Changes In Mean Annual Temperature Research Articles

Estimating the uncertainty of Australian area‐average temperature anomalies

AbstractAn important metric for communicating the context and impact of climate change is regionally or nationally averaged temperature anomalies. Quantifying the associated uncertainty adds confidence in the reporting of temperature records and trends. For area‐averaged temperature anomalies derived from point‐source observations we model the uncertainty by a three‐step process: (1) observation random error; (2) spatial analysis grid point uncertainty; and (3) area‐average uncertainty. Each step should reflect the method used to calculate the area average. For Australian area‐average temperature anomalies, the observation random error is modelled as the sum of the sampling uncertainty and the uncertainty in the adjustment process. Daily maximum and minimum temperature time series from the 104 non‐urban locations of the Australian Climate Observation Reference Network—Surface Air Temperature (ACORN‐SAT) version 2 dataset for 1981–2010 are used to estimate the sampling uncertainty, based on predicted location pair zero‐distance correlations having values of less than 1.0. ACORN‐SAT version 2 breakpoint information is used to estimate the uncertainty from the selection of reference stations used in the detection and homogenization processes. Monthly area‐average temperature uncertainty is estimated for the 1910–2018 period from Monte Carlo simulations using the observation uncertainty and the available ACORN‐SAT network for each month. The uncertainty in annual area‐average temperature anomalies is then obtained from the monthly uncertainties and inter‐month correlations modelled with a periodic auto‐regressive model. The ±2σ annual mean temperature area‐average uncertainty is ±0.084°C in 2018 and ± 0.176°C in 1910. The larger value in 1910 is primarily due to decreased ACORN‐SAT coverage over areas of inland Australia. The Australian annual mean temperature change and associated uncertainty from ACORN‐SAT version 2 over 1910–2018 is found to be 1.42 ± 0.28°C. This is consistent with global air temperature warming by around 1°C since 1850.

Geochemical characteristics of Holocene loess-paleosol sequences in central Chinese Loess Plateau and their implications for East Asian monsoon evolution

The geochemical composition and magnetic susceptibility (MS) of three sections (Weinan, Jingchuan and Jingbian) in the central Chinese Loess Plateau, located along a north-south climate gradient, were analyzed at high resolution in order to reconstruct changes in weathering intensity and hence Asian monsoon evolution during the Holocene. The results show distinct differences in element composition between the loess and paleosol layer, as well as spatial differences which reflect changes in mean annual temperature and annual precipitation along the climatic gradient. The measured major element compositions, combined with the results of previous research, indicate that the provenance of the Holocene loess-paleosol sequences in the central Chinese Loess Plateau was constant over time and space. The degree of chemical weathering in the study area is relatively weak and at an intermediate weathering stage. Based on a magnetic susceptibility age model, the East Asian summer monsoon changes recorded by the loess-paleosol sequences show a distinct two-stage pattern of evolution, with a gradual increase during 13.1–8.5 ka and a gradual decrease thereafter. Comparison of the results with climate records from elsewhere indicates that the East Asian monsoon evolution was mainly controlled by changes in Northern Hemisphere summer insolation and ice sheets.

The climatic debt is growing in the understorey of temperate forests: Stand characteristics matter

AbstractAimClimate warming reshuffles biological assemblages towards less cold‐adapted but more warm‐adapted species, a process coined thermophilization. However, the velocity at which this process is happening generally lags behind the velocity of climate change, generating a climatic debt the temporal dynamics of which remain misunderstood. Relying on high‐resolution time series of vegetation data from a long‐term monitoring network of permanent forest plots, we aim at quantifying the temporal dynamics – up to a yearly resolution – of the climatic debt in the understorey of temperate forests before identifying the key determinants that modulate it.LocationFrance.Time period1995–2017.Taxa studiedVascular plants.MethodsWe used the community temperature index (CTI) to produce a time series of understorey plant community thermophilization, which we subsequently compared to a time series of mean annual temperature changes over the same period and for the same sites. The direction and magnitude of the difference (i.e., the climatic debt) was finally analysed using linear mixed‐effect models to assess the relative contributions of abiotic and biotic determinants, including forest stand characteristics.ResultsWe found a significant increase in CTI values over time (0.08–0.09 °C/decade), whereas the velocity of mean annual temperature changes was three times higher over the same period (0.22–0.28 °C/decade). Hence, the climatic debt increased over time and was greater in forest stands with higher basal area or older trees as well as under warmer macroclimate. By contrast, a greater frequency of anthropogenic disturbances decreased the climatic debt, while natural disturbances and herbivory had no impact.ConclusionsAlthough often overlooked in understanding the climatic debt of forest biodiversity, changes in forest stand characteristics may modulate the climatic debt by locally modifying microclimatic conditions. Notably, the buffering effect of the upper canopy layer implies microclimate dynamics that may provide more time for understorey plant communities to locally adapt.

