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Background: Urban areas are a significant and rapidly expanding part of the global landscape. Urban expansion occurs alongside climate change, with both linked to declines in native species. However, urban environments can offer alternative resources during extreme climatic events such as droughts. Aims: We sought to identify bird species that had an increased presence in the major urban center of south-west Western Australia during a climate anomaly characterized by record low rainfall and high temperatures. Methods: Using eBird data, we analyzed changes in the reporting rates of all bird species in the period from January 2019 to August 2024. Generalized linear models were used to assess the influence of cumulative 6-month, 12-month, and 18-month rainfall on species reporting rates. Key results: Reporting rates increased dramatically (up to nine times higher than average) around the time of the drought, before reducing back to the average once the drought was broken for four species: (1) the black-shouldered kite; (2) the black-tailed native-hen; (3) the tawny-crowned honeyeater; and (4) the western spinebill. Cumulative 6-month rainfall was a strong predictor for the raptor and the two honeyeaters. Other similar species showed no significant change in reporting rate, suggesting the effect is highly species dependent. Conclusions: Multiple different types of birds may utilize urban areas during drought events. Further research is needed to identify what drives movement of wildlife in response to such events, and the type of urban resources the birds are using. Implications: Urban ecosystems should be integrated into broader conservation plans to support species through the interacting challenges posed by climate change and urbanization. Urban areas are expanding rapidly, leading to habitat and biodiversity loss. However, they may offer resources during environmental stressors like drought. Our study in south-west Western Australia found dramatic increases in reporting rates for four bird species during a climate anomaly, highlighting their adaptive behavioural responses and the potential of urban areas as refuges. Photograph by Harry Moore. [ABSTRACT FROM AUTHOR]

A major restriction in predicting plant community response to future climate change is a lack of long-term data needed to properly assess species and community response to climate and identify a baseline to detect climate anomalies. Here, we use a 106-year dataset on a Sonoran Desert plant community to test the role of extreme temperature and precipitation anomalies on community dynamics at the decadal scale and over time. Additionally, we tested the climate sensitivity of 39 desert plant species and whether sensitivity was associated with growth form, longevity, geographic range, or local dominance. We found that desert plant communities had shifted directionally over the 106 years, but the climate had little influence on this directional change primarily due to nonlinear shifts in precipitation anomalies. Decadal-scale climate had the largest impact on species richness, species relative density, and total plant cover, explaining up to 26%, 45%, and 55% of the variance in each, respectively. Drought and the interaction between the frequency of freeze events and above-average summer precipitation were among the most influential climate factors. Increased drought frequency and wetter periods with frequent freeze events led to larger reductions in total plant cover, species richness, and the relative densities of dominant subshrubs Ambrosia deltoidea and Encelia farinosa. More than 80% of the tested species were sensitive to climate, but sensitivity was not associated with a species' local dominance, longevity, geographic range, or growth form. Some species appear to exhibit demographic buffering, where when they have a higher sensitivity to drought, they also tend to have a higher sensitivity to favorable (i.e., wetter and hotter) conditions. Overall, our results suggest that, while decadal-scale climate variation substantially impacts these desert plant communities, directional change in temperature over the last century has had little impact due to the relative importance of precipitation and drought. With projections of increased drought in this region, we may see reductions in total vegetation cover and species richness due to the loss of species, possibly through a breakdown in their ability to demographically buffer climatic variation, potentially changing community dynamics through a change in facilitative and competitive processes. [ABSTRACT FROM AUTHOR]

Knowledge of the responses and feedbacks of vegetation dynamics to interannual climate anomalies in the semiarid area of north China is lacking. This study addresses this issue through climate modelling for 1991–2006 with the Weather Research and Forecast (WRF) model, into which a locally empirical vegetation dynamic (VED) scheme was implemented. The VED scheme was built on the basis of regression models of the leaf area index (LAI), green vegetation fraction (GVF), and surface albedo (ALB) with ambient temperature and humidity as independent variables. Using the update WRF model, the climate simulations were carried out with turning on and off VED, respectively. By comparing the simulations outputs with each other, we find that the interannual variability of precipitation from simulations with turning on VED is larger than that from simulations with turning off VED. The larger interannual variability of precipitation could be explained by VED feedback. Vegetation growth would be more vigorous, as a response, under the more precipitation, because which brings more available water. In turn, vigorous vegetation leads to more evapotranspiration and, hence, precipitable water; as a result, there would be more precipitation. It is reversed for the years with less precipitation. Such interactions between vegetation and precipitation could be summarized as positive feedback loops. This study suggests that the interannual precipitation variability can be enlarged by VED through positive evapotranspiration–precipitation feedback. It is therefore necessary to consider the vegetation dynamics for future downscaled regional climate predictions to pursue more reliable interannual climate variability. [ABSTRACT FROM AUTHOR]

