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Understanding deep-time marine biodiversity change under the combined effects of climate and connectivity changes is fundamental for predicting the impacts of modern climate change in semi-enclosed seas. We quantify the Late Miocene-Early Pliocene [11.63 to 3.6 million years (Ma)] taxonomic diversity of the Mediterranean Sea for calcareous nannoplankton, dinocysts, foraminifera, ostracods, corals, molluscs, bryozoans, echinoids, fishes, and marine mammals. During this time, marine biota was affected by global climate cooling and the restriction of the Mediterranean's connection to the Atlantic Ocean that peaked with the Messinian salinity crisis. Although the net change in species richness from the Tortonian to the Zanclean varies by group, species turnover is greater than 30% in all cases, reflecting a high degree of reorganization of the marine ecosystem after the crisis. The results show a clear perturbation already in the pre-evaporitic Messinian (7.25 to 5.97 Ma), with patterns differing among groups and subbasins. [ABSTRACT FROM AUTHOR]

Seasonal hindcasts have previously been demonstrated to show multi‐decadal variability in skill across the twentieth century in indices describing El‐Niño Southern Oscillation (ENSO), which drives global seasonal predictability. Here, we analyze the skill of predicting ENSO events' magnitude and spatial pattern, in the CSF‐20C coupled seasonal hindcasts in 1901–2010. We find minima in the skill of predicting the first (in 1930–1950) and second (in 1940–1960) principal components of sea‐surface temperature (SST) in the tropical Pacific. This minimum is also present in the spatial correlation of SSTs, in 1930–1960. The skill reduction is explained by lower ENSO magnitude and variance in 1930–1960, as well as decreased SST persistence. The SST skill minima project onto surface winds, leading to worse predictions in coupled hindcasts compared to hindcasts using prescribed SSTs. Questions remain about the offset between the first and second principal components' skill minima, and how the skill minima impact the extra‐tropics. Plain Language Summary: Seasonal forecasts use slowly changing elements of the climate system to predict average weather and climate several months ahead, and have applications across the energy, agriculture, and insurance industries. The most important signal is El‐Niño Southern Oscillation (ENSO), an ocean temperature pattern in the tropical Pacific which varies between warm and cold phases every 2–7 years. ENSO's specific pattern, including how warm/cold it is compared to normal, and where heating/cooling is concentrated, influences global weather. Seasonal forecasting models are tested by running 'reforecasts': comparing a 'forecast' of the past with observations. In this study, we investigate how skilfully reforecasts from a state‐of‐the‐art seasonal forecasting model reproduce observations, for sea‐surface temperatures in the tropical Pacific (where ENSO occurs). We analyze reforecast skill in every Northern Hemisphere winter from 1901 to 2010 and find periods of high skill at the start and end of the century, with reduced skill in 1930–1960. This was likely caused by a reduction in the size of ENSO events, and decreased sea‐surface temperature memory. This reduction in ocean skill leads to lower skill for surface‐level winds. These results are important for understanding whether season‐ahead predictability changes over decades/centuries, and how climate change might impact this predictability. Key Points: The skill of predicting the spatial pattern of ENSO events in coupled seasonal hindcasts is low in 1930–1960, compared to before and afterThe skill minimum is attributable to lower ENSO variability and decreased SST persistence in the mid‐century periodDecreased skill in the SST spatial pattern is linked to decreased surface wind skill in coupled hindcasts (vs. atmosphere‐only hindcasts) [ABSTRACT FROM AUTHOR]

