Climate Change and Integrated Regional Water Management in California: A Preliminary Assessment of Regional Approaches

California Department of Water Resources (DWR) | June 6th, 2012

This report examines the initial steps that IRWM regions are taking in response to new requirements to address climate change vulnerabilities and consider greenhouse gas

This report examines the initial steps that IRWM regions are taking in response to new requirements to address climate change vulnerabilities and consider greenhouse gas emissions in IRWM plans. Given our evolving understanding of climate change impacts and appropriate adaptation strategies, effectively integrating climate change into planning is a challenging task. This report seeks to learn from initial steps by IRWM regions in order to inform future guidance and support. It also identifies key considerations for DWR and IRWM regions in analyzing and adapting to climate change risks within an adaptive management framework. Specifically, this report seeks to: 1. Assess the manner and degree to which the climate change requirements in the 2010 IRWM Guidelines are met in Round 1 Proposition 84 Planning and Implementation grant proposals, and in recently approved IRWM plans 2. Assess current IRWM regional approaches to analyzing and adapting to climate change risks, in light of the overall goal to promote an adaptive management approach 3. Provide recommendations on key steps for DWR and IRWM regions to support the development of informative climate change analyses and mechanisms for adaptive management at regional and state levels This assessment is based on a review of the current IRWM climate change requirements, existing IRWM plans, and Planning and Implementation grant proposals funded in 2011. It is also informed by interviews conducted by DWR regional climate change specialists with representatives of IRWM regions regarding their plans to address climate change.

Climate change and its influence on water systems increases the cost of electricity system decarbonization

Nature Portfolio (Springer Nature) | November 25th, 2024

Climate Change and Rural Water for Frontline Communities in the Southwest United States

Pacific Institute | March 26th, 2024

Climate change is threatening rural water supply and quality in the Southwest United States and will intensify water challenges in the coming years. Climate impacts such

Climate change is threatening rural water supply and quality in the Southwest United States and will intensify water challenges in the coming years. Climate impacts such as prolonged drought conditions and extreme high temperatures paired with groundwater depletion and reduced mountain snowpack are increasing the risk of water supply shortages in the region. Climate change models project an increase in temperature and an overall decline in average annual precipitation in the Southwest, though punctuated with extreme precipitation and more damaging flooding events.

Climate Change and Sea Level Rise Scenarios for California Vulnerability and Adaptation Assessment

California Energy Commission (CEC) | July 31st, 2012

This white paper provides an evaluation of physical elements of climate change and sea level rise that are contained in the California Climate Change Vulnerability and Ad

This white paper provides an evaluation of physical elements of climate change and sea level rise that are contained in the California Climate Change Vulnerability and Adaptation Assessment. The analyses use six global climate models, each run under the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios B1 and A2 scenarios. From the global climate models and associated downscaled output, these scenarios contain a range of warming, continued interannual and decadal variation of precipitation with incremental changes by the middle and end of twenty-first century, substantial loss of mountain snow pack, and a range of sea level rise along the California coast.

Climate Change and the Agricultural Sector in the San Francisco Bay Area: Changes in Viticulture and Rangeland Forage Production Due to Altered Temperature and Precipitation Patterns

California Energy Commission (CEC) | July 31st, 2012

Climate change has the potential to alter the San Francisco Bay Area’s agricultural production, a $2 billion industry. Two of the top sectors, wine and ranching, are ex

Climate change has the potential to alter the San Francisco Bay Area’s agricultural production, a $2 billion industry. Two of the top sectors, wine and ranching, are examined in this paper. Downscaled models suggest that forage production in Bay Area rangelands may be enhanced by future conditions in most years, at least in terms of peak standing crop. However, the timing of production is as important as its peak, and altered precipitation patterns could mean delayed germination and earlier senescence, resulting in shorter growing seasons. An increase in the frequency of extremely dry years also increases the uncertainty of forage availability. Similarly, wine grape yields are projected to increase throughout much of the Bay Area, but wine grape quality may decline substantially under future climate conditions, as the crop ripens earlier during hotter months. The implications for these shifts in wine grape and forage production are that the aspects of Bay Area agriculture most sensitive to climate change are not yields, but subtler nuances of production such as quality and timing. Adaptive measures will need to be taken to maintain the economic viability of these enterprises.

Climate change and the aridification of North America

National Academy of Sciences (NAS) | May 19th, 2020

Discussions of droughts and their impacts often center on the lack of precipitation, just as assessments of hydrologic impacts under a changing climate most ofte

Discussions of droughts and their impacts often center on the lack of precipitation, just as assessments of hydrologic impacts under a changing climate most often focus on how average precipitation in a given locale is likely to change in the future. Within climate science, however, focus has begun to include the growing role warming temperatures are playing as a potent driver of greater aridity: hotter climate extremes; drier soil conditions; more severe drought; and the impacts of hydrologic stress on rivers, forests, agriculture, and other systems. This shift in the hydrologic paradigm is most clear in the American Southwest, where declining flows in the region’s two most important rivers, the Colorado and Rio Grande, have been attributed in part to increasing temperatures caused by human activities, most notably the burning of fossil fuels. Warmer summers are also likely to reduce flows in the Columbia River, as well as in rivers along the Sierra Nevada in California. Now, an important study [Increased drought severity tracks warming in the United States’ largest river basin, J.T. Martin et al] documents how warming is also causing flow declines in the northern Rocky Mountains and in the largest river basin in the United States, the Missouri. This work further highlights the mechanisms behind the temperature-driven river flow declines and places more focus on how anthropogenic climate warming is progressively increasing the risk of hot drought and more arid conditions across an expanding swath of the United States.

