b'Session II: Drivers, controls and time lagsmeeting the expectationsClimate change is accelerating phosphorus transfer to catchmentsHaygarth PM1 1Lancaster Environment Centre, Lancaster University, UKThe link between agricultural land and catchment science is now well established, but less so is the role that climate change plays in accelerating the transfers of nutrients like phosphorus.This paper describes a team effort that has been studying the extent to which phosphorus losses from agricultural land are being impacted by climate change. The paper will discuss the great challenge in determining this, with all the complexities, controversies and uncertainties incatchment science that surround it. By focussing on three UK catchments, we show thatthe effect of climate change on average winter phosphorus loads (predicted to increase by up to 30% by the 2050s) will be limited only by large-scale agricultural changes (e.g. a 2080% reduction in phosphorus inputs). Achieving quality water in diverse and productive agricultural landscapes under a changing climate is going to be a massive challenge. It is less than a century since we started mining rock phosphate, but in the context of a 4.5 billion year old earth and the acceleration due to climate, we are living through a switching point for the earth system, and catchment science is at the heart of this. We urgently need to innovate systems to avert this and to raise these issues up the agenda.6'