raised profound economic, environmental and cultural is­sues whose implications for society bear serious examina­tion. The same can be said for property regimes regarding access to water and other resources. This is particularly sig­nificant when the multiple functions and changing circum­stances of agriculture in the future are properly taken into consideration.
     The increasing globalization of property regimes and forms of public/private interaction and the strongly influ­ential role NAE has in shaping these changes have powerful implications for the rest of the world. Upon consideration of changes that may be appropriate for the NAE region, it is proposed that NAE not impose those changes on nations and regions that may have good reasons for choosing other legal and institutional arrangements. Achieving the best bal­ance between the value of internationally uniform arrange­ments and the value of arrangements adapted to place and context can be a key issue for achieving development and sustainability goals.

6.2 Future Needs and Priorities for AKST
In NAE the evolution of agricultural science and technology during the last decades has been largely driven by academic and disciplinary approaches with the ambition to better understand biological and agronomical mechanisms of sim­plified and focused systems. Such approaches have led to high-level science that has in some respects ignored organi­zational impacts, particularly contextual elements (from bi­ological sciences as well as from social sciences) affected by the deployment of that science, in nonlinear and unpredict­able ways. These disciplinary approaches are not sufficient to address a complex problem—as a whole—and could be supplemented with more systems and overall approaches such as "complex system"14 approaches. These new ap­proaches are today more developed in the ecological do­main and consider all relevant sub-systems or components and their inter-relations as well as their associated social, economic and policy frameworks. They require a multiple scale approach, both from a spatial (from local to global) and temporal (from short to long term) point of view.
     Putting the focus on complexity and trans-disciplinary approaches does not devalue disciplinary efforts that supply basic knowledge for some of the components of the overall

14 A "complex system" is a network of many components whose aggregate behaviour is both due to, and gives rise to, multiple-scale structural and dynamic patterns that are not inferable from a system description that spans only a narrow window of resolution (Parrot and Kok, 2000). It leads to emerging new features or proprieties that cannot be predicted from the components. Complexity differs from other analyti­cal approaches in that it is based on a conceptual model in which entities exist in a hierarchy of interrelated organisa­tional levels. The main features of complex systems are (1) the non-linearity of relationships, (2) the occurrence of both negative and positive feedback loops, (3) their openness (show pattern of stability, even if usually far from energetic equilib­rium), (4) their history, keeping memory of past events, (5) they may be nested, each component of a complex system may itself be a specific "complex system."

complex system. But, it highlights the importance of mo­bilizing AKST more in this direction that has been under­developed until now and is essential for understanding both the operation and the evolution of the whole system. This will be all the more important as the number of variables and their interrelations increase, many of them being uncer­tain and addressing different scaling systems (Box 6-1).
     As far as global phenomena are concerned, one of the major challenges of the next decades is to develop agricul­tural activities that respond better to climate change: NAE could play a leading role in this domain. NAE could also consider its role in helping to deal with the spread and emer­gence of disease: the anticipation and management of new and emerging diseases, the occurrence of which is partly due to climate and partly due to rapid globalization. One other area where AKST can contribute to is to reduce the depen­dence of the NAE region on petroleum based fuels by devel­oping alternative sources of energy and also by developing energy efficient supply chains at the global level. The NAE region has supported the implementation and development of agricultural activities in many other regions to enrich NAE's own food and nonfood systems. Another challenge for the next 50 years will be to contribute to a sustainable economic, social and environmental development in these regions.
     As far as local phenomena are concerned, future agricul­tural research and development must consider broadening its concerns to address explicitly and directly the multiple func­tions of agriculture (production of food and fiber includ­ing land conservation, maintenance of landscape structure, sustainable management of natural resources, biodiversity preservation and contribution to the socioeconomic viabil­ity of rural areas (OECD, 2001) both in Europe and North America. Several broad areas of research are required in or­der to move towards this goal in a deliberate and logical fashion as detailed in the following sections.

6.2.1. Responding to climate change
Greenhouse gas (GHG) emissions from agriculture are in the range of 7-20% of total country emission inventories (by radiative effect) for NAE and are a contributor to climate change. AKST could be mobilized to mitigate this change while helping agriculture adapt to these changes.

6.2.1.1  Mitigate climate change through agriculture
The influence of agriculture on climate is significant but complex. Agriculture could help in reducing the increase in greenhouse gas emissions and in some cases, through ex­pansion of some agricultural practices and land-use changes and development of new ones, can also contribute to a de­crease in GHG. Some examples of agricultural practices and their potential benefits are given below:
•     increase carbon sequestration in agricultural soils for example through no or minimum tillage, cover crops and green manures leading to an increase in soil carbon levels. Additional research on the enabling conditions and the magnitude of the net effect on GHG emissions could be useful;
•     directly sequester carbon from flue gasses in intensively grown crops in closed conditions (Betts et al., 2007);
•     increase carbon sequestration via land use change (Bro-