Projected Increases In Temperature Research Articles

Simulation of population dynamics of Bulinus globosus: Effects of environmental temperature on production of Schistosoma haematobium cercariae.

BackgroundTemperature is an important factor that influences the biology and ecology of intermediate host (IH) snails and the schistosome parasites they transmit. Although temperature shifts due to climate change has been predicted to affect the life history traits of IH snails and parasite production, the mechanisms of how this may affect parasite abundance and disease risks are still not clear.Materials and methodsUsing data from laboratory and field experiments, we developed a deterministic compartmental simulation model based on difference equations using a weekly time step that represented the life cycle of Bulinus globosus. We simulated snail population dynamics and the associated production of cercariae assuming current environmental temperatures as well as projected temperature increases of 1 °C and 2 °C.ResultsThe model generated snail fecundity and survival rates similar to those observed in the laboratory and also produced reasonable snail population dynamics under seasonally varying temperatures representative of generally favorable environmental conditions. Simulated relative abundances of both snails and cercariae decreased with increasing environmental temperatures, with maximum snail abundances decreased by 14% and 27%, and maximum cercariae productions decreased by 8% and 17%, when temperatures were increased by 1 °C and 2 °C, respectively.ConclusionThe results indicate that future rise in temperature due to climate change may alter the abundance of B. globosus and impact on the prevalence of schistosomiasis. Furthermore, increased temperatures may not linearly influence the abundance of S. haematobium. These results may have important implications for schistosomiasis control programmes in view of temperature driven changes in the life history traits of B. globosus and S. haematobium. Our study recommends that the use of deterministic models incorporating the effects of temperature on the life history traits of IH snails would be vital in understanding the potential impact of climate change on schistosomiasis incidences and prevalence.

Biogeophysical controls on soil-atmosphere thermal differences: implications on warming Arctic ecosystems

Soil temperature (ST) has a key role in Arctic ecosystem functioning and global environmental change. However, soil thermal conditions do not necessarily follow synoptic temperature variations. This is because local biogeophysical processes can lead to a pronounced soil-atmosphere thermal offset (∆T) while altering the coupling (βT) between ST and ambient air temperature (AAT). Here, we aim to uncover the spatiotemporal variation in these parameters and identify their main environmental drivers. By deploying a unique network of 322 temperature loggers and surveying biogeophysical processes across an Arctic landscape, we found that the spatial variation in ∆T during the AAT≤0 period (mean ∆T = 6.0 °C, standard deviation ± 1.2 °C) was directly and indirectly constrained by local topography controlling snow depth. By contrast, during the AAT>0 period, ∆T was controlled by soil characteristics, vegetation and solar radiation (∆T = −0.6 °C ± 1.0 °C). Importantly, ∆T was not constant throughout the seasons reflecting the influence of βT on the rate of local soil warming being stronger after (mean βT = 0.8 ± 0.1) than before (βT = 0.2 ± 0.2) snowmelt. Our results highlight the need for continuous microclimatic and local environmental monitoring, and suggest a potential for large buffering and non-uniform warming of snow-dominated Arctic ecosystems under projected temperature increase.

Effect of climate change on sowing and harvest dates of spring barley and maize in Poland

AbstractClimate change and projected temperature increase is recognised to have significant impact on agricultural production and crop phenology. This study evaluated the climate change impact on sowing and harvest dates of spring barley and maize in the boundaries of two largest catchments in Poland - the Vistula and the Odra. For this purpose, an agro-hydrological Soil and Water Assessment Tool has been used, driven by climate forcing data provided within the Coordinated Downscaling Experiment - European Domain experiment projected to the year 2100 under two representative concentration pathways: 4.5 and 8.5. The projected warmer climate significantly affected the potential scheduling of agricultural practices, accelerating the occurrence of sowing and harvest dates. The rate of acceleration was dependent on the time horizon and representative concentration pathways scenario. In general, the rate of sowing/harvest advance was accelerating in time and, also from representative concentration pathways 4.5 to 8.5, reaching 23 days for spring barley and 30 days for maize (ensemble mean for the far future under representative concentration pathways 8.5).

