Plants Surviving Global Warming on Mountainsides

Many people are worried that the increase in temperature predicted by the IPCC to result from the ongoing rise in the air's CO₂content will be so great and occur so fast that many species of plants living on mountainsides will not be able to migrate upward in elevation rapidly enough to avoid extinction. Scherrer and Korner (2011), however, suggest a different way for plants to avoid the as-yet-unrealized but potential problem.

Working in the temperate-alpine zone near Furka Pass in the Swiss central Alps on three steep mountain slopes with north-north-west, west and south-south-east exposures (all located well above the climatic tree line), the two Swiss scientists used high-resolution infrared thermometry and large numbers of small data loggers "to assess the spatial and temporal variation of plant-surface and ground temperatures as well as snow-melt patterns for 889 plots distributed across the three alpine slopes," with the goal of identifying "thermal habitat preferences in alpine plant species across mosaics of topographically controlled micro-habitats," in order to see just how far (and, consequently, just how fast) a plant might have to migrate to remain within its zone of livability in a rapidly warming world.

Within their study area, Scherrer and Korner observed a substantial variation between micro-habitats in seasonal mean soil temperature (ΔT = 7.2°C), plant-surface temperature (ΔT = 10.5°C) and season length (>32 days), with meter-scale thermal contrasts significantly exceeding IPCC warming projections for the next hundred years.

In discussing their findings, the two researchers state that their data "indicate a great risk of overestimating alpine habitat losses in isotherm-based model scenarios" -- such as the climate envelope approach -- concluding, in fact, that "due to their topographic variability, alpine landscapes are likely to be safer places for most species than lowland terrain in a warming world."