Interannual Climate Change Research Articles

Grasslands support more diverse and resilient earthworm communities to climate change than croplands in Central Europe

Diversity and community composition of earthworms, key drivers of ecosystem functions, are increasingly threatened by global change, including climate and land-use change. However, empirical evidence for interactions of these concurrent drivers in affecting earthworm communities is scarce. Here, we investigated the effects of an experimentally imposed climate change scenario, including warming and altered precipitation patterns, and land use with two croplands (both conventional farming and organic farming characterize a three-year crop rotation) and two grasslands (intensively-used meadow and extensively-used meadow) on earthworm communities across different seasons and years in a field experiment. Compared with grasslands, earthworms in croplands have lower species richness (-26 %), abundance (-80 %), and biomass (-73 %), particularly the abundance of juveniles (-83 %) and Aporrectodea rosea (-76 %) as well as the biomass of juveniles (-84 %), A. rosea (-72 %), Octolasion cyaneum (-47 %), and Lumbricus terrestris (-83 %). Due to extreme droughts in Central Europe from 2018 to 2020, earthworm abundance and biomass were low across land-use types, but in grassland they increased (abundance: +80 %; biomass: +85 %) in 2021 presumably due to increased moisture conditions. Main effects of experimental climate change and intensified management practices as well as interaction of experimental climate change and land use on abundance and biomass of earthworms were non-significant. Notably, experimental climate change and land use interactively altered earthworm community composition, with the most pronounced difference between ambient and future climate in croplands than in grasslands. This indicates that earthworm community composition more sensitively reflects changes in environmental conditions than earthworm abundance and biomass, but the latter two negatively responded to prolonged drought conditions. Our results indicate that grasslands have a higher resilience of earthworm populations to buffer adverse environmental conditions than croplands. Overall, this study provides a comprehensive overview of the response of earthworms to inter-annual climatic variability and experimental climate change under different land-use types.

Climate change affects plant aboveground biomass by regulating the growth periods in alpine grasslands of the Tibetan Plateau, China

Climate change significantly affects plant biomass and phenological occurrence time in alpine grasslands of Tibetan Plateau. The changes in phenological periods are closely related to the length of vegetative and reproductive growth periods, which may further affect aboveground biomass accumulation. In this study, based on fixed-point observations of plant biomass and phenology as well as the corresponding climatic data from 1997 to 2020 in the alpine grasslands of Tibetan Plateau, we used statistical methods such as ordinary linear regression and piecewise structural equation model to explore the characteristics of interannual climate change in the study area, the variation trends of plant biomass and phenological periods, and the correlations between biomass and phenological and climatic factors. The results showed that mean annual temperature and annual precipitation in the study area increased significantly from 1997 to 2020, suggesting a clear "warm-wet" trend. Aboveground biomass and relative biomass of Stipa sareptana var. krylovii (the dominant species) decreased significantly. However, absolute and relative biomass of subdominant species (Kobresia humilis) increased significantly, indicating that the dominance of K. humilis increased. The warm-wet climates enhanced aboveground biomass accumulation of K. humilis by extending the period of reproductive growth. Mean annual temperature and annual precipitation decreased aboveground biomass of S. sareptana by shortening the length of vegetative growth period. In a word, the warmer and wetter climate significantly affected aboveground biomass accumulation by regulating the changes in the phenological period, and the interspecific difference in their response resulted in a larger change in community composition. This study area may show a trend from alpine grassland to alpine meadow, and thus further works are urgently needed.

