that directly support agricultural production (such as main­taining fertile soils, nutrient cycling, pollination), services that contribute directly to the quality of human life (such as cultural and aesthetic values of the landscape) and services that contribute towards global life-supporting functions (such as carbon sequestering, maintenance of biogeochemi-cal cycles, supply of fresh water, provision of wildlife habi­tats) (Björklund, 2004). Growing populations and activities put increasing pressure on land, soil and water resources. Current estimates suggest that 10-20% of the global ter­restrial area has degraded soils, and that that area is extend­ing. Pressure on land and water will be further exacerbated by climatic change. Lack of access to natural resources is a major reason for many local, regional and (trans-) national conflicts. This applies, currently, to low-income countries, where food, forests, wildlife, fisheries and energy sources, which are bound to land and water, form the basis for the livelihood of a large share of the population.
     Resource use in the NAE region has been and remains very high. At the same time, resource used by growing economies such as China, India and Brazil increases at an accelerated pace. If the world as a whole would follow the patterns of consumption experienced in NAE, global resource use is estimated to double within the next 10-15 years. However, there is still an enormous slack in resource use efficiency, namely water and nutrient use efficiency, leav­ing much scope for improvement (Smil, 2000). Inefficient use of resources and overexploitation of non-renewable re­sources are obstacles, whereas sustainable production and consumption are key to sustainable development (within NAE and globally).
     Agriculture generates waste and pollution, yet it also conserves and recycles natural resources, and can signifi­cantly contribute to the enrichment of landscapes and cre­ation of habitats for wildlife.
     Agriculture both causes and is affected by changes in natural resource availability and quality.
     In the following paragraphs we describe major trends and uncertainties related to changes in and threats to agri­culture resulting from changes in natural resources and vice versa, agriculture's impact on natural resource availability and quality.
     Among the major threats affecting agriculture in the NAE region are climatic change, water scarcity, soil erosion and biodiversity loss (see http://ec.europa.eu/environment/ agriculture/index.htm).
     On the other hand, NAE agriculture affects natural re­source availability and quality mainly through its demands on land, soil, water and energy for producing biomass (food, feed, fiber and fuel), its impacts on the environment from inappropriate management practices such as soil, wa­ter and air pollution through excessive use of agrochemi-cals, soil degradation (erosion, organic matter decline and compaction) and biodiversity loss (see http://ec.europa.eu/ environment/soil/pdf/soillight.pdf; ). However, there is also a range of environmental benefits created by agriculture such as maintenance of semi-natural habitats for wildlife and of agricultural landscapes thanks to its important en­vironmental   services   (see   http://ec.europa.eu/agriculture/ publi/fact/envir/2003_en.pdf).

Effects on agriculture
Favorable climatic and soil conditions are the basis of fer­tile, diversified and rich agricultural landscapes in the NAE region. The impacts of natural resources are often concen­trated locally and regionally, although some are of national and international significance. Land, water and other natu­ral resources are limited. Resource scarcity and competing claims for scarce natural resources, among different agricul­tural land use types and with other land uses are increas­ing. That competition is currently very alarming in the very densely populated agricultural lowlands of Asia where fer­tile arable land is reduced by its conversion for other than agricultural uses (Van Ittersum et al., 2004). In the NAE region, under current climatic conditions, water is at times scarce in parts of NAE such as in the Mediterranean re­gion. That water scarcity will become more severe with an­ticipated climate change. More extreme weather conditions will lead to more frequent drought and heat stress, more intensive precipitation, frequent flooding, erosion and poor trafficability of agricultural land. Despite many efforts in the NAE region to reduce environmental degradation and improve the quality and availability of the natural resource base, policies and new technologies have not been sufficient to reverse unsustainable trends (Van Camp et al., 2004).

Agricultural impacts on natural resource availability and quality
Agriculture has a significant effect on the environment in the NAE region. In the European Union, for instance, about 50% of the lands are farmed. Many of the environmental effects of agricultural activities are confined to the sector itself, but off-farm effects are also important. In its study "The Limits to Growth" more than 30 years ago, the Club of Rome showed how population growth and natural re­sources interact and impose limits on industrial and eco­nomic growth. As an example, the first global assessment of soil degradation found that 38% of currently used agri­cultural land has been degraded. Such phenomena are signs of an "overshoot"12 or, an imbalance between availability, quality and claims on the earth's natural resources, beyond what can be sustained over time. A core question of the various "limits to growth" scenarios was: How may the ex­panding global population and economy interact with and adapt to the earth's limited carrying capacity over the next 100 years? The simulation model applied to that end has been criticized for underestimating the power of technology and for not adequately representing the adaptive capacity of the free market. Its "30 years update" (Meadows et al., 2004) concludes that: "We are still drawing on the world's resources faster than they can be restored, and we are releas­ing wastes and pollutants faster than the Earth can absorb them to render them harmless." This is in line with analyses by European research agencies that led to, among others, the recent EU strategy on soil protection (e.g., Van Camp et al., 2004), and the EU Thematic Strategy on the sustainable use of natural resources. Human demand started to exceed

12 To go too far, to grow so large so quickly that limits are ex­ceeded (after Meadows et al., 2004)