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Changes between two time slices (1961–1990 and 2071–2100) in hydroclimatological conditions for South America have been examined using an ensemble of regional climate models. Annual mean precipitation (P), evapotranspiration (E) and potential evapotranspiration (EP) are jointly considered through the balances of land water and energy. Drying or wetting conditions, associated with changes in land water availability and atmospheric demand, are analysed in the Budyko space. The water supply limit (E limited by P) is exceeded at about 2% of the grid points, while the energy limit to evapotranspiration (E = EP) is overall valid. Most of the continent, except for the southeast and some coastal areas, presents a shift toward drier conditions related to a decrease in water availability (the evaporation rate E/P increases) and, mostly over much of Brazil, to an increase in the aridity index (Ф = EP/P). These changes suggest less humid conditions with decreasing surface runoff over Amazonia and the Brazilian Highlands. In contrast, Argentina and the coasts of Ecuador and Peru are characterized by a tendency toward wetter conditions associated with an increase of water availability and a decrease of aridity index, primarily due to P increasing faster than both E and EP. This trend towards wetter soil conditions suggest that the chances of having larger periods of flooding and enhanced river discharges would increase over parts of southeastern South America. Interannual variability increases with Ф (for a given time slice) and with climate change (for a given aridity regimen). There are opposite interannual variability responses to the cliamte change in Argentina and Brazil by which the variability increases over the Brazilian Highlands and decreases in central-eastern Argentina.

To mitigate the climate change-induced water shortage and realize the sustainable development of agriculture, drip irrigation, a more efficient water-saving irrigation method, has been intensively implemented in most arid agricultural regions in the world. However, compared to traditional border irrigation, how drip irrigation affects the biophysical conditions in the cropland and how crops physiologically respond to changes in biophysical conditions in terms of water, heat and carbon exchange remain largely unknown. In view of the above situation, to reveal the mechanism of drip irrigation in improving spring wheat water productivity, paired field experiments based on drip irrigation and border irrigation were conducted to extensively monitor water and heat fluxes at a typical spring wheat field (Triticum aestivum L.) in Northwest China during 2017–2020. The results showed that drip irrigation improved yield by 10.3 % and crop water productivity (i.e., yield-to-evapotranspiration-ratio) by 15.6 %, but reduced LAI by 16.9 % in contrast with border irrigation. Under drip irrigation, the lateral development of spring wheat roots was promoted by higher soil temperature combined with frequent dry-wet alternation in the shallow soil layer (0–20 cm), which was the basis for efficient absorption of water and fertilizer, as well as efficient formation of photosynthate. Meanwhile, drip irrigation increased net radiation and decreased latent heat flux by inhibiting leaf growth, thereby increased sensible heat, causing a higher soil temperature (+1.10 ℃) and canopy temperature (+1.11 ℃). Further analysis proved that soil temperature was the key factor affecting yield formation. Based on the above conditions, the decrease in leaf distribution coefficient (−0.030) led to the decrease in evapotranspiration (−5.7 %) and the increase in ear distribution coefficient (+0.029). Therefore, drip irrigation emphasized the role of soil moisture in the soil-plant-atmosphere continuum, enhanced crop activity by increasing field temperature, especially soil temperature, and finally improved yield and water productivity via carbon reallocation. The study revealed the mechanism of drip irrigation for improving spring wheat yield, and would contribute to improving Earth system models in representing agricultural cropland ecosystems with drip irrigation and predicting the subsequent biophysical and biogeochemical feedbacks to climate change.

