According to the third National Climate Assessment, the Northwest region is particularly susceptible to changes in the timing of streamflow, which will reduce their water supply in summer and cause far-reaching ecological and socioeconomic consequences. Additionally, the Southwest region will also face water supply issues as drought and increased warming foster wildfires and increase competition for already scarce resources. 

The Northwest region faces a wide variety of challenges due to climate change, many of which will negatively impact forests and plants in the region. Increasing wildfire risk due to water deficits as well as insect and disease outbreaks are already causing widespread tree die-off and transforming the ecological landscape in the region. Many tree species will likely shift from their current locations to more climatically suitable habitats, and 21 to 38 currently existing plant species may leave the region entirely by late this century.


Warmer temperatures, water deficits, and subsequent drought will increase stress on the Southwest’s rich diversity of plant species. The region’s ecological landscape is likely to see significant changes as widespread tree death and fires are expected to increase. As fires contribute to changes in vegetation, invasive plant species will likely spread further throughout the region. Warmer winters will also lead to exacerbated outbreaks of pests, like the bark beetle, which typically die in cold weather. Overall, historical and projected climate change have put 40% of the Southwest vulnerable to shifts in major vegetation types.

More information on climate change impacts in these regions is available in the National Climate Assessment’s Northwest and Southwest chapters.

NOAA’s Regional Resources

NOAA has a wide range of resources that can help public gardens in the Northwest and Southwest respond to and mitigate the effects of climate change in these regions.

U.S. Climate Resiliency Toolkit

The U.S. Climate Resilience Toolkit provides scientific tools, information, and expertise to help people manage their climate-related risks and opportunities, and improve their resilience to extreme events. The site offers a variety of information including a five-step process for becoming more resilient to climate-related hazards, real-world case studies, a catalog of freely available tools, federally developed training courses, and explanations of how climate variability and change can impact particular regions.

Western Regional Climate Services Director

NOAA’s Western Regional Climate Services Director provides the data, tools, and information that help private and public sector constituents in the western United States reduce their risk and improve their resiliency to the impacts of climate variability and change. Western region resources are available for Arizona, California, Idaho, Montana, Nevada, Oregon, Utah, and Washington.

Western Regional Climate Center

The Western Regional Climate Center acts as a repository of historical climate data and information, engages in applied research related to climate issues, and improved the coordination of climate-related activities at state, regional, and national scales. The Center also disseminates high-quality climate data and information pertaining to the western United States, including Arizona, California, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, and Washington.

National Weather Service Western Region Headquarters

The National Weather Service Western Region Headquarters provides scientific support, promotes and implements decision support services, manages different programs to ensure quality and provide direction, and offers field support in implementing new programs and policies in the West, which is comprised of Arizona, California, Idaho, Montana, Nevada, Oregon, Utah, and Washington.

Regional Integrated Sciences and Assessments Program

NOAA’s Regional Integrated Sciences and Assessments program supports research teams that conduct interdisciplinary and regionally relevant research to inform resource management, planning, and public policy in various regions across the United States.

American Association of State Climatologists

The American Association of State Climatologists is a professional scientific organization that provides climate services for 47 states across the nation through integration of data quality control, communication among sectors, and coordinated referral of customer inquiries.