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USGS2021

Connectivity and climate change toolkit

The Association of Fish and Wildlife Agencies’ Climate Adaptation Committee charged a small working group in September of 2019 to develop a toolkit focused on climate-informed landscape connectivity. The purpose is to provide state fish and wildlife agency planners and managers with the information necessary to ensure climate considerations are being accounted for and incorporated in the planning and implementation of terrestrial and aquatic connectivity initiatives.

Report↗

USGS2022

The impact of future climate on wetland habitat in a critical migratory waterfowl corridor of the Prairie Pothole Region

Depressional wetlands are extremely sensitive to changes in temperature and precipitation, so understanding how wetland inundation dynamics respond to changes in climate is essential for describing potential effects on wildlife breeding habitat. Millions of depressional basins make up the largest wetland complex in North America known as the Prairie Pothole Region (PPR). The wetland ecosystems that have formed in these basins provide important migratory-bird breeding habitat. The southeast portion of the U.S. PPR in Minnesota and Iowa has faced some of the greatest challenges in wetland conservation. Many existing prairie-pothole wetlands are small (<1 ha) and shallow (<2 m) and are typically not inundated with surface water year-round. Our goal with this project is to increase the efficacy of mapping tools used by management agencies to predict future changes in water levels in the PPR. We accomplish this goal by improving the link between existing data (about wetland water characteristics) and existing tools (mapping products). Our results successfully validated (2009-2021) the current mapping tool (a wetland hydrology model) used by the U.S. Fish and Wildlife Service (USFWS) to manage 22 wetlands in Minnesota. We were able to hindcast wetland water levels to 1984 and assess the accuracy of a satellite-derived surface water product and forecast water levels through 2099 using a suite of modeled climate data. This newly refined link between monitoring data and remote sensing tools will increase understanding and prediction for other wetlands beyond our study sites and through the Minnesota and Iowa portions of the PPR. Through conference presentations, publications, and development of an interactive climate change dashboard we are now working with managers to determine how we can help incorporate these predicted changes to waterfowl breeding habitat into their future management, acquisition, and restoration strategy.

Alberta, Iowa, Manitoba, Minnesota, Montana, Nebra↗

USGS2021

Foreword to this special issue on climate change and the critical zone geophysics

Welcome to this special issue on the use of geophysics in climate change and critical zone (CZ) research. The importance of these research areas cannot be overstated, and yet when we were selecting contributions for this special issue, we wrestled with the fundamental question: are climate change and the critical zone two separate research areas, or one? In other words, would there be a clear distinction between critical-zone focused articles and those addressing climate change, or would there be significant overlap making that distinction irrelevant. As we worked through the excellent submissions, it became more and more clear that any geophysical study addressing one of these elements would almost certainly be impacted in some way by the other.

FastTIMES↗

USGS2017

Permafrost-related processes and recent response to climatic changes

Permafrost-related processes have direct and indirect consequences to northern environments, but the impacts are affected by complex interactions involving positive and negative feedbacks at the surface (Jorgenson et al. 2010), climatic trends and fluctuations (Romanovsky et al. 2010; Konishchev 2011), and terrain and ground ice conditions (French and Shur 2010, Ukraintseva et al. 2012; Murton 2013). The degradation (reduction of thickness and/or lateral extent) of permafrost and the related disturbance of the surface are associated with a diverse set of processes such as thermokarst (the thawing of ice-rich permafrost or the melting of massive ice followed by subsidence of the ground surface and potential formation of a water body), thermal erosion (downwearing from moving water), thermal abrasion (backwearing from moving water), and thermal denudation associated with hillslope processes (downslope movement of soil or rock, such as frost creep, solifluction and cryogenic landslides including active-layer detachments and retrogressive thaw slumps). At the same time, the aggradation of permafrost and related processes (e.g., frost heave and formation of ice wedges and pingos) are still occurring during the observed climatic warming trend in the northern hemisphere. For example, the drainage of thermokarst lakes expose taliks (unfrozen ground beneath the water body) to the negative mean-annual ground surface temperatures in the continuous and discontinuous permafrost zone, which results in talik freezing accompanied by accumulation of ground ice. Both permafrost aggradation and degradation associated with thermokarst and other thaw-related features requires further observation and study to determine the pan-Arctic response of the landscape to climatic trends and fluctuations.