Climate variation explains more than half of cotton yield variability in China

Many studies have examined the role of mean climate change in agriculture. However, the impact of interannual climate change in different regions on crop yields remains poorly understood. Here, this study combined historical climate and yield data to quantitatively analyze the effects of climate variation on cotton (Gossypium hirsutum L.) yield variability in major cotton-growing areas of China. Climate variation accounted for 54.42%, 58.10%, and 50% of the cotton yield variability in the Yellow River basin (YER), Yangtze River basin (YAR) and northwest inland (NOI), respectively. The combined effect of the three climate variables increased the cotton yields by 9.51% in the YER but decreased the yields by 6.77% and 0.45% in the YAR and NOI, respectively. In addition, the cotton yield increased mainly because the average temperature increased and the solar radiation decreased in the YER, with values of 2.82% and 5.56%, respectively. Rainfall was the main driver of the cotton yield in the YAR, and the increased rainfall reduced the cotton yield by 3.92%. In the NOI, increased solar radiation reduced the cotton yield by 3.47%. Yield variation at the provincial scale was mainly generated by complex models. Moreover, cotton yields showed nonlinear changes in most provinces, and the yield greatly fluctuated in the NOI. The study uniquely illustrates the impact of climatic variation on cotton yield variability in China and further identifies the main driving factors affecting yield variability, with the aim of formulating effective agricultural cultivation management strategies to buffer future crop production from the effects of climate change and to improve cotton production.

Climate Sensitivity of the Arid Scrublands on the Tibetan Plateau Mediated by Plant Nutrient Traits and Soil Nutrient Availability

Climate models predict the further intensification of global warming in the future. Drylands, as one of the most fragile ecosystems, are vulnerable to changes in temperature, precipitation, and drought extremes. However, it is still unclear how plant traits interact with soil properties to regulate drylands’ responses to seasonal and interannual climate change. The vegetation sensitivity index (VSI) of desert scrubs in the Qaidam Basin (NE Tibetan Plateau) was assessed by summarizing the relative contributions of temperature (SGST), precipitation (SGSP), and drought (temperature vegetation dryness index, STVDI) to the dynamics of the normalized difference vegetation index (NDVI) during plant growing months yearly from 2000 to 2015. Nutrient contents, including carbon, nitrogen, phosphorus, and potassium in topsoils and leaves of plants, were measured for seven types of desert scrub communities at 22 sites in the summer of 2016. Multiple linear and structural equation models were used to reveal how leaf and soil nutrient regimes affect desert scrubs’ sensitivity to climate variability. The results showed that total soil nitrogen (STN) and leaf carbon content (LC), respectively, explained 25.9% and 17.0% of the VSI variance across different scrub communities. Structural equation modeling (SEM) revealed that STN and total soil potassium (STK) mediated desert scrub’s VSI indirectly via SGST (with standardized path strength of −0.35 and +0.32, respectively) while LC indirectly via SGST and SGSP (with standardized path strength of −0.31 and −0.19, respectively). Neither soil nor leave nutrient contents alone could explain the VSI variance across different sites, except for the indirect influences of STN and STK via STVDI (−0.18 and 0.16, respectively). Overall, this study disentangled the relative importance of plant nutrient traits and soil nutrient availability in mediating the climatic sensitivity of desert scrubs in the Tibetan Plateau. Integrating soil nutrient availability with plant functional traits together is recommended to better understand the mechanisms behind dryland dynamics under global climate change.

Hatching phenology of the brown shrimp Crangon crangon in the southern North Sea: inter-annual temperature variations and climate change effects

Abstract Crangon crangon is a key species in the southern North Sea and the most valuable target of coastal fisheries. Recruitment and stock development are highly variable. As recruitment is based on larval production, we determined the timing of larval release in relation to the annual temperature course and the winter water temperature. The annual temperature courses over 50 years (1961–2010) showed a strong inter-annual variation but also a continuous increase in winter water temperatures. The share of ovigerous C. crangon females starts to increase in October/November, reaches a maximum in May, and decreases continuously towards September/October. During cold winters (0°C), egg development is strongly retarded and hatching of larvae culminates in a sharp peak in early June. Warm winters (6°C) facilitate embryogenesis and the earliest larvae hatch in January and February. The temperature sums from November to April correlated significantly with the lowest winter water temperatures. Consequently, the lowest winter water temperatures provide a good indication for the appearance of C. crangon larvae and an estimate for the match or mismatch with the spring bloom and the production of microzooplankton, the preferred food of C. crangon larvae.

