Climate model forecasts indicate an increase in extreme hydrologic events, including floods and droughts, for California and the western U.S. in the future. To better understand what the consequences of this future change in climate may be, USGS scientists are studying the frequency, magnitude, and impacts of past hydroclimate variability and extremes in the region. This project produces well-dated, high-resolution reconstructions of past climate, from a network of sample sites that preserve geologic records of past conditions associated with north Pacific climate dynamics. Results of this effort will provide much needed data that is pertinent to assessments of the impacts of future climate change on terrestrial and aquatic ecosystems, fire frequency, natural hazards (e.g. floods, landslides), and water quality and availability.
Statement of Problem: Climate variability in the western U.S., including extreme hydrologic events, is driven by atmospheric dynamics and circulation patterns over the North Pacific Ocean (NPAC). Due to the relatively short length of the instrumental record (~150 years) and lack of well-dated, high-resolution hydroclimate reconstructions, details of past NPAC dynamics and impacts on the climate of California and the western U.S. remain unclear. The proposed project aims to address this problem by developing well-dated, high temporal resolution paleoclimate datasets that are sensitive to changes in the NPAC system. These datasets will be created from a network of sample sites targeted to fill existing data gaps in space and time. The results will increase our understanding of the complex and dynamic climate systems driving NPAC variability at multi-decadal to millennial time scales. The geographic coverage of this project is well suited to the task through inclusion of sites sensitive to climate systems from the tropical Pacific (Line Islands), sub-tropical Atlantic and Pacific (central America, Mexico) and mid-latitude north Pacific (northern California, Great Basin).
Why this Research is Important: Model predictions of increased hydrologic extremes in the western U.S. highlight the need for adaptive natural resources management and hazard mitigation given an uncertain future. The proposed research will provide data that characterizes past water availability and quality, flood events, wildfire activity, and changes in terrestrial and aquatic ecosystems. This project also aims to gain insight into the processes that drove past variability by explaining precipitation patterns and atmospheric teleconnections across space and time. A better understanding of drivers and impacts of past changes will improve predictions of future conditions and management strategies in the face of uncertainty.
Objective(s): This project focuses on the following overarching research questions: What were the patterns of past hydroclimate variability in western North America? What were the timing, magnitude, and impacts of past changes in western North American climate on decadal to centennial time scales? Ultimately, we seek to better understand the evolution of climate patterns and drivers of change in the North Pacific and their impacts on terrestrial ecosystems.
With these questions in mind, our objectives are to develop a network of precise datasets to better understand the timing, magnitude and geographic patterns of major climate events and transitions. We will specifically focus on reconstructing extreme hydrologic events (i.e., atmospheric river activity, large storm events, drought), long-term fire histories, and El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) conditions. These datasets cover the period from the full glacial (~25,000 years ago) to the present. We will synthesize our results with existing datasets of Holocene hydroclimate variability, taking special consideration of age control and sampling resolution to better constrain the timing and patterns of past change. This project also conducts ongoing experiments to test and develop paleoclimate proxy methods.
Methods: This project produces datasets from sediment cores retrieved from lakes and marshes. We study microfossils, charcoal, sedimentary properties, and geochemistry of sediment in order to determine the natural (or pre human-influence) record of climate variability (on annual to centennial time scales) in lacustrine sediments in the western United States. Age control is provided by 14C (radiocarbon dating), 210Pb (lead 210 isotope analysis), and, where possible, exotic pollen and volcanic tephra deposits. An emphasis is placed on studying sediments that accumulated rapidly, which record decadal events that can be compared directly with other high-resolution regional climate records.
Below are other science projects associated with this project.
Past Perspectives of Water in the West
Wetlands in the Quaternary
Pacific Ocean Patterns, Processes, and Productivity (POP3): Impacts of ancient warming on marine ecosystems and western North America
Reconstructing Ocean Circulation & Hydroclimate in the Subtropical Atlantic
Natural Drought and Flood Histories from Lacustrine Archives
Holocene Hydroclimate of Western North America
Paleohydrology of Desert Wetlands
Terrestrial Records of Holocene Climate Change: Fire, climate and humans
- Overview
Climate model forecasts indicate an increase in extreme hydrologic events, including floods and droughts, for California and the western U.S. in the future. To better understand what the consequences of this future change in climate may be, USGS scientists are studying the frequency, magnitude, and impacts of past hydroclimate variability and extremes in the region. This project produces well-dated, high-resolution reconstructions of past climate, from a network of sample sites that preserve geologic records of past conditions associated with north Pacific climate dynamics. Results of this effort will provide much needed data that is pertinent to assessments of the impacts of future climate change on terrestrial and aquatic ecosystems, fire frequency, natural hazards (e.g. floods, landslides), and water quality and availability.
Sources/Usage: Public Domain.Laguna de Atexcac, a deep maar crater lake in eastern Mexico. Statement of Problem: Climate variability in the western U.S., including extreme hydrologic events, is driven by atmospheric dynamics and circulation patterns over the North Pacific Ocean (NPAC). Due to the relatively short length of the instrumental record (~150 years) and lack of well-dated, high-resolution hydroclimate reconstructions, details of past NPAC dynamics and impacts on the climate of California and the western U.S. remain unclear. The proposed project aims to address this problem by developing well-dated, high temporal resolution paleoclimate datasets that are sensitive to changes in the NPAC system. These datasets will be created from a network of sample sites targeted to fill existing data gaps in space and time. The results will increase our understanding of the complex and dynamic climate systems driving NPAC variability at multi-decadal to millennial time scales. The geographic coverage of this project is well suited to the task through inclusion of sites sensitive to climate systems from the tropical Pacific (Line Islands), sub-tropical Atlantic and Pacific (central America, Mexico) and mid-latitude north Pacific (northern California, Great Basin).