Background: As climate research continues to highlight the global shifts in temperature and precipitation, more research is needed to understand how climate anomalies impact human health outcomes. In this paper, we analyze one of the paths through which climate anomalies affect health (in particular, child's health) within one of poorest countries in the world (Honduras).Methods: Using the GPS location of the household, we link information on child health and house amenities from the Honduras Demographic Health Survey 2011-2012 dataset (a nationally representative sample) with climate data (1981-2012) from the Climate Research Unit (CRU TS3.21). We use generalized estimating equations for binary logistic models and spatial association to analyze these data.Results: We show that 1) areas experiencing significant temperature anomalies are also the ones with the worst child respiratory problems and 2) in households with poor amenities - such as access to sanitation and clean water, children tend to have a high incidence of respiratory diseases and diarrhea .Conclusions: We conclude that, as climate change increases the incidence of climate anomalies, tackling in advance those household environmental factors responsible for poor child health outcomes (better sanitation and clean cooking fuel) can prevent a further deterioration of children's health in Honduras. [ABSTRACT FROM AUTHOR]

• Developing a measurement to quantify vegetation diversity at large spatial scales. • Integrating resistance and resilience into one indicator to estimate stability. • Ecosystem stability varies dramatically with elevations and vegetation types. • Vegetation diversity can enhance ecosystem stability at large spatial scales. The unprecedented climate change over the past decades is likely to have ubiquitous and profound impacts on ecosystems. Assessing the vegetation response and ecosystem stability to climate variability is of great importance for developing more sustainable strategies in ecosystem management. Different types of vegetation respond to climate disturbances in various ways and the insurance hypothesis states that biodiversity is able to improve ecosystem stability, so there is a compelling need to further test whether diversity of vegetation composition could increase stability at large scales. In this study, we estimated the response of stability in a comprehensive and accurate metric of the ecosystem to short-term climate anomalies by combining resistance and resilience using an autoregressive modeling method in the Taihang Mountains, an important geographical demarcation line in north China. Our results showed that ecosystem stability differed dramatically with elevations and vegetation types. Mid-elevation zones at the altitude between 500 and 2000 m were particularly stable. However, high-elevation zones (above 2000 m) and low-elevation zones (below 500 m) were comparatively vulnerable. Trade-offs between resistance and resilience were widely observed and stability was largely determined by resilience, especially for ecosystems lied below the elevation of 2000 m. Among all vegetation types, steppes and shrubs were much more stable under climate fluctuations. In contrast, broad-leaf forests had the lowest stability, which was only higher than the cultivated crops. Stability was significantly correlated with the diversity of vegetation composition, a confirmation of insurance effects at large spatial scales. This implies that the vegetation diversity at large spatial scales can enhance the ability of ecosystems to maintain stabilization under climatic fluctuations or recover quickly from climate disturbances. [ABSTRACT FROM AUTHOR]

