Drier and Hotter: Managing Climate Risks in the Southwest

Wednesday, April 2, 2014 — The Environmental and Energy Study Institute (EESI) held a briefing examining the current and projected impacts of climate change in the Southwest and regional efforts to manage these risks. The Southwest is already the driest and hottest region in the United States, and California is in the midst of a historic drought. The draft Third National Climate Assessment (NCA) – the final version is expected soon – projects that the region’s climate may become even more severe. These changes are having substantial adverse effects on the regional economy and quality of life, forcing local leaders to develop creative solutions to combat drought and other extreme conditions. How can the Southwest best address current impacts while also building climate resiliency to manage risk and foster long-term prosperity?

The effects of climate change already are being felt in the Southwest, which the NCA defines as Arizona, California, Colorado, Nevada, New Mexico, and Utah. Snowpack levels have fallen over the past 50 years, limiting a key source of the region’s water supply. From 2001-2010, the streamflow of the region’s major rivers was 5-37 percent lower than the 20th century average. Prolonged droughts and insect infestations have made forest ecosystems more vulnerable to wildfires and disease. Rising sea levels have increased flooding and erosion in California's coastal areas.

Climate change is expected to disrupt the livelihoods of many in the Southwest. Today, 56 million Americans live in the region. By 2050, its population is projected to rise to 94 million, putting additional strain on water resources. Water scarcity threatens the region's irrigation-dependent agriculture sector, which accounts for 79 percent of regional water withdrawals. The Southwest is home to more than half of the nation's high-value specialty crops, such as vegetables, fruits, and nuts. Because these crops are particularly vulnerable to weather extremes, climate change will likely reduce yields.

Many state and local authorities in the Southwest are moving forward with climate adaptation initiatives. California released a draft revision of its adaptation strategy in December 2013. New Mexico’s Active Water Resource Management program, which gives the state the tools to administer scarce water resources in cases of drought, has been cited as a model for other states. Salt Lake City, Tucson and Flagstaff formed the Western Adaptation Alliance in 2010 to share resources and best practices to improve local resiliency. The Alliance has grown to include Denver, Las Vegas, Phoenix, and others.

• Eleanor Bastian, Legislative Director, Office of Rep. Diana DeGette (D-CO), expressed concern that "the impacts of climate change in the Southwest pose a very serious challenge."
• Dr. Patrick Gonzalez, Climate Change Scientist, U.S. National Park Service, described the current impacts of climate change already visible in the Southwest. Winter snowfall has dropped by about 7 percent since 1950, tree mortality has doubled, vegetation is shifting upslope in certain areas, and sea level has risen. Climate change is the single largest factor explaining the increase in wildfires throughout the 20th century. And, climate change has contributed to the most extensive bark beetle outbreak in 125 years.
• Future climate change will be more severe. Temperatures will likely increase by 2 to 4 degrees Celsius, while persistent drought will take hold over a large area of the region (with some areas seeing more rainfall).
• The ecological impacts of these changes will include an increase in wildfires and dieback of woodlands and forests.
• Chris Treese, External Affairs Manager, Colorado River District, discussed some of the challenges facing the Colorado River Basin. For example, 90 percent of the water is in the Upper Basin, but 90 percent of the population lives in the Lower Basin. The Greater Los Angeles Basin relies on the Colorado River Basin for most of its water.
• In the future, the region’s irrigated agricultural areas will be heavily displaced due to a growing population, while the supply of water will fall 9 percent (from 15 to 13.6 million acre-feet). A recent study found that imbalances between water and population will grow if the projected impacts of climate change are realized.
• A combination of solutions will need to be implemented, as current water demands already outstrip supply. The current Basin-wide gap is covered by finite reserves, and significant actions are required to meet the region’s water needs.
• Margaret Bowman, Acting Environment Program Director, Walton Family Foundation, focused on how to respond to the water issues facing the Southwest. She said that business-as-usual is not sustainable, but that this crisis is solvable.
• The United States needs to invest in a few critical solutions, including: upgrade water-saving and irrigation techniques for agriculture; begin “water banking,” a market-based approach that allows farmers and ranchers to bank their water voluntarily; use water as efficiently as possible in cities; and improve efforts to recycle wastewater and storm water. Implementing these solutions might possibly be enough to fill the current water gap in the Colorado River Basin.
• Urban water efficiency is the least expensive and fastest option to save water. Cities could gain one million acre feet of additional water savings through improved landscaping techniques, municipal water audits, and other methods.
• Louis Blumberg, Director of the California Climate Change Program, The Nature Conservancy, discussed three themes: water issues in California, national infrastructure to reduce climate risk, and California’s current resilience efforts. According to Blumberg, the current response by the state is not enough: "it’s like the state went out to buy a fire extinguisher while the fire was burning."
• Nature can be a powerful tool to address these threats, and therefore it is important to restore natural systems to fight climate change. This can include rehabilitating degraded forests and meadows, ecologically-based thinning to reduce the impact of wildfires, reconnecting rivers to natural floodplains, and restoring marshes and wetlands.
• The Nature Conservancy in California is promoting ways to reduce climate risk via natural infrastructure. Natural infrastructure has many direct and indirect benefits, including water savings, wildlife habitat, recreation, higher property values, and emissions reductions.