AbstractClimate change alters surface water availability (WA; precipitation minus evapotranspiration, P − ET) and consequently impacts agricultural production and societal water needs, leading to increasing concerns on the sustainability of water use. Although the direct effects of climate change on WA have long been recognized and assessed, indirect climate effects occurring through adjustments in terrestrial vegetation are more subtle and not yet fully quantified. To address this knowledge gap, here we investigate the interplay between climate‐induced changes in leaf area index (LAI) and ET and quantify its ultimate effect on WA during the period 1982–2016 at the global scale, using an ensemble of data‐driven products and land surface models. We show that ~44% of the global vegetated land has experienced a significant increase in growing season‐averaged LAI and climate change explains 33.5% of this greening signal. Such climate‐induced greening has enhanced ET of 0.051 ± 0.067 mm year−2 (mean ± SD), further amplifying the ongoing increase in ET directly driven by variations in climatic factors over 36.8% of the globe, and thus exacerbating the decline in WA prominently in drylands. These findings highlight the indirect impact of positive feedbacks in the land–climate system on the decline of WA, and call for an in‐depth evaluation of these phenomena in the design of local mitigation and adaptation plans.

In European documents, practice and policies of regional and spatial development, functional urban regions (FURs) are recognized as the regions with one or more urban settlements and their in (direct) impact zone(s). The historical connection of the city and its surroundings, as well as the contemporary trends in networking of cities and their hinterland, imply the issues of better modalities for the establishment of such FURs that would be economically more productive, socially inclusive and more environmentally sustainable. The concept of urban governance, along with supporting segments, is proposed as the model for future planning of resistant FURs. It was considered what cities and their functional areas should take in order to prospectively enable an establishing the sustainable spatial and regional development of the Republic of Serbia. The paper tries to answer how much are FURs adjustable, what is their “threshold” of vulnerability, to which they can face the side effects of climate change.

Abstract Coals and coaly mudstones are found in the late Paleozoic Paganzo Basin, forming a key stratigraphic level deposited during the Bashkirian – Moscovian interval of relative tectonic quiescence. Coal beds vary from bituminous high volatility type C to sub-bituminous type A and, the coaly mudstones are kaolinitic-rich and presently used in the ceramic industry. Taking in account the stratigraphic position, facies associations, and the characteristics of the organic-rich levels, three domains were recognized within the basin: 1) The western domain (Precordillera) where paralic coals formed in transitional (mainly estuarine) environments, 2) The central domain (western Sierras Pampeanas) with limnic coals formed in floodplain areas, and 3) The eastern domain (eastern Sierras Pampeanas and Nevados del Famatina), in which coals are almost absent and are replaced by kaolinitic-rich coaly mudstones. Sea-level changes and climatic conditions related to the end of the Gondwanan glaciation played critical roles in the formation of coals and coaly mudstones. Regarding sea-level changes, three main transgressive events were identified in the Paganzo Basin. The oldest one corresponds to the “Namurian” postglacial transgression that produced no coal beds. The second event is the Pennsylvanian transgression 1, which favored the formation of coals and coaly mudstones in both coastal (i.e estuarine) and inland (i.e fluvial) environments. The third transgression, Pennsylvanian transgression 2, produced only very thin and scarce coal seams. During the transition from glacial (late Serpukhovian) to early postglacial climates (early Bashkirian), the vegetation was scarce and not suitable for the development of extensive mires. The post-glacial (late Bashkirian-early Moscovian) climatic amelioration, characterized by humid and temperate conditions, facilitated the proliferation of the NBG flora composed of hygrophilous elements as equisetalean, arborescent to sub-arborescent lycophytes and pteridosperms fronds, together with some gymnosperm that produced large amounts of organic detritus. On the contrary, the transition from subhumid to semiarid climate (late Moscovian-Kasimovian) led to the declination of the arborescent floras and the disappearance of coal beds. Although climate can be assumed to have simultaneously affected the whole basin, fluvial systems needed time to adjust to the sea-level changes and, therefore, at least two possibilities should be considered regarding the chronostratigraphic significance of the coal horizon. Firstly, that sea-level rise effectively controlled the equilibrium profile of channels well inland and coals and coaly mudstones across the Paganzo Basin form a time-transgressive horizon with a lag time not yet quantified based on the available paleontological and radiometric data. Secondly, that the growing of the riparian vegetation led by the ameliorating climatic conditions resulted in the almost synchronic formation of coals in the three domains.