Highlights • Drought evolutions during 2009–2011 over Southwest China are revisited. • Roles of precipitation and ET 0 anomalies are quantified with a separation method. • ET 0 's impacts can be comparable to precipitation's, especially at monthly scale. • A reference framework is proposed to comprehensively understand drought evolutions. Abstract With intensifying climate change, droughts over Southwest China (SWC) are drawing increasing interest. The droughts of 2009–2011 have attracted special concern. However, the roles of atmospheric evaporative demand [reflected by reference evapotranspiration (ET 0)] and precipitation (P) anomalies in drought evolutions are still unclear. To that end, we revisited the evolution of the 2009–2011 SWC meteorological droughts quantitatively and comprehensively by quantifying the ET 0 and P impacts. In terms of three drought parameters [i.e., drought intensity (DI), area (DA), and duration (DD)], SWC experienced the second most severe drought of the 1961–2012 period in 2009. Evident differences existed among the drought conditions in different months, i.e., more severe droughts occurred in February–March 2009, September 2009 to March 2010, and June–October 2011. Based on the annual means over drought regions, the 2009 and 2011 DI (DA) could be attributed to lower P, but the P and ET 0 impacts [P, ET 0 , and P-and-ET 0 (which reflects drought occurrence due to their combined impacts only)] were comparable in 2010. In addition, P reduction was responsible for DD during 2009–2011. Except in January–March, which were dominated mostly by P, DI (DA) was generally dominated by ET 0 (ET 0 or P-and-ET 0) over the three years. While P dominated spatially and temporally for the majority of the 36 months for DI (DD), some areas were mainly affected by ET 0 (ET 0 or P-and-ET 0). Therefore, to better understand drought evolutions and improve drought monitoring and forecasting, the impacts of ET 0 anomalies should be fully considered. The results of this study provide an important reference framework for comprehensively understanding the underlying mechanisms of droughts not only in SWC but also in other regions around the world. [ABSTRACT FROM AUTHOR]

Seasonal and interannual dynamics of bioluminescence intensity and succession of the major phytoplankton taxonomic groups were analyzed using the six-year monitoring of Crimean coastal waters (the northern Black Sea) in 2009–2014. Monitoring program included regular CTD and bioluminescence intensity casts in the upper 60 m layer by means of "Salpa-M" sonde accompanied with phytoplankton sampling from subsurface (∼0.2 m) and from the layer of maximal bioluminescence intensity. Years with anomalous warm and cold preceding fall-winter periods were defined on the basis of remotely sensed monthly sea surface temperature (SST) and long-term records on coastal SST measuring station. It was shown that succession of phytoplankton and net vertical bioluminescence patterns in subsequent spring-summer seasons depend upon the SST anomaly during preceding fall-winter period. In "cold" years a minimal bioluminescence intensity associated with a diminished biomass and species abundance of luminous dinoflagellates as well as diatoms and dinoflagellates groups as a whole were observed. A number of luminous dinoflagellate species dropped out of spring phytoplankton community (e.g., Scrippsiella cf. acuminata). As a result, a typical spring peak of bioluminescence in the upper mixed layer has not been observed during these years. In contrast maximal bioluminescence intensity and phytoplankton abundance in spring-summer was observed in "warm" years; biomass and bioluminescence intensity peaks shift to earlier month (April) in comparison to "moderate" years; period of dinoflagellate dominance was more extended during the spring-summer succession phase. Overall, group of dinoflagellates including luminous species, seems to be the most sensitive group of algae to climatic SST anomalies in coastal waters of the northern Black Sea. Hence, the bioluminescence in the upper sea layer can act as an indicator of climate-induced phytoplankton community restructuring. • Spring-summer succession of phytoplankton is affected by the Black Sea SST anomalies during preceding fall-winter period. • In "cold" years minimal IBP was observed along with diminished biomass and species abundance of diatoms and dinoflagellates. • In "warm" years high IBP and phytoplankton abundance in spring-summer was observed with peaks shifting to earlier month (April). • Group of dinoflagellates including luminous species seems to be the most sensitive to climatic SSTA in the northern Black Sea. • Bioluminescence in the upper sea layer can serve as an indicator of climate-induced phytoplankton community restructuring. [ABSTRACT FROM AUTHOR]