Environmental changes of the stadial/interstadial type during the Late Saalian (MIS-6) – Multi-proxy record at the Wola Starogrodzka site, central Poland

Marine, lacustrine and terrestrial records from many sites located in various regions of the world suggest that the climate amelioration at the end of MIS-6 (Late Saalian) was interrupted by the short-termed cooling just prior to the MIS-6/MIS-5e boundary (Saalian/Eemian). This climatic event might be similar to the transition between interstadial conditions of the Allerød and stadial conditions of the Younger Dryas at the end of the Last Glacial (MIS-2). On the other hand, the results of quite numerous palaeobotanical studies show no stadial-interstadial oscillations below the Saalian/Eemian boundary, but reflect the gradual improvement of climate and increasing density of vegetation at that time. In western and central Europe, environment changes at the end of the Late Saalian are poorly recognized. Therefore, each new record illustrating this part of the Late Pleistocene is extremely important. We examined two profiles at the Wola Starogrodzka site, central Poland, by high-resolution analyses of pollen, Cladocera, plant macroscopic remains, mineral grain size and distribution, and organic matter content. The studied sequences represent the closing phase of the Late Saalian (in Poland called the Warta Stage of Odranian), and the early to middle part of the Eemian Interglacial. Change of the stadial-interstadial-stadial type at the end of the Late Saalian was registered both in aquatic and terrestrial environment. The recorded interstadial was correlated with Zeifen interstadial, while the following stadial – with the Kattegat stadial. Quantitative palaeoclimate reconstruction based on pollen data (modern analogue technique) showed the change in mean annual temperature by ca. 3 °C at that time.

Negative effects of multiple global change factors on soil microbial diversity

Soil microbial diversity is one of the key factors affecting the structure and function of the belowground ecosystem; yet, little is known about the response of microbial diversity to multiple global change factors. Here, we conducted a global meta-analysis based on data collected from 237 published papers to explore the effect of multiple global change factors (elevated carbon dioxide (eCO2), warming, elevated nitrogen addition (eN), wetting–drying cycle, drought, decreased precipitation (precipitation(−)), and increased precipitation (precipitation(+))) on microbial diversity (Shannon index) across different ecosystems (cropland, grassland, forest, shrubland, desert, wetland, and tundra). Global change decreased soil bacterial and fungal diversity by an average of 2.9% and 3.5%, respectively. For each global change factor, the effect sizes of precipitation(−), eN, wetting–drying cycle, and drought on soil microbial diversity were negative, whereas the effect sizes of eCO2, warming, and precipitation(+) were positive. This phenomenon was driven by changes in mean annual temperature (MAT) and edaphic factors (especially soil pH, bulk density and organic carbon content) rather than mean annual precipitation. Moreover, the effect size of soil microbial diversity linearly declined with increasing MAT, suggesting that microbial diversity was highly dependent on climate conditions at the global scale. In addition, two- and three-way interactions of global change factors aggravated the negative effects of individual effects. We suggest that it is essential to conduct long-term, multiple-factor experiments to assess the response of soil microbial diversity to global change because multiple global change factors often occur simultaneously.

Spatial heterogeneity of tree diversity response to climate warming in montane forests.