Book chapter↗

USGS2022

Climate change and ‘alien species in National Parks’: Revisited

The US National Park Service mission includes conserving native species and historical landscapes ‘unimpaired for the enjoyment of future generations’. However, humans have increased the introduction of non-native species that can become invasive and which have harmful impacts on native species and landscapes. We revisit two previous papers, ‘Alien Species in National Parks: Drawing Lines in Space and Time’, published in 1995 by D.B. Houston and E.G. Schreiner, and ‘Climate Change and “Alien Species in National Parks”: Revisited’, published in 2014 by T.J. Stohlgren, J.R. Resnik and G.E. Plumb, to demonstrate the organizational progress that has been made in reducing impacts of invasive species despite the increasing pressure of increasing numbers of non-native species. The National Park Service has continued efforts on invasive plant management, established an Invasive Animal Program in 2018 and developed a Pest & Invasive Species Project Kit to compile information to inform management regardless of taxonomic group. Additionally, the Park Service has expanded their toolset to make decisions related to invasive species and climate change to focus on achievable goals. Since the 1995 publication, the scale of invasion has increased, and impacts of climate change are more noticeable since the 2014 publication, increasing the complexity in trying to achieve the National Park Service mission.

Book chapter↗

USGS2024

Climate science and adaptation planning support for State Wildlife Action Plans in the North Central region

Final report for an NC CASC project to identify needs and provide support for states in the North Central region and Idaho to integrate climate science and adaptation into their State Wildlife Action Plans (SWAPs). Our objectives were to: 1) engage with state wildlife agencies in the North Central region to identify their needs for climate-informed planning support and 2) collaboratively develop products that will help them better integrate climate adaptation strategies into SWAPs.

Colorado, Idaho, Montana, Nebraska, North Dakota, ↗

USGS2024

Understanding and forecasting potential recruitment of Lake Michigan fishes by modeling growth and survival of larval stages with coupled climate, biophysical, and bioenergetics models

Individual adult fish can produce huge numbers of small offspring, but most die in the first weeks of life. Environmental changes that lead to even small changes in early life survival can have a disproportionate impact on the number of fish that survive and ultimately support fisheries. Lake Michigan supports valuable recreational and commercial fisheries that can fluctuate with how well fish survive in early life. Statistical models have revealed linkages between survival and climate characteristics, such as water temperature, but the exact mechanisms remain unclear and how future climate will affect the survival of young fish is highly uncertain. We integrated a series of models to investigate how climate variability may explain historical variation in the survival of young alewife and yellow perch, two fish populations that support key fisheries either directly or indirectly, while also projecting their future survival in the mid-21st century under different scenarios informed by consultation with fishery managers. Our model results revealed how spring and summer water temperatures in Lake Michigan can affect the environment in which young alewife and yellow perch grow and survive. Specifically, in years when lake warming is rapid, young fish are more likely to be transported from their natal, productive, nearshore environments to cooler and less productive offshore environments, unless adults also spawn earlier in these warm years. Furthermore, model predictions of prey abundance for young fish in the mid-21st century indicate less favorable conditions for growth and survival compared to predictions based solely on warming temperatures. With completion of the final products in the coming year, including predicted growth and survival of young fish under different future scenarios, fishery managers will have more information to share with stakeholders regarding how expectations may need to be modified regarding alewife and yellow perch productivity.

Lake Michigan↗

USGS2025

Effects of climate change on midwestern ecosystems: Appalachian – Interior – Northeast Mesic Forest