There are many uncertainties in future climate, including how the Earth may react to different types of radiative forcing, such as CO2, aerosols, and even geoengineered changes in the amount of sunlight absorbed by Earth's surface. Here, we analyze model simulations where the climate system is subjected to an abrupt change of the solar constant by ±4%, and where the atmospheric CO2 concentration is abruptly changed to quadruple and half its preindustrial value. Using these experiments, we examine how clouds respond to changes in solar forcing, compared to CO2, and feedback on global surface temperature. The total cloud response can be decomposed into those responses driven by changes in global surface temperature, called the temperature mediated cloud feedbacks, and responses driven directly by the forcing that are independent of the global surface temperature. In this paper, we study the temperature mediated cloud changes to answer two primary questions: (a) How do temperature mediated cloud feedbacks differ in response to abrupt changes in CO2 and solar forcing? And (b) Are there symmetrical (equal and opposite) temperature mediated cloud feedbacks during global warming and global cooling? We find that temperature mediated cloud feedbacks are similar in response to increasing solar and increasing CO2 forcing, and we provide a short review of recent literature regarding the physical mechanisms responsible for these feedbacks. We also find that cloud responses to warming and cooling are not symmetric, due largely to non‐linearity introduced by phase changes in mid‐to‐high latitude low clouds and sea ice loss/formation. Plain Language Summary: As the global mean temperature changes, there are changes in cloud amount, location, and thickness, which can all impact the radiative balance of the Earth. Cloud changes driven directly by global temperature change are called temperature mediated cloud feedbacks. In this paper, we study the temperature mediated cloud feedbacks that occur in model simulations where the amount of sunlight incident upon the Earth is increased or decreased abruptly, and then held constant for 150 years. We compare the cloud changes in these experiments with experiments where the CO2 concentration is similarly increased or decreased abruptly and held constant for 150 years. In doing so we find that the temperature mediated cloud feedbacks following abrupt changes in solar radiation are characteristically similar to those occurring following CO2 increase. There are however substantial differences in the temperature mediated cloud feedbacks that occur while the climate is warming versus cooling. Key Points: The temperature mediated cloud changes and feedbacks incurred by changes in solar and CO2 forcing are similarOptical depth changes at high latitudes produce substantial differences in cloud feedbacks in cooling and warming experimentsLikewise, tropical circulations respond differently in models to cooling and warming, with a stronger change in the Walker circulation in warming experiments [ABSTRACT FROM AUTHOR]

Reflectance spectroscopy is rapid, inexpensive, and non-destructive and can provide important information about the mineralogy of rocks and sediments. We measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau, with the aim of developing a rapid methodology for detecting paleoclimatic changes. We obtained visible/near-infrared (VNIR) and short-wave infrared (SWIR) spectroscopy data from the red clay in the Jianzha Basin, and analyzed their relationship with independent paleoclimatic records, including mineral contents and environmental magnetic parameters. The results show that the VNIR parameters, including D500, D900, R500, and R900 (where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm, respectively) are temperature-sensitive and correlated with the magnetic susceptibility, frequency-dependent magnetic susceptibility, and the marine δ18O record. The results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital timescales. SWIR parameters, such as AS1400, D1400/D1900 and D1900 (where AS represents the asymmetry of the absorption peaks around 1400 nm), are correlated with the illite and montmorillonite content, and they are sensitive to the weathering intensity. The spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at ∼8.5 Ma and global climatic cooling at ∼7.2 Ma, and thus they are applicable as both regional and global paleoenvironmental indicators. [ABSTRACT FROM AUTHOR]

This study investigates the mechanisms underlying the varied climate changes witnessed during mass extinctions in the Phanerozoic Eon. Climate shifts during mass extinctions have manifested as either predominant global cooling or predominant warming, yet the causes behind these occurrences remain unclear. We emphasize the significance of sedimentary rock temperature in comprehending these climate shifts. Our research reveals that low-temperature heating of sulfide leads to global cooling through the release of sulfur dioxide (SO2), while intermediate-temperature heating of hydrocarbons and carbonates releases substantial carbon dioxide (CO2), contributing to global warming. High-temperature heating additionally generates SO2 from sulfate, further contributing to global cooling. Different degrees of contact heating of the host rock can lead to different dominant volatile gas emissions, crucially driving either warming or cooling. Moreover, medium to high-temperature shock-heating resulting from asteroid impacts produces soot from hydrocarbons, also contributing to global cooling. Large-scale volcanic activity and asteroid impacts are both events that heat rocks, emitting the same gases and particles, causing climate changes. The findings elucidate the critical role of heating temperature and heating time in understanding major climate changes during mass extinctions. [ABSTRACT FROM AUTHOR]

The Earth's radiative cooling is a key driver of climate. Determining how it is affected by greenhouse gas concentration is a core question in climate-change sciences. Due to the complexity of radiative transfer processes, current practices to estimate this cooling require the development and use of a suite of radiative transfer models whose accuracy diminishes as we move from local, instantaneous estimates to global estimates over the whole globe and over long periods of time (decades). Here, we show that recent advances in nonlinear Monte Carlo methods allow a paradigm shift: a completely unbiased estimate of the Earth's infrared cooling to space can be produced using a single model, integrating the most refined spectroscopic models of molecular gas energy transitions over a global scale and over years, all at a very low computational cost (a few seconds). [ABSTRACT FROM AUTHOR]

