REUTERS/STRINGER Brazil

Water Management and Climate Change

By: Kathy Jacobs and Paul Fleming

Editor’s Note: The following is an excerpt from The Water Problem: Climate Change and Water Policy in the United States, edited by Pat Mulroy, on sale March 28, 2017.

ADOPTING A RISK MANAGEMENT FRAMEWORK

Managing risk is about managing perceptions as much as it is about managing the “real” risks that might be identified by experts. Though many Americans are not convinced that climate change is real or that it is caused by humans, that is not a good reason to ignore it. The failure to acknowledge the implications of climate change increases the risk of system failure for water managers. Especially for those who are operating in the “reality gap” (that is, working with customers or board members who are not willing to consider the scientific evidence of climate change), one approach is to frame decisions in the language of due diligence and risk management. For example, even if there is only a small chance that change climate is occurring, being wrong can have serious consequences. Properly applying a risk management framework means that all risks need to be considered, especially those with severe consequences, even if there is a low probability of a particular extreme event occurring. This explanation should provide sufficient space to permit consideration of climate change in the context of varied political perspectives. Being prepared for a wide range of future conditions is simply best practice for water managers.

REUTERS/David Mercado

Given that 97 percent of climate scientists agree that climate change is already occurring, and that changes in the water cycle have been documented on every continent, water utility managers are on the front line of the climate conversation. Acknowledging the human-caused component of climate change is important, particularly in the context of longer-term decisions. This is because the human influence alters the nature of the future we need to be prepared for. For example, if we were to assume that every change we are now observing is due to natural variability, then we would expect a return to normal or historical average conditions as we understand them. This has totally different implications for long-term water management than acknowledging that there is a driver of change (increasing total energy in the Earth’s atmosphere) that is pushing the system out of equilibrium and potentially outside the envelope of historical variability. Understanding the changes we are seeing through this second lens tells us that the impacts we are now observing are likely to escalate over time unless total global emissions actually decline in the near future, which seems unlikely. Understanding that there is a trajectory of change rather than simple variability around a “normal condition” — in other words, understanding that stationarity is dead — leads to a very different kind of approach for a water resource manager.

WATER AND CLIMATE

The water cycle integrates social, environmental, and physical systems in multiple ways. Alterations in the water cycle are driving the impacts of climate change through changes in snowpack, precipitation, flooding, seasonality of runoff and other events. For example, a reduction in total snowpack (due to more rain and less snow) and earlier snowmelt are having significant impacts on water-supply conditions across the U.S. West — in California, the Pacific Northwest, and the Colorado River basin. More intense precipitation has been observed in every region of the United States, even in places where the total rainfall is declining. More intense heat and drought conditions have also been linked to climate change in multiple parts of the country. These changes have a range of cascading effects on ecosystems, water supply, water quality, flood control, and economic sectors such as forestry, agriculture, and coastal and marine systems. Of course, there have been floods and droughts in the past, but the combination of the social, ecological, and physical changes that are occurring now means that the pace of change is accelerating and the challenges for water managers are also growing.

Climate is a driver of water-supply conditions, and changes in snowpack, temperature, and precipitation intensity, seasonality, or volume lead to a wide range of potential risks that ripple across economic sectors and communities.

What does “stationarity is dead” mean in a water management context? It means changes in average conditions are occurring, but, more important, it means changes in extremes, which could have dramatic consequences. It means that historical conditions are no longer a reliable basis for future planning and that static standards, such as engineering rule curves for dam operations or intensity/duration/frequency curves for sizing drainage systems, are no longer optimal. It means more uncertainty, perhaps more variability, but also the opportunity to think broadly about water-supply reliability and the secondary implications for the full range of water resource management business practices, planning approaches, and decision-making processes, in the context of a range of other factors.

REUTERS/David Mercado

Climate is a driver of water-supply conditions, and changes in snowpack, temperature, and precipitation intensity, seasonality, or volume lead to a wide range of potential risks that ripple across economic sectors and communities. These changes affect demand for water, assets and infrastructure of utilities, and the capacity to provide reliable services, but they also have implications throughout and beyond the water sector. They affect energy supply and demand, agricultural productivity, and both natural and urban systems. The crosscutting, multifaceted implications of climate change mean that water resource managers will not only need to consider the associated technical and scientific issues but will also need to engage in understanding and managing the strategic, policy, political, and organizational implications of climate change across multiple sectors as well. It is imperative that water resource managers reimagine their roles and responsibilities in light of the challenges of a changing climate.

Learn more and pre-order The Water Problem: Climate Change and Water Policy in the United States.

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