scholarly journals Projected change in rangeland fractional component cover across the sagebrush biome under climate change through 2085

Ecosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Matthew Rigge ◽  
Hua Shi ◽  
Kory Postma

2016 ◽  
Vol 16 (1) ◽  
pp. 239-253 ◽  
Author(s):  
I. Lehtonen ◽  
A. Venäläinen ◽  
M. Kämäräinen ◽  
H. Peltola ◽  
H. Gregow

Abstract. The target of this work was to assess the impact of projected climate change on forest-fire activity in Finland with special emphasis on large-scale fires. In addition, we were particularly interested to examine the inter-model variability of the projected change of fire danger. For this purpose, we utilized fire statistics covering the period 1996–2014 and consisting of almost 20 000 forest fires, as well as daily meteorological data from five global climate models under representative concentration pathway RCP4.5 and RCP8.5 scenarios. The model data were statistically downscaled onto a high-resolution grid using the quantile-mapping method before performing the analysis. In examining the relationship between weather and fire danger, we applied the Canadian fire weather index (FWI) system. Our results suggest that the number of large forest fires may double or even triple during the present century. This would increase the risk that some of the fires could develop into real conflagrations which have become almost extinct in Finland due to active and efficient fire suppression. However, the results reveal substantial inter-model variability in the rate of the projected increase of forest-fire danger, emphasizing the large uncertainty related to the climate change signal in fire activity. We moreover showed that the majority of large fires in Finland occur within a relatively short period in May and June due to human activities and that FWI correlates poorer with the fire activity during this time of year than later in summer when lightning is a more important cause of fires.



2018 ◽  
Vol 22 (4) ◽  
pp. 2163-2185 ◽  
Author(s):  
Stefan Liersch ◽  
Julia Tecklenburg ◽  
Henning Rust ◽  
Andreas Dobler ◽  
Madlen Fischer ◽  
...  

Abstract. Climate simulations are the fuel to drive hydrological models that are used to assess the impacts of climate change and variability on hydrological parameters, such as river discharges, soil moisture, and evapotranspiration. Unlike with cars, where we know which fuel the engine requires, we never know in advance what unexpected side effects might be caused by the fuel we feed our models with. Sometimes we increase the fuel's octane number (bias correction) to achieve better performance and find out that the model behaves differently but not always as was expected or desired. This study investigates the impacts of projected climate change on the hydrology of the Upper Blue Nile catchment using two model ensembles consisting of five global CMIP5 Earth system models and 10 regional climate models (CORDEX Africa). WATCH forcing data were used to calibrate an eco-hydrological model and to bias-correct both model ensembles using slightly differing approaches. On the one hand it was found that the bias correction methods considerably improved the performance of average rainfall characteristics in the reference period (1970–1999) in most of the cases. This also holds true for non-extreme discharge conditions between Q20 and Q80. On the other hand, bias-corrected simulations tend to overemphasize magnitudes of projected change signals and extremes. A general weakness of both uncorrected and bias-corrected simulations is the rather poor representation of high and low flows and their extremes, which were often deteriorated by bias correction. This inaccuracy is a crucial deficiency for regional impact studies dealing with water management issues and it is therefore important to analyse model performance and characteristics and the effect of bias correction, and eventually to exclude some climate models from the ensemble. However, the multi-model means of all ensembles project increasing average annual discharges in the Upper Blue Nile catchment and a shift in seasonal patterns, with decreasing discharges in June and July and increasing discharges from August to November.



2020 ◽  
Author(s):  
Marco Gaetani ◽  
Benjamin Sultan ◽  
Serge Janicot Serge Janicot ◽  
Mathieu Vrac ◽  
Robert Vautard ◽  
...  