Exploring Heat Stress Relief Measures among the Australian Labour Force.

Australia experiences frequent heat waves and generally high average temperatures throughout the continent with substantial impacts on human health and the economy. People adapt to heat by adopting various relief measures in their daily lives including changing their behaviour. Many labour intensive outdoor industries implement standards for heat stress management for their workforce. However, little is known about how people cope with heat at their workplaces apart from studies targeting some specific industries where labourers are exposed to extreme heat. Here, we analysed responses from 1719 people in the Australian labour force to self-reported heat stress and associated coping mechanisms. Three quarters of respondents experienced heat stress at their workplace with fatigue and headache being the two most frequently stated symptoms. Almost all of those who were affected by heat would hydrate (88%), 67% would cool, and 44% would rest as a strategy for coping with heat. About 10% intended to change their jobs because of heat stress in the workplace. We found differences in heat relief measures across gender, education, health, level of physical intensity of job, and time spent working outside. People working in jobs that were not very demanding physically were more likely to choose cooling down as a relief measure, while those in labour intensive jobs and jobs that required considerable time outside were more likely to rest. This has potential consequences for their productivity and work schedules. Heat affects work in Australia in many types of industry with impact dependent on workforce acclimatisation, yet public awareness and work relief plans are often limited to outdoor and labour intensive industries. Industries and various levels of government in all sectors need to implement standards for heat management specific to climate zones to help people cope better with high temperatures as well as plan strategies in anticipation of projected temperature increases.

Clown knifefish (Chitala ornata) oxygen uptake and its partitioning in present and future temperature environments

It has been argued that tropical ectotherms are more vulnerable to the projected temperature increases than their temperate relatives, because they already live closer to their upper temperature limit. Here we examine the effects of a temperature increase in environmental temperature to 6°C above the present day median temperature (27°C) in the freshwater air-breathing fish Chitala ornata, on aspects of its respiratory physiology in both normoxia and in hypoxia. We found no evidence of respiratory impairment with elevated temperature. The standard metabolic rate (SMR) and routine metabolic rate (RMR) in the two temperatures in normoxia and hypoxia increased with Q10 values between 2.3 and 2.9, while the specific dynamic action (SDA) and its coefficient increased from 7.8 to 14.7% in 27°C and 33°C, respectively. In addition, Chitala ornata exhibited significantly improved growth at the elevated temperature in both hypoxic and normoxic water. While projected temperature increases may negatively impact other essential aspects in this animal's environment, we see no evidence of a negative impact on this species itself.

Potential changes in number of generations of oriental fruit fly, Bactrocera Dorsalis (Diptera: Tephritidae) on mango in India in response to climate change scenarios

The oriental fruit fly, Bactrocera dorsalis (Hendel) is a major pest of mango crop in India and the present studies conducted to estimate the number of generations in relation to changing temperature on mango fruits across eight different geographically isolated major mango growing locations of India. The prediction of insect pest generations and generation time was done for baseline (1961 to 1990),present (1969 to 2005), near future (2021 to 2050) and distant future (2071 to 2098) periods using A1B emission scenario data from the regional circulation model (RCM), Providing Regional Climates for Impacts Studies (PRECIS) model. The degree days models using minimum and maximum temperature were used to obtain cumulative degree days (DD) for each generation of B. dorsalis using a temperature threshold of 13°C. It was estimated that faster accumulation of degree days would make possible for occurrence of one or two additional generations with shortened mean life cycle (5 to 7 days less) in near and distant future climate change periods compared to baseline and present periods at majority of locations. Increased number of generations and reduction of generation time at majority of mango growing locations of India suggest that the incidence of B. dorsalis may likely to increase due to projectedincrease in temperatures during future climate change scenarios.