ВЛИЯНИЕ ИЗМЕНЕНИЙ КЛИМАТА НА БИОПРОДУКТИВНОСТЬ НАЗЕМНЫХ ЭКОСИСТЕМ В БЕЛОРУССКО-УКРАИНСКОМ ПОЛЕСЬЕ

The influence of interannual and long-term climate change impacts on net primary production (NPP) of terrestrial ecosystems in the central part of the Belarusian-Ukrainian Polesie region (50.7°-53° N, 25.5°-31.5° E) are investigated using satellite observations and reanalysis data. The results show that nowadays Polesie belongs to the zone of excessive heat and solar radiation resources and insufficient moisture resources. The interannual variations in NPP in Polesie are 2-3 times higher than in the other parts of Eastern Europe. Climate change in the recent 50 years led to the reduction of the total carbon stock in the vegetation cover of the region (at the rate of ~750000 t/year). However, a number of natural and anthropogenic processes not related to the climate compensate the climate-related carbon loss in the terrestrial biomass. Moreover, these processes cause a slow growth of carbon at the rate of 140000 t/year in the region.

Quantitative Assessment of the Effects of Climate Change and Human Activities on Grassland NPP in Altay Prefecture

Grassland degradation in Altay Prefecture is of considerable concern as it is a threat that hinders the sustainable development of the local economy and the stable operation of the livestock industry. Quantitative assessment of the relative contributions of climate change and human activities, which are considered as the dominant triggers of grassland degradation, to grassland variation is crucial for understanding the grassland degradation mechanism and mitigating the degraded grassland in Altay Prefecture. In this paper, the Carnegie-Ames-Stanford Approach model and the Thornthwaite memorial model were adopted to simulate the actual net primary productivity (NPPA) and potential net primary productivity (NPPP) in the Altay Prefecture from 2000 to 2019. Meanwhile, the difference between potential NPP and actual NPP was employed to reflect the effects of human activities (NPPH) on the grassland. On this basis, we validated the viability of the simulated NPP using the Pearson correlation coefficient, investigated the spatiotemporal variability of grassland productivity, and established comprehensive scenarios to quantitatively assess the relative roles of climate change and human activities on grassland in Altay prefecture. The results indicate three main points. (1) The simulated NPPA was highly consistent with the MOD17A3 dataset in spatial distribution. (2) Regions with an increased NPPA accounted for 70.53% of the total grassland, whereas 29.47% of the total grassland area experienced a decrease. At the temporal scale, the NPPA presented a slightly increasing trend (0.83 g C m–2 yr–1) over the study period, while the trends of NPPP and NPPH were reduced (–1.31 and –2.15 g C m–2 yr–1). (3) Compared with climate change, human activities played a key role in the process of grassland restoration, as 66.98% of restored grassland resulted from it. In contrast, inter-annual climate change is the primary cause of grassland degradation, as it influenced 55.70% of degraded grassland. These results could shed light on the mechanisms of grassland variation caused by climate change and human activities, and they can be applied to further develop efficient measures to combat desertification in Altay Prefecture.

Relative humidity and agricultural activities dominate wildfire ignitions in Yunnan, Southwest China: Patterns, thresholds, and implications

