Southwest

The Colorado River is the dominant water source for the southwestern United States, crossing through seven states before reaching Mexico. The river supplies water to approximately 36 million people, irrigates nearly six million acres of farmland within and beyond the basin, and contributes an estimated 26 billion dollars each year to the region’s recreational economy. Yet the Colorado...

In California, increased wildfire activity has been linked to decreasing snowpack and earlier snowmelt. Not only has this translated into a longer fire season, but reduced snowpack has cascading effects that impact streamflow, water supplies, agricultural productivity, and ecosystems. California receives 80% of its precipitation during the winter, so mountain snowpack plays a critical...

Natural climate variability can obscure or enhance long-term trends in experienced weather due to climate change. This can happen temporarily on timescales of a season to several years to a decade or two. Natural variability is poorly described and attributed to specific causes, contributing to uncertainty and misunderstandings about the nature of climate change that stakeholders and...

This project links climate, hydrological, and ecological changes over the next 30 years in a Great Basin watershed. In recent years, climate variability on annual and decadal time scales has been recognized as greater than commonly perceived with increasing impacts on ecosystems and available water resources. Changes in vegetation distribution, composition and productivity resulting from...

To understand potential climate change impacts on ecosystems, water resources, and numerous other natural and managed resources, climate change data and projections must be downscaled from coarse global climate models to much finer resolutions and more applicable formats. This project conducted comparative analyses to better understand the accuracy and properties of these downscaled...

The goal of this project was to examine how temperature and precipitation could change by the mid 21st century over the greater Los Angeles region. Major findings for temperature are: (1) large variability in the magnitude exists among downscaled global climate model projections over LA, but all predict warming; (2) warming is smaller over the ocean and coastal zone, but larger in the...

Native Americans are one of the most vulnerable populations to climate change in the United States because of their reliance upon the natural environment for food, livelihood, and cultural traditions. In the Southwest, where the temperature and precipitation changes from climate change are expected to be particularly severe, tribal communities may be especially vulnerable. Through this...

In California, the near-shore area where the ocean meets the land is a highly productive yet sensitive region that supports a wealth of wildlife, including several native bird species. These saltmarshes, mudflats, and shallow bays are not only critical for wildlife, but they also provide economic and recreational benefits to local communities. Today, sea-level rise, more frequent and...

Biodiversity is declining worldwide, and this trend could potentially become more severe as climate conditions change. An integral component of proactive adaptive management planning requires forecasts of how changes in climate will affect individual species. This need has been identified my multiple federal agencies, including the U.S. Fish and Wildlife Service, National Park Service...

Changing climate conditions have been identified as a major threat to the sustainability and availability of water resources in the Southwestern U.S. Long-term decreases in precipitation can lead to reductions in regional groundwater levels and loss of groundwater storage in aquifers for some communities. Reduced precipitation can also lead to lower water levels in streams and losses in...

Fire in the western U.S. poses one of the greatest threats to human and ecological communities alike. In fact, fire management is the largest single expenditure of land management funds on federal lands. Now, climate change is altering wildfire patterns. Climate change in the West is creating warmer and drier conditions, resulting in an increase in the amount of dead vegetation available...