High-Elevation Hydropower and Climate Warming in California

2007 ◽  
Author(s):  
Kaveh Madani ◽  
Jay Lund
Keyword(s):  
Climate Warming ◽  
High Elevation

Simulating High-Elevation Hydropower with Regional Climate Warming in the West Slope, Sierra Nevada

2014 ◽  
Vol 140 (5) ◽  
pp. 714-723 ◽  
Author(s):  
David E. Rheinheimer ◽  
Joshua H. Viers ◽  
Jack Sieber ◽  
Michael Kiparsky ◽  
Vishal K. Mehta ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Climate Warming ◽  
Regional Climate ◽  
High Elevation ◽  
The West

Rapid Ecohydrological Response of a Mountaintop Peatland to Recent Climate Warming in Northeast China

2021 ◽  
Author(s):  
Tingwan Yang ◽  
Hongyan Zhao ◽  
Zhengyu Xia ◽  
Zicheng Yu ◽  
Hongkai Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Climate Warming ◽  
Northeast China ◽  
Environmental Changes ◽  
Detrended Correspondence Analysis ◽  
Plant Macrofossils ◽  
Testate Amoebae ◽  
High Elevation ◽  
Changbai Mountains ◽  
Recent Climate

<p>Montane bogs—peat-forming ecosystems located in high elevation and receiving their water supply mostly from meteoric waters—are unique archives of past environmental changes. Studying these ecosystems and their responses to recent climate warming will help improve our understanding of the sensitivity of high-elevation peatlands to regional climate dynamics. Here, we report a post-bomb radiocarbon-dated, high-resolution, and multi-proxy record in Laobaishan bog (LBS), a mountaintop bog from the Changbai Mountains Range in Northeast China. We analyzed plant macrofossils and testate amoebae of a 41-cm peat core dated between 1970 and 2009 to document the ecohydrological response of peatland to the anthropogenic warming in recent decades. We quantitatively reconstruct the surface wetness changes of LBS bog using the first axis of the detrended correspondence analysis (DCA) of plant macrofossil assemblages and depth to water table (DWT) inferred by transfer function of testate amoebae assemblages. We distinguished two hydroclimate stages: the moist stage before the 1990s and the rapidly drying stage since the 1990s. During the moist stage, plant macrofossils were characterized by the low abundance of <em>Sphagnum capitifolium</em> and <em>Polytrichum strichum</em> that prefer dry habitats, and testate amoebae assemblages were dominated by low abundance of dry-adapted <em>Assulina muscorum</em> and <em>Corythion dubium</em>. High score of first axis and low DWT also suggested a moist habitat at LBS. After the transition into the drying stage, the abundance of <em>S. capitifolium</em> and <em>P. strichum</em> increased and that of <em>A. muscorum</em> and <em>C. dubium</em> showed similar trend. Score of first axis and DWT reconstructions show that LBS have experienced rapid surface desiccation since the 1990s. Based on the high-resolution gridded reanalysis data, these ecohydrological changes occurred with a rapid increase in temperature (~1°C) but without notable change in total precipitation during the growing season (May–September) since the 1990s. Besides, backward trajectory analysis showed no apparent changes in atmospheric circulation pattern since the 1990s, supporting our interpretation that the ecohydrological changes in LBS bog were induced by climate warming. These results demonstrate that the plant communities, microbial assemblages, and peatland hydrology of montane peatland show a sensitive response to climate warming that might be in larger amplitude than the low-elevation areas.</p>

Climate warming does not adequately translate to increased radial stem growth of coniferous species along the Alpine treeline ecotone

2020 ◽  
Author(s):  
Walter Oberhuber ◽  
Ursula Bendler ◽  
Vanessa Gamper ◽  
Jacob Geier ◽  
Anna Hölzl ◽  
...  
Keyword(s):  
Climate Warming ◽  
Tree Growth ◽  
Growth Response ◽  
Growing Season ◽  
High Elevation ◽  
Stem Growth ◽  
Stone Pine ◽  
Recent Climate ◽  
Swiss Stone Pine ◽  
Competition For Resources

