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At least 721 records · Page 40Linked to original sources
USGS2016

Holocene climate changes in eastern Beringia (NW North America) – A systematic review of multi-proxy evidence

Reconstructing climates of the past relies on a variety of evidence from a large number of sites to capture the varied features of climate and the spatial heterogeneity of climate change. This review summarizes available information from diverse Holocene paleoenvironmental records across eastern Beringia (Alaska, westernmost Canada and adjacent seas), and it quantifies the primary trends of temperature- and moisture-sensitive records based in part on midges, pollen, and biogeochemical indicators (compiled in the recently published Arctic Holocene database, and updated here to v2.1). The composite time series from these proxy records are compared with new summaries of mountain-glacier and lake-level fluctuations, terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies to clarify multi-centennial- to millennial-scale trends in Holocene climate change. To focus the synthesis, the paleo data are used to frame specific questions that can be addressed with simulations by Earth system models to investigate the causes and dynamics of past and future climate change. This systematic review shows that, during the early Holocene (11.7–8.2 ka; 1 ka = 1000 cal yr BP), rather than a prominent thermal maximum as suggested previously, temperatures were highly variable, at times both higher and lower than present (approximate mid-20th-century average), with no clear spatial pattern. Composited pollen, midge and other proxy records average out the variability and show the overall lowest summer and mean-annual temperatures across the study region during the earliest Holocene, followed by warming over the early Holocene. The sparse data available on early Holocene glaciation show that glaciers in southern Alaska were as extensive then as they were during the late Holocene. Early Holocene lake levels were low in interior Alaska, but moisture indicators show pronounced differences across the region. The highest frequency of both peatland and thaw-lake initiation ages also occurred during the early Holocene. During the middle Holocene (8.2–4.2 ka), glaciers retreated as the regional average temperature increased to a maximum between 7 and 5 ka, as reflected in most proxy types. Following the middle Holocene thermal maximum, temperatures decreased starting between 4 and 3 ka, signaling the onset of Neoglacial cooling. Glaciers in the Brooks and Alaska Ranges advanced to their maximum Holocene extent as lakes generally rose to modern levels. Temperature differences for averaged 500-year time steps typically ranged by 1–2 °C for individual records in the Arctic Holocene database, with a transition to a cooler late Holocene that was neither abrupt nor spatially coherent. The longest and highest-resolution terrestrial water isotope records previously interpreted to represent changes in the Aleutian low-pressure system around this time are here shown to be largely contradictory. Furthermore, there are too few records with sufficient resolution to identify sub-centennial-scale climate anomalies, such as the 8.2 ka event. The review concludes by suggesting some priorities for future paleoclimate research in the region.

Quaternary Science Reviews↗
USGS2019

Investigating (a)symmetry in a small mammal’s response to warmingand cooling events across western North America over the late Quaternary

Many mammalian populations conform spatially and temporally to Bergmann’s rule. This ecogeographic pattern is driven by selection for larger body masses by cooler temperatures and smaller ones by warming temperatures. However, it is unclear whether the response to warming or cooling temperatures is (a)symmetrical. Studies of the evolutionary record suggest that mammals evolve smaller body sizes more rapidly than larger ones, suggesting that it may be “easier” to adapt to warmingclimates than cooling ones. Here, we examine the potential asymmetrical response of mammals to past temperature fluctuations.We use the fossil midden record of the bushy-tailed woodrat, Neotoma cinerea, a well-studied animal that generally conforms to Bergmann’s rule, to test the ability of populations to respond to warming versus cooling climate throughout its modern range in western North America over the late Quaternary.We quantified the response to temperature change, as characterized by the Greenland Ice Sheet Project 2 temperature record, using N. cinerea presence/absence and “darwins.” Ourresults show that populations within the modern range of N. cinerea show little difference between warming and cooling events. However, northern, peripheral populations are absent during older, cooler periods, possibly due to climate or taphonomy. Our study suggests adaptation in situ may be an underestimated response to future climate change.

