Climate Envelope Models of Plants and Animals

Nogues-Bravo (2009) writes that climate envelope models (CEMs) -- which are often employed to predict species responses to global warming (and whether or not a species will be able to survive projected temperature increases) -- "are sensitive to theoretical assumptions, to model classes and to projections in non-analogous climates, among other issues." So how appropriate are they for this particular purpose, i.e., determining whether or not a particular species will be driven to extinction by hypothesized planetary warming?

In an exercise that addresses this important question, Nogues-Bravo reviews the scientific literature pertaining to the issue.

In the researcher's own words, "the studies reviewed: (1) rarely test the theoretical assumptions behind niche modeling such as the stability of species climatic niches through time and the equilibrium of species with climate; (2) they only use one model class (72% of the studies) and one palaeoclimatic reconstruction (62.5%) to calibrate their models; (3) they do not check for the occurrence of non-analogous climates (97%); and (4) they do not use independent data to validate the models (72%)."

According to Nogues-Bravo, "ignoring the theoretical assumptions behind niche modeling and using inadequate methods for hindcasting," may well produce "a cascade of errors and naïve ecological and evolutionary inferences." Hence, he concludes "there are a wide variety of challenges that CEMs must overcome [italics added] in order to improve the reliability of their predictions through time." And until these challenges are met, climate-alarmist contentions of impending species extinctions must be considered little more than guesswork.