AIBS News: Our biological heritage under siege

Climate change and the politics of causal reasoning: the case of climate change and migration

“…The first was the emergence of environmentalism. Migration – held implicitly to be a bad or aberrant phenomenon – was used, through the 1970s, 1980s and 1990s, to put a human face on an otherwise abstract concern about environmental change and degradation (Jacobson ; Tolba ; Foley ). As early as 1988, Jodi Jacobsen had suggested that an (apparent) decline in the planet's habitability was increasingly evident in the numbers of ‘environmental refugees’, the existence of which she claimed was a ‘yardstick of habitability’.…”

Sustainable development: Scientific and ethical assessments

“…Arable land is (currently) the only area in which the heavy power subsidies required by modern agriculture can be applied, and this area is almost saturated. Moreover, at least 7 million hectares (Tolba, 1989) have to be abandoned each year because of overexploitation. Alternative processes to generate nutrients will have to be developed, but still seem to be far in the future.…”

“…The replacement of natural ecosystems (especially tropical forests) by agriculture results in a loss of biodiversity --90% of the world's food is derived from just 15 plant and 8 animal species (Wilson, 1988;Pimentel et al, 1989), while estimates of the existing number of species on Earth are in the millions (Pimentel et al, 1992) --and consequently in a loss of biophysical activity sustaining the biosphere's bio-geo-chemical cycles (Wright, 1990;Giampietro and Pimentel, 1991a). Moreover, intensive agriculture results in a loss of top soil, lowering of water tables, and pollution due to the use of chemicals (Risser, 1981;Pimentel et al, 1987Pimentel et al, , 1989Tolba, 1989;Lal and Pierce, 1991). Many scientists fear that a further increase in "human scale" (= population size x consumption per capita) will push the Earth system into a situation of non-sustainability and increase the risk of a future collapse of the biosphere's structure~function (Odum E.P., 1971(Odum E.P., , 1989Lieth and Whittaker, 1975;Pimentel, 1979, 1989;Daly and Cobb, 1989).…”

Exposition on Skepticism

“…For instance, in India, soil is being lost at 30 to 40 times its sustainability rate (Koshoo and Tejwani 1993). The rate of soil loss in Africa is increasing not only because of livestock overgrazing but also because shortages of wood fuel make the burning of crop residues essential (Tolba 1989). During the summer of 2000, NASA photographed a cloud of African soil being blown across the Atlantic Ocean, further attesting to the massive soil erosion problem in Africa.…”