space and growth: a survey of empirical evidence ... - ResearchGate

18 Maria Abreu, Henri L.F. de Groot and Raymond J.G.M. FloraxAlthough the bulk of this section will be concerned with models ofabsolute location, there are a few studies in the non-spatial econometricsliterature that deal with relative location, notably studies of spillovers andtechnology diffusion. We conclude this section by discussing their significance,and how they relate to the spatial dependence models typically estimated in thespatial econometrics literature that will be reviewed in Section 2.2.Within the literature using models of absolute location there are somestudies that incorporate geographical variables directly into the analysis, so thatgrowth is a function of variables that are invariant over time and thereforeexogenous (since they precede economic growth and development). Typicalexamples are Hall and Jones (1996), Sachs and Warner (1997) and Lee et al.(1997), who find that latitude is a negative determinant of growth, aftercontrolling for other social, political and economic factors.Another part of the literature deals with the indirect effects of geographythrough different channels. The idea is that geographical variables can be used asinstruments for other variables that have a direct effect on growth. Onehypothesis linking absolute location with growth emphasizes the higherincidence of infectious diseases in the tropics. Among them, malaria is unique inthat it is not a consequence of poverty, and the feasibility of eradicating it ismainly determined by climate and ecology. This allows the authors to either treatit as exogenous, or to instrument it using geographical variables. Bloom andSachs (1998) and Gallup and Sachs (2001) find that the incidence of malaria hasa negative effect on economic growth, after controlling for other variablesrelated to policy, human capital and general health.A related channel through which geography can have an impact on growthis agriculture. Agricultural productivity in the tropics is low because tropicalsoils are poor in nutrients (winter frost is essential for creating a rich topsoil) andsusceptible to erosion, rainfall is variable, and pests and diseases are widespread(again due to the lack of winter frost). In addition, only a small amount ofagricultural research is carried out with tropical agriculture in mind, and whilemachines and other equipment can be used across climate zones, new cropvarieties need to be adapted to tropical climates. Gallup and Sachs (2000) findthat agricultural productivity growth is substantially lower in the tropics, whileMasters and McMillan (2001) show that growth increases sharply with thenumber of days of winter frost, particularly at low levels of frost.The relationships found in the literature on geography and growth have ledto a debate on the relative merits of geography, policy and institutions inexplaining long-run growth. It has been argued that the quality of institutions andpolicy may be affected by geographical and climatic conditions. For example,Acemoglu et al. (2001) argue that settler mortality rates in the European coloniesdetermined whether or not the colony became an extractive state with weak