event 26 окт. 2011

Nexus Blog // Managing Water over Climate-relevant Timescales

How Water Makes Green Economies a Moving Target

category Nexus Blog
Alex Z./Shutterstock
The unpredictability caused by unprecedented rates of climate change presents a further challenge to water, food, and energy security During a 2008 panel for the IPCC's launch of a report on water and climate, a hydrologist and an engineer called for additional monitoring and research to detect the effects of climate change. The third member of the panel, a frustrated World Bank infrastructure lender, declared in response, "I can't wait thirty years for precise science to tell me how much global warming contributed to a particular drought or flood. I want to see climate adaptation programs based on non-precise decision making. I need to make investment decisions now." The lender's concerns are neither trivial nor unusual. In 2004, for instance, Rwanda briefly lost 90 percent of its electrical capacity following systematic wetlands destruction and a drought, putting the country's development trajectory at risk and worsening the ecological damage already incurred. Indeed, climate-adaptive management of resources such as forests, soils, water, and fisheries is the basis for "green" cities, energy production, agriculture, and water supply and sanitation systems. Poor investment and management decisions risk climate-initiated ecological transformations, which in turn could trigger economic crises. The challenges presented by climate change impacts are especially acute in a globalizing world. The impacts of too much and too little water extend far beyond the localities where they occur and are capable of disrupting national food and energy security as well as the global economy. The water cycle — surface and ground water, precipitation, soil moisture, snowpack and glaciers, flow regime and hydroperiod, runoff, and evapotranspiration — responds to even small shifts in climate in unpredictable ways. For humans, climate change is water change. But climate change also means there is no balanced nexus point for water, food, and energy security, since the weight between these areas moves with the shifting climate regime. Reaching a green economy is technically challenging, especially through the medium of water infrastructure. The difficulty of determining future hydrological conditions based on past records of climate and hydrologic regimes has been called the "death of stationarity", which refers to the assumption that future climate conditions have "predictable uncertainty"; that is, the frequency and severity of flood or drought events can be accurately estimated, which allows water managers (and economists) to manage risk. Climate change undermines this assumption by suggesting that the future holds unpredictable uncertainty. Most water-related infrastructure for energy, agriculture, and supply and sanitation is designed to function over decadal or even century-scale time spans, but traditional methods of design do not take account of a non-stationary climate over operational lifetimes. Climate change represents a serious crisis for water resource management and economic development success. The scale of the problem is enormous. The U.S. has more than 40,000 large dams, while China, India, Brazil, and many other countries are entering a new "golden era" of unprecedented and rapid water infrastructure development. The Hoover dam in the Colorado river basin, for instance, was designed in the 1930s based on observations made during three of the wettest decades of the past millenium, but Lake Mead now consistently stores only about 30 percent of its designed capacity. Precipitation trends are now moving closer to the 1200-year mean, which implies that the basin faces difficult tradeoffs between agriculture, cities, and energy production. Climate-infrastructure mismatches are likely to produce a host of serious repercussions for ecosystems and economies. They are also likely to reduce economic growth through low rates of electrical production or irregular agricultural harvests while wasting scarce investment capital. Ecologically, poorly designed water infrastructure is likely to reduce the inherent resilience and adaptive capacity of these nations' ecosystems, permanently altering lakes, rivers, soils, and fisheries. Climate-infrastructure mismatches may actually make poor nations even poorer. How can we enable both economic and ecological sustainability? We propose a three-step process: -Consider alternatives to building new infrastructure. Particularly for large projects such as the U.S. Hoover dam or China's South-to-North Water Transfer Project, the risks for investors, communities, and ecosystems are extremely high given uncertainties in future hydrological conditions. One or two decades of apparently successful implementation are likely to be followed by very difficult tradeoffs between socio-economic and ecological impacts, with both likely losing to the overly optimistic expectations created when long-term impacts and non-stationarity are not considered. -Explicitly integrate ecosystems into infrastructure development. The emerging practice of integrating of functional and intact ecosystems into water resource management can help humans and ecosystems adjust to emerging climate impacts, an approach to climate change adaptation referred to in the Netherlands as "building with nature". -View the reduction of infrastructure and ecosystem climate vulnerability as a continual process. The assumption of stationarity results in infrastructure designed for a single climate future, but designing for multiple potential climate regimes may be a more conservative and economically viable alternative. Equally important with infrastructure design is the need to create institutional structures capable of flexible operations, as well as more research into bio-indicators to track ecological integrity through time and anticipate ecological tipping points. Climate change is making sustainable development a much broader concept that is harder to both define and achieve. Targeting a single balance point between energy, water, and food security will foster a new (and temporary) stationarity. Dynamic water resource management should be central to our long-term growth and investment strategies to help economies and terrestrial and freshwater ecosystems to adjust to an uncertain future.


Many thanks for comments and feedback from Tracy Farrell and LeRoy Poff.

John Matthews is the Director of Freshwater Climate Change at Conservation International and co-leads the secretariat for the Alliance for Global Water Adaptation. Bart Wickel is the Lead Hydrologist and Sarah Freeman the Water Resources Engineer with the WWF in Washington DC. Contact {J.Matthews@conservation.org}; {Bart.Wickel@wwfus.org}; {Sarah.Freeman@wwfus.org}

Please contact {jcornforth@stakeholderforum.org} for a full list of citations used in this blog.

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