Guzmán G I, Alonso A M (2008). A comparison of energy use in conventional and organic olive oil production in Spain, in Agricultural Systems Volume 98, Issue 3 The current situation of worldwide concern over the emission of greenhouse gases and their effect on the climate demands an evaluation, from the perspective of energy efficiency and more specifically of non-renewable energy sources, of tendencies for change in the management of agricultural systems which have arisen in recent years.

Increasing temperatures, changing precipitation, rising sea levels, more intense and frequent extreme weather events and melting glaciers, ice sheets and Arctic sea ice are some of the challenges for Europe already triggered by global climate change, says a report released by the European Environment Agency, the World Health Organisation Regional Office for Europe and the Joint Research Centre of the European Commission.