California Nevada Applications Program

The National Climate Assessment was released on May 6, 2014. The Southwest chapter (Chapter 20) documents critical climate change impacts to the region’s coasts and forests, and projects increased risks to water resources reliability, agriculture, and public health. The chapter notes the special vulnerabilities of native nations and U.S.-Mexico border cities, due to high rates of poverty, and low tax bases for generating resources needed to develop and improve infrastructure, such as safe roads and water treatment and distribution. The chapter also points to adaptive responses by state and local governments, water utilities, forest managers, and federal agencies, to reduce the impacts of current and future changes. The chapter gives an example of how the region can reduce its production of heat-trapping greenhouse gases through adjustment of energy sources used in the generation of electricity, while also reducing water use. See http://nca2014.globalchange.gov/report/regions/southwest.

The Southwest Chapter for the National Climate Assessment was based on The Assessment of Climate Change in the Southwest United States, a technical input report published in May 2013. The technical input report is a summary and synthesis of the past, present, and projected future of the region’s climate, examining what this means for the health and well-being of human populations and the environment throughout the six Southwestern states—Arizona, California, Colorado, Nevada, New Mexico, and Utah—an area that includes vast stretches of coastline, an international border, and the jurisdictions of more than one hundred Native nations. This year, results from this report were distributed through presentations, publications, and media coverage throughout the Southwest.

Most organized discussion about climate change within the Colorado River Basin (CRB) has addressed projected climate impacts and specific rules for operating under surplus and shortage. This project moved the discussion from awareness to action and coordination by assessing regional adaptation capabilities and cataloging existing adaptation efforts in the broader CRB. In collaboration with the WWA and CNAP, researchers convened a workshop of key stakeholders and agencies from across a spectrum of sectors in the CRB to (a) foster communication of the extent of existing and planned climate adaptation initiatives, (b) catalogue projects, documents, and alliances whose work, expertise, and connections can be leveraged to develop sustained and ongoing assessment, (c) evaluate the scientific capacity within the region to address climate adaptation issues and to leverage existing federal labs, data centers, and new climate services initiatives (NOAA, DOI), and (d) assess science, decision-making, and communication needs in the region.

The workshop focused on water as the major medium through which climate change impacts will manifest in the CRB, and looked broadly at issues of both water and land management, as well as recreation, tourism, environmental flows, and urban adaptation. Follow-up from the workshop included a webinar series, designed to maintain communication, invite new participants, and to give an opportunity for ongoing and new initiatives to “show and tell” and for participants to network.

This project was part of the US National Climate Assessment coordinated by the US Global Climate Research Program.

This project explored innovative ways to address risk and resilience related to hydroclimatic extremes in both the upper and lower tails of streamflow probability distributions. The goal was to transfer the knowledge and record length that climate information and paleodata provide into useful tools for hydrologic decision making involving risk and resilience related to both floods and drought. Specific objectives included: (1) transfer of information from tree-ring reconstructions about past extreme streamflow episodes to water managers for integration into operations; (2) ongoing construction of a flood hydroclimatology database for linking climate, floods, and paleofloods; (3) interaction with stakeholders to develop innovative ways to use the flood database information; and (4) exploration of issues surrounding flood risk and human behavior to improve flood hazard management and flood warning practice.

Several recent studies estimate that the future streamflow of the Colorado River will decline due to drought and climate change. However, estimates from these projections range from less than 10% to a 45% decline by 2050. This cross-RISA research team explored why this large range exists and suggested ways that scientists and other stakeholders could apply these projections for future research and adaptation efforts.

Although the projections show drastically different amounts of streamflow reduction, it is still evident across all studies that Colorado River streamflow will be reduced due to climate change. Additionally, current reconstructions of the worst possible drought for the Colorado River are underestimates of the severity and duration of drought that has occurred, and that could occur, in the Colorado River Basin.

Climate information can aid in improving the targeting of fuels treatments and prescribed burns, determining the positioning and movement of initial attack resources, and informing staffing and budgeting decisions. Fire managers at the regional and forest level in California, Arizona, and New Mexico were surveyed to gather information on the timing of key fire management decisions. The survey included year-long decision calendars to assess when and how to efficiently convey climate information to fire managers. Researchers sought to gain insights into decision processes and information flows in fire management, in order to identify optimal points in the decision networks of fire management agencies where climate information may be inserted into decision processes.

The Southwest is one of the most sensitive regions of the U.S. to climate change and variability. It is essential to understand the full scope of climate variability and change in the Southwest and how to communicate in ways that enable effective decision mak­ing. The goals of this project are to (1) lead efforts to communicate about climate variability and change to decision and policy makers in, and relevant to, the Southwest, and (2) make climate knowledge useful for stakeholder understanding and decision making.

This project assessed the impact that the National Seasonal Assessment Workshop (NSAW) seasonal and monthly fire outlooks have on decision makers who collaborate to manage wildfires in the western U.S. Researchers asked who uses the in­formation in these products, for what purposes, and the economic benefits of using them. This project evaluated how these products are being used and also analyzed network patterns across regional and federal networks of fire management to see how information was communicated across agencies.