<p>Independence in energy production is a key aspect of development in West African countries, which are facing fast population growth and climate change. Sustainable development is based on the availability of renewable energy sources, which are tightly tied to climate variability and change. In the context of current and projected climate change, development plans need reliable assessment of future availability of renewable resources.</p><p>In this study, the change in the availability of photovoltaic (PV) and wind energy in West Africa in the next decades is assessed. Specifically, the time of emergence (TOE) of climate change in PV and wind potential is estimated in 29 CMIP5 climate projections.</p><p>The ensemble robustly simulates a shift into a warmer climate in West Africa, which already occurred, and projects a decrease in solar radiation at the surface to occur by the 70s. The reduction in solar radiation is associated with a projected increase in the monsoonal precipitation in the 21st century. It results a likely change into climate conditions less favourable for PV energy production by the 40s. On the other hand, the projected change in the monsoonal dynamics will drive the increase in low level winds over the coast, which in turn will result in a robustly simulated shift into climate conditions favourable to wind power production by mid-century. Results show that climate model projections are skilful at providing usable information for adaptation measures to be taken in the energy sector.</p>



2021 ◽  
Vol 9 ◽  
Author(s):  
Jianjun Yu ◽  
Pam Berry ◽  
Benoit P. Guillod ◽  
Thomas Hickler

Forests provide important ecosystem services but are being affected by climate change, not only changes in temperature and precipitation but potentially also directly through the plant-physiological effects of increases in atmospheric CO2. We applied a tree-species-based dynamic model (LPJ-GUESS) at a high 5-km spatial resolution to project climate and CO2 impacts on tree species and thus forests in Great Britain. Climatic inputs consisted of a novel large climate scenario ensemble derived from a regional climate model (RCM) under an RCP 8.5 emission scenario. The climate change impacts were assessed using leaf area index (LAI) and net primary productivity (NPP) for the 2030s and the 2080s compared to baseline (1975–2004). The potential CO2 effects, which are highly uncertain, were examined using a constant CO2 level scenario for comparison. Also, a climate vulnerability index was developed to assess the potential drought impact on modeled tree species. In spite of substantial future reductions in rainfall, the mean projected LAI and NPP generally showed an increase over Britain, with a larger increment in Scotland, northwest England, and west Wales. The CO2 increase led to higher projected LAI and NPP, especially in northern Britain, but with little effect on overall geographical patterns. However, without accounting for plant-physiological effects of elevated CO2, NPP in Southern and Central Britain and easternmost parts of Wales showed a decrease relative to 2011, implying less ecosystem service provisioning, e.g., in terms of timber yields and carbon storage. The projected change of LAI and NPP varied from 5 to 100% of the mean change, due to the uncertainty arising from natural weather-induced variability, with Southeast England being most sensitive to this. It was also the most susceptible to climate change and drought, with reduced suitability for broad-leaved trees such as beech, small-leaved lime, and hornbeam. These could lead to important changes in woodland composition across Great Britain.



Author(s):  
Femi S. Omotayo ◽  
Philip G. Oguntunde ◽  
Ayorinde A. Olufayo

This study was carried to determine the trend of cocoa yield and climatic variables and assessment of the impact of climate change on the future yield of cocoa in Ondo State, Nigeria. Annual trend statistics for cocoa yield and climatic variables were analyzed for the state using Mann-Kendall test for trend and Sen’s slope estimates. Downscaled data from six Global Circulation Models (GCMs) were used to examine the impact of climate change on the future yield of cocoa in the study area. The results of trends analysis in Ondo State showed that yield decreased monotonically at the rate of 492.18 tonnes/yr (P<0.05). An increased significant trend was established in annual rainfall trend. While Maximum temperature, minimum temperature, and mean temperature all increased at the rate of 0.02/yr (P<0.001). The ensemble of all the GCMs projected a mid-term future decrease of about 9,334 tonnes/yr by 2050 and a long-term future decrease of 13,504 tonnes/yr of cocoa by 2100. The economic implication of these is that, if the projected change in the yield of cocoa as predicted by the ensemble of all the GCMs should hold for the future, it means that Ondo state may experience a loss of about $22,470,018.22 and $32,308,584.32 by the year 2050 and 2100 respectively according to the present price of the commodity in the world market. Measures are to be taken by the government and farmers to find a way of mitigating the impacts of climate change on the future yield of the cocoa study area. This research should be extended to other cocoa producing areas in Nigeria.