Projected hydrological changes in the North Carolina piedmont using bias-corrected North American Regional Climate Change Assessment Program (NARCCAP) data

Study regionThe Haw River basin in the North Carolina Piedmont. Study focusSimulation of hydrologic change by projected CO2 and climate using the Soil and Water Assessment Tool (SWAT) hydrologic model. Biases of climate output from the North American Regional Climate Change Assessment Program (NARCCAP) were corrected using the LOCal Intensity (LOCI) scaling method for precipitation and Fourier functions for temperature. New hydrological insights for the regionEvapotranspiration (ET) and water yield (WY) with projected CO2, precipitation, and temperature during 2044–2070 were affected by each climate factor separately and synergistically. Increasing CO2 to 600ppm only scenario resulted in an ET decrease (5–17%) which led to WY increase (17–36%). With projected temperature increases (1–5°C) only scenarios, ET was projected to increase noticeably (12–112%) especially in winter and spring. The amount of projected ET increase was reduced by a CO2 increase to 600ppm due to decreased stomatal conductance. Projected WY varied due to the high variability of future precipitation patterns (−54% to 33%) but generally increased when solely precipitation projections were applied. However, WY with combined effects of CO2, precipitation, and temperature did not show significant changes compared with the historical WY. Therefore, it is necessary to incorporate interactions of precipitation, temperature, and CO2 to simulate future water availability in the North Carolina Piedmont.

The impact of climate change on developed economies

We use sub-national data to examine the relationship between temperature and growth within the United States and the European Union. Different from previous studies based on national data, we find that the optimal temperature is much lower. Because most of production takes place in areas with temperatures above the optimal temperature, projected temperature increases have significantly negative impact on the economic growth of the United States and the European Union. Our results suggest more proactive climate policy.

The latest in packaging news: from CO2 to plastic

We use sub-national data to examine the relationship between temperature and growth within the United States and the European Union. Different from previous studies based on national data, we find that the optimal temperature is much lower. Because most of production takes place in areas with temperatures above the optimal temperature, projected temperature increases have significantly negative impact on the economic growth of the United States and the European Union. Our results suggest more proactive climate policy.

Climate change versus land-use change—What affects the mountain landscapes more?

Land use and climate change are both strong drivers of landscape transformation. Using a representative valley of the Central Alps (Stubai Valley, Tyrol, Austria) we assess (1) the historical and likely future spatial patterns of land use/land cover (LULC), (2) the influence of temperature increase on the LULC distribution, and (3) the speed at which these changes will occur. Based on the historical landscape development and spatially explicit models, the effects of various land use and climate scenarios were modelled. Employing a pan-Alpine model, we were able to detect the temporal trajectory of spatial reforestation. The results show that land-use changes that already occurred during the last decades are responsible for the main future LULC changes (by secondary succession). Only an extreme land abandonment scenario and extreme climate scenarios (5K temperature increase) would bring about similar changes in LULC distribution and expansion of the forested areas. While alpine grasslands, alpine pioneer formation and glaciers would shrink drastically, especially deciduous forests would spread. To a considerable degree, such changes might take place over the next 300 years. By contrast, the increase in forest areas triggered by temperature changes would be slower and longer termed (up to 700–800 years).The effects and intensity of land-use change in the investigated valley, that is comparable to many regions in the Alps, will be at least equally severe and responsible for transformation of the landscape as those of a projected temperature increase.

Modeled Effects of Climate Change and Plant Invasion on Watershed Function Across a Steep Tropical Rainfall Gradient

Climate change is anticipated to affect freshwater resources, but baseline data on the functioning of tropical watersheds is lacking, limiting efforts that seek to predict how watershed processes, water supply, and streamflow respond to anticipated changes in climate and vegetation change, and to management. To address this data gap, we applied the distributed hydrology soil vegetation model (DHSVM) across 88 watersheds spanning a highly constrained, 4500 mm mean annual rainfall (MAR) gradient on Hawai‘i Island to quantify stream flow at 3-h time-steps for eight years in response to the independent and interactive effects of (1) large observed decrease in MAR; (2) projected warming and altered precipitation; and (3) four scenarios of forest invasion by the high water-demanding non-native tree species Psidium cattleianum. The model captured 62% of variability in measured flow at daily time scales, 95% at monthly time scales, and 98% at annual time scales. We found that low DHSVM modeled flow (Q90) and storm flow (Q10) responses to observed declines in rainfall dwarfed those of projected temperature increase or invasion, with flow decline positively correlated with MAR. As a percentage of streamflow, temperature and invasion reductions were negatively correlated with MAR. By comparison, warming alone had little effect on Q90 or Q10, but both decreased with increasing P. cattleianum cover, and projected effects of declining MAR were accentuated when combined with P. cattleianum and warming. Restoration mitigated some effects of climate warming by increasing stream base flows, with the relative effects of restoration being larger in drier versus wetter watersheds. We conclude that potential changes in climate in tropical environments are likely to exert significant effects on streamflow, but managing vegetation can provide mitigating benefits.