Why this Research is Important: Model predictions of increased hydrologic extremes in the western U.S. highlight the need for adaptive natural resources management and hazard mitigation given an uncertain future. The proposed research will provide data that characterizes past water availability and quality, flood events, wildfire activity, and changes in terrestrial and aquatic ecosystems. This project also aims to gain insight into the processes that drove past variability by explaining precipitation patterns and atmospheric teleconnections across space and time. A better understanding of drivers and impacts of past changes will improve predictions of future conditions and management strategies in the face of uncertainty.
Sources/Usage: Public Domain.Liberty Lake, one of several deep alpine lakes in the Ruby Mountains, NV. Objective(s): This project focuses on the following overarching research questions: What were the patterns of past hydroclimate variability in western North America? What were the timing, magnitude, and impacts of past changes in western North American climate on decadal to centennial time scales? Ultimately, we seek to better understand the evolution of climate patterns and drivers of change in the North Pacific and their impacts on terrestrial ecosystems.
With these questions in mind, our objectives are to develop a network of precise datasets to better understand the timing, magnitude and geographic patterns of major climate events and transitions. We will specifically focus on reconstructing extreme hydrologic events (i.e., atmospheric river activity, large storm events, drought), long-term fire histories, and El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) conditions. These datasets cover the period from the full glacial (~25,000 years ago) to the present. We will synthesize our results with existing datasets of Holocene hydroclimate variability, taking special consideration of age control and sampling resolution to better constrain the timing and patterns of past change. This project also conducts ongoing experiments to test and develop paleoclimate proxy methods.
Methods: This project produces datasets from sediment cores retrieved from lakes and marshes. We study microfossils, charcoal, sedimentary properties, and geochemistry of sediment in order to determine the natural (or pre human-influence) record of climate variability (on annual to centennial time scales) in lacustrine sediments in the western United States. Age control is provided by 14C (radiocarbon dating), 210Pb (lead 210 isotope analysis), and, where possible, exotic pollen and volcanic tephra deposits. An emphasis is placed on studying sediments that accumulated rapidly, which record decadal events that can be compared directly with other high-resolution regional climate records.
Sources/Usage: Public Domain.Fourteen meters of sediment cores collected from Laguna Ek'Naab, Peten, Guatemala. - Science
Below are other science projects associated with this project.
Past Perspectives of Water in the West
In the intermountain west, seasonal precipitation extremes, combined with population growth, are creating new challenges for the management of water resources, ecosystems, and geologic hazards. This research contributes a comprehensive long-term context for a deeper understanding of past hydrologic variability, including the magnitude and frequency of drought and flood extremes and ecosystem...Wetlands in the Quaternary
Wetlands accumulate organic-rich sediment or peat stratigraphically, making them great archives of past environmental change. Wetlands also act as hydrologic buffers on the landscape and are important to global biogeochemical cycling. This project uses wetland archives from a range of environments to better understand how vegetation, hydrology, and hydroclimate has changed on decadal to multi...Pacific Ocean Patterns, Processes, and Productivity (POP3): Impacts of ancient warming on marine ecosystems and western North America
Projections for AD 2100 suggest warming of +1-4°C in the North Pacific Ocean, which will result in widespread transformations throughout the marine environment and western North America. Many of these changes are beyond the predictive capabilities of current climate models. To better address this future uncertainty, our team is developing a geological framework using past warm intervals as...Reconstructing Ocean Circulation & Hydroclimate in the Subtropical Atlantic
Changes in rainfall patterns as a result of anthropogenic climate change are already having large ecological and socioeconomic impacts across the globe. Increases in flood damage, wildfire damage, and agricultural losses can all be attributed to anomalous rainfall events and prolonged droughts across the United States in recent years. Additionally, Atlantic Ocean circulation, which has a large...Natural Drought and Flood Histories from Lacustrine Archives
Previous work performed as part of the USGS Holocene Synthesis project illuminated complex centennial-scale patterns of drought and wetter-than-average conditions across the North American continent interior during the past two millennia, where paleorecord data coverage is sparse. In order to explain the patterns of naturally-occurring drought, floods, and storms for the past, identified by the...Holocene Hydroclimate of Western North America
The objectives of this project are to reconstruct detailed histories of Holocene hydroclimate and corresponding environmental change from geological archives such as lake sediment, peat, and wood to more fully understand past, ongoing, and future change and its impacts.Paleohydrology of Desert Wetlands
Springs and wetlands are among the most highly threatened ecosystems on Earth. Although geographically limited, they support more than 20% of all the threatened and endangered species in the United States. Scientists from the U.S. Geological Survey are examining the rock record to determine how springs and wetlands responded to abrupt climate change during prehistoric times and the recent geologic...Terrestrial Records of Holocene Climate Change: Fire, climate and humans
Large wildfires have raged across the western Americas in the past decade including the Las Conchas, New Mexico fire that burned 44,000 acres in a single day in 2011 (Orem and Pelletier, 2015, Geomorphology 232: 224-238, and references therein), the 2016 Fort McMurray, Alberta fire that required evacuating an entire city, and the 2015 Alaskan fire season that burned more than 5 million acres... - News
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