2020 ◽  
Vol 80 (2) ◽  
pp. 85-104
Author(s):  
N Lockart ◽  
AS Kiem ◽  
R Chiong ◽  
HH Askland ◽  
A Maguire ◽  
...  

Drought is a natural phenomenon that can have prolonged and widespread impacts on many communities and environments. The impact of climate change on drought is uncertain, which makes it challenging to quantify how future droughts will affect society. This study uses downscaled rainfall data from 4 global climate models (GCMs) and 2 time windows (1990-2009; 2060-2079) to estimate changes in the average length and intensity of single drought events, and the total number of months experiencing drought during each time window for the Hunter region of Australia. This region was chosen as it is economically important for Australia, and will be the focus of future work that examines the social and policy implications of projected climate change impacts on drought and human displacement. The changes in drought characteristics are assessed using Standardised Precipitation Index and deciles approaches, and 2 datasets: (1) downscaled GCM rainfall; and (2) historical gridded rainfall adjusted via a quantile-quantile approach conditioned on the GCM rainfall. Key findings are that the changes in drought characteristics vary spatially across the study region, and are highly dependent on the downscaled GCM rainfall used, with some regions showing opposing changes in drought characteristics between the ensemble members. Further, the change in drought characteristics between the current and future time windows tends to be greater using the downscaled GCM rainfall when compared with the GCM-adjusted historical rainfall. These results pose the question of how GCM projections should be used to develop robust but cost-effective climate adaptation strategies.



Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2300 ◽  
Author(s):  
Xin Li ◽  
Ke Zhang ◽  
Vladan Babovic

Estimates of the projected changes in precipitation and temperature have great significance for adaption planning in the context of climate change. To obtain the climate change information at regional or local scale, downscaling approaches are required to downscale the coarse global climate model (GCM) outputs to finer resolutions in both spatial and temporal dimensions. The multi-site, multi-variate downscaling approach has received considerable attention recently due to its advantage in providing distributed, physically coherent downscaled meteorological fields for subsequent impact modeling. In this study, a newly developed multi-site multivariate statistical downscaling approach based on empirical copula was applied to downscale grid-based, monthly precipitation, maximum and minimum temperature outputs from nine global climate models to site-specific, daily data over four weather stations in Singapore. The advantage of this approach lies in its ability to reflect the at-site statistics, inter-site and inter-variable dependencies, and temporal structure in the downscaled data. The downscaling was conducted for two projection periods (i.e., the 2021–2050 and 2071–2100 periods) under two emission scenarios (i.e., representative concentration pathway (RCP)4.5 and RCP8.5 scenarios). Based on the downscaling results, projected changes in daily precipitation, maximum and minimum temperatures were examined. The results show that there is no consensus on the projected change in average precipitation over the two future periods. The major uncertainty for precipitation projection comes from the GCMs. For daily maximum and minimum temperatures, all downscaled GCMs project an increase of average temperature in the future. These change signals could be different from those of the original GCM data, both in magnitude and in direction. These findings could assist in adaption planning in Singapore in response to emerging climate risks.



2012 ◽  
Vol 16 (5) ◽  
pp. 1335-1347 ◽  
Author(s):  
J. Jarsjö ◽  
S. M. Asokan ◽  
C. Prieto ◽  
A. Bring ◽  
G. Destouni