Wildfires are land-surface processes and ecological disturbances occurring around the world. The wildfire regime in Yunnan Province of Southwest China is recognized as similar to that of the adjoining Indo-China Peninsula, a global hotspot for wildfires. However, the ignition mechanisms in this region remain unclear, with interactions among ecosystem features, local agricultural activities, and fire weather controlled by the West Pacific and Indian Ocean monsoons. Based on the ground records of 5145 confirmed wildfire events in Yunnan during the period of 2003–2015, we used a logistic regression model to estimate the local environmental controls on wildfire ignitions. Results highlighted the primary role of meteorology-driven characters, especially the prevalent importance of daily minimum relative humidity across the region. The threshold of the relative humidity was 37.48% ± 15.60% for the 50% ignition probability. Relative humidity also dominated ignition over years, with fuel conditions relatively stable and playing a minor role in contrast to the inter-annual climate changes. Moreover, agriculture-related ignition comprised most wildfire records, and human activities deeply shaped the spatiotemporal patterns of ignition. The distance to the nearest village was the primary factor during the beginning of the agricultural season, with a farming radius of 1.2 km as a key threshold for ignition. The complementary roles among influential factors were prominent at county scale. Among counties, the variation of ignition mechanisms corresponded to the influence paths of the two monsoons. This study highlights the importance of ground wildfire records in deriving critical wildfire ignition information such as environmental thresholds and change rates, which can provide important insights for sustainable forest management in this region, including wildfire monitoring, ignition control, fuel structure adjusting, and implementing differentiated strategies for fire prevention with regard to the environmental contexts.

Different response of earlywood vessel features of Fraxinus mandshurica to rapid warming in warm-dry and cold-wet areas

Xylem anatomical features are constantly adapting to changing environmental conditions, and are directly related to the key functions and physiological processes of trees. However, little is known about the responses of xylem to recent rapid warming in many areas. Based on the anatomical features of the xylem of Fraxinus mandshurica Rupr. from 14 sites in two contrasting areas (warm-dry and cold-wet) of northeast China, the plasticity response and adaptation strategies of radial growth, earlywood vessels (EWV), and hydraulic features of F. mandshurica to climate change were studied. Results showed that, compared with the cold-wet area, F. mandshurica in warm-dry area had wider rings, larger vessel area, higher number of vessels (VN), larger hydraulic diameters (Dh) and higher theoretical tree-ring hydraulic conductivity (Kh). On the contrary, the vessel density (VD), percentage of EWV (PC) and xylem-specific theoretical hydraulic conductivity (Ks) in warm-dry area was lower than those in cold-wet area. In these two areas, the RW, mean vessel area (MVA), total vessel area (TVA), VN, Dh, and Kh were significantly positively correlated with temperature, and negatively correlated with winter moisture. However, the PC, VD, and Ks were inversely related to climate factors in the two areas. F. mandshurica can adjust the density and proportion of EWV by changing the configuration of earlywood and latewood to cope with the interannual climate change and balance the hydraulic efficiency and safety. Rapid warming significantly increased the growing season length and hydraulic efficiency of F. mandshurica in warm-dry and cold-wet areas, thus maximizing carbon fixation. This provides a potential physiological explanation for the growth increase and range expansion of the main broadleaf tree species in temperate zone of northeast China in recent years. F. mandshurica in warm-dry areas benefits greatly from continuous climate warming, but the risk of hydraulic failure may increase.

Characterizing Growing Season Length of Subtropical Coniferous Forests with a Phenological Model

Understanding plant phenological change is of great concern in the context of global climate change. Phenological models can aid in understanding and predicting growing season changes and can be parameterized with gross primary production (GPP) estimated using the eddy covariance (EC) technique. This study used nine years of EC-derived GPP data from three mature subtropical longleaf pine forests in the southeastern United States with differing soil water holding capacity in combination with site-specific micrometeorological data to parameterize a photosynthesis-based phenological model. We evaluated how weather conditions and prescribed fire led to variation in the ecosystem phenological processes. The results suggest that soil water availability had an effect on phenology, and greater soil water availability was associated with a longer growing season (LOS). We also observed that prescribed fire, a common forest management activity in the region, had a limited impact on phenological processes. Dormant season fire had no significant effect on phenological processes by site, but we observed differences in the start of the growing season (SOS) between fire and non-fire years. Fire delayed SOS by 10 d ± 5 d (SE), and this effect was greater with higher soil water availability, extending SOS by 18 d on average. Fire was also associated with increased sensitivity of spring phenology to radiation and air temperature. We found that interannual climate change and periodic weather anomalies (flood, short-term drought, and long-term drought), controlled annual ecosystem phenological processes more than prescribed fire. When water availability increased following short-term summer drought, the growing season was extended. With future climate change, subtropical areas of the Southeastern US are expected to experience more frequent short-term droughts, which could shorten the region’s growing season and lead to a reduction in the longleaf pine ecosystem’s carbon sequestration capacity.

