The Intergovernmental Panel on Climate Change (IPCC) has produced compelling analysis showing that elevated greenhouse gas concentrations will cause global climate alterations that will impact key components of the hydrologic cycle, including precipitation, evapotranspiration, soil moisture, and runoff. Global climate change will only exacerbate conflicts over water resources. As precipitation and runoff patterns become more volatile and difficult to predict, conflict over river system development is likely to increase. These alterations will challenge governments in many countries around the world to develop coping strategies if they are to manage their water resources to provide the current level of human and environmental requirements.
To illustrate, California will be much warmer and drier, making water an even more precious and scarce resource, and water allocation a more contentious issue. Simulations suggest that the average annual delivery of water to irrigated agriculture may be reduced as much as 30%. Urban growth in the region has the potential to claim as much as 20% of available water supplies under this climate future, much higher than the 8% now dedicated to this sector. Environmentally important flow patterns in the systems that now occur roughly once every two years will potentially be absent three out of four years in the future. River water temperatures may render impossible the goal of restoring certain anadromous fish runs.
In the past, research on the potential impacts of climate change on the hydrologic cycle has been narrowly focused on isolated components of the cycle, for example watershed response, agricultural yield, and land cover change. NHI is working to meet the urgent need for integrated and holistic analysis that can illuminate the full suite of potential conflicts and tradeoffs that climate change may force upon water managers in the coming decades. Utilization of this type of analysis can assist state, national and international policy makers in evaluating greenhouse gas reduction strategies. Further, such a holistic watershed analysis may also motivate major greenhouse gas emitters to commit to an aggressive action plan for reducing greenhouse gas emissions on a global level.
Since 2001, NHI has been engaged in (1) building tools to better understand the policy implications of climate change and (2) developing adaptive strategies.