The Appalachian-Interior-Northeast Mesic Forest ecosystem, historically buffered by cool, moist conditions, may experience significant stress under future climate change, particularly due to intensifying droughts and milder winters in the midwestern United States. Droughts are expected to intensify in frequency and severity, depleting soil moisture, increasing tree mortality, and reshaping species composition. Increasing aridity and disrupted hydrologic cycles will likely accelerate soil erosion, deplete nutrients, and heighten wildfire risk. Meanwhile, milder winters may reduce snowpack insulation, increase freeze-thaw cycles, and alter growing seasons, potentially amplifying cold stress, disrupting phenology, and contributing to shifts in habitat structure and community composition. While easing winter severity may temporarily boost plant productivity and facilitate species migration into and throughout the Midwest, it can also increase the risk of frost damage for early-leafing trees and disrupt ecological relationships, such as plant-pollinator interactions. Together, these stressors may drive fundamental shifts in habitat structure and community composition, favoring drought-, fire-, and cold-tolerant species, while historically dominant, moisture-dependent species decline. Species with limited drought resistance, such as those with shallow roots or low water-use efficiency, may be especially vulnerable, while drought-adapted taxa could gain a competitive advantage. This shift could trigger a departure from over a century of mesophication in the Appalachian-Interior-Northeast Mesic Forest, which has favored shade-loving, moisture-dependent species in fire-suppressed landscapes. As a result, these forests may be particularly ill-equipped to withstand the novel environmental conditions imposed by intensifying droughts and milder winters. The Appalachian-Northeast Mesic Forest habitat group, dominated by eastern hemlock ( Tsuga canadensis ) and eastern white pine ( Pinus strobus ), is likely particularly vulnerable, as both dominant species are projected to decline due to increasing drought stress and shifting competitive dynamics. In the North-Central Beech - Maple - Basswood Forest, the Driftless Area of Wisconsin, Minnesota, and Iowa may be more vulnerable than more eastern portions of the habitat due to its already drier conditions, with climate change expected to push these communities beyond favorable conditions. Species interactions, including invasive species, pests, and herbivory, are also likely to be reshaped by climate change, compounding stress on habitat groups throughout the Appalachian-Interior-Northeast Mesic Forest. Warmer winters and increased disturbance may facilitate the expansion of invasive species, which outcompete native vegetation and alter ecosystem dynamics. At the same time, pests and pathogens are likely to become more destructive, as milder winters enhance their survival and spread and drought weakens tree defenses. Additionally, rising white-tailed deer ( Odocoileus virginianus ) populations, supported by warmer winters, may shift forest regeneration patterns by selectively browsing on sensitive seedlings and saplings, limiting the recruitment of historically dominant tree species while favoring browse-resistant plants. Collectively, these pressures can drive significant and ongoing ecological transformation in the Appalachian-Interior-Northeast Mesic Forest, highlighting the need for adaptive management strategies to sustain biodiversity and ecosystem function.

Illinois, Indiana, Iowa, Michigan, Minnesota, Miss↗

USGS2025

Effects of climate change on midwestern ecosystems: Eastern North American temperate freshwater marsh, wet meadow and shrubland

The Eastern North American Temperate Freshwater Marsh, Wet Meadow and Shrubland is a hydrologically dynamic ecosystem highly sensitive to shifts in water availability. Across the Midwest, climate change is expected to intensify two primary stressors, flooding and drought, resulting in increased hydrologic variability that may threaten the persistence of these wetlands. Increased spring precipitation and more frequent extreme rainfall events are projected to cause deeper, longer-lasting inundation, while rising temperatures, reduced snowpack, and heightened evaporative demand are likely to increase the frequency and severity of droughts. Changes in hydrology may significantly alter both habitat structure and community composition. Physical disturbance from scouring and erosion may intensify, while nutrient and sediment loading from surrounding land uses may lead to eutrophication and terrestrialization. Vegetation zonation is likely to become destabilized under more extreme hydrological conditions, with flood-tolerant or droughtadapted species replacing those with narrower hydrologic tolerances. The two habitat groups within this broader ecosystem show differing vulnerabilities. The Eastern North American Freshwater Marsh, including both Great Lakes coastal and inland systems, is considered among the most hydrologically dynamic and disturbance-prone wetland types. Vegetation in these marshes is typically stratified along water depth gradients, forming distinct zones that depend on variable hydrology to persist, but deep or prolonged inundation can disrupt this zonation and reduce plant diversity. In contrast, the Midwest Wet Prairie, Wet Meadow and Shrub Swamp, generally lacks persistent surface water and relies on precipitation and snowmelt to maintain seasonal saturation. As a result, this habitat group is especially prone to drying and potentially susceptible to woody encroachment and shifts toward drier-adapted plant communities. Across both habitat groups, invasive species are expected to gain a competitive edge under future climate conditions. Invasive wetland plants often exhibit high plasticity and can tolerate a wide range of disturbances and hydrologic conditions, allowing them to expand rapidly during both flood and drought periods. Interacting pressures underscore the growing vulnerability of the Eastern North American Temperate Freshwater Marsh, Wet Meadow and Shrubland under future climate scenarios.

