water loss will critically depend on the timing and splits of fertilizer application, type of crop protection and tillage. Policies need to support the diffusion of improved or "best practices" by environmental regulations that aim at reduc­ing nitrate and pesticide leaching. The rigorist approach of such regulations depends on societal choices, which in turn also co-determine the preferred production orientation and farming systems.
     Striving for food security and responding to the conse­quences of globalization of markets and global environmen­tal change (including climate change) are some of the major challenges of our time (CGIAR Science Council, 2005; Ro-etter et al., 2007). In the future, particular attention needs to be given to climate change and possible (mitigative) ad­aptation options, as it is superimposed on and will influence other major challenges for agriculture such as the produc­tion of sufficient, affordable, high-quality, safe food, as well as feed, fiber and biobased fuel. So far, climate-induced risks and opportunities for agricultural systems have not been sufficiently addressed by AKST.
     One of the challenges for AKST is to improve its adap­tive capacity. This will be required and beneficial for the sector irrespective of the precise impact of global environ­mental change.
     Closely related to this is the development of modern, resource-use efficient and low emission farming systems and agricultural practices. For the design and ex ante evaluation of such systems, the development of better tools like crop models, farm household models and regional land use (opti­mization) models—linked to GIS—can be very helpful. Such tools will be crucial for analyzing the consequences of pos­sible alternative development pathways on agricultural pro­duction and natural resource use. Improved methods and tools together with appropriate stakeholder participation have a high potential to support and promote well-informed policy designs and the implementation of effective policies.
     Directly related to this is the challenge for AKST to gen­erate the means that can contribute to conflict resolution regarding competition for scarce natural resources. During the 1990s, some public AKST systems (CGIAR and NARS partners world-wide) have tried to respond to that challenge seriously, e.g., by developing ecoregional research method­ologies (Bouma et al., 2007). Both, top down and bottom up approaches to Natural Resource Management (NRM) have been developed (Van Ittersum et al., 2004), with the top down approaches directed more towards policy makers and regional resource managers and the bottom up approaches more towards participatory technology development and support for decision making on optimizing resource use at the local level. Both approaches are required and need to be interlinked in the future to effectively support NRM by improving decision making on land/resource use issues. If the future world opts to achieve sustainability goals mainly through technological solutions and refuses to change its attitude towards consumption and dietary issues, AKST will have to be organized differently than in a world that considers solutions only sustainable if they increase equity, are owned and accepted by local resource managers and contribute to environmental sustainability. In the first case, AKST should be organized to seek local solutions by link­ing local knowledge networks tightly to global networks of

excellence. Whereas, in the latter case, a local learning ap­proach should be promoted to better integrate the different local knowledge centers and link them to global centers of excellence for tapping the relevant disciplinary knowledge. Likewise, in a world that favors technological solutions above behavioral change, AKST will have to focus more on technological improvements in precision agriculture and conventional, specialized agriculture to restrict negative en­vironmental effects than on integrated systems of organic agriculture that minimize emissions through recycling and avoid the use of agrochemicals. The focus of AKST will also depend heavily on whether choices clearly support a biobased economy in which biofuels play a big role. Given the threats of global environmental change, a AKST that di­rects its efforts towards the development of sustainable, (en­ergy, water, nutrient, and labor use efficient), economically viable farming and land use systems that serve the multiple development objectives of rural areas will be beneficial for natural resources quality and the environment under differ­ent plausible futures. Finally, if society decides to make a serious effort to overcome environmental degradation and resource depletion, well designed technologies will be effec­tive tools in supporting sustainable development.
     To enhance the aesthetic value and sustainability of the landscape, research will be needed on ornamental plants, genetic exchanges with wild species and improved manage­ment strategies to preserve the natural biodiversity of local crops as well as wild species and to contribute to sustain­ability issues, such as recycling strategies, energy production and fire prevention (ETP, 2005).
     Last, little research has been carried out on the sustain­ability of coastal fishing production systems which are still intensive, while aquaculture production systems, on the contrary need to be intensified and new species introduced. The priority given to fisheries and aquaculture will differ ac­cording to the type of agricultural research and innovation system. Ecosystem-oriented AKST will favor the sustain­ability of coastal fishing while AKST directed to local food supply should favor aquaculture. Market-led AKST will probably put little priority on these themes in their present condition.

5.4.6 Climate change and variability
To counter the increasing effects of climate change on ag­riculture will require a wider and stronger spectrum of adaptation responses as well as efforts to reduce energy needs  and emissions.  Increasing temperatures, more er­ratic precipitation patterns and increased risks of droughts, particularly in the southwestern parts of USA and Europe, coupled with a northern shift of cropping zones, will lead to changes in agricultural systems and production regions. Extreme events will severely challenge adaptive capacity. AKST could be developed to provide better adaptation and mitigation responses.

5.4.6.1 Ongoing trends
Agricultural systems, forestry and fisheries are quite sensi­tive to climate change and variability and can be strongly af­fected by them. Concurrently, land use and land use change, particularly through  agricultural  and  forestry  activities, can strongly influence climate. There is now unequivocal