Quaternary Research↗
USGS2020

Historical and prehistorical water levels of Mormon Lake, Arizona as a measure of climate change on the southwest Colorado Plateau, USA

Mormon Lake, elevation 2166 m with maximum historic surface area of 31.4 km 2 , lies in a forested endorheic basin covering 103 km 2 . It is the largest unaltered freshwater body on the 337,000 km 2 Colorado Plateau. Prehistorical (before AD 1878) highstands were ca. 9 and 24 m relative to depocenter datum. These levels likely occurred during four multidecadal episodes of cool, wet conditions between ca. 3.55 and 0.20 ka BP. Maximum historical levels (early 1900s) were up to 7.9 m, whereas modern (post-1941) levels were frequently zero or relatively low. Historical climate records indicate reconstructed lake levels correlate directly with annual precipitation and inversely with temperature. Early highstands were associated with above average precipitation and the lowest temperatures of the 116 yr record. The lake receded after 1941; thereafter, frequent drying and low-water levels resulted from recurrent drought and steadily increasing temperatures. Consequently, a wet episode from the 1970s to the 1990s had precipitation like the early 1900s, but highstands were only ca. 3.8 m. The historical lake-level chronology is consistent with changes of hydrologic balance predicted by climate models, that is, reduced effective precipitation (precipitation minus evaporation). These changes, particularly aridification, apparently began in the 1970s or earlier. Global oceanic and atmospheric climate modulate lake levels and regional hydroclimate.

Arizona↗
USGS2003

Are there spurious temperature trends in the United States Climate Division database?

The United States (U.S.) Climate Division data set is commonly used in applied climatic studies in the United States. The divisional averages are calculated by including all available stations within a division at any given time. The averages are therefore vulnerable to shifts in average station location or elevation over time, which may introduce spurious trends within these data. This paper examines temperature trends within the 15 climate divisions of New England, comparing the NCDC's U.S. Divisional Data to the U.S. Historical Climate Network (USHCN) data. Correlation and multiple regression revealed that shifts in latitude, longitude, and elevation have affected the quality of the NCDC divisional data with respect to the USHCN. As a result, there may be issues with regard to their use in decadal-to century-scale climate change studies.

Geophysical Research Letters↗
USGS2010

Use of output from high‐resolution atmospheric models in landscape‐scale hydrologic models: An assessment

In this paper we investigate the feasibility of coupling regional climate models (RCMs) with landscape‐scale hydrologic models (LSHMs) for studies of the effects of climate on hydrologic systems. The RCM used is the National Center for Atmospheric Research/Pennsylvania State University mesoscale model (MM4). Output from two year‐round simulations (1983 and 1988) over the western United States is used to drive a lake model for Pyramid Lake in Nevada and a streamfiow model for Steamboat Creek in Oregon. Comparisons with observed data indicate that MM4 is able to produce meteorologic data sets that can be used to drive hydrologic models. Results from the lake model simulations indicate that the use of MM4 output produces reasonably good predictions of surface temperature and evaporation. Results from the streamflow simulations indicate that the use of MM4 output results in good simulations of the seasonal cycle of streamflow, but deficiencies in simulated wintertime precipitation resulted in underestimates of streamflow and soil moisture. Further work with climate (multiyear) simulations is necessary to achieve a complete analysis, but the results from this study indicate that coupling of LSHMs and RCMs may be a useful approach for evaluating the effects of climate change on hydrologic systems.

Water Resources Research↗
USGS2022

Restoration for resilience: The role of plant-microbial interactions and seed provenance in ecological restoration

With global efforts to restore grassland ecosystems, researchers and land management practitioners are working to reconstruct habitat that will persist and withstand stresses associated with climate change. Part of these efforts involve movement of plant material potentially adapted to future climate conditions from native habitat or seed production locations to a new restoration site. Restoration practice often follows this plant-centered, top-down approach. However, we suggest that restoration of belowground interactions, namely between plants and arbuscular mycorrhizal fungi or rhizobia, is important for restoring resilient grasslands. In this synthesis we highlight these interactions and offer insight into how their restoration might be included in current grassland restoration practice. Ultimately, restoration of belowground interactions may contribute to grassland habitat that can withstand and respond to future climate uncertainties.