Illinois, Indiana, Iowa, Michigan, Minnesota, Miss↗

USGS2025

Effects of climate change on Midwestern ecosystems: Central and Eastern North American Grassland and Shrubland

The Central and Eastern North American Grassland and Shrubland ecosystem may be increasingly shaped by intensifying drought and shifting seasonality. Rising temperatures and more variable precipitation, marked by longer dry spells, are projected to increase evapotranspiration and soil moisture deficits, and yield more frequent drought. At the same time, warming temperatures are projected to advance spring onset and extend the growing season. Drought may alter habitat structure by accelerating soil erosion, disrupting nutrient cycling, increasing physiological stress on plants, and reducing productivity. These changes are expected to shift community composition toward species adapted to water limitation and fluctuating resources, reducing much of the herbaceous cover that characterizes this ecosystem. Seasonal shifts may restructure habitat by altering phenology and f lowering dynamics, potentially increasing productivity but also heightening the risk of late-season frost damage. Community composition is expected to shift toward early-emerging species, particularly coolseason (C3) grasses, and species with phenological flexibility. Altered phenology may also lead to mismatches between plants and pollinators and increase pollinator competition at the beginning and end of the growing season, with potential consequences for reproduction. Although these overarching stressors affect the entire ecosystem, their specific impacts likely vary with local habitat conditions. In the Central and Northern Tallgrass Prairie, which are historically firemaintained habitats dominated by a mix of warm-season (C4) and cool-season (C3) grasses and forbs, climate change may shift community composition by favoring deep-rooted forbs and established shrubs while displacing shallow-rooted species, including many native grasses. These changes, especially in the absence of fire, may promote woody encroachment and drive long-term community reassembly. In the Central Interior Acidic Open Glade and Barrens, characterized by shallow, drought-prone soils, climate change may reinforce xeric assemblages and reduce the abundance of mesic species. In the absence of f ire, shrubs rather than larger woody species, are more likely to increase, as water limitations constrain the establishment of trees. In the Eastern North American Ruderal Meadow and Shrubland, which lack native species richness and structural stability, disturbance-tolerant invaders may increasingly dominate. Drought and earlier springs are expected to reinforce early successional dynamics and further constrain the restoration potential of these already degraded habitats. Across the region, invasive species, herbivory, and microbial and fungal communities are also expected to respond to climate change. Invasive plants with ruderal traits and flexible phenologies are likely to benefit from drought-driven disturbance, post-drought resource pulses, and longer, earlier growing seasons. These species often germinate and flower earlier than natives, gaining priority access to resources as seasonal timing shifts. Herbivory by increasing white-tailed deer (Odocoileus virginianus) populations is expected to intensify, particularly during drought, when plant defenses are weakened, and during extended growing seasons, which prolong forage availability. This selective browsing may contribute to declines in native forbs while indirectly promoting non-native grasses. Microbial and fungal communities, like plant communities, are likely vulnerable to both drought and shifting seasonality. Reduced soil moisture may suppress microbial activity and decomposition, while shifts in fungal community composition, particularly declines in arbuscular mycorrhizal fungi, may impair plant drought tolerance. Adaptation strategies for the Central and Eastern North American Grassland and Shrubland may require managers to anticipate and respond to these changes through both resistance-based approaches, such as restoring fire regimes and reinforcing native species dominance, and acceptance of some potential transitions, such as facilitating drought-tolerant and phenologically flexible species establishment and adjusting fire regimes to align with altered phenology.

