Rising sea levels are being caused by a change in the volume of the world's oceans due to temperature increase, deglaciation (uncovering of glaciated land because of melting of the glacier), and ice melt. This data viewer can provide a preliminary look at sea level rise and how it might affect coastal resources across the United States (with the exception of Alaska and Louisiana). Data and maps can be used at several scales to help gauge trends and prioritize actions for different scenarios.
This data viewer can provide a preliminary look at sea level rise and how it might affect coastal resources across the United States (with the exception of Alaska and Louisiana). Data and maps can be used at several scales to help gauge trends and prioritize actions for different scenarios.
This synthesis integrates recent research concerning socioecological resilience in the Sierra Nevada, southern Cascade Range, and Modoc Plateau. Among the focal topics are forest and fire ecology; soils; aquatic ecosystems; forest carnivores; air quality; and the social, economic, and cultural components of socioecological systems. A central theme is the importance of restoring key ecological processes to mitigate impacts of widespread stressors, including changes in climate, fire deficit and fuel accumulations, air pollution, and pathogens and invasive species.
Ten headwater catchments in the southern Sierra Nevada have been studied since 2003 with regard to climate conditions, water yield, and water quality. Five of the catchments are in the current rain-snow interface climate zone and five are in the snow-dominated zone. Since there is only a 1,000 foot difference between these zones, the higher elevation catchments are expected to transition to a combination of rain and snow as climate changes in California. Studying how the lower elevation area functions gives us insight about how the higher elevation area will function with a changing climate; for the southern Sierra Nevada this is predicted to be less snow and more rain with about the same total amount of precipitation. This knowledge is very important as 50% of the surface water for California originates in the Sierra Nevada.
What will the rivers of the Pacific Northwest look like in the future? Will they be stable or unstable? Will they have salmon or other species? Will the waters be cold and clear or warm and muddy? These questions motivate our study of the effects of climate warming on streams draining the Cascade Mountains.
Previous studies have shown that snowpacks throughout the Cascades are highly vulnerable to warming temperatures, readily changing from snow to rain, and melting earlier. Less certain is how these changes are likely to affect streamflows, particularly in streams that derive much of their flow from deep groundwater and springs. These groundwater streams, which are currently characterized by very stable bed, banks, and vegetation, are particularly sensitive to increasing peak flows in the winter. We want to know how changing snowpacks and increased peak flows are likely to affect these channels, potentially changing their suitability as habitat for threatened species such as bull trout and spring Chinook. Results from our work, which include field and modeling components, will be used to guide management decisions affecting these streams: how dams are operated, whether water suppliers need to worry about turbidity, and how we should manage riparian vegetation.
A key challenge for resource and land managers is predicting the consequences of climate warming on streamflow and water resources. Over the last century in the western US, significant reductions in snowpack and earlier snowmelt have led to an increase in the fraction of annual streamflow during winter, and a decline in the summer. This study explores the relative roles of snowpack accumulation and melt, and landscape characteristics or 'drainage efficiency', in influencing streamflow. An analysis of streamflow during 1950-2010 for 81 watersheds across the western US indicates that summer streamflows in watersheds that drain slowly from deep groundwater and receive precipitation as snow are most sensitive to climate warming. During the spring, however, watersheds that drain rapidly and receive precipitation as snow are most sensitive to climate warming. Our results indicate that not all trends in the western US are associated with changes in snowpack dynamics; we observe declining streamflow in late fall and winter in rain-dominated watersheds as well. These empirical findings have implications for how streamflow sensitivity to warming is interpreted across broad regions.