Natural Areas Journal↗
USGS2022

Medium spatial resolution mapping of global land cover and land cover change across multiple decades from Landsat

Land cover maps are essential for characterizing the biophysical properties of the Earth’s land areas. Because land cover information synthesizes a rich array of information related to both the ecological condition of land areas and their exploitation by humans, they are widely used for basic and applied research that requires information related to land surface properties (e.g., terrestrial carbon models, water balance models, weather, and climate models) and are core inputs to models and analyses used by natural resource scientists and land managers. As the Earth’s global population has grown over the last several decades rates of land cover change have increased dramatically, with enormous impacts on ecosystem services (e.g., biodiversity, water supply, carbon sequestration, etc.). Hence, accurate information related to land cover is essential for both managing natural resources and for understanding society’s ecological, biophysical, and resource management footprint. To address the need for high-quality land cover information we are using the global record of Landsat observations to compile annual maps of global land cover from 2001 to 2020 at 30 m spatial resolution. To create these maps we use features derived from time series of Landsat imagery in combination with ancillary geospatial data and a large database of training sites to classify land cover at annual time step. The algorithm that we apply uses temporal segmentation to identify periods with stable land cover that are separated by breakpoints in the time series. Here we provide an overview of the methods and data sets we are using to create global maps of land cover. We describe the algorithms used to create these maps and the core land cover data sets that we are creating through this effort, and we summarize our approach to accuracy assessment. We also present a synthesis of early results and discuss the strengths and weaknesses of our early map products and the challenges that we have encountered in creating global land cover data sets from Landsat. Initial accuracy assessment for North America shows good overall accuracy (77.0 ± 2.0% correctly classified) and 79.8% agreement with the European Space Agency (ESA) WorldCover product. The land cover mapping results we report provide the foundation for robust, repeatable, and accurate mapping of global land cover and land cover change across multiple decades at 30 m spatial resolution from Landsat.

Frontiers in Remote Sensing↗
USGS2019

A General Lake Model (GLM 3.0) for linking with high-frequency sensor data from the Global Lake Ecological Observatory Network (GLEON)

The General Lake Model (GLM) is a one-dimensional open-source code designed to simulate the hydrodynamics of lakes, reservoirs, and wetlands. GLM was developed to support the science needs of the Global Lake Ecological Observatory Network (GLEON), a network of researchers using sensors to understand lake functioning and address questions about how lakes around the world respond to climate and land use change. The scale and diversity of lake types, locations, and sizes, and the expanding observational datasets created the need for a robust community model of lake dynamics with sufficient flexibility to accommodate a range of scientific and management questions relevant to the GLEON community. This paper summarizes the scientific basis and numerical implementation of the model algorithms, including details of sub-models that simulate surface heat exchange and ice cover dynamics, vertical mixing, and inflow–outflow dynamics. We demonstrate the suitability of the model for different lake types that vary substantially in their morphology, hydrology, and climatic conditions. GLM supports a dynamic coupling with biogeochemical and ecological modelling libraries for integrated simulations of water quality and ecosystem health, and options for integration with other environmental models are outlined. Finally, we discuss utilities for the analysis of model outputs and uncertainty assessments, model operation within a distributed cloud-computing environment, and as a tool to support the learning of network participants.

Geoscientific Model Development↗
USGS2012

Walrus distributional and foraging response to changing ice and benthic conditions in the Chukchi Sea

Arctic species such as the Pacific walrus ( Odobenus rosmarus divergens ) are facing a rapidly changing environment. Walruses are benthic foragers and may shift their spatial patterns of foraging in response to changes in prey distribution. We used data from satellite radio-tags attached to walruses in 2009-2010 to map walrus foraging locations with concurrent sampling of benthic infauna to examine relationships between distributions of dominant walrus prey and spatial patterns of walrus foraging. Walrus foraging was concentrated offshore in the NE Chukchi Sea, and coastal areas of northwestern Alaska when sea ice was sparse. Walrus foraging areas in August-September were coincident with the biomass of two dominant bivalve taxa (Tellinidae and Nuculidae) and sipunculid worms. Walrusforaging costs associated with increased travel time to higher biomass food patches from land may be significantly higher than the costs from sea ice haul-outs and result in reduced energy storesin walruses. Identifying what resources are selected by walruses and how those resources are distributed in space and time will improve our ability to forecast how walruses might respond to a changing climate.