Illinois, Indiana, Iowa, Michigan, Minnesota, Miss↗

USGS2026

Final project peport for “Mapping riparian vegetation response to climate change on the San Carlos Apache Reservation and Upper Gila River watershed to inform restoration priorities: 1935 to present – Phase 2: Focus on tamarisk vegetation”

Riparian ecosystems play a critical role in supporting wildlife habitats, maintaining water quality, and sustaining ecological resilience in arid landscapes. In the Upper Gila River level-4 Hydrologic Unit Code (HUC-4; Identification Number – 1504) watershed of Arizona and New Mexico, and across areas of the San Carlos Apache Tribe of the San Carlos Apache Reservation (hereafter, Tribe/Tribal – entity; or Reservation - place), riparian ecosystems have been substantially altered by the widespread expansion of tamarisk ( Tamarix spp.), an invasive and non-native riparian species. Tamarisk has high water use and increased flammability, making it a growing concern as droughts intensify across the southwestern United States (U.S.). Recent research indicates that tamarisk is increasingly stressed under prolonged drought conditions, which can elevate wildfire risk and further degrade riparian habitat. In response, the U.S. Geological Survey (USGS) Western Geographic Science Center, in collaboration with the Tribe, developed remote sensing–based tools to map riparian vegetation composition and monitor vegetation condition over time. These tools enable accurate identification of tamarisk extent, detection of vegetation stress, and comparison with native species such as cottonwood and willow. This information directly supports restoration and management actions, including targeted tamarisk removal, protection of endangered species habitat, and prioritization of areas for native vegetation recovery. The tools also provide insight into how riparian vegetation responds to changing climate and hydrologic conditions, strengthening long-term planning for riparian forest management. Findings from this work demonstrate that riparian vegetation responses vary across river systems, indicating differences in plant composition and hydro-climatic conditions. Tamarisk on both the Gila and San Carlos Rivers generally exhibit greater declines in greenness in response to higher temperature as well as lower precipitation and river flow, while cottonwood ( Populus fremontii ) and willow (Salix spp.) are particularly sensitive to changes in discharge along the San Carlos River and respond more directly to both high and low flows, with more moderate responses to precipitation and temperature. By providing actionable, science-based information, this research supports climate adaptation planning, wildfire risk reduction, and improved riparian ecosystem health, with benefits that extend beyond the Reservation to regional water and wildlife conservation efforts.

Arizona, New Mexico↗

USGS2003

Mid-Holocene climates of the Americas: a dynamical response to changed seasonality

Simulations of the climatic response to mid-Holocene (6 ka BP) orbital forcing with two coupled ocean–atmosphere models (FOAM and CSM) show enhancement of monsoonal precipitation in parts of the American Southwest, Central America and northernmost South America during Northern Hemisphere summer. The enhanced onshore flow that brings precipitation into Central America is caused by a northward displacement of the inter-tropical convergence zone, driven by cooling of the equatorial and warming of the northern subtropical and mid-latitude ocean. Ocean feedbacks also enhance precipitation over the American Southwest, although the increase in monsoon precipitation there is largely driven by increases in land-surface temperature. The northward shift in the equatorial precipitation band that causes enhanced precipitation in Central America and the American Southwest has a negative feedback effect on monsoonal precipitation in northern South America. The simulations demonstrate that mid-Holocene aridity in the mid-continent of North America is dynamically linked to the orbitally induced enhancement of the summer monsoon in the American Southwest, with a spatial structure (wet in the Southwest and dry in the mid-continent) similar to that found in strong monsoon years today. Changes in winter precipitation along the west coast of North America, in Central America and along the Gulf Coast, caused by southward-displacement of the westerly storm tracks, indicate that changes in the Northern Hemisphere winter monsoon also play a role in regional climate changes during the mid-Holocene. Although the simulations with FOAM and CSM differ in detail, the general mechanisms and patterns are common to both. The model results thus provide a coherent dynamical explanation for regional patterns of increased or decreased aridity shown by vegetation, lake status and aeolian data from the Americas.

Climate Dynamics↗

USGS2013

Analysis of the present and future winter Pacific-North American teleconnection in the ECHAM5 global and RegCM3 regional climate models