Variations of southern hemisphere (SH) climate variables are often linked to the southern annular mode (SAM) variability. We examined such linkage by seasons using state-of-the-art atmosphere and ocean/sea-ice reanalyses. The associated SAM related anomaly (SRA) fields of the climate variables, denoting anomalies corresponding to the same variation in SAM, are overall consistent across the reanalyses. Among the atmospheric products, 20CRV2 differs from ERA-interim and CFSR in the sea-level pressure SRAs over the Amundsen Sea, resulting in less warming over the Antarctic Peninsula. Among the ocean reanalyses, ORAP5 and C-GLORS exhibit the largest consistency. The major difference between them and the lower-resolution CFSR and SODA reanalyses is deeper penetration of anomalous meridional currents. Compared to the other ocean reanalyses, CFSR exhibits stronger and spatially more coherent surface-current SRAs, resulting in greater SRAs of sea-ice motion and ice thickness along the ice edges. The SRAs of sensible and total surface heat fluxes are reduced in CFSR due to ocean–atmosphere coupling. Significant sea-ice concentration SRAs are present on the west side of peninsulas along the east Antarctica coast in spring and winter, most notably in ORAP5 and C-GLORS, implying changes in new-ice production and shelf-water formation. Most atmosphere and ocean variables manifest an annular SRA pattern in summer and a non-annular pattern in the other seasons, with a wavenumber-3 structure strongest in autumn and weakest in summer. The wavenumber-3 structure should be related to the zonal wave three pattern of the SH circulation, the relation of which to SAM needs further exploration. [ABSTRACT FROM AUTHOR]

The wintertime haze day (HD) in the Yangtze River Delta (YRD) region of China shows a significant upward trend during the past decades due to the rapid industrialization and urbanization. Besides the enhanced anthropogenic emission, climate change also plays the important role in the long term HD variations. In this study, the significant decadal variation of wintertime HD during the period 1960–2012 in YRD is examined by the empirical orthogonal function (EOF) analysis, featured as less HD occurrence before 1980 and more occurrence after 2000. The numerical simulations by the global transport and chemical model (Model for Ozone and Related chemical Tracers, MOZART) with the same emission inventory suggest 8.4% enhancement of wintertime PM 2.5 (particulate matter with the equivalent diameter of air dynamics less than or equal to 2.5 μm) mass concentration in YRD during 2001–2009 compared with that during 1971–1979 attributed to meteorological changes, indicating the significant effect of climate anomaly on the decadal variations of wintertime HD. Through the composite analysis on the atmospheric dynamical and thermal conditions based on the reanalysis data, the faster warming in the lower and middle troposphere over the continent in the recent decade is suggested to be important for the out-of-phase decadal HD variation in YRD. The thermal anomaly not only reverses the zonal thermal difference of land-sea to stimulate the anomalous southerlies over YRD leading to reduced prevailing north wind in winter, but also develops the deep inversion below the mid-troposphere to enhance the atmospheric stability. As a result, more frequent and persistent air stagnations in recent decade are expected for the reduction of atmospheric horizontal dispersion and vertical diffusion capacity leading to more occurrence of wintertime HD in YRD. [ABSTRACT FROM AUTHOR]

By employing the singular value decomposition (SVD) analysis, we have investigated in the present paper the covariations between circulation changes in the Northern (NH) and Southern Hemispheres (SH) and their associations with ENSO by using the NCEP/NCAR reanalysis, the reconstructed monthly NOAA SST, and CMAP precipitation along with NOAA Climate Prediction Center (CPC) ENSO indices. A bi-hemispheric covariation mode (hereafter BHCM) is explored, which is well represented by the first mode of the SVD analysis of sea surface pressure anomaly (SLPA-SVD1). This SVD mode can explain 57.36% of the total covariance of SLPA. BHCM varies in time with a long-term trend and periodicities of 3-5 years. The long term trend revealed by SVD1 shows that the SLP increases in the equatorial central and eastern Pacific but decreases in the western Pacific and tropical Indian Ocean, which facilitates easterlies in the lower troposphere to be intensified and El Niño events to occur with lower frequency. The spatial pattern of the BHCM looks roughly symmetric about the equator in the tropics, whereas it is characterized by zonal disturbances in the mid-latitude of NH and is highly associated with AAO in the mid-latitude of SH. On inter-annual time scales, the BHCM is highly correlated with ENSO. The atmosphere in both the NH and SH responds to sea surface temperature anomalies in the equatorial region, while the contemporaneous circulation changes in the NH and SH in turn affect the occurrence of El Niño/La Niña. In boreal winter, significant temperature and precipitation anomalies associated with the BHCM are found worldwide. Specifically, in the positive phase of the BHCM, temperature and precipitation are anomalously low in eastern China and some other regions of East Asia. These results are helpful for us to better understand interactions between circulations in the NH and SH and the dynamical mechanisms behind these interactions. [ABSTRACT FROM AUTHOR]