Many studies reported biotic change along a continental warming gradient. However, the temporal and spatial change of tree diversity and their sensitivity to climate warming might differ from region to region. Understanding of the variation among studies with regard to the magnitude of such biotic changes is minimal, especially in montane ecosystems. Our aim is to better understand changes in spatial heterogeneity and temporal dynamics of mountain tree communities under climate warming over the past four decades. In 2017, we resurveyed and recorded all tree species from 107 long‐term monitoring plots that were first studied between 1974 and 1976. These plots were located in montane forests in the Giant Panda National Park (GPNP), China. Our results showed that spatial differences were found in tree species diversity changes response to mean annual temperature change over the past four decades. Tree species richness increased significantly under climate warming in Minshan (MS) and Xiaoxiangling (XXL) with higher warming rate than Qionglai (QLS) and Liangshan (LS). The trees species diversity in MS and XXL were more sensitive to climatic warming. MS and XXL should receive priority protection in the next conservation plan of the GPNP. The GPNP should avoid taking a “one‐size‐fits‐all” approach for diversity conservation due to spatial heterogeneity in plant community dynamics.

Testing Seven Hypotheses to Determine What Explains the Current Planthopper (Fulgoridae) Geographical and Species Richness Patterns in China.

Simple SummaryAlthough there are many described species and ample geographical distribution data available on planthoppers (Fulgoridae) in China, the research on the underlying mechanisms of macro-scale richness patterns is still scant. To contribute to unraveling these mechanisms, we tested seven hypotheses related to contemporary environments and historical climate stability by relating the species richness to 15 environmental variables. The historical climate stability, ambient energy, and productivity hypotheses are superior to other hypotheses in explaining the current richness patterns of planthoppers. Based on these main hypotheses, we narrowed the mechanisms underlying contemporary planthopper distribution in China. Furthermore, other factors not included in this study (i.e., orogenic processes and geological isolation) may significantly contribute to richness patterns identified here.Although many hypotheses have been proposed to understand the mechanisms underlying large-scale richness patterns, the environmental determinants are still poorly understood, particularly in insects. Here, we tested the relative contributions of seven hypotheses previously proposed to explain planthopper richness patterns in China. The richness patterns were visualized at a 1° × 1° grid size, using 14,722 distribution records for 1335 planthoppers. We used ordinary least squares and spatial error simultaneous autoregressive models to examine the relationships between richness and single environmental variables and employed model averaging to assess the environmental variable relative roles. Species richness was unevenly distributed, with high species numbers occurring in the central and southern mountainous areas. The mean annual temperature change since the Last Glacial Maximum was the most important factor for richness patterns, followed by mean annual temperature and net primary productivity. Therefore, historical climate stability, ambient energy, and productivity hypotheses were supported strongly, but orogenic processes and geological isolation may also play a vital role.

Long‐Term Variability and Tendencies in Middle Atmosphere Temperature and Zonal Wind From WACCM6 Simulations During 1850–2014

AbstractLong‐term variability of middle atmosphere temperature (T) and zonal wind (U) is investigated using a three‐member ensemble of historical simulations of NCAR's Whole Atmospheric Community Climate Model latest version 6 (WACCM6) for 1850–2014 (165 years). The model reproduces the climatological features of T and U. The contributions of Quasi Biennial Oscillation (QBO) at 10 and 30 hPa, solar cycle (SC), El Niño‐Southern Oscillation (ENSO), ozone depleting substances (ODS), carbon dioxide (CO2), and stratospheric sulfate aerosol (volcanic eruptions) to change in monthly zonal mean T and U are analyzed using multiple linear regression. The signal due to CO2 increase dominates as a predictor of the net multidecadal global annual mean temperature change at all levels in the middle atmosphere. Contributions from ODS also affect the net multidecadal global mean temperature trend in the stratosphere. Because of similarities in the time evolution of the emissions of CO2 and ODS, the analysis of existing model output cannot accurately separate the attributions of cooling to these two dominant forcing processes. On shorter time scales, solar flux variations are the largest source of variability in the mesosphere while volcanic eruptions are the largest in the stratosphere. In the stratosphere and mesosphere, both QBO and ENSO can significantly impact zonal mean temperature and zonal‐mean zonal wind depending on latitudes, but their impact on the multidecadal global mean temperature trend is very small.