We use the NCEP/NCAR Reanalysis (NCEP) and the MPI/ECHAM5 general circulation model to drive the RegCM3 regional climate model to assess the ability of the models to reproduce the spatiotemporal aspects of the Pacific-North American teleconnection (PNA) pattern. Composite anomalies of the NCEP-driven RegCM3 simulations for 1982–2000 indicate that the regional model is capable of accurately simulating the key features (500-hPa heights, surface temperature, and precipitation) of the positive and negative phases of the PNA with little loss of information in the downscaling process. The basic structure of the PNA is captured in both the ECHAM5 global and ECHAM5-driven RegCM3 simulations. The 1950–2000 ECHAM5 simulation displays similar temporal and spatial variability in the PNA index as that of NCEP; however, the magnitudes of the positive and negative phases are weaker than those of NCEP. The RegCM3 simulations clearly differentiate the climatology and associated anomalies of snow water equivalent and soil moisture of the positive and negative PNA phases. In the RegCM3 simulations of the future (2050–2100), changes in the location and extent of the Aleutian low and the continental high over North America alter the dominant flow patterns associated with positive and negative PNA modes. The future projections display a shift in the patterns of the relationship between the PNA and surface climate variables, which suggest the potential for changes in the PNA-related surface hydrology of North America.

Climate Dynamics↗

USGS2011

Impacts of past climate and sea level change on Everglades wetlands: placing a century of anthropogenic change into a late-Holocene context

We synthesize existing evidence on the ecological history of the Florida Everglades since its inception ~7 ka (calibrated kiloannum) and evaluate the relative impacts of sea level rise, climate variability, and human alteration of Everglades hydrology on wetland plant communities. Initial freshwater peat accumulation began between 6 and 7 ka on the platform underlying modern Florida Bay when sea level was ~6.2 m below its current position. By 5 ka, sawgrass and waterlily peats covered the area bounded by Lake Okeechobee to the north and the Florida Keys to the south. Slower rates of relative sea level rise ~3 ka stabilized the south Florida coastline and initiated transitions from freshwater to mangrove peats near the coast. Hydrologic changes in freshwater marshes also are indicated ~3 ka. During the last ~2 ka, the Everglades wetland was affected by a series of hydrologic fluctuations related to regional to global-scale fluctuations in climate and sea level. Pollen evidence indicates that regional-scale droughts lasting two to four centuries occurred ~1 ka and ~0.4 ka, altering wetland community composition and triggering development of characteristic Everglades habitats such as sawgrass ridges and tree islands. Intercalation of mangrove peats with estuarine muds ~1 ka indicates a temporary slowing or stillstand of sea level. Although sustained droughts and Holocene sea level rise played large roles in structuring the greater Everglades ecosystem, twentieth century reductions in freshwater flow, compartmentalization of the wetland, and accelerated rates of sea level rise had unprecedented impacts on oxidation and subsidence of organic soils, changes/loss of key Everglades habitats, and altered distribution of coastal vegetation.

Florida↗

USGS2015

Projected changes in diverse ecosystems from climate warming and biophysical drivers in northwest Alaska

Climate warming affects arctic and boreal ecosystems by interacting with numerous biophysical factors across heterogeneous landscapes. To assess potential effects of warming on diverse local-scale ecosystems (ecotypes) across northwest Alaska, we compiled data on historical areal changes over the last 25–50 years. Based on historical rates of change relative to time and temperature, we developed three state-transition models to project future changes in area for 60 ecotypes involving 243 potential transitions during three 30-year periods (ending 2040, 2070, 2100). The time model, assuming changes over the past 30 years continue at the same rate, projected a net change, or directional shift, of 6 % by 2100. The temperature model, using past rates of change relative to the past increase in regional mean annual air temperatures (1 °C/30 year), projected a net change of 17 % in response to expected warming of 2, 4, and 6 °C at the end of the three periods. A rate-adjusted temperature model, which adjusted transition rates (±50 %) based on assigned feedbacks associated with 23 biophysical drivers, estimated a net change of 13 %, with 33 ecotypes gaining and 23 ecotypes losing area. Major drivers included shrub and tree expansion, fire, succession, and thermokarst. Overall, projected changes will be modest over the next century even though climate warming increased transition rates up to 9 fold. The strength of this state-transition modeling is that it used a large dataset of past changes to provide a comprehensive assessment of likely future changes associated with numerous drivers affecting the full diversity of ecosystems across a broad region.

