ABSTRACT
The placing of a monetary value on the services provided by ecosystems has become a major activity of environmental economists. To be sure, there are detractors, who claim that the dollars or euros attached to some services undervalue the natural systems, which have a range of functions that are not capable of being valued in these terms. But there is also growing evidence that even if we take only the services that have been valued the numbers are very large and can tilt the balance of decision-making when evaluating development or conservation options in favor of approaches that protect the natural resource base.1 Some authors (Adamowicz 2004; Silva and Pagiola 2003; Smith 2000) have looked at the use of valuation of ecosystems for policy purposes. They find that some actions have indeed resulted from the work that has been done in this area, such as damage assessment cases in the USA, controls on some pollutants based on evaluations of human health, cost-benefit analysis of water resource planning, forest resource use planning, and tax revenues from the improvement of the environmental quality. However, there have not been as many applications as one would hope for, and the majority of the ecosystem valuation studies have been of an academic nature and have not intended to influence decisions (Markandya and Pascual 2014). To understand the role of economic valuation we have to see it in the context
of the problem that is being addressed. This book mainly looks at selected functioning ecosystems in Central America and the services they provide now and will provide in the future under different climate scenarios. It discusses the most suitable biophysical models for each of the ecosystem services that are studied. For hydropower the authors used the MAPSS model, while the water and recreational services are analyzed with the use of the Holdridge zone model, in which four “life zones” or “Holdridge systems” are identified, each characterized by bio-temperature (temperature range allowing vegetative growth), annual precipitation and humidity. In each case biophysical models aim to provide a link between the state of the system and the quantity and quality of the service provided. With climate change the functioning and size of the biophysical systems will alter and as a consequence so will the values derived from them.