Cherries (Prunus Subgenus Cerasus) have economic value and ecological significance, yet their phylogeny, geographic origin, timing, and dispersal patterns remain challenging to understand. To fill this gap, we conducted a comprehensive analysis of the complete chloroplast genomes of 54 subg. Cerasus individuals, along with 36 additional genomes from the NCBI database, resulting in a total of 90 genomes for comparative analysis. The chloroplast genomes of subg. Cerasus exhibited varying sizes and consisted of 129 genes, including protein-coding, transfer RNA, and ribosomIal RNA genes. Genomic variation was investigated through InDels and SNPs, showcasing distribution patterns and impact levels. A comparative analysis of chloroplast genome boundaries highlighted variations in inverted repeat (IR) regions among Cerasus and other Prunus species. Phylogeny based on whole-chloroplast genome sequences supported the division of Prunus into three subgenera, I subg. Padus, II subg. Prunus and III subg. Cerasus. The subg. Cerasus was subdivided into seven lineages (IIIa to IIIg), which matched roughly to taxonomic sections. The subg. Padus first diverged 51.42 Mya, followed by the separation of subg. Cerasus from subg. Prunus 39.27 Mya. The subg. Cerasus started diversification at 15.01 Mya, coinciding with geological and climatic changes, including the uplift of the Qinghai–Tibet Plateau and global cooling. The Himalayans were the refuge of cherries, from which a few species reached Europe through westward migration and another species reached North America through northeastward migration. The mainstage of cherry evolution was on the Qing–Tibet Plateau and later East China and Japan as well. These findings strengthen our understanding of the evolution of cherry and provide valuable insights into the conservation and sustainable utilization of cherry's genetic resources. [ABSTRACT FROM AUTHOR]

Energy is the need for the future, and to fulfill this need, the use of renewable energy is a must. Furthermore, to counter the problem of global warming and climate change, the transition toward unconventional sources of energy is a requirement. Total global energy is majorly used in three sectors, namely, heating and cooling, transport, and electricity; however, the use and growth of renewable energy among these sectors are different. In this article, we discuss the potential of renewable energy in these sectors, the challenges associated with their large-scale deployment, and the possible solutions. [ABSTRACT FROM AUTHOR]

Summary: Many tree genera in the Malesian uplands have Southern Hemisphere origins, often supported by austral fossil records. Weathering the vast bedrock exposures in the everwet Malesian tropics may have consumed sufficient atmospheric CO2 to contribute significantly to global cooling over the past 15 Myr. However, there has been no discussion of how the distinctive regional tree assemblages may have enhanced weathering and contributed to this process. We postulate that Gondwanan‐sourced tree lineages that can dominate higher‐elevation forests played an overlooked role in the Neogene CO2 drawdown that led to the Ice Ages and the current, now‐precarious climate state. Moreover, several historically abundant conifers in Araucariaceae and Podocarpaceae are likely to have made an outsized contribution through soil acidification that increases weathering. If the widespread destruction of Malesian lowland forests continues to spread into the uplands, the losses will threaten unique austral plant assemblages and, if our hypothesis is correct, a carbon sequestration engine that could contribute to cooler planetary conditions far into the future. Immediate effects include the spread of heat islands, significant losses of biomass carbon and forest‐dependent biodiversity, erosion of watershed values, and the destruction of tens of millions of years of evolutionary history. [ABSTRACT FROM AUTHOR]

Ongoing rapid climate change has a major effect on marine fauna, and understanding these faunal changes analogous to future climatic periods is crucial. The Oligocene is commonly considered a critical transition period, linking the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Here, we show the response of marine benthic foraminifera to the early Oligocene climatic changes at Ocean Drilling Program (ODP) Hole 1138A of the Southern Ocean (Indian Sector). We made use of the diversity parameters, the relative abundance of dominant benthic foraminifera, and isotopic data to understand past oceanographic changes. Our results suggest that the early Oligocene was an interval of unstable conditions dominated by the species of high oxygen, intermediate food supply, and well-ventilated, cold, corrosive bottom water conditions. The species richness abruptly decreases at the end of the studied interval, which shows the major Southern Hemisphere glaciation. During this time, species were characterized by relatively cold and carbonate-corrosive bottom water. Additionally, the present study of the benthic foraminiferal abundance and diversity indices reveals the cooling of the Southern Ocean at the early and late stages of the studied interval interrupted by a short-lived warming event. The study further enhances the understanding of paleo-marine ecology by evaluating the response of deep-sea benthic foraminifera to global climate change. [ABSTRACT FROM AUTHOR]