Abstract. This paper quantifies and conditions expected hydrological responses in the Aral Sea Drainage Basin (ASDB; occupying 1.3% of the earth's land surface), Central Asia, to multi-model projections of climate change in the region from 20 general circulation models (GCMs). The aim is to investigate how uncertainties of future climate change interact with the effects of historic human re-distributions of water for land irrigation to influence future water fluxes and water resources. So far, historic irrigation changes have greatly amplified water losses by evapotranspiration (ET) in the ASDB, whereas 20th century climate change has not much affected the regional net water loss to the atmosphere. Results show that errors in temperature (T) and precipitation (P) from single GCMs have large influence on projected change trends (for the period 2010–2039) of river runoff (R), even though the ASDB is spatially well resolved by current GCMs. By contrast, observed biases in GCM ensemble mean results have relatively small influence on projected R change trends. Ensemble mean results show that projected future climate change will considerably increase the net water loss to the atmosphere. Furthermore, the ET response strength to any future T change will be further increased by maintained (or increased) irrigation practices, which shows how climate change and water use change can interact in modifying ET (and R). With maintained irrigation practices, R is likely to decrease to near-total depletion, with risk for cascading ecological regime shifts in aquatic ecosystems downstream of irrigated land areas. Without irrigation, the agricultural areas of the principal Syr Darya river basin could sustain a 50% higher T increase (of 2.3 °C instead of the projected 1.5 °C until 2010–2039) before yielding the same consumptive ET increase and associated R decrease as with the present irrigation practices.



2011 ◽  
Vol 62 (9) ◽  
pp. 1082 ◽  
Author(s):  
John R. Morrongiello ◽  
Stephen J. Beatty ◽  
James C. Bennett ◽  
David A. Crook ◽  
David N. E. N. Ikedife ◽  
...  

Freshwater environments and their fishes are particularly vulnerable to climate change because the persistence and quality of aquatic habitat depend heavily on climatic and hydrologic regimes. In Australia, projections indicate that the rate and magnitude of climate change will vary across the continent. We review the likely effects of these changes on Australian freshwater fishes across geographic regions encompassing a diversity of habitats and climatic variability. Commonalities in the predicted implications of climate change on fish included habitat loss and fragmentation, surpassing of physiological tolerances and spread of alien species. Existing anthropogenic stressors in more developed regions are likely to compound these impacts because of the already reduced resilience of fish assemblages. Many Australian freshwater fish species are adapted to variable or unpredictable flow conditions and, in some cases, this evolutionary history may confer resistance or resilience to the impacts of climate change. However, the rate and magnitude of projected change will outpace the adaptive capacities of many species. Climate change therefore seriously threatens the persistence of many of Australia’s freshwater fish species, especially of those with limited ranges or specific habitat requirements, or of those that are already occurring close to physiological tolerance limits. Human responses to climate change should be proactive and focus on maintaining population resilience through the protection of habitat, mitigation of current anthropogenic stressors, adequate planning and provisioning of environmental flows and the consideration of more interventionist options such as managed translocations.



2013 ◽  
Vol 71 (3) ◽  
pp. 725-738 ◽  
Author(s):  
J. E. Toft ◽  
J. L. Burke ◽  
M. P. Carey ◽  
C. K. Kim ◽  
M. Marsik ◽  
...  

Abstract Many diagnoses of declining marine species and habitats along US coasts point to upland and freshwater sources of imperilment. Yet, little work has examined how and whether activities on land affect marine resources. Similarly, the impacts of climate change on coastal systems are among the most certain; yet, few studies have explored how alternative management and climate scenarios will affect the delivery of diverse benefits to people from coasts. We estimated how Dungeness crab (Metacarcinus magister) and Pacific oyster (Crassostrea gigas) harvest in Hood Canal, WA, may change given predictions of land uses and effects of climate change. These two marine species are critical components of local commercial and recreational fisheries and thus represent key “ecosystem service” endpoints. We found that Dungeness crab harvest responds strongly to effects of climate change, as mediated by increased ocean temperature, whereas Pacific oyster harvest is more responsive to projected change in land-use/land-cover due to increased nutrient loading to the marine system. These changes vary spatially throughout Hood Canal. These results can be used as a heuristic framework to help decision-makers, planners, and other stakeholders in the region as they work to target conservation and restoration activities and plan for future growth in a changing climate.



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