Selective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species.

Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established ten experimental plots including the five Arisaema species in high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using a unified formula for reproductive isolation. Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

Forest Fire Regime in a Mediterranean Ecosystem: Unraveling the Mutual Interrelations between Rainfall Seasonality, Soil Moisture, Drought Persistence, and Biomass Dynamics

Frequent and severe droughts typically intensify wildfires provided that there is enough fuel in situ. The extent to which climate change may influence the fire regime and long time-scale hydrological processes may soften the effect of inter-annual climate change and, more specifically, whether soil-water retention capacity can alleviate the harsh conditions resulting from droughts and affect fire regimes, are still largely unexplored matters. The research presented in this paper is a development of a previous investigation and shows in what way, and to what extent, rainfall frequency, dry season length, and hydraulic response of different soil types drive forest fires toward different regimes while taking into consideration the typical seasonality of the Mediterranean climate. The soil-water holding capacity, which facilitates biomass growth in between fire events and hence favors fuel production, may worsen the fire regime as long dry summers become more frequent, such that the ecosystem’s resilience to climate shifts may eventually be undermined.

Dynamics in the emergence of dormant and non-dormant herbaceous species from the soil seed bank from a Brazilian dry forest

AbstractAimsIn dry tropical forests, herbaceous species may have dormancy mechanisms and form persistent and transient seed banks in the soil. Evolutionarily acquired, these mechanisms are efficient for the establishment and survival of these herbs, especially in forests with unpredictable climates, such as the Caatinga. Thus, our objective was to verify whether the studied herbaceous species adopt the physical dormancy mechanism and how these natural barriers are overcome, to understand the temporal dynamics existing in the soil seed bank from a Brazilian dry tropical forest.MethodsSeeds of five native herbaceous species from the Caatinga forests were selected and submitted to pre-germinative treatments for verifying the presence of physical dormancy. We collected soil samples in the rainy and dry seasons for four consecutive years and monitored the emergence of the selected herbaceous in the greenhouse. We verified the differences in germination and seed bank emergence in the soil by generalized linear models.Important FindingsThe presence and absence of physical dormancy were observed in seeds from Caatinga herbaceous species. We found intraspecific and interspecific differences in the herbaceous emergence from soil seed banks between years and climatic seasons. In perennial herbs, consecutive lack of emergence between seasons and years was frequent, which suggests a direct relationship with the mechanism of physical dormancy and the environmental conditions necessary to overcome integument barriers. In these species, seed dimorphism and dormancy may confer additional advantages to their survival. Moreover, presenting intermediate levels of physical dormancy in an annual species may be an evolutionary adjustment to rainfall unpredictability. In contrast, we found that the annual herb without dormancy is more sensitive to seasonal and interannual climate changes, as evidenced by the increase and significant reduction of its emergence in the soil seed bank. These differences acquired evolutionarily are advantageous for the establishment of herbaceous populations, mainly in semiarid regions with an unpredictable climate.