Chukchi Sea↗
USGS2013

The influence of precipitation, vegetation and soil properties on the ecohydrology of sagebrush steppe rangelands on the INL site

The INL Site and other landscapes having sagebrush steppe vegetation are experiencing a simultaneous change in climate and floristics that result from increases in exotic species. Determining the separate and combined/interactive effects of climate and vegetation change is important for assessing future changes on the landscape and for hydrologic processes. This research uses the 72 experimental plots established and initially maintained for many years as the “Protective Cap Biobarrier Experiment” by Dr. Jay Anderson and the Stoller ESER program, and the experiment is also now referred to as the “INL Site Ecohydrology Study.” We are evaluating long-term impacts of different plant communities commonly found throughout Idaho subject to different precipitation regimes and to different soil depths. Treatments of amount and timing of precipitation (irrigation), soil depth, and either native/perennial or exotic grass vegetation allow researchers to investigate how vegetation, precipitation and soil interact to influence soil hydrology and ecosystem biogeochemistry. This information will be used to improve a variety of models, as well as provide data for these models.

Report↗
USGS2019

Extreme coastal water level in Washington state: Guidance to support sea level rise planning

This document provides guidelines for assessing exposure to future coastal flooding during extreme coastal water level events – whether these are due to tides, surge, wave run-up, or, more likely, a combination of the three. These guidelines provide information about the current and future magnitude of extreme coastal water levels across Washington State and the underlying processes that influence them. This information is intended to be combined with sea level projections to assess future exposure to coastal flooding along Washington’s coastline. Although the results of our analyses can be combined with any available sea level projections, this report is intended as a companion to the localized sea level rise projections (Miller et al., 2018) developed as part of the Washington Coastal Resilience Project. The Washington Coastal Resilience Project was a three-year effort to rapidly increase the state’s capacity to prepare for sea level rise. The project aimed to improve risk projections, provide better guidelines for land use planners and strengthen capital investment programs for coastal restoration and infrastructure. Partners in the Washington Coastal Resilience Project included Washington Sea Grant, Washington Department of Ecology, Island County, King County, NOAA Office for Coastal Management, Pacific Northwest National Laboratory, Padilla Bay National Estuary Research Reserve, The City of Tacoma, The Nature Conservancy, U.S. Geological Survey, University of Oregon, University of Washington Climate Impacts Group, University of Washington Department of Earth and Space Sciences, Washington Department of Fish and Wildlife and Western Washington University. The 2018 sea level projections are described in an accompanying technical report, along with a review of the science related to sea level rise (Miller et al., 2018). The report and all associated supporting information are available on the Washington Coastal Hazards Resilience Network website (http://www.wacoastalnetwork.com/).

Washington↗
USGS2020

Comment on 'Kidron (2018): Biocrust research: A critical view on eight common hydrological‐related paradigms and dubious theses. Ecohydrology, e2061'

Kidron (2018) uses a straw man argument in an attempt to debunk eight putative hydrological‐related paradigms he believes to be “common among hydrologists, ecologists, or microbiologists that investigate biocrusts.” These paradigms relate to the roles of physical crusts and vascular plants in biocrust development, the major drivers (climate, porosity, hydrophobicity, and exopolysaccharides) of hydrology (infiltration and runoff), and the effect of mosses on hydrology and therefore vascular plants. We see two major problems with his arguments. First, they assume that the paradigms in question are generally accepted by biocrust researchers. Second, they are based on Kidron's (2018) world view of biocrusts, which has largely been informed by his own studies from a single, distinctly unique area of sand dunes at the Nizzana Research Site in the Negev Desert, Israel. This narrow focus and the selective use of published material disqualify his arguments. Our collective experience, based on more than 250 person years of biocrust research, and more than 700 scientific publications on biocrusts from all continents including Antarctica, indicates that, far from the straw man arguments proposed by Kidron (2018), there is no evidence to support the existence of a unifying theory that captures the global effects of biocrusts on hydrology. Our collective works demonstrate that, contrary to claims by Kidron (2018), the hydrological effects of biocrusts are strongly nuanced, varying with, but not limited to, differences in ecological context, landscape position, site condition, crust type and composition, climatic zone, soil texture and porosity, surface morphology, and spatial scale (reviewed in Weber, Büdel, & Belnap, 2016). Below, we critically analyse each of Kidron's (2018) paradigms, providing rigorous empirical evidence to show that none represent commonly held views among the biocrust research community.