Climate change of the 21st century over China from the ensemble of RegCM4 simulations

Climate change in the 21st century over China and its different sub-regions is investigated in the study, based on the ensemble of a set of dynamical downscaling experiments over East Asia. The model employed in the experiments is the International Center for Theoretical Physics’ Regional Climate Model, version 4 (RegCM4), at 25-km grid spacing, driven by five different CMIP5 (phase 5 of the Coupled Model Intercomparison Project) global models under the Representative Concentration Pathways RCP4.5 and RCP8.5. The model version used was customized for better performance over the region. Ten sub-regions of China were defined, with consideration paid to local economic and societal developments, vulnerability of ecosystems, and sensitivity to future climate changes. A substantial warming in the future in China is projected, and this warming is more pronounced over the Tibetan Plateau during DJF (December-January-February) and Northwest China (where dry climate prevails) during JJA (June-July-August). A broad increase in temperature extreme indices—Namely, TXx (annual maximum daily maximum surface air temperature) and TNn (annual minimum daily minimum surface air temperature)—is reported, along with increased mean temperature. The results suggest more frequent and intense heat waves in the warm seasons, and thus more risks in terms of human health and mortality, over the sub-regions of Beijing-Tianjin-Hebei, the Yangtze Delta, the Guangdong-Hong Kong-Macao Greater Bay Area, and the Cross-Taiwan Strait Coasts, with their dense cities and populations. Meanwhile, the warming over the Tibetan Plateau may lead to degradation of frozen soil and glacial melt, and thus a greater frequency of related geological hazards, while increased evapotranspiration following the warming over the Arid and Semi-arid Northwest and Losses Plateau sub-regions may worsen the situation with respect to water resource shortages. Precipitation change in DJF shows a prevailing increase in northern China, with good agreement among the ensemble members. The increase is largest in the Northwest China sub-region. In southern China, small changes with a slight decrease in the southern part of the Yunnan-Guizhou Plateau are found. In JJA, precipitation increases over western China, the northern part of Northeast China, and the Yellow-Huai River basins, and shows small changes over other areas. A general increase in the precipitation extreme index (RX1day, the annual maximum 1-day precipitation) is found over the whole country, indicating more extreme precipitation events in the future. For the CDD index (the largest number of consecutive days when the daily precipitation amount is less than 1 mm), a general increase in the north and a decrease in the south are found. Regarding the increases of heavy precipitation events, the Arid and Semi-arid Northwest and Losses and Tibetan Plateau sub-regions, with their fragile ecosystems, may experience relatively more landslide and debris flow events; while over the more populated sub-regions, special concern is needed with respect to the likely greater frequency and more intense nature of flooding and urban-flooding events. Quantitatively, the increases in annual mean temperature, TXx, and TNn in the mid-21st (2041–2060) century relative to the present day (1986–2005) over the whole of China under RCP4.5/RCP8.5 are 1.6/2.2°C, 1.7/2.2°C, and 1.9/2.7°C, respectively. For precipitation, RX1day, and CDD, the values of change are 4%/5%, 9%/12%, and both around −2 d, respectively. The changes become more pronounced with time. By the end of the 21st century (2081–2098), under the higher scenario of RCP8.5, the changes in annual mean temperature, TXx, TNn, precipitation, RX1day and CDD are 4.6, 4.7, 5.5°C, 12%, 25%, and −4 d, respectively. Finally, the deficiencies and uncertainties that remain in projecting the future climate over the region are also outlined and discussed in the paper.

Surface soil n-alkane molecular and δD distributions along a precipitation transect in northeastern China