Proxy-based Northern Hemisphere temperature reconstruction for the mid-to-late Holocene

The observed late twentieth century warming must be assessed in relation to natural long-term variations of the climatic system. Here, we present a Northern Hemisphere (NH) temperature reconstruction for the mid-to-late Holocene of the past 6000 years, based on a synthesis of existing paleo-temperature proxies that are capable of revealing centennial-scale variability. This includes 56 published temperature records across the NH land areas, with a sampling resolution ranging from 1 to 100 years and a time span of at least 1000 years. The composite plus scale (CPS) method is adopted with spatial weighting to develop the NH temperature reconstruction. Our reconstruction reveals abrupt cold epochs that match well the Bond events during the past 6000 years. The study further reveals two prominent cycles in NH temperature: 1700–2000-year cycle during the mid-to-late Holocene and 1200–1500-year cycle during the past 3500 years. Our reconstruction indicates that the late twentieth century NH temperature and its rate of warming are both unprecedentedly high over the past 5000 years. By comparing our reconstruction with the projected temperature increase scenarios, we find that temperature by the end of the twenty-first century would likely exceed any peaks during the mid-to-late Holocene.

Simulation of climate change impacts on grain sorghum production grown under free air CO2 enrichment

Abstract Potential impacts of climate change on grain sorghum (Sorghum bicolor) productivity were investigated using the CERES-sorghum model in the Decision Support System for Agrotechnology Transfer v4.5. The model was first calibrated for a sorghum cultivar grown in a free air CO2 enrichment experiment at the University of Arizona, Maricopa, Arizona, USA in 1998. The model was then validated with an independent dataset collected in 1999. The simulated grain yield, growth, and soil water of sorghum for the both years were in statistical agreement with the corresponding measurements, respectively. Neither simulated nor measured yields responded to elevated CO2, but both were sensitive to water supply. The validated model was then applied to simulate possible effects of climate change on sorghum grain yield and water use efficiency in western North America for the years 2080-2100. The projected CO2 fertilizer effect on grain yield was dominated by the adverse effect of projected temperature increases. Therefore, temperature appears to be a dominant driver of the global climate change influencing future sorghum productivity. These results suggest that an increase in water demand for sorghum production should be anticipated in a future high-CO2 world.

Assessing tree germination resilience to global warming: a manipulative experiment using sugar maple (Acer saccharum)

AbstractA climate warming of 2–5°C by the end of the century will impact the likelihood of seed germination of sugar maple (Acer saccharum), a dominant tree species which possesses a restricted temperature range to ensure successful reproduction. We hypothesize that seed origin affects germination due to the species' local adaptation to temperature. We tested this by experimentally investigating the effect of incubation temperature and temperature shifting on sugar maple seed germination from seven different seed sources representing the current species range. Survival analysis showed that seeds from the northern range had the highest germination percentage, while the southern range had the lowest. The mean germination percentage under constant temperatures was best when temperatures were ≤5°C, whereas germination percentages plummeted at temperatures ≥11°C (5.8%). Cool shifting increased germination by 19.1% over constant temperature treatments and by 29.3% over warm shifting treatments. Both shifting treatments caused earlier germination relative to the constant temperature treatments. A climate warming of up to +5°C is shown to severely reduce germination of seeds from the southern range. However, under a more pronounced warming of 7°C, seed germination at the northern range become more affected and now comparable to those found from the southern range. This study states that the high seed germination percentage found in sugar maple at the northern range makes it fairly resilient to the warmest projected temperature increase for the next century. These findings provide forest managers with the necessary information to make accurate projections when considering strategies for future regeneration while also considering climate warming.