Ecohydrology↗
USGS2014

Environmental impacts of utility-scale solar energy

Renewable energy is a promising alternative to fossil fuel-based energy, but its development can require a complex set of environmental tradeoffs. A recent increase in solar energy systems, especially large, centralized installations, underscores the urgency of understanding their environmental interactions. Synthesizing literature across numerous disciplines, we review direct and indirect environmental impacts – both beneficial and adverse – of utility-scale solar energy (USSE) development, including impacts on biodiversity, land-use and land-cover change, soils, water resources, and human health. Additionally, we review feedbacks between USSE infrastructure and land-atmosphere interactions and the potential for USSE systems to mitigate climate change. Several characteristics and development strategies of USSE systems have low environmental impacts relative to other energy systems, including other renewables. We show opportunities to increase USSE environmental co-benefits, the permitting and regulatory constraints and opportunities of USSE, and highlight future research directions to better understand the nexus between USSE and the environment. Increasing the environmental compatibility of USSE systems will maximize the efficacy of this key renewable energy source in mitigating climatic and global environmental change.

Renewable and Sustainable Energy Reviews↗
USGS2022

Getting ahead of flash drought: From early warning to early action

Flash droughts, characterized by their unusually rapid intensification, have garnered increasing attention within the weather, climate, agriculture, and ecological communities in recent years due to their large environmental and socioeconomic impacts. Because flash droughts intensify quickly, they require different early warning capabilities and management approaches than are typically used for slower-developing “conventional” droughts. In this essay, we describe an integrated research-and-applications agenda that emphasizes the need to reconceptualize our understanding of flash drought within existing drought early warning systems by focusing on opportunities to improve monitoring and prediction. We illustrate the need for engagement among physical scientists, social scientists, operational monitoring and forecast centers, practitioners, and policy-makers to inform how they view, monitor, predict, plan for, and respond to flash drought. We discuss five related topics that together constitute the pillars of a robust flash drought early warning system, including the development of 1) a physically based identification framework, 2) comprehensive drought monitoring capabilities, and 3) improved prediction over various time scales that together 4) aid impact assessments and 5) guide decision-making and policy. We provide specific recommendations to illustrate how this fivefold approach could be used to enhance decision-making capabilities of practitioners, develop new areas of research, and provide guidance to policy-makers attempting to account for flash drought in drought preparedness and response plans.

Bulletin of American Meteorological Society (BAMS)↗
USGS2020

Western bumble bee: Declines in United States and range-wide information gaps

In recent decades, many bumble bee species have declined due to changes in habitat, climate, and pressures from pathogens, pesticides, and introduced species. The western bumble bee ( Bombus occidentalis ), once common throughout western North America, is a species of concern and will be considered for listing by the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Act (ESA). We attempt to improve alignment of data collection and research with USFWS needs to consider redundancy, resiliency, and representation in the upcoming species status assessment. We reviewed existing data and literature on B. occidentalis , highlighting information gaps and priority topics for research. Priorities include increased knowledge of trends, basic information on several life‐history stages, and improved understanding of the relative and interacting effects of stressors on population trends, especially the effects of pathogens, pesticides, climate change, and habitat loss. An understanding of how and where geographic range extent has changed for the two subspecies of B. occidentalis is also needed. We outline data that could be easily collected in other research projects that would increase their utility for understanding range‐wide trends of bumble bees. We modeled the overall trend in occupancy from 1998 to 2018 of Bombus occidentalis within the continental United States using existing data. The probability of local occupancy declined by 93% over 21 yr from 0.81 (95% CRI = 0.43, 0.98) in 1998 to 0.06 (95% CRI = 0.02, 0.16) in 2018. The decline in occupancy varied spatially by landcover and other environmental factors. Detection rates vary in both space and time, but peak detection across the continental United States occurs in mid‐July. We found considerable spatial gaps in recent sampling, with limited sampling in many regions, including most of Alaska, northwestern Canada, and the southwestern United States. We therefore propose a sampling design to address these gaps to best inform the ESA species status assessment through improved assessment of how the spatial distribution of stressors influences occupancy changes. Finally, we request involvement via data sharing, participation in occupancy sampling with repeated visits to distributed survey sites, and complementary research to address priorities outlined in this paper.