Corals reveal ENSO-driven synchrony of climate impacts on both terrestrial and marine ecosystems in northern Borneo

Extreme climate events, such as the El Niños in 1997/1998 and 2015/16, have led to considerable forest loss in the Southeast Asian region following unprecedented drought and wildfires. In Borneo, the effects of extreme climate events have been exacerbated by rapid urbanization, accelerated deforestation and soil erosion since the 1980s. However, studies quantifying the impact of interannual and long-term (>3 decades) climatic and anthropogenic change affecting Borneo’s coastal and coral reef environments are lacking. Here, we used coral cores collected in Miri-Sibuti Coral Reefs National Park, Sarawak (Malaysia) to reconstruct the spatio-temporal dynamics of sea surface temperature and oxygen isotopic composition of seawater from 1982 to 2016, based on paired oxygen isotope and Sr/Ca measurements. The results revealed rising sea surface temperatures of 0.26 ± 0.04 °C per decade since 1982. Reconstructed δ18Osw displayed positive excursion during major El Niño events of 1983, 1997/98 and 2015/16, indicating drought conditions with less river runoff, rainfall and higher ocean salinities. La Niñas were generally associated with lower δ18Osw. We observed a long-term shift from more saline conditions between 1982 and 1995 towards less saline conditions after 1995, which are in agreement with the regional freshening trend, punctuated by saline excursion during El Niños. The decadal shifts were found to be driven by the Pacific Decadal Oscillation (PDO). This study provides the first long-term data on El Niño Southern Oscillation (ENSO)-driven synchrony of climate impacts on both terrestrial and marine ecosystems in northern Borneo. Our results suggest that coral records from northern Borneo are invaluable archives to detect regional ENSO and PDO impacts, and their interaction with the Asian-Australian monsoon, on the hydrological balance in the southern South China Sea beyond the past three decades.

Impact of climate change on primary production of Inner Mongolian grasslands

Climate change has dramatic impacts on the aboveground net primary productivity (ANPP) of grassland ecosystems. Understanding the impacts of interannual climate change on grassland ecosystems allows strategies to be developed for their sustainable management and protection. However, climate change coupled with overgrazing contribute to the degradation of grassland ecosystems worldwide, affecting the ANPP. In this study, we quantified the effects of temperature, precipitation, and richness of the ANPP across the meadow, typical, and desert steppes on the Inner Mongolian Plateau between 2011 and 2013. Our results indicated that the ANPP of the three grassland types increased significantly as the national ecological program of “Returning Grazing Land to Grassland” implemented by the Chinese government” progressed. There was a significant positive correlation between precipitation and the ANPP of the three types of grasslands. While, temperature had a significant impact on the desert steppes of ANPP. It also implied interaction models between climate factors and richness of three different grassland types. These results have important implications for predicting grassland productivity and developing a grassland restoration plan under climate change in the Inner Mongolian Plateau and beyond.

Spatiotemporal Variation of Cold Eddies in the Upwelling Zone off Northeastern Taiwan Revealed by the Geostationary Satellite Imagery of Ocean Color and Sea Surface Temperature

The upwelling zone off northeastern Taiwan (UZONT) is one of the hot spots with mesoscale ocean eddies (MOEs) and eddy-induced transports in the north Pacific Ocean. We start from the temporal and spatial variations in MOEs in the UZONT, based on the Himawari-8 SST product and the GOCI chlorophyll-a product time series, respectively. Their relationship with three major factors, including the Kuroshio, typhoon, and El Niño/La Niña events, are then investigated. The spatiotemporal variations in MOEs serve as ideal indicators by which to understand the influences on the UZONT due to interannual environmental factors and climate change.

Three decades of annual growth, mortality, physical condition, and microsite for ten tropical rainforest tree species.

