Land-use change due to agriculture has often been considered a local issue, but it is now one of the main driving forces of global environmental change. Ecosystem changes are being driven by demand for food and fiber for the world’s growing population, and our attempts to increase agricultural production have indirect effects that may lead to critical tipping points in global system properties.

Rapid, global intensification and extensification of agriculture are being driven by shifts to more meat-heavy diets, increasing trade in agricultural products, growing demand for biofuels, and a growing human population. Efforts to increase agricultural production often focus on production to the exclusion of other ecosystem functions important in sustaining wildlife habitat, high quality water supplies, and places to recreate. Ecosystem resilience may be diminished as a result, increasing the likelihood of crossing “tipping points”. Tipping points are thresholds beyond which the past response of the system no longer predicts the future; they are often triggered by positive feedbacks which can cause a shift to a new regime of system regulation. Crossing tipping points can produce sudden and large shifts in the supply of ecosystem services. In this session we focus on agriculture- and water-mediated tipping points. Examples include eutrophication of freshwater and estuarine systems through fertilizer runoff, salinization from irrigation, and changes in climate caused by alterations of water flows between land and atmosphere. While such tipping points have been studied and monitored at small scales, there have been few synthetic attempts to understand and model large-scale regime shifts. Such understanding is necessary to develop agricultural and development policies that sustain rather than degrade the biosphere.

In this session, we identify potential ‘tipping points’ or regime shifts, related to water and agriculture, that could have major consequences for the future of ecosystem services globally. We present new research assessing potential tipping points, and discuss new methods to detect, assess, and avoid undesired regime shifts.