Ecosphere↗
USGS2019

Northern forest winters have lost cold, snowy conditions that are important for ecosystems and human communities

Winter is an understudied but key period for the socio-ecological systems of northeastern North American forests. A growing awareness of the importance of the winter season to forest ecosystems and surrounding communities has inspired several decades of research, both across the northern forest and at other mid- and high-latitude ecosystems around the globe. Despite these efforts, we lack a synthetic understanding of how winter climate change may impact hydrological and biogeochemical processes and the social and economic activities they support. Here we take advantage of 100 years of meteorological observations across the northern forest region of the northeastern U.S. and eastern Canada to develop a suite of indicators that enable a cross-cutting understanding of 1) how winter temperatures and snow cover have been changing and 2) how these shifts may impact both ecosystems and surrounding human communities. We show that cold and snow-covered conditions have generally decreased over the past 100 years. These trends suggest positive outcomes for tree health as related to reduced fine root mortality and nutrient loss associated with winter frost but negative outcomes as related to the northward advancement and proliferation of forest insect pests. In addition to effects on vegetation, reductions in cold temperatures and snow cover are likely to have negative impacts on the ecology of the northern forest through impacts on water, soils, and wildlife. The overall loss of coldness and snow cover may also have negative consequences for logging and forest products, vector-borne diseases and human health, recreation and tourism, and cultural practices, which together represent important social and economic dimensions for the northern forest region. These findings advance our understanding of how our changing winters may transform the socio- ecological system of a region that has been defined by the contrasting rhythm of the seasons. Our research also identifies a trajectory of change that informs our expectations for the future as the climate continues to warm.

Ecological Applications↗
USGS2015

Predicting ecological responses of the Florida Everglades to possible future climate scenarios: Introduction

Florida’s Everglades stretch from the headwaters of the Kissimmee River near Orlando to Florida Bay. Under natural conditions in this flat landscape, water flowed slowly downstream as broad, shallow sheet flow. The ecosystem is markedly different now, altered by nutrient pollution and construction of canals, levees, and water control structures designed for flood control and water supply. These alterations have resulted in a 50 % reduction of the ecosystem’s spatial extent and significant changes in ecological function in the remaining portion. One of the world’s largest restoration programs is underway to restore some of the historic hydrologic and ecological functions of the Everglades, via a multi-billion dollar Comprehensive Everglades Restoration Plan. This plan, finalized in 2000, did not explicitly consider climate change effects, yet today we realize that sea level rise and future changes in rainfall (RF), temperature, and evapotranspiration (ET) may have system-wide impacts. This series of papers describes results of a workshop where a regional hydrologic model was used to simulate the hydrology expected in 2060 with climate changes including increased temperature, ET, and sea level, and either an increase or decrease in RF. Ecologists with expertise in various areas of the ecosystem evaluated the hydrologic outputs, drew conclusions about potential ecosystem responses, and identified research needs where projections of response had high uncertainty. Resource managers participated in the workshop, and they present lessons learned regarding how the new information might be used to guide Everglades restoration in the context of climate change.

Florida↗
USGS2011

Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer- to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral- and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates assessment of current and future consequences of a changing climate, emphasizes regional differences in biophysical factors, and points to linkages that may exist but that currently lack supporting research. The framework also serves as a visual tool for resource managers and policy makers to develop regional and global management strategies and to inform policies related to climate mitigation and adaptation.

Alaska↗