The Policy & Practice of Climate Change & Water
13/06/19 Filed in: Guest Blog
This article was written by Wyatt Arnold, Engineer, Water Resources at the California Department of Water Resources Climate Change Program.
To illuminate potential risks connected with the deeply uncertain future, planners with limited resources must often choose between two approaches. Option 1 provides a limited number of intensely bright yet narrowly focused spotlights (analogous to top-down analysis through downscaling of global climate models). Option 2 provides an unlimited number of glowing sticks, which may only softly brighten their surroundings, but cumulatively provide a more comprehensive perspective of the situation (analogous to bottom-up analysis through approaches such as decision scaling). The second approach seems more worthwhile when tackling the wide range of climate changes projected for California within the next 30 years — from an overall increase of 1 to 4 degrees Celsius and from 20 percent less to 30 percent more overall precipitation.
In collaboration with researchers at the Hydrosystems Research Group at the University of Massachusetts, Amherst, we adopted the second approach for assessing long-term and persistent hydrologic impacts of climate change on the California State Water Project (SWP). The SWP is a water storage and delivery system that extends more than two-thirds the length of California, serves 27 million people, and irrigates more than three quarters of a million acres of farmland.
We summarize results of our bottom-up, decision scaling study in an online story map to facilitate access to the crucial information produced and the methods and thinking that went into its production.