Recent climate variability and anomaly in the Great Lakes region provided a valuable opportunity in examining the response and regulation of ecosystem carbon cycling across different ecosystems. A simple Bayesian hierarchical model was developed and fitted against three-year (2011–2013) net ecosystem CO 2 exchange ( F CO 2 ) data observed at three eddy-covariance sites (i.e., a deciduous woodland, a cropland, and a marsh) in northwestern Ohio. The model was designed to partition the variation of gross ecosystem production (GEP), ecosystem respiration (ER) and F CO 2 that resulted directly from the short-term environmental forcing (i.e., direct effect) and indirectly from the changes of ecosystem functional traits (e.g., structural, physiological, and phenological traits) (i.e., indirect effect). Interannual variation of F CO 2 was mainly driven by indirect effects, accounting for 54%, 89%, and 86% of the interannual variation at the woodland, cropland, and marsh sites, respectively. On the other hand, direct climatic effects accounted for 33% of interannual F CO 2 variation at the woodland site and became irrelevant (<10%) at the cropland and marsh sites. In general, annual GEP and ER at each site tended to co-vary and dampen the interannual variability in F CO 2 . Yet, year-to-year changes of GEP and ER were not spatially synchronous, suggesting that the ecosystem's response to climate was strongly site-specific in terms of the annual net CO 2 uptake. Future research should focus on the disparate response among ecosystems and develop a suitable framework to examine the mechanisms that drive differences in closely co-located ecosystems. [ABSTRACT FROM AUTHOR]

The El-Niño Southern Oscillation (ENSO), one of the most well-known climate modes, can lead to large-scale climate variability and subsequent crop loss, posing a severe risk to global food security. The study's main goal was to examine the synchronous impacts of ENSO and the probability of simultaneous ENSO–related crop loss on the global yields of major crops and investigate the predictability of finer-scale variation in crop yields based on ENSO-related large-scale climate precursors. Here, using updated crop census data for ∼12,000 political units, the study first investigated the synchronous impact of ENSO on yield variability of major crops (i.e., maize, rice, wheat, and soybean) using Synthetic Analysis and bootstrap method, and then estimated the probability of simultaneous crop loss in the top five crop-producing countries by copula approach. Finally, multiple regression was developed to identify the best forecast model, the corresponding ENSO indices, and the lead time for each political unit based on pre-occurred ENSO indices. The results show that 12.8% (2.1%), 13.4% (6.4%), 11.8% (10.2%), and 8.4% (18.3%) of wheat, rice, maize, and soybean harvest areas were significantly negatively (positively) associated with El Niño, respectively; and 7% (11.7%), 20.2% (3.4%), 5.8% (5.6%), and 14% (6.4%) with La Niña. El Niño reduced global-mean crop yield by 1.32%, 1.33%, and 0.37% for wheat, rice, and maize, respectively, but increased it for soybean by 1.9%. La Niña reduced the global mean yield for rice (2.1%), maize (1.5%), and soybean (1.3%) but increased it for wheat (1.0%). Rice (6.6%) had the highest probability of simultaneous loss during the El Niño phase, whereas La Niña is soybean (5.9%). Based on the early ENSO signals, crop yield could be reliably forecasted for ∼32.05%, ∼42.2%, ∼21%, and ∼ 26.37% of global harvest areas, with R2 being 0.24, 0.26, 0.24, and 0.23 and a lead time of 1–12 months, for wheat, rice, maize, and soybean, respectively. The results suggest that although the reliable yield prediction based on ENSO indexes alone can be developed in a limited proportion of harvest areas, it is skillful in the ENSO-sensitive regions. The findings improved the understanding of ENSO-induced crop yield variability and developed novel approaches to forecast global crop yields based on early ENSO signals. [Display omitted] • The synchronous and pre-occurred impacts of ENSO on global yield variation remain elusive. • The predictability of finer-scale yield variation was investigated based on early ENSO signals. • The ENSO impacts varied with the crop type, growing season, location, and ENSO phase. • Approximately a fourth of (23–26%) yield variation could be reliably forecasted by ENSO indices alone. • The resultant global patterns of ENSO impacts on crop yield are valuable for developing an effective early warning system. [ABSTRACT FROM AUTHOR]