Alaska↗

USGS2015

Climate change implications in the northern coastal temperate rainforest of North America

We synthesized an expert review of climate change implications for hydroecological and terrestrial ecological systems in the northern coastal temperate rainforest of North America. Our synthesis is based on an analysis of projected temperature, precipitation, and snowfall stratified by eight biogeoclimatic provinces and three vegetation zones. Five IPCC CMIP5 global climate models (GCMs) and two representative concentration pathways (RCPs) are the basis for projections of mean annual temperature increasing from a current average (1961–1990) of 3.2 °C to 4.9–6.9 °C (5 GCM range; RCP4.5 scenario) or 6.4–8.7 °C (RCP8.5), mean annual precipitation increasing from 3130 mm to 3210–3400 mm (3–9 % increase) or 3320–3690 mm (6–18 % increase), and total precipitation as snow decreasing from 1200 mm to 940–720 mm (22–40 % decrease) or 720–500 mm (40–58 % decrease) by the 2080s (2071–2100; 30-year normal period). These projected changes are anticipated to result in a cascade of ecosystem-level effects including: increased frequency of flooding and rain-on-snow events; an elevated snowline and reduced snowpack; changes in the timing and magnitude of stream flow, freshwater thermal regimes, and riverine nutrient exports; shrinking alpine habitats; altitudinal and latitudinal expansion of lowland and subalpine forest types; shifts in suitable habitat boundaries for vegetation and wildlife communities; adverse effects on species with rare ecological niches or limited dispersibility; and shifts in anadromous salmon distribution and productivity. Our collaborative synthesis of potential impacts highlights the coupling of social and ecological systems that characterize the region as well as a number of major information gaps to help guide assessments of future conditions and adaptive capacity.

Alaska, British Columbia↗

USGS2017

Evidence for a climate-induced ecohydrological state shift in wetland ecosystems of the southern Prairie Pothole Region

Changing magnitude, frequency, and timing of precipitation can influence aquatic-system hydrological, geochemical, and biological processes, in some cases resulting in system-wide shifts to an alternate state. Since the early 1990s, the southern Prairie Pothole Region has been subjected to an extended period of increased wetness resulting in marked changes to aquatic systems defining this region. We explored numerous lines of evidence to identify: (1) how the recent wet period compared to historical variability, (2) hydrological, geochemical, and biological responses, and (3) how these responses might represent a state shift in the region’s wetland ecosystems. We analyzed long-term climate records and compared how different hydrological variables responded in this wet period compared to decades before the observed shift. Additionally, we used multi-decadal records of waterfowl population and subsurface tile drain records to explore wildlife and human responses to a shifting climate. Since 1993, a novel precipitation regime corresponded with increased pond numbers, ponded-water depths, lake levels, stream flows, groundwater heights, soil-moisture, waterfowl populations, and installation of subsurface tile drains in agricultural fields. These observed changes reflect an alteration in water storage and movement across the landscape that in turn has altered solute sources and concentrations of prairie-pothole wetlands and has increased pond permanence. Combined, these changes represent significant evidence for a state shift in the ecohydrological functioning of the region’s wetland ecosystems, a shift that may require a significant refinement of the previously developed “wetland continuum” concept.

Prairie Pothole Region↗

USGS2018

How will East African maize yields respond to climate change and can agricultural development mitigate this response?

We analyze the response of Kenyan maize yields to near-term climate change and explore potential mitigation options. We model county level yields as a function of rainfall and temperature during a period of increased regional warming and drying (1989–2008). We then do a counter factual analysis by comparing existing maize yields from 2000 to 2008 to what yields might have been if observed warming and drying trends had not occurred. We also examine maize yields based on projected 2026–2040 climate trends. Without the observed warming and drying trends, Eastern Kenya would have had an 8% increase in maize yields, which in turn would have led to a net production increase of 500,000 metric tons. In Western Kenya, the magnitude of change is higher but the relative changes in predicted values are smaller. If warming and drying trends continue, we expect future maize yields to decline by 11% in Eastern Kenya (vs. 7% in Western Kenya). We also examine whether these future losses might be offset through agricultural development. For that analysis, we use a household panel dataset (2000, 2005) with measurements of individual farm plot yields, inputs, and outputs. We find that under a scenario of aggressive adoption of hybrid seeds and fertilizer usage coupled with warming and drying trends, yields in Western Kenya might increase by 6% while those in Eastern Kenya could increase by 14%. This increase in yields might be larger if there is a corresponding increase in usage of drought-tolerant hybrids. However, wide prediction intervals across models highlight the uncertainty in these outcomes and scenarios.

Climatic Change↗