2014 Effects of mid-latitude westerlies on the paleoproductivity at the Atlantic margin of South Africa during the penultimate glacial cycle: evidence from coccolith Sr/Ca ratios[disponible en anglès]
2011, CRITICAL REVIEWS IN PLANT SCIENCES - número/volum 1-2/30 - ISSN: 0735-2689 - Pàgines 45-63 - DOI 10.1080/07352689.2011.554352
Tots els autors:
Nancy Arizpe; Mario Giampietro; Jesus Ramos-Martin
The serious food crisis in 2007 has reinstated the issue of food security. In particular, it evokes an old set of questions associated with the sustainability of an adequate food supply: are we facing a systemic shortage of arable land for food production? How serious is the oil dependence of food security in relation to peak oil (the point in time when the maximum rate of global oil extraction is reached)? To answer these questions one has to study the role of technical inputs in agricultural production, especially those inputs generated from fossil energy (how much fossil energy is used? for which inputs? in relation to which tasks?). This paper provides a synchronic comparison—e.g., comparing the use of technical inputs in 21 countries belonging to different typologies, at a given point in time—and a diachronic comparison, e.g., comparing the use of technical inputs in the same sample of 21 countries, over a time window of 12 years (1991-2003). The results confirm the conclusions of previous studies and include the following: (i) current pattern of inputs use reflects the existence of different typologies of constraints in different typologies of countries. Wealthier countries must have a very high productivity of labor, whereas poor and crowded countries must have a very high productivity of land. Different technical inputs are used for different purposes: irrigation and fertilizers are used to boost yield per hectare; machinery and infrastructures to boost the productivity of labor; and (ii) when looking at the changes over the period of 12 years we see a constant and worrisome trend. The pattern of energy use in agriculture associated with the paradigm of industrial agriculture (High External Input Agriculture) has been simply amplified, by doing more of the same, with only minor adjustments in special countries. For those looking for a major transition toward a different pattern of production more focused on rural development, ecological compatibility and quality food, this is a reason for concern.