Hydrogen isotope compositions of leaf wax long-chain n-alkanes (δDalk) buried in soils have the potential to provide records of continental paleoclimatic and paleohydrological changes. However, different factors and processes influence the δDalk signature, making interpretation of the soil isotope record complicated. The relative humidity/aridity and vegetation types (C3 vs C4 plants) are two major factors responsible for the soil δDalk variations. In most cases, the interaction between relative humidity/aridity and temperature cannot be separated. Here, we analyzed the δDalk compositions in surface soils along the Northeast China Transect (NECT), where the mean annual precipitation (MAP) varies from ca. 120 to 815 mm, yet the mean annual temperature changes little, providing a setting to test the role of relative humidity/aridity in soil δDalk variations, independent of temperature changes. At the same time, the western part of the NECT, which is mainly a grassland environment, provides a test of the effects of C3 and C4 grasses on soil δDalk changes. In the semi-humid eastern NECT region, the δDalk values and their apparent fractionation relative to precipitation exhibit a strong negative correlation with the aridity index and a close relationship with soil water content. This finding supports the idea that the soil δDalk values are mainly influenced by relative aridity and that the impact of evapotranspiration, including soil evaporation and transpiration-induced 2H enrichment of woody plant leaf water, plays a vital role in shaping soil δDalk. In the semi-arid and arid western NECT region, the δDalk values and their apparent fractionations show no relationship with any environmental factors. However, in the westernmost area, soil δDalk values tend to show a negative relationship with the increasing proportion of C4 plants. This pattern probably indicates that in the arid area the soil δDalk values vary more closely with plant types than with the environmental variables. This study provides new insights into deciphering the relationship between soil δDalk values and relative humidity/aridity, and it affirms the applicability of δDalk in paleo-hydrologic reconstructions.

Geographical variation in morphological leaf traits of <i>Huperzia serrata </i>(lycopodiaceae) from Vietnam

Morphological leaf traits can be used to assess adaptive responses of plants to environmental conditions. To assess how the representation of Huperzia serrata leaf traits, such as leaf length (LL), leaf width (LW) and leaf area (LA) response to changes in mean annual temperature (MAT), sunshine duration (SuH), mean annual precipitation (MAP), air humidity (Hu), intraspecific variation of the morphological leaf traits of the species was analyzed along a geographical gradient of Vietnam. The results showed that among the three populations at the three sites, leaf sizes increased with MAT and MAP. Huperzia serrata, climatic factors, morphological leaf traits, Vietnam.

Recent responses to climate change reveal the drivers of species extinction and survival

Climate change may be a major threat to biodiversity in the next 100 years. Although there has been important work on mechanisms of decline in some species, it generally remains unclear which changes in climate actually cause extinctions, and how many species will likely be lost. Here, we identify the specific changes in climate that are associated with the widespread local extinctions that have already occurred. We then use this information to predict the extent of future biodiversity loss and to identify which processes may forestall extinction. We used data from surveys of 538 plant and animal species over time, 44% of which have already had local extinctions at one or more sites. We found that locations with local extinctions had larger and faster changes in hottest yearly temperatures than those without. Surprisingly, sites with local extinctions had significantly smaller changes in mean annual temperatures, despite the widespread use of mean annual temperatures as proxies for overall climate change. Based on their past rates of dispersal, we estimate that 57-70% of these 538 species will not disperse quickly enough to avoid extinction. However, we show that niche shifts appear to be far more important for avoiding extinction than dispersal, although most studies focus only on dispersal. Specifically, considering both dispersal and niche shifts, we project that only 16-30% of these 538 species may go extinct by 2070. Overall, our results help identify the specific climatic changes that cause extinction and the processes that may help species to survive.

Geographical variation in morphological leaf traits of <i>Huperzia serrata </i>(lycopodiaceae) from Vietnam

Morphological leaf traits can be used to assess adaptive responses of plants to environmental conditions. To assess how the representation of Huperzia serrata leaf traits, such as leaf length (LL), leaf width (LW) and leaf area (LA) response to changes in mean annual temperature (MAT), sunshine duration (SuH), mean annual precipitation (MAP), air humidity (Hu), intraspecific variation of the morphological leaf traits of the species was analyzed along a geographical gradient of Vietnam. The results showed that among the three populations at the three sites, leaf sizes increased with MAT and MAP. Huperzia serrata, climatic factors, morphological leaf traits, Vietnam.

