Data Appendix Definitions and Sources of Variables

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Tundra
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.409.477; http://douglas-hibbs.com/HibbsArticles/DEA.pdf

Climate is constructed on the basis of Köppen’s widely used system of climatic classification. 1 The classification schedule is vegetation-based and divides climate into five major types which Köppen refers to as A,B,C,D, and E. Climate A corresponds to wet tropical climates, B to dry tropical climates, C and D to temperate, mid-latitude climates, and E to tundra and ice. In constructing our Climate variable we made a ranking of climates according to how favorable they are to agriculture. Countries with type B and E climates have been given a value of 0. Most of the tropical dry countries in this category are found in the Sahara and on the Arabian peninsula. The tropical climates in the A category were scored 1. Precipitation is abundant and biodiversity great, but the heavy rainfall typically does not favor annual grasses. Countries with temperate climates of type Cfa, Cwa, and D (humid subtropical and continental) were scored 2. A particular subgroup within the nontropical climates is the Mediterranean and west coast climates (Csa, Csb, Cfb, Cfc) with more or less hot, dry summers and wet winters. These types of climate are found in the