Searching for Practical and Flexible Definitions of Extreme Events under a Changing Climate Guido Franco Public Interest Energy Research (PIER) Program California Energy Commission ASP Research Colloquium June 15, 2011

Climate Change Research at the Energy Commission PIER was created in the late 1990s and started working in earnest on climate change in 2001 First PIER Assessment for California released in 2003 PIER created the California Climate Change Center in 2003 –First state-sponsored climate change research initiative in the USA –Designed to complement national/international programs –Annual budget ~ $6 million –Areas of research: 1) climate monitoring, analysis, and modeling; 2) GHG inventory methods; 3) Options to reduce net GHG emissions; and 4) impacts and adaptation studies More than 150 scientific PIER reports produced so far resulting in multiple publications in scientific journals

2006 Assessment Led by PIER About 17 scientific papers Special Issue in Climatic Change “Our Changing Climate” contributed to the passage of AB32 Emphasis on physical impacts

Vulnerability and Adaptation Study: extreme events Work in progress

Study Design Interviews with practitioners to determine how they define extreme events for their sector. Use past events if a definition is not available Use the climate and sea level rise projections available for California (BCSD and BCCA and VIC): daily, 12 Km Re-define extreme events, if needed, using the variables that are “well” modeled Identify potential extreme events that have not occurred yet in the historical record Estimate the possibility of concurrent extreme events

Lessons learned so far There are no standard definitions of extreme events Past events can be used to define them. Three examples: –Mortality and morbidity effects with two consecutive days with temperatures above 9x percentile – California Department of Public Health –Electricity system under stress if weighted average temperatures in California are above 9x F (warming every where in CA) – CA Energy Commission –CA Freeze January Damages to citrus, berry, and vegetable crops. $1.4 billion estimated in damage/costs. NOAA

Cumulative distribution functions of January daily minimum temperature across the regions (plotted roughly geographically). The Y axis shows the probability (zero to one) of experiencing the indicated temperature or lower on any particular day in January. Results from the historical run are in blue; the future run is in red. Source: Pierce, et al Draft PIER Report

Lessons learned so far (cont.) Integrating parameters such as river flows can be better predictors (e.g., good correlation between three-day average river flows and flooding) Extremes events should be considered in their regulatory and legal context. For example, the last draught in California was exacerbated by regulatory impediments to the exportation of water via the Delta

An example of a potential extreme event without an historical precedent

There are Important Energy Facilities in the Delta The Sacramento-San Joaquin Delta is protected by levees. Delta islands are below sea level Energy Facilities: –Underground natural gas reservoirs –Transmission lines –Power plants on the west side of the Delta Source: PPIC 2007

GPS and InSAR (Synthetic Aperture Radar Interferometry) suggest a synoptic subsidence throughout the Delta at rates of 5-20 mm/yr Projections including sea-level rise indicate large-scale overtopping threat in the 21st century Sea level rise and increased river flows in the winter will increase the possibility of a catastrophic failure of the Delta Source: Mount and Twiss, 2005 (with modifications) Source: B. Brooks et al., Draft PIER report 2011.

Some issues with the Climate Projections for California

Source: Franco et al., 2003

Source: Pierce et al, Draft PIER Report

Yearly precipitation change (%, compared to ) Source: Pierce et al., Draft PIER Report

Thank you !