<p>It is well established, that tree growth at high elevations is mainly limited by low temperature during the growing season and climate warming was frequently found to lead to more growth and expansion of trees into alpine tundra. However, dendroclimatological studies revealed contradictory growth response to recent climate warming at the upper elevational limit of tree growth, and transplant experiments unveiled that high elevation tree provenances are not adequately benefiting from higher temperatures when planted at lower elevation. We therefore re-evaluated growth response of trees to recent climate warming by developing tree ring series of co-occurring conifers (Swiss stone pine (<em>Pinus cembra</em>), European larch (<em>Larix decidua</em>), and Norway spruce (<em>Picea abies</em>)) along several altitudinal transects stretching from the subalpine zone to the krummholz-limit (1630–2290 m asl; n=503 trees) in the Central European Alps (CEA). We evaluated whether trends in basal area increment (BAI) are in line with two phases of climate warming which occurred from 1915–1953 and from mid-1970s until 2015. We expected that BAI of all species shows an increasing trend consistent with distinct climate warming during the study period (1915–2015) amounting to >2 °C. Although enhanced tree growth was detected in all species in response to climate warming, results revealed that at subalpine sites (<em>i</em>) intensified climate warming since mid-1970s did not lead to corresponding increase in BAI, and (<em>ii</em>) increase in summer temperature primarily favored growth of Norway spruce, although Swiss stone pine dominates at high altitude in the CEA and therefore was expected to mainly benefit from climate warming. At treeline BAI increase was above the determined age trend in all species, whereas at the krummholz-limit only deciduous larch showed minor growth increase. We explain missing adequate growth response to recent climate warming (<em>i</em>) by strengthened competition for resources (primarily nutrients and light) in increasingly denser stands at subalpine sites leading to changes in carbon allocation among tree organs, and (<em>ii</em>) by frost desiccation injuries of evergreen tree species at the krummholz-limit. Our findings indicate that tree growth response to climate warming at high elevation is possibly nonlinear, and that increasing competition for resources and the influence of climate factors beyond the growing season impair stem growth. </p>

scholarly journals Climate and land use influences on changing spatiotemporal patterns of mountain vegetation cover in southwest China

2021 ◽  
Author(s):  
Shanshan Jiang ◽  
Xi Chen ◽  
Keith Smettem ◽  
Tiejun Wang
Keyword(s):  
Land Use ◽  
Climate Warming ◽  
Vegetation Index ◽  
Southwest China ◽  
High Elevation ◽  
Spatiotemporal Patterns ◽  
Land Uses ◽  
Cultivated Land ◽  
Vegetative Cover ◽  
High Elevations

<p>Understanding the spatiotemporal patterns of vegetative cover in relation to climate and land uses is essential for effective management of ecology and the environment. In this study, spatial and temporal changes of the normalized difference vegetation index (NDVI) and potential influencing factors were analyzed in different elevations and land uses across southwest China. Results showed: (1) there was a critical elevation of 3400 m, with different NDVI responses to climate and human interventions above and below 3400 m. Below 3400 m, mean NDVI in each land use area and the whole region did not change with elevation due to compensative effects of decreasing cultivated land and increasing woodland and grassland towards high elevations. Above 3400 m, cultivation effectively ceases. NDVI decreased with elevation as alpine plant species shifted from woody trees to alpine grass, primarily related to declining temperature towards high altitudes. (2) NDVI responses to climate change and human activities are also different above and below 3400 m. NDVI below 3400 m increased significantly after 1980s, primarily as a result of reforestation on hillslopes and improved agricultural productivity. Above 3400 m, under climate warming since the 1980s, NDVI did not increase significantly in 1990s and even decreased in 2000s as the consecutive rise of temperature is higher towards higher altitudes in the 2000s. (3) The area-weighted NDVIs illustrated that from 1980s to 2000s, the increased mean NDVI in the whole region arose from contributions of 20.93, 60.66 and 18.41% changes in NDVIs in cultivated land, woodland and grassland, respectively. In 2000s, the proportion of the woody trees contribution to NDVI increased due to reforestation in the low elevation area (<3400 m), but decreased due to shift of the woody trees to alpine grass under the consecutive climate warming in the high elevation area (>3400 m). The decease of NDVI in the high elevations did not alter increasing trend of NDVI across the whole region during 1982-2015. However, in future, the greening could diminish or even cease as climate warming continues and effects of artificially managed ecological restoration reduce.</p>

Debris-cover on glaciers in the Austrian Alps. Regional patterns, Changes and Significance.