We investigated carbon allocation in a cool-temperate forest in central Japan in years of contrasting climate anomalies: an early spring warming induced by the El Niño Southern Oscillation in 2002 and a low summer photosynthetic photon flux density (PPFD) induced by a stationary rain front in 2003. Observations of eddy flux, biometric variables, and chamber measurements from 1999 to 2006 and interannual variations in fine root net primary production (frNPP) were analyzed in conjunction with a terrestrial biosphere model simulation with multiple biometric constraints. Compared to the annual means (excluding 2002 and 2003), the low summer PPFD in 2003 reduced the annual gross primary productivity (GPP; −6%), soil respiration (SR; −11%), and ecosystem respiration (RE; −5%). Under the low summer PPFD, CO 2 fluxes commonly decreased but components of the NPP were not affected. The low variation in NPP is explained by previous findings that NPP is more sensitive to climate conditions before or during the early stage of the growing season. The early spring warming in 2002 increased the GPP (8%) and woody tissue NPP (wNPP; 55%) and decreased the frNPP (−33%) and SR (−6%). Although early spring warming prolonged the growing season, the foliage NPP (fNPP) and litterfall were invariant. The increase in wNPP and the decrease in frNPP imply that the forest decreased frNPP in favor of wNPP under the high spring temperature. Although the frNPP was estimated by model-data integration, we argue that the decrease in frNPP is plausible because the decrease in SR cannot be explained without the contribution from fine root respiration. These results suggest that increasing or decreasing patterns of component fluxes cannot necessarily be inferred from the GPP. Factors such as the nature and duration of climate anomalies and allocation shift between components of the NPP may need to be considered when characterizing carbon allocation under anomalous climate events. [ABSTRACT FROM AUTHOR]

Temperature records for the Russian territory in summer 2010 are presented. The potential role that the current global warming plays in the formation of abnormally hot summers in the European part of Russia is discussed. Although the main reason for the extreme heat wave in 2010 was a quasi-stationary anticyclone blocking westerlies, global warming could also contribute to the observed temperature extremums adversely affecting the biota. [ABSTRACT FROM AUTHOR]

In climate science, an anomaly is the deviation of a quantity from its annual cycle. There are many ways to define annual cycle. Traditionally, this annual cycle is taken to be an exact repeat of itself year after year. This stationary annual cycle may not reflect well the intrinsic nonlinearity of the climate system, especially under external forcing. In this paper, we re-examine the reference frame for anomalies by re-examining the annual cycle. We propose an alternative reference frame for climate anomalies, the modulated annual cycle (MAC) that allows the annual cycle to change from year to year, for defining anomalies. In order for this alternative reference frame to be useful, we need to be able to define the instantaneous annual cycle: we therefore also introduce a new method to extract the MAC from climatic data. In the presence of a MAC, modulated in both amplitude and frequency, we can then define an alternative version of an anomaly, this time with respect to the instantaneous MAC rather than a permanent and unchanging AC. Based on this alternative definition of anomalies, we re-examine some familiar physical processes: in particular SST re-emergence and ENSO phase locking to the annual cycle. We find that the re-emergence mechanism may be alternatively interpreted as an explanation of the change of the annual cycle instead of an explanation of the interannual to interdecadal persistence of SST anomalies. We also find that the ENSO phase locking can largely be attributed to the residual annual cycle (the difference of the MAC and the corresponding traditional annual cycle) contained in the traditional anomaly, and, therefore, can be alternatively interpreted as a part of the annual cycle phase locked to the annual cycle itself. In addition to the examples of reinterpretation of physics of well known climate phenomena, we also present an example of the implications of using a MAC against which to define anomalies. We show that using MAC as a reference framework for anomaly can bypass the difficulty brought by concepts such as “decadal variability of summer (or winter) climate” for understanding the low-frequency variability of the climate system. The concept of an amplitude and frequency modulated annual cycle, a method to extract it, and its implications for the interpretation of physical processes, all may contribute potentially to a more consistent and fruitful way of examining past and future climate variability and change. [ABSTRACT FROM AUTHOR]