Climate Change and the Delta

University of California, Davis (UC Davis) | October 1st, 2016

Climate change amounts to a fast approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic

Climate change amounts to a fast approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic variability, complex water-management systems have been developed, even as the Delta’s natural ecosystems have been largely devastated. Climate change is projected to challenge these management and ecological systems in different ways that are characterized by different levels of uncertainty. Future precipitation changes are less certain, with as many climate models projecting wetter conditions as drier. Warmer temperatures will likely enhance evaporation and raise water temperatures. Consequently, climate change is projected to yield both more extreme flood risks and greater drought risks. Effects on the Delta ecosystem that are traceable to warming include sea level rise, reduced snowpack, earlier snowmelt and larger storm-driven streamflow, warmer and longer summers, warmer summer water temperatures, and water-quality changes. These changes and their uncertainties will challenge the operations of water projects and uses throughout the Delta’s watershed and delivery areas. Although the effects of climate change on Delta ecosystems may be profound, the end results are difficult to predict, except that native species will fare worse than invaders. Successful preparation for the coming changes will require greater integration of monitoring, modeling, and decision-making across time, variables, and space than has been historically normal.

Climate Change and the Delta: A Synthesis (Public Review Draft)

Delta Stewardship Council (Delta Council) | March 23rd, 2018

The Delta Reform Act of 2009 (Water Code Section 85066) requires that the Delta Stewardship Council adopt a Delta Plan (the Plan) to achieve the coequal goals of providin

The Delta Reform Act of 2009 (Water Code Section 85066) requires that the Delta Stewardship Council adopt a Delta Plan (the Plan) to achieve the coequal goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem (Water Code Section 85000). In the time since the Plan was adopted in 2013, a significant shift in State planning for Delta ecosystem protection, restoration, and enhancement has occurred, prompting review of the Delta Plan to  examine whether its strategies are still suited to achieve the ecological goals of the Delta Reform Act. As such, the Delta Stewardship Council (Council) is developing an amendment of the Plan’s Chapter 4, Protect, Restore, and Enhance the Delta Ecosystem. Council staff are reviewing the best-available science to inform amendment of Chapter 4 of the Delta Plan. To support this effort, Council staff have developed three science  synthesis papers. This paper focuses on the effects of climate change in the Delta and is accompanied by two other papers focused on the Delta ecosystem (terrestrial and  aquatic resources) and restoration. Climate change is of interest for the Chapter 4  amendment given recent rapid advancements in research on climate change and its  effects on the Delta ecosystem that have occurred since the Delta Plan was adopted in  2013 (Dettinger et al. 2016). Climate change has the potential to significantly affect the Delta ecosystem by raising  air and water temperatures, changing the timing and volume of flows into and through  the Delta, increasing tidal inundation with sea-level rise (SLR), and increasing salinity  intrusion into the Delta. Climate change is recognized as a global stressor in Chapter 4 of the 2013 Delta Plan, but the effects of climate change on Delta ecosystems are  discussed only briefly and with limited consideration of management strategies that address the issue. Chapter 4 of the Delta Plan identifies five key stressors to the Delta  ecosystem and core strategies for addressing each. Climate change has interrelated  effects on all five core strategy areas: Delta flows, habitat, water quality, non-native 28 species, and hatcheries and harvest management. The Delta Reform Act specifies consideration of “the future impact of climate change and sea-level rise” (Water Code Section 85066), and identifies a restoration timeline horizon of 2100 (Water Code Section 85302). More generally, Executive Order B-30-15, signed by Governor Brown in April 2015, requires that State agencies incorporate climate change into planning and investment decisions, and that they prioritize natural infrastructure and actions for climate preparedness.

Climate change and variability drive increasing exposure of marine heatwaves across US estuaries

Nature Portfolio (Springer Nature) | March 6th, 2025

Marine heatwaves (MHWs) are among the greatest threats to marine ecosystems, and while substantial advances have been made in oceanic MHWs, little is known about estuarin

Marine heatwaves (MHWs) are among the greatest threats to marine ecosystems, and while substantial advances have been made in oceanic MHWs, little is known about estuarine MHWs. Utilizing a temperature dataset spanning over two decades and 54 stations distributed across 20 estuaries in the United States National Estuarine Research Reserve System, we present a comprehensive analysis of estuarine MHW characteristics and trends. Long-term climate-change-driven warming is driving more frequent MHWs along the East Coast, and if trends continue, this region will be in a MHW state for ~ 1/3 of the year by the end of the century. In contrast, the vast majority of the West Coast showed no trends, highlighting the potential for future thermal refugia. The West Coast was more strongly influenced by climate variability through the enhancement/suppression of MHWs during different phases of climate modes, suggesting long-term predictability potential. These results can provide guidance for management actions and planning in these critical environments.

Climate Change and Water

Intergovernmental Panel on Climate Change (IPCC) | July 21st, 2008

The Technical Paper addresses the issue of freshwater. Sea-level rise is dealt with only insofar as it can lead to impacts on freshwater in coastal areas and beyond. Clim

The Technical Paper addresses the issue of freshwater. Sea-level rise is dealt with only insofar as it can lead to impacts on freshwater in coastal areas and beyond. Climate, freshwater, biophysical and socio-economic systems are interconnected in complex ways. Hence, a change in any one of these can induce a change in any other. Freshwater-related issues are critical in determining key regional and sectoral vulnerabilities. Therefore, the relationship between climate change and freshwater resources is of primary concern to human society and also has implications for all living species.