Paleoclimate

Climate-driven forest disturbances, particularly drought-induced tree mortality and large high-severity fires from increasingly warm and dry conditions, are altering forest ecosystems and the ecosystem services society depends on (e.g., water supplies) in the Southern Rockies and across the Western U.S. We will combine unique, long-term place-based ecological data, diverse methods (e.g., paleo...

PRISM5 addresses how the world, and particularly the US east coast, is affected by climate change. We study past warm climates from the Pliocene, Middle Miocene and early Eocene because these periods provide a suite of natural climate experiments in which marine ecosystems responded to rapidly changing temperature, sea-level and atmospheric CO2 for comparison to modern and future climate change...

On a global scale, wetland systems have been affected by climate extremes, changing sea level, and population growth, reducing their capacity to moderate storm surge, filter contaminants, store carbon, and provide habitats for fish and wildlife. This research takes a long-term perspective on the resilience of wetlands to a range of climatic and human-induced changes and provides critical data to...

The past decade encompasses some of the most extensive fire activity in recorded history. An area the size of Vermont (~24,000 km2) burned in a single Siberian fire in the summer of 2019 (Kehrwald et al., 2020 and references therein) while Australia, Indonesia and the Amazon have all experienced their most intense fires in recorded history (van Wees et al, 2021 and references therein). As more...

Warming and thawing of permafrost soils in the Arctic is expected to become widespread over the coming decades. Permafrost thaw changes ecosystem structure and function, affects resource availability for wildlife and society, and decreases ground stability which affects human infrastructure. Since permafrost soils contain about half of the global soil carbon (C) pool, the magnitude of C losses...

Drought and fire are powerful disturbance agents that can trigger rapid and lasting changes in the forests of western North America. Over the last decade, increases in fire size and severity coincided with warming, drought, and earlier snowmelt, factors that projected climatic changes are likely to exacerbate. However, recent observations are brief relative to the lifespans of trees and include...

Desert springs and wetlands are among the most biologically productive, diverse, and fragile ecosystems on Earth. They are home to thousands of rare, endemic, and endangered plants and animals and reflect the availability and health of emergent groundwater. Despite the ecological importance of these wetlands, our knowledge of how they might respond to predicted future climate change is limited...

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...

Estuaries and their surrounding wetlands are coastal transition zones where freshwater rivers meet tidal seawater. As sea levels rise, tidal forces move saltier water farther upstream, extending into freshwater wetland areas. Human changes to the surrounding landscape may amplify the effects of this tidal extension, impacting the resiliency and function of the upper estuarine wetlands. One visible...

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...

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...

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...