2021 ◽  
Author(s):  
Jan-Christoph Otto ◽  
Fabian Fleischer ◽  
Robert Junker ◽  
Daniel Hölbling
Keyword(s):  
Climate Warming ◽  
Regional Scale ◽  
Eastern Alps ◽  
High Elevation ◽  
Regional Variability ◽  
Mountain Areas ◽  
Regional Patterns ◽  
Austrian Alps ◽  
Glacier System ◽  
Debris Cover

<p>Debris cover on glaciers is an important component of glacial systems as it influences climate-glacier dynamics and thus the lifespan of glaciers. Increasing air temperatures, permafrost thaw, as well as rock faces freshly exposed by glacier downwasting results in increased rockfall activity and debris input into the glacier system. In the ablation zone, negative mass balances result in an enhanced melt-out of englacial debris to the glacier system. Glacier debris cover thus represents a signal of climate warming in mountain areas. To assess the temporal development of debris on glaciers of the Eastern Alps, Austria, we mapped debris cover on 255 of the more than 800 glaciers using Landsat data at three time steps between 1996 and 2015. We applied a ratio-based threshold classification technique using existing glacier outlines. The debris cover evolution was subsequently compared to glacier changes. Glacier and glacier catchment characteristics have been analysed using GIS techniques and statistics in order to investigate potential reasons for debris cover change.</p><p>Across the Austrian Alps debris cover increased by more than 10% between 1996 and 2015 while glaciers retreated significantly in response to climate warming. Debris cover distribution shows regional variability with some mountain ranges being characterised by mean debris cover on glaciers of up to 75%. We also observed a general rise of mean elevation of debris cover on glaciers in Austria. Debris cover distribution and dynamics are highly variable due to topographic, lithological and structural settings that determine the amount of debris delivered to and stored in the glacier system. Lower relative debris cover is observed on glaciers with higher mean and maximum elevation. Additionally, glaciers with increased mean slope, as well as catchments with large areas of steep slopes and a high elevation range of these slopes tend to show higher debris cover. Both parameters indicate that the influence of the steep rockwalls in the glacier catchment is a first order control on debris cover at regional scale. We can also show that catchments with a high percentage of potential permafrost distribution contain glaciers with a higher relative debris cover.</p><p>Despite strong variation in debris cover, all glaciers investigated melted at increasing rates. We conclude that the retarding effects of debris cover on the mass balance and melt rate of Austrian glaciers is strongly subdued compared to other mountain areas. The study indicates that if this trend continues many glaciers in Austria may become fully debris covered in the future. However, since debris cover seems to have little impact on melt rates in the study area it will therefore not lead to a prolonged existence of debris-covered ice compared to clean ice glaciers.</p>

scholarly journals Elevational differences in developmental plasticity determine phenological responses of grasshoppers to recent climate warming

2015 ◽  
Vol 282 (1809) ◽  
pp. 20150441 ◽  
Author(s):  
Lauren B. Buckley ◽  
César R. Nufio ◽  
Evan M. Kirk ◽  
Joel G. Kingsolver
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Developmental Plasticity ◽  
Adult Emergence ◽  
High Elevation ◽  
Full Life Cycle ◽  
Recent Climate ◽  
Adult Body ◽  
Phenological Shifts ◽  
Advanced Development

Annual species may increase reproduction by increasing adult body size through extended development, but risk being unable to complete development in seasonally limited environments. Synthetic reviews indicate that most, but not all, species have responded to recent climate warming by advancing the seasonal timing of adult emergence or reproduction. Here, we show that 50 years of climate change have delayed development in high-elevation, season-limited grasshopper populations, but advanced development in populations at lower elevations. Developmental delays are most pronounced for early-season species, which might benefit most from delaying development when released from seasonal time constraints. Rearing experiments confirm that population, elevation and temperature interact to determine development time. Population differences in developmental plasticity may account for variability in phenological shifts among adults. An integrated consideration of the full life cycle that considers local adaptation and plasticity may be essential for understanding and predicting responses to climate change.

Climate warming and growth of high-elevation inland lakes on the Tibetan Plateau

2009 ◽  
Vol 67 (3-4) ◽  
pp. 209-217 ◽  
Author(s):  
Jingshi Liu ◽  
Siyuan Wang ◽  
Shumei Yu ◽  
Daqing Yang ◽  
Lu Zhang
Keyword(s):  
Tibetan Plateau ◽  
Climate Warming ◽  
High Elevation ◽  
The Tibetan Plateau ◽  
Inland Lakes
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