The impact of elevated CO2 and temperature on grain quality of rice grown under open-air field conditions.

Rising atmospheric CO2 is accompanied by global warming. However, interactive effects of elevated CO2 and temperature have not been well studied on grain quality of rice. A japonica cultivar was grown in the field using a free-air CO2 enrichment facility in combination with a canopy air temperature increase system in 2014. The gas fumigation (200 µmol mol(-1) above ambient CO2 ) and temperature increase (1 °C above ambient air temperature) were performed from tillering until maturity. Compared with the control (ambient CO2 and air temperature), elevated CO2 increased grain length and width as well as grain chalkiness but decreased protein concentrations. In contrast, the increase in canopy air temperature had less effect on these parameters except for grain chalkiness. The starch pasting properties of rice flour and taste analysis of cooked rice indicated that the palatability of rice was improved by CO2 and/or temperature elevation, with the combination of the two treatments showing the most significant changes compared with ambient rice. It is concluded that projected CO2 in 2050 may have larger effects on rice grain quality than the projected temperature increase. Although deterioration in milling suitability, grain appearance and nutritional quality can be expected, the taste of cooked rice might be better in the future environment. © 2015 Society of Chemical Industry.

Regional climate change scenarios over southern South America for future climate (2080-2099) using the MM5 Model. Mean, interannual variability and uncertainties

This work focuses on evaluating the climate change projected by the end of the 21st century under the SRES A2 emission scenario over southern South America using the regional model MM5. The model projects: (i) an increase of precipitation over central Argentina, Uruguay and southern Brazil during summer and fall; (ii) a decrease in precipitation over most of the study domain during winter and spring; (iii) an important decrease in precipitation over central and southern Chile, through the year. In general, the projected temperature increase depends on the season and the examined area; particularly, it is highest over tropical and subtropical latitudes in spring and over high latitudes in summer. The MM5 model projects: (i) an increase of the interannual precipitation variability of precipitation over central Argentina and Uruguay regardless the season; (ii) a slight decrease in interannual temperature variability over large extents of Argentina for summer and winter; (iii) a slight increase in interannual temperature variability at transition seasons; with highest values over central Chile in autumn and over north central Argentina in spring. From the reliability assessment of regional climate projections, it can be concluded that signal-to-noise ratio is high for temperature and low for precipitation. Therefore, the MM5 model is a useful tool in the generation of regional climate change scenarios of high resolution over southern South America, particularly for temperature, and is a starting point to perform studies related to impacts of climate change.

Downscaling Climate Projections over La Plata Basin

Regional Climate Models are important tools, which are increasingly being used in studies of impacts and adaptation to climate change at local scale. The goal of this work is to assess the climate change over the La Plata Basin, using the Eta Regional model with a resolution of 10 km. Initial and boundary conditions used by the model are provided by the Eta-20 km model and the HadGEM2-ES Global model. The RCP 4.5 scenario was used for simulations of the future climate. The evaluation of the present climate (1961-1990) shows that the model represents well the spatial and temporal distribution of precipitation and temperature in the region. The model underestimates precipitation over large areas in summer, and overestimates in Southern Brazil in winter. Simulated temperature shows a good correlation with CRU data, with bias less than 1°C. The bias of temperature and precipitation in this simulation setup for the La Plata Basin is substantially reduced in comparison with previous literature using regional models. The climatic projections are shown in timeslices: 2011-2040, 2041-2070, and 2071-2099. In the three timeslices, the simulation project has a trend for an increase in precipitation during summer in Argentina, Uruguay, and southernmost Brazil. This increase is only projected in Southern Brazil during winter. The negative anomaly of precipitation appears in a large portion of the model domain during summer and is limited to some states in Southeast and Central-West Brazil in winter. The area with largest warming is projected in the northern portion of the domain. The projected increase in temperature reaches about 4°C in 2071-2099.

