Vulnerability to global
environmental change in natural
ecosystems and rural areas:
A question of latitude?
Exequiel Ezcurra, Alfonso Valiente-Banuet,
Oscar Flores-Villela, and Ella Vázquez-Domínguez
In July 1990, an intergovernmental group of experts, convened by the World Meteorological Organization and the United Nations Environment Programme, produced a document summarizing what was known at that time on the biophysical perspectives of global climatic change (GIESCC 1990; IPCC 1990a). One of their main conclusions was that it can be inferred with a high level of certainty that during the next century the average temperature of the earth will rise steadily at a rate of 0.3°C per decade if the emission of greenhouse gases continues at its present trend. According to this expert panel, the Intergovernmental Panel on Climate Change (IPCC), a sea-level rise of approximately 5 cm per decade will affect natural ecosystems in different ways and will significantly disrupt the water balance in many regions of the globe. The same panel recently revised its estimates to predict a temperature rise of 1.4–5.8°C and a sea-level rise of about 0.09–0.88 m by the year 2100 (IPCC 2001).
Large-scale climatic variation is an important element, but by no means the only one, of a series of large-scale Disruptions in the global environment that are threatening the sustainability of the biosphere as a whole. Apart from the systemic effect of the emission of gases at a biospheric level, other phenomena are contributing significantly to so-called “global change.” Among these, pollution of air and water resources, soil depletion and erosion, deforestation, overgrazing, and depletion of biological diversity are possibly the most important.