Findings

Screenshot of cover page for Climate Assessment Report.

01: Summary for Decision Makers

This book is the integrated knowledge of 121 experts from some 50 agencies, research centers, and organizations across the Southwest and beyond.

02: Overview

The Southwest is home to a variety of natural landscapes that are important to the region’s climate and that respond uniquely to climate change.

03: The Changing Southwest

The region’s climate is highly varied and strongly influenced by topography, storm tracks, and proximity to oceans (seen here from space).

04: Present Weather and Climate: Average Conditions

Streamflows in the four major drainage basins of the Southwest were 5–37% lower during 2001–2010 than their average flows in the 20th century.

05: Present Weather and Climate: Evolving Conditions

Climate models project reduced Southwest mountain snowpack during springtime for the rest of this century, mostly due to warmer temperatures.

06: Future Climate: Projected Average

Several key weather phenomena lead to extreme and flooding precipitation across the Southwest, while also contributing to water supplies.

07: Future Climate: Projected Extremes

Habitat for native cutthroat trout is projected to decrease by up to 58 percent due to temperature increases and competition with other species.

08: Natural Ecosystems

Sea level along the California coast has risen gradually over the past century—about 8 inches (20 cm)—a rate that will accelerate in the future.

09: Coastal Issues

Reduced water supplies lead to undesirable changes in almost all human and natural systems, including agriculture, energy, and industry.

10: Water: Impacts, Risks, and Adaptation

One way to adapt to climate change induced water shortages is to shift the mix of crops grown and to use more efficient irrigation technology.

11: Agriculture and Ranching

Delivery of electricity may become more vulnerable to disruption due to a variety of climate-induced extreme heat and drought events.

12: Energy: Supply, Demand, and Impacts

The unique characteristics of Southwest cities will shape the ways they will be affected by climate change and the ways they will adapt.

13: Urban Areas

Reducing overall vehicle miles traveled (as by single occupancy vehicles) will reduce regional greenhouse gas emissions.

14: Transportation

Climate change will increase heat-related morbidity and mortality and will affect respiratory health from increased wildfire particulate matter.

15: Human Health

Climate change exposes the populations in the border region to uneven impacts, due to cultural, institutional, and economic differences.

16: Climate Change and U.S.-Mexico Border Communities

Limited resources and poor economic conditions reduce the resilience and increase the vulnerability of Southwestern tribes to climate change.

17: Unique Challenges Facing Southwestern Tribes

There are low-cost or revenue-generating opportunities for emission reductions, especially in energy efficiency and renewable energy.

18: Climate Choices for a Sustainable Southwest

There is much research evidence and agreement that water cycle changes and increasing temperatures signal future water supply challenges.

19: Moving Forward with Imperfect Information

Input on research needs helps craft national scientific priorities and strategies, implemented regionally by agencies and organizations.

20: Research Strategies for Addressing Uncertainties