Cardinal temperatures and thermal time in Polaskia Backeb (Cactaceae) species: Effect of projected soil temperature increase and nurse interaction on germination timing

Cardinal temperatures and thermal time are useful tools to quantify the impact of climate change on plant developmental processes such as seed germination. In this study, we quantified the thermal germination behaviour of two cactus species and predicted the effect of increased soil temperature (under a shrub canopy and in unshaded areas) on germination timing under projected climate change scenarios. To achieve these aims, seeds of both species were germinated across a range of temperatures from 5 to 40 °C, and a probit cardinal temperature model was employed to obtain the thermal coefficients. Projected temperature increase by 2090–2099 according to IPCC scenarios B1, A1B and A2 were estimated and environmental and soil heat sum were calculated. We conclude that an increase in soil temperature is predicted to alter the timing of germination but this will not be detrimental to the proportion of seeds which germinate. Thus mitigation of extreme temperatures, such as achieved under a shrub canopy, is not a crucial factor for germination success in these Polaskia species during the 21st century.

Application of a stochastic weather generator to assess climate change impacts in a semi-arid climate: The Upper Indus Basin

Summary Assessing local climate change impacts requires downscaling from Global Climate Model simulations. Here, a stochastic rainfall model (RainSim) combined with a rainfall conditioned weather generator (CRU WG) have been successfully applied in a semi-arid mountain climate, for part of the Upper Indus Basin (UIB), for point stations at a daily time-step to explore climate change impacts. Validation of the simulated time-series against observations (1961–1990) demonstrated the models’ skill in reproducing climatological means of core variables with monthly RMSE of Differences between a control (1961–1990) and future (2071–2100) regional climate model (RCM) time-slice experiment were then used to provide change factors which could be applied within the rainfall and weather models to produce perturbed ‘future’ weather time-series. These project year-round increases in precipitation (maximum seasonal mean change:+27%, annual mean change: +18%) with increased intensity in the wettest months (February, March, April) and year-round increases in mean temperature (annual mean +4.8 °C). Climatic constraints on the productivity of natural resource-dependent systems were also assessed using relevant indices from the European Climate Assessment (ECA) and indicate potential future risk to water resources and local agriculture. However, the uniformity of projected temperature increases is in stark contrast to recent seasonally asymmetrical trends in observations, so an alternative scenario of extrapolated trends was also explored. We conclude that interannual variability in climate will continue to have the dominant impact on water resources management whichever trajectory is followed. This demonstrates the need for sophisticated downscaling methods which can evaluate changes in variability and sequencing of events to explore climate change impacts in this region.

Do global warming-induced circulation pattern changes affect temperature and precipitation over Europe during summer?

Future climate change projections are not limited to a simple warming, but changes in precipitation and sea level pressure (SLP) are also projected. The SLP changes and the associated atmospheric circulation changes could directly mitigate or enhance potential projected changes in temperature and precipitation associated with rising temperatures. With the aim of analysing the projected circulation changes and their possible impacts on temperature and precipitation over Europe in summer [June–July–August (JJA)], we apply an automatic circulation type classification method, based on daily SLP, on general circulation model (GCM) outputs from the Coupled Model Intercomparison Project phase 5 (CMIP5) database over the historical period (1951–2005) and for climate under two future scenarios (2006–2100). We focus on summer as it is the season when changes in temperature and precipitation have the highest impact on human health and agriculture. Over the historical observed reference period (1960–1999), our results show that most of the GCMs have significant biases over Europe when compared to reanalysis data sets, both for simulating the observed circulation types and their frequencies, as well as for reproducing the intraclass means of the studied variables. The future projections suggest a decrease of circulation types favouring a low centred over the British Isles for the benefit of more anticyclonic conditions. These circulation changes mitigate the projected precipitation increase over north-western Europe in summer, but they do not significantly affect the projected temperature increase and the precipitation decrease over the Mediterranean region and eastern Europe. However, the circulation changes and the associated precipitation changes are tarnished by a high uncertainty among the GCM projections.