Temporal Changes in China’s Air Temperature Distribution and Its Impact on Hot Extreme Occurrence

The likelihood of experiencing hot extremes has drastically increased due to global warming. Using 554 ground-based air temperature stations, changes in the number of hot days (NHD) in the Chinese mainland during 1960 to 2011 was investigated. We found that the NHD of the current period (1991–2011) was 70% higher than that of the base period (1960–1990). This NHD increment was attributed to the increased summer air temperature mean and its extended hot tail length—defined as the range of the mean and 90th percentile of summer air temperature. To distinguish the relative contribution of air temperature mean and hot tail length change to the NHD occurrence, a numerical-based frame work was proposed. Results showed that global warming (mean temperature increase) contributes approximately 75% of the total NHD increment. Although the average contribution of the hot tail length change is relatively small, it dominates the NHD change in regions where global warming is insignificant, e.g., the central part of China. Results suggest that frameworks and models that fail to capture the air temperature tail changes will result in biased low hot extreme occurrence estimations. This low bias would be particularly significant in regions where the mean temperature change is marginal. Hence, capturing the tail change should be the key model evaluation criterion in regions where the annual mean temperature change is relatively insignificant.

CLIMATE AND SILVICULTURAL IMPLICATIONS IN MODIFYING STAND COMPOSITION IN MIXED FIR-PINE STANDS

ABSTRACT A growing concern exists over the decreasing proportion of Scots pine (Pinus sylvestris L.) trees in mixed Trojan fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. Ex Boiss] Coode & Cullen)-Scots pine forests in northern Turkey. Given the changes in mean annual temperature and annual precipitation for the last 40 years in the region, understanding of the sensitivity of Trojan fir and Scots pine trees to changing climate seems to be critical so that better management strategies can be developed against the potential climate extremes of the future in the region. Moreover, our knowledge on the influence of current silvicultural methods on seedling density and growth in these forests is limited. Therefore, in this study, the growth response (i.e., radial growth) of Trojan fir and Scots pine trees to the changing climate were examined. In addition, the influence of current silvicultural practices on seedling growth and density in these forests was also monitored. Trojan fir appeared more sensitive to the climatic variables (i.e., temperature and precipitation) than Scots pine in the region. It was also found that the current silvicultural practices might favor Trojan fir over Scots pine in these forests. Natural dynamics and current silvicultural implications would benefit Trojan fir, however, given the species’ potential sensitivity to the changing climate, current silvicultural approaches can be modified to favor Scots pine, and to increase the resilience of these forests against climate extremes expected in the region’s future.

Small-scale fishers’ perceptions of climate change and its consequences on fisheries: the case of Sanyathi fishing basin, Lake Kariba, Zimbabwe

Small-scale fisheries, especially in developing countries, are susceptible to the negative impacts of climate change. Changing climate is one of the factors altering fish productivity, resulting in declining fish catches. Studies have been done to investigate the nature and extent of these impacts. However, research indicates that fishers in developing countries are unaware of the climate change phenomena. Therefore, it is crucial to understand how small-scale fishers perceive climate change at a local level. This study presents small-scale fishers’ perceptions of climate change and further elucidates on the impacts of climate change on fish production in Sanyathi fishing basin, Lake Kariba, Zimbabwe. Mixed method research approaches were employed in the study. Semi-structured questionnaires were administered to 66 fishers. Meteorological time series data were used to triangulate the fishers’ perceptions of climate change. Cross-tabulations (chi-square tests) and descriptive statistics were used to analyse the data. Results indicated that 92% of the fishers are aware of climate change. There is a significant (p < 0.05) categorical variable association between climate change perceptions and fish catches. However, there are no statistically significant (R2 = 0.08, p > 0.05, n = 30) changes in mean annual temperature from 1987 to 2016. There is a statistically significant increase in rainfall (R2 = 0.14, p < 0.05, n = 30) over the three decades. The results suggest that it is crucial for policy and development agencies to consider the fishers’ perceptions of climate change to formulate appropriate climate responses at the local level.

Contrasting effects of winter and summer climate on Holocene montane vegetation belts evolution in southeastern Qinghai-Tibetan Plateau, China