Abstract Cutting costs in farms is the main concern for several stakeholders, specifically for farmers. Reducing energy costs allows for, at the very least, two relevant outcomes, one concerning increases in the net farm income and the other relating to the environment and the promotion of more sustainable farming and rural development. In turn, the agricultural sector may itself be a relevant source of renewable and clean energies. Considering these motivations, this research/study has intended to explore the concept of agricultural energy, highlighting the main insights from literature, and to stress the relationships between this concept and relevant farming indicators. The findings obtained may provide interesting support for the several related stakeholders, namely, policymakers, farmers and researchers. To achieve these objectives, literature available on scientific platforms was explored and statistical relationships were established, through econometric approaches (allowing for spatial effects), between structural characteristics from farms in the European Union. The findings reveal that the several instruments within the Common Agricultural Policy (CAP) should further address the relationships between financial support and sustainability. For example, it could be interesting to index the direct payments from the 1st CAP Pillar with farm indicators that consider dimensions related with the efficiency and savings in costs. In the current context, it is possible to increase the output and area with energy cost growths of 0.423 and 0.375% points, respectively, and increase the total crops output/ha growth and the utilised agricultural area with energy costs/ha growth of 0.243 and −0.225% points, respectively.

AbstractExtreme weather events can have strong negative impacts on species survival and community structure when surpassing lethal thresholds. Extreme, short‐lived, winter warming events in the Arctic rapidly melt snow and expose ecosystems to unseasonably warm air (for instance, 2–10 °C for 2–14 days) but upon return to normal winter climate exposes the ecosystem to much colder temperatures due to the loss of insulating snow. Single events have been shown to reduce plant reproduction and increase shoot mortality, but impacts of multiple events are little understood as are the broader impacts on community structure, growth, carbon balance, and nutrient cycling. To address these issues, we simulated week‐long extreme winter warming events – using infrared heating lamps and soil warming cables – for 3 consecutive years in a sub‐Arctic heathland dominated by the dwarf shrubsEmpetrum hermaphroditum, Vaccinium vitis‐idaea(both evergreen) andVaccinium myrtillus(deciduous). During the growing seasons after the second and third winter event, spring bud burst was delayed by up to a week forE. hermaphroditumandV. myrtillus, and berry production reduced by 11–75% and 52–95% forE. hermaphroditumandV. myrtillus, respectively. Greater shoot mortality occurred inE. hermaphroditum(up to 52%),V. vitis‐idaea(51%), andV. myrtillus(80%). Root growth was reduced by more than 25% but soil nutrient availability remained unaffected. Gross primary productivity was reduced by more than 50% in the summer following the third simulation. Overall, the extent of damage was considerable, and critically plant responses were opposite in direction to the increased growth seen in long‐term summer warming simulations and the ‘greening’ seen for some arctic regions. Given the Arctic is warming more in winter than summer, and extreme events are predicted to become more frequent, this generates large uncertainty in our current understanding of arctic ecosystem responses to climate change.

Antarctic biota evolved under the influence of a suite of geological and climatic factors, including geographic isolation of the landmass and continental shelves, extremely low temperatures and seasonality. Current warming trends in the continent and surrounding oceans may trigger substantial shifts in community composition and biodiversity, impacting the dominance of cold-adapted over more generalist species. Until recently, the diversity of microorganisms in cold environments was investigated only in terms of distribution, with little attention to their functional roles in important environmental processes. The 'omic' methodologies now offer effective tools to investigate the relationships between biodiversity and ecosystem functioning and to understand the evolutionary principles of adaptation and tolerance/resistance to extreme conditions. In this review we summarise how cold temperatures affect the physiology of microorganisms and focus on the molecular mechanisms of cold adaptation revealed by recent biochemical and genetic studies.