Clear evidence provided by the singular value decomposition (SVD) analysis to the normalized difference vegetation index (NDVI) and precipitation data identifies that there exists a sensitive region of vegetation-climate interaction located in the transitional zone over northern China and its surrounding areas, where the vegetation cover change has the most significant influence on summer precipitation over China. Comparison of reanalysis data with station data provides a good method to assess the impacts of land use change on surface temperature, and the most obvious contribution of land use change may be to lead to notable warming over northern China in the interdecadal time scale. Based on the new statistical results, a high-resolution regional integrated environmental model system (RIEMS) is employed to investigate the effects of land surface degradation over the transitional zone and its surrounding areas (northern China and southern Mongolia) on the regional climate. Land degradation results in the decreases in precipitation over northern and southern China, and the increase in between, and increased and decreased temperature over vegetation change areas and the adjacent area to the south, respectively. Not only would it change the surface climate, but also bring the significant influence on the atmospheric circulation. Both the surface climate and circulation changes generally agree to the observed interdecadal anomalies over the last five decades. These integrated statistical and simulated results imply that land surface degradation over the transitional zone in northern China and its surrounding areas could be one of the main causes responsible for the climate anomalies over China, especially the drought over northern China. [ABSTRACT FROM AUTHOR]

The Late Holocene was characterized by several centennial-scale climate oscillations including the Roman Warm Period, the Dark Ages Cold Period, the Medieval Warm Period and the Little Ice Age. The detection and investigation of such climate anomalies requires paleoclimate archives with an accurate chronology as well as a high temporal resolution. Here, we present 230Th/U-dated high-resolution multi-proxy records (δ13C, δ18O and trace elements) for the last 2500 years of four speleothems from Bunker Cave and the Herbstlabyrinth cave system in Germany. The multi-proxy data of all four speleothems show evidence of two warm and two cold phases during the last 2500 years, which coincide with the Roman Warm Period and the Medieval Warm Period, as well as the Dark Ages Cold Period and the Little Ice Age, respectively. During these four cold and warm periods, the δ18O and δ13C records of all four speleothems and the Mg concentration of the speleothems Bu4 (Bunker Cave) and TV1 (Herbstlabyrinth cave system) show common features and are thus interpreted to be related to past climate variability. Comparison with other paleoclimate records suggests a strong influence of the North Atlantic Oscillation at the two caves sites, which is reflected by warm and humid conditions during the Roman Warm Period and the Medieval Warm Period, and cold and dry climate during the Dark Ages Cold period and the Little Ice Age. The Mg records of speleothems Bu1 (Bunker Cave) and NG01 (Herbstlabyrinth) as well as the inconsistent patterns of Sr, Ba and P suggests that the processes controlling the abundance of these trace elements are dominated by site-specific effects rather than being related to supra-regional climate variability. [ABSTRACT FROM AUTHOR]

• Alpine grasslands were more stable than temperate grasslands. • The stability of grasslands showed altitudinal dependence. • The shifts of stability dimensionality signaled grassland state transitions. Ecosystems are experiencing unprecedented climate change during the past decades, which drove evident shifts in ecosystem states, processes and functions. Understanding ecosystem stability is critical for accurately assessing and predicting ecosystem state shifts when exposed to climate fluctuations. Here, we disentangled and evaluated the dimensionality of ecosystem stability in terms of productivity substituted by normalized differential vegetation index (NDVI) in response to climate changes in temperature, precipitation, and solar radiation, temporally or spatially. Invariability, resistance, and resilience were considered as the stability components for five different grassland types across the Tibetan Plateau. The dimensionality of ecosystem stability was derived from the pairwise correlation matrics between invariability, resistance, and resilience. Our results confirmed that ecosystem productivity stability is grassland-type specific, with alpine meadows and steppes being more stable than temperate meadows, steppes, and desert-steppes. The dimensionality and components of grassland stability on the Tibetan Plateau showed strong altitudinal dependence. Invariability and resistance first increased and then decreased along increasing altitudes, with their maximums peaking at the middle-altitudes of ~3,750 m. However, the resilience of ecosystem productivity linearly increased with increasing altitudes. Correlations among stability components were highest at the altitude of ~ 3,300 m, where is the transition zone between temperate and alpine grasslands and the lowest dimensionality of ecosystem stability. Finally, we suggest that the altitudinal shifts of stability dimensionality might be the signals of grassland state transition from temperate to alpine grasslands on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