Montane vegetation belts are sensitive to climate change; however, it is uncertain to what degree their evolution is influenced by changes in mean annual temperature or seasonal climate. In this study, we use pollen assemblages from a high elevation lake (3780 m.a.s.l.) in the Gongga Mountains on the southeast margin of the Qinghai-Tibetan Plateau, China, to study changes in altitudinal vegetation zones during the last 12,000 years. The relationships between vegetation belts and winter and summer climate parameters are analyzed. Results indicate that winter temperature mainly controlled the development of evergreen broadleaved forest (Cyclobalanopsis and Taxodiaceae), deciduous broadleaved forest (Betula), and sub-alpine shrubland (Rosaceae, Cyperaceae and Gramineae dominated). In contrast, the development of temperate coniferous forest (Pinus and Tsuga) and alpine herbfield (Artemisia and Chenopodiaceae) was mainly controlled by summer temperature and precipitation. Results show that winter temperature gradually increased from the Greenlandian to Meghalayan, indicating that the main driving factor was winter solar insolation in the Northern Hemisphere. Meanwhile, changes in summer temperature and precipitation are consistent with the results from Indian monsoon-dominated areas of China, suggesting that the summer climate in this region is mainly driven by the migration of the Intertropical Convergence Zone. Our findings suggest that the influence of seasonal climate changes should be considered on the evolution of montane vegetation belts.

Detection of human influences on temperature seasonality from the nineteenth century

It has been widely reported that anthropogenic warming is detectable with high confidence after the 1950s. However, current palaeoclimate records suggest an earlier onset of industrial-era warming. Here, we combine observational data, multiproxy palaeo records and climate model simulations for a formal detection and attribution study. Instead of the traditional approach to the annual mean temperature change, we focus on changes in temperature seasonality (that is, the summer-minus-winter temperature difference) from the regional to whole Northern Hemisphere scales. We show that the detectable weakening of temperature seasonality, which started synchronously over the northern mid–high latitudes since the late nineteenth century, can be attributed to anthropogenic forcing. Increased greenhouse gas concentrations are the main contributors over northern high latitudes, while sulfate aerosols are the major contributors over northern mid-latitudes. A reduction in greenhouse gas emissions and air pollution is expected to mitigate the weakening of temperature seasonality and its potential ecological effects.

Analysis of Climate Change in the Caucasus Region: End of the 20th–Beginning of the 21st Century

The study of climate, in such a diverse climatic region as the Caucasus, is necessary in order to evaluate the influence of local factors on the formation of temperature and precipitation regimes in its various climatic zones. This study is based on the instrumental data (temperatures and precipitation) from 20 weather stations, located on the territory of the Caucasian region during 1961–2011. Mathematical statistics, trend analysis, and rescaled range Methods were used. It was found that the warming trend prevailed in all climatic zones, it intensified since the beginning of global warming (since 1976), while the changes in precipitation were not so unidirectional. The maximum warming was observed in the summer (on average by 0.3 °C/10 years) in all climatic zones. Persistence trends were investigated using the Hurst exponent H (range of variation 0–1), which showed a higher trend persistence of annual mean temperature changes (H = 0.8) compared to annual sum precipitations (H = 0.64). Spatial-correlation analysis performed for precipitations and temperatures showed a rapid decrease in the correlation between precipitations at various weather stations from R = 1 to R = 0.5, on a distance scale from 0 to 200 km. In contrast to precipitation, a high correlation (R = 1.0–0.7) was observed between regional weather stations temperatures at a distance scale from 0 to 1000 km, which indicates synchronous temperature changes in all climatic zones (unlike precipitation).

It’s so hot: predicting climate change effects on urban tourists’ time–space experience

Progressive changes in mean annual temperatures are arguably the strongest evidence of ongoing climate change. In destinations with a Mediterranean climate, in contrast to the colder months, during summer, rising air temperatures are believed to inhibit tourist movements and activities, and consequently affect tourists’ evaluation of and satisfaction with their experiences. To the best of our knowledge, no previous study has investigated the potential impact of climate change on tourists’ time–space activity using actual behavioural tracking-based information. Data collected via GPS technology and a post-visit survey of tourists (n = 404) visiting Lisbon during the summer were analysed via structural equation modelling (PLS-SEM). The results report empirical evidence of the present impact of (summer) weather on urban tourists’ time–space activity and on their intra-destination experience evaluation. Specifically, maximum air temperature is found to have a significant negative effect on overall satisfaction, while the meteorological conditions of the entire day reveal a significant impact on tourists’ activities and movements. The results are particularly useful for the sustainable adaptive management of urban attractions and destinations that are especially vulnerable to climate change, as well as in managing its adverse impact on tourists’ experiences.