow plant community.  Indeed, the authors state that "warming did not induce shifts in abundance of short-lived species, graminoids, forbs, shrubs, or in total vegetation cover."  Neither did the warming affect species richness or species distributions along the elevation gradient of the moraine.  Of particular note was the authors' observation that they "found no evidence that warming facilitated adults or seedlings of sagebrush, a shrub characteristic of lower elevation ecosystems."

What it means
Of all the horror stories spawned by global warming scenarios produced by climate models, none came to pass in this experiment.  No plants were forced to migrate towards cooler plots, none died from effects of temperature stress, ecosystem species richness was not reduced, biodiversity was not decimated, and invading species from warmer lower elevations did not take over the heated plots.  In fact, not a single bad thing happened.