Abstract This study introduces a new concept, that of ‘landscape efficiency’, understood as the state in which the economic flows of social metabolism in a land matrix are improved while maintaining the patterns and processes of landscape ecology as healthy as possible. This concept is used to explore the hypothesis that a serious reduction in this efficiency, typified by significant landscape degradation, underlies the increase observed in external inputs and the corresponding loss of energy efficiency that the agrarian system has undergone over the last 150 years. In the present article, a structural and functional analysis of the landscape changes experienced by an area in the Vallès county (Barcelona Metropolitan Area in Catalonia, Spain) is conducted, employing an innovative methodology that combines two indicators taken over from landscape ecology (land cover diversity and ecological fragmentation) with two new socio-ecological indices recently developed by two of the authors of this study (landscape metrics and ecological connectivity). Our results point to an increase in land cover heterogeneity, ecological fragmentation and anthropogenic barriers, as well as to a growth in landscape diversity. All these changes are associated with a substantial reduction in the ecologically functioning areas and the county’s ecological connectivity, and have resulted in a severe loss of landscape functionality and efficiency in the study area. The changes have gone hand-in-hand with a sharp reduction in agrarian energy returns on energy inputs, suggesting the need for a more in-depth cross-disciplinary dialogue between the natural and social sciences to develop, from a common historical background, new criteria and methods to ensure more sustainable types of energy and land-use planning.

Abstract The article analyses the interaction between security and environment in the Mediterranean, focusing on the paradigmatic example of the Israeli-Palestinian conflict over water resources in the Jordan River basin. Control of water can hardly be considered the main cause of conflict between Israel and Palestine, but it certainly has increased the potential for conflict and had a long-term negative effect on the environment. The article starts with an historical reconstruction of the main attempts to reach a cooperative solution to water management in the Jordan River basin. These attempts failed as a consequence of the emergence of a zero-sum game between the co-riparian countries of the basin. The lack of cooperation has had a heavy impact on water quantity and quality. Two third of the deep wells in the centre of Israel are polluted, partly due to the infiltration of untreated wastewater from West Bank sites. The level of the coastal aquifer has fallen and sea water has penetrated it. As a consequence, much of the population of the Gaza Strip now has access only to brackish water that does not meet the WHO standard for drinking water. The 1995 Oslo Interim Agreement recognised the water rights of Palestinians and the need to share water resources. Its aftermath witnessed new cooperative efforts involving offi cials, experts and people of both sides. The so-called “Second Intifada”, however, blocked cooperation in many sectors and provoked large-scale damage to the water infrastructure. The violent outbreaks of October 2000 had a serious impact on the wells, the water infrastructure and the wastewater disposal system. Reportedly, the Israeli deliberately filled up wells in Gaza as retaliation against the Palestinian attack on Israeli settlements, did not allow the Palestinians to buy spare parts for pumps, and kept water tankers from reaching the Palestinian villages. The Israeli authorities did not directly plan these acts of vandalism - they are mainly the consequences of an escalation of violence among the settlers - but were responsible for not taking action to prevent them and forbidding the use water as a weapon against Palestinians. The separation barrier Israeli has been building since 2002 does not follow the Green Line, but creates a de facto annexation of 16% of the West Bank. The wall keeps people on either side of the Wall separated from their land, water resources and socialties.