The Specter of Species Extinction
VIII. Our Appraisal of the Parmesan and Yohe (2003) Study
The Parmesan and Yohe study is much like the study of Root et al. It begins with the same initial filtering of data - Parmesan and Yohe say their "analyses ignore species classified as stable" - once again stacking the deck for success, as they would define it. It then proceeds to look intently at two, as opposed to Root et al.'s four, types of data: those dealing with phenological shifts and those dealing with range-boundary changes or, as they alternatively describe the latter subject, distribution/abundance shifts.
With respect to the latter category, which is the one of pertinence to the CO2-induced global warming extinction hypothesis, Parmesan and Yohe (PY) say they conducted "a quantitative assessment covering > 1,046 species." Although this description of their work makes it sound incredibly comprehensive, it refers to the contents of but 19 scientific papers. Six of these articles were included in Root et al.'s Tier 1 group of studies (T1.1, T1.4, T1.5, T1.7, T1.9, T1.11), while one was included in their Tier 2 group (T2.5). Hence, we will next analyze PY's additional twelve papers of potential pertinence in the same way we did those of Root et al., i.e., in the order in which they appear in PY's list of references.