In lowland tropical rainforest, hundreds of tree species typically occur within mesoscale landscapes (50-500ha). There is no consensus ecological theory that accounts for the coexistence of so many species with similar morphologies and the same fundamental requirements of light, nutrients, water, and physical space. In part this is due to the limited understanding of post-establishment ecology for the vast majority of tropical tree species. Of even more concern is the lack of understanding of how these trees are responding to on-going atmospheric and climatic changes. Here we present long-term data on the post-establishment ecology of ten species of tropical rainforest trees that span a broad life-history spectrum. The study site was upland (non-swamp) old-growth tropical wet forest at the La Selva Biological Station (N.E. Costa Rica). Focal individuals from established seedlings to mature trees were assessed annually, with an emphasis on accuracy and long-term consistency of the observations. The annual time-step, rare for longterm studies in tropical rainforest, captures the typically abrupt changes in forest structure and light environments, the frequent instances of major physical damage, and the trees' responses to these events and to interannual and long-term climatic variation. With the completion of the study in 2016, the data for survivorship, growth, and microsite conditions span 4,499 individuals and 34yr. The first ten years of these data were published as an Ecology/Ecological Archives data paper in 2000 (Clark and Clark 2000), with two subsequent update publications (Clark and Clark 2006, 2012). This final update adds the final six years of observations, digitized field comments, and histories of points of measurement on the trees. The metadata now include the scanned original field data-sheets for the entire study and a narrative detailing the annual qa/qc of the data. The data set is unique for its scope (years of continuous annual measurements, number of monitored individuals), the in-depth documentation, and the unrestricted data access. The data have been used to study life history patterns, tree ecology through ontogeny, and effects on tree performance from interannual and long-term climatic and atmospheric change. They have also contributed to numerous remote-sensing studies. No copyright or proprietary restrictions are associated with the use of this data set other than citation of the paper; the authors believe scientific data should be freely available for scientific use. The authors would appreciate notification of when and how data are used, but this is discretionary on the part of the data users and is in no sense mandatory.

Indian monsoon inter-annual variability and climate change

Indian monsoon inter-annual variability and climate change

The differential futures of ski tourism in Ontario (Canada) under climate change: the limits of snowmaking adaptation

The international ski tourism industry is highly vulnerable to inter-annual climate variability and climate change. Accordingly, there is a strong need to advance our understanding of climate risk for this multi-billion tourism market that is so important to mountain regions around the world. This study addressed major limitations in the ski tourism literature, while concurrently supporting priority information needs of ski tourism stakeholders. An improved version of SkiSim 2.0 is applied to all 34 alpine ski areas in southern Ontario (Canada) to examine potential changes in the capacity of this regional marketplace. Model improvements include differential snowmaking capacities of individual ski areas, updated snowmaking decision rules, as well as a new indicator, termed ‘terrain-days’, to estimate changes in system capacity. The results project two fundamentally different futures for this ski tourism marketplace under climate change. If the international community succeeds in achieving the + 2°C Paris Agreement policy goal, then losses in system capacity can be limited to less than 10% in the mid- and late-century. In contrast, a high-end emission scenario (RCP 8.5) would severely disrupt this ski tourism market by mid-century, with system capacity losses between 28% and 73%.

Decadal Western Pacific Warm Pool Variability: A Centroid and Heat Content Study

We examine several characteristics of the Western Pacific Warm Pool (WP) in the past thirty years of mixed interannual variability and climate change. Our study presents the three-dimensional WP centroid (WPC) movement, WP heat content anomaly (HC) and WP volume (WPV) on interannual to decadal time scales. We show the statistically significant correlation between each parameter’s interannual anomaly and the NINO 3, NINO 3.4, NINO 4, SOI, and PDO indices. The longitudinal component of the WPC is most strongly correlated with NINO 4 (R = 0.78). The depth component of the WPC has the highest correlation (R = −0.6) with NINO3.4. The WPV and NINO4 have an R-Value of −0.65. HC has the highest correlation with NINO3.4 (R = −0.52). During the study period of 1982–2014, the non-linear trends, derived from ensemble empirical mode decomposition (EEMD), show that the WPV, WP depth and HC have all increased. The WPV has increased by 14% since 1982 and the HC has increased from −1 × 108 J/m2 in 1993 to 10 × 108 J/m2 in 2014. While the largest variances in the latitudinal and longitudinal WPC locations are associated with annual and seasonal timescales, the largest variances in the WPV and HC are due to the multi-decadal non-linear trend.