• Precipitation and phenology regulate pattern and partitioning of water fluxes. • Boreal forest poses larger EWA but smaller ET and T / ET than of tropical and temperate forests. • ET in boreal deciduous and evergreens are comparable while their EWA and T / ET are very distinct. • MODIS reflectance underestimates boreal larch's ET by approximately 23%. • Machine learning algorithm is accurate in the ET gap-filling. High latitude boreal forests are experiencing dramatic changes in climate and hydrology. It is not clear how boreal forests will adapt to hydrological change or how stable they will be to extreme climate fluctuations and shifts in ecosystem water availability (EWA; residuals between precipitation and evapotranspiration). Although there have been numerous studies in North American and European boreal forests, the Siberian boreal region is underrepresented. Moreover, Siberia is dominated by deciduous conifers (larch) that may have different response to shifting hydrology than boreal evergreens do. We observed evapotranspiration (ET) by eddy covariance technique and transpiration (T) by sap-flow probes on a subsample of trees within the flux-tower footprint through two growing seasons in a larch forest in northernmost China. Ecosystems at the margins of their zone could be amongst the first to experience significant shifts in structure and function. At this site there have already been signs of permafrost degradation and more frequent temperature and precipitation anomalies. The canopy-dominant larch accounted for half the total T fluxes. The remaining 50% was distributed evenly among intermediate and suppressed trees. T is the dominant subcomponent in ET , where overall T / ET varies of 66%–84% depending on precipitation patterns. In dormant and early growing seasons, T still constitutes a majority of ET even though the canopy foliage is not fully developed because cold soil creates a negative soil to air vapor pressure gradient that impedes evaporation. However, in the peak growing season, excess precipitation reduces T while providing sufficient wetness for surface evaporation. ET from standard data product based on MODIS satellite reflectance underestimates tower ET by 17%–29%. Solar-induced chlorophyll fluorescence measured by satellite is well correlated with tower ET (r 2 = 0.69–0.73) and could provide a better basis for regional ET extrapolations. A global comparison of data for 2000–2018 period reveals that boreal forests not only have the smallest annual MODIS ET but also the least EWA compared to temperate and tropical forests. Also, even though boreal deciduous and evergreens have comparable annual ET , their T / ET and EWA are distinct. This work highlights how short-term precipitation extremes may shift ecosystem function and structure by changing EWA through exported runoff. Sites along boreal ecotones are critical to observe for signs of shifts in their structure, function, and response to climate anomalies. [ABSTRACT FROM AUTHOR]

A stalagmite from Dim Cave in southern Turkey contains a climate record documenting rapid and significant changes in amounts of precipitation between ~132 ka and ~128 ka, during the penultimate glacial – interglacial transition. Some U–Th dates have been compromised by carbonate dissolution but rigorous selection and tuning to δ18O records from other speleothems has generated a robust age model. Growth rate was initially very slow but a rapid increase at ~129 ka was accompanied by strong negative trends in δ18O and δ13C, a combination implying the onset of much wetter conditions. Isotopic values at ~129 ka suggest that groundwater recharge rates and biogenic activity in the soil zone exceeded those of the early Holocene. A significant isotopic enrichment event at ~128 ka, during which there was alternating aragonite and calcite deposition, documents a strong drying event with a duration of ~200 years. A concurrent decrease in 87Sr/86Sr ratios indicates increased groundwater residence times and the cumulative evidence suggests amounts of rainfall fell from well above to slightly below present-day levels. Similar δ18O enrichment events are present in coeval speleothem records from southwest France and the Northern Alps, and these, together with pollen evidence from Italy, Greece and the Iberian margin of drier conditions at this time, imply that a climate anomaly extended across the northern Mediterranean borderlands. The timing, duration and structure of this episode are consistent with marine evidence of strong North Atlantic cooling early in the last interglacial and there is a resemblance to the Holocene 8.2 ka event recorded globally in many proxy-climate archives. Image 1 • A speleothem from Turkey provides a climate record through Termination II. • Isotopic evidence shows rainfall increased at the start of the last interglacial. • A dry period lasting ~200 years occurred early in the last interglacial. • The isotopic structure of the dry event is similar to the Holocene 8.2 ka event. • A synchronous climate anomaly is identified in other European speleothems. [ABSTRACT FROM AUTHOR]