In the recent years, radiative cooling has emerged as a promising technology for space cooling applications. Nevertheless, radiative cooling phenomenon is dependent on weather conditions and it presents some performance limitations, meaning that the cooling capacity is limited in some climates. The radiative cooling potential is the maximum theoretical limit that can be achieved. In this study we analyse the evolution of the radiative cooling potential in Europe under the context of climate change. Radiative cooling potential maps for the period 2020–2050 are provided. The results reveal that radiative cooling potential remains constant for this period, evidencing a resilience of this technology during the following decades. We also provide a seasonal study of the potential by regions. Summer, when cooling needs are higher, is the season with the least nocturnal energy potential and the second with the highest nocturnal power potential. Shifting to all-day radiative cooling, the energy potential increases by 1.64 in winter; 2.97 in spring; 4.03 in summer and 2.2 in autumn. [ABSTRACT FROM AUTHOR]

This review identifies a critical problem in the fundamental physics of current climate models. The large greenhouse effect of rising CO2 assumed in climate models is assessed by six key observations from ground- and satellite-based measurements. This assessment is enhanced by statistical analyses and model calculations of global or regional mean surface temperature changes by conventional climate models and by a conceptual quantum physical model of global warming due to halogen-containing greenhouse gases (halo-GHGs). The postulated large radiative forcing of CO2 in conventional climate models does not agree with satellite observations. Satellite-observed warming pattern resembles closely the atmospheric distribution of chlorofluorocarbons (CFCs). This review helps understand recent remarkable observations of reversals from cooling to warming in the lower stratosphere over most continents and in the upper stratosphere at high latitudes, surface warming cessations in the Antarctic, North America, UK, and Northern-Hemisphere (NH) extratropics, and the stabilization in NH or North America snow cover, since the turn of the century. The complementary observation of surface temperature changes in 3 representative regions (Central England, the Antarctic, and the Arctic) sheds new light on the primary mechanism of global warming. These observations agree well with not CO2-based climate models but the CFC-warming quantum physical model. The latter offers parameter-free analytical calculations of surface temperature changes, exhibiting remarkable agreement with observations. These observations overwhelmingly support an emerging picture that halo-GHGs made the dominant contribution to global warming in the late 20th century and that a gradual reversal in warming has occurred since ~2005 due to the phasing out of halo-GHGs. Advances and insights from this review may help humans make rational policies to reverse the past warming and maintain a healthy economy and ecosystem. [ABSTRACT FROM AUTHOR]

Although climate change has been implicated as a major catalyst of diversification, its effects are thought to be inconsistent and much less pervasive than localized climate or the accumulation of species with time. Focused analyses of highly speciose clades are needed in order to disentangle the consequences of climate change, geography, and time. Here, we show that global cooling shapes the biodiversity of terrestrial orchids. Using a phylogeny of 1,475 species of Orchidoideae, the largest terrestrial orchid subfamily, we find that speciation rate is dependent on historic global cooling, not time, tropical distributions, elevation, variation in chromosome number, or other types of historic climate change. Relative to the gradual accumulation of species with time, models specifying speciation driven by historic global cooling are over 700 times more likely. Evidence ratios estimated for 212 other plant and animal groups reveal that terrestrial orchids represent one of the best-supported cases of temperature-spurred speciation yet reported. Employing >2.5 million georeferenced records, we find that global cooling drove contemporaneous diversification in each of the seven major orchid bioregions of the Earth. With current emphasis on understanding and predicting the immediate impacts of global warming, our study provides a clear case study of the long-term impacts of global climate change on biodiversity. [ABSTRACT FROM AUTHOR]

The existence of global warming is common knowledge. However, it can be predicted that there may be cooling zones worldwide based on the mechanism of terrestrial biophysical processes. Here, the Theil–Sen median trend, the Mann–Kendall trend test method, continuous wavelet transformation, and the Hurst exponent were used to study the cooling trends, abrupt change times, periodicity, and future sustainability of temperature changes in different cooling zones since the 1900s based on the CRU dataset. We found an amazing result; 8,305,500 km2 of land surface had been cooling since the 1900s, covering five continents and 32 countries, accounting for 86% of land area in China, and distributed over 16 zones. The average cooling rate of the cooling zones was −0.24 °C/century. The maximum cooling rate was −1.40 °C/century, and it was 1.43 times the average rate of global land warming (0.98 °C/century). The cooling zones near the sea were greatly influenced by ocean currents and were mainly affected by a small time scale periodicity of less than 30 years, whereas the cold zones located relatively far from the sea and less affected by ocean currents were mainly affected by medium time scales of more than 30 years. Moreover, 32.33% of the cooling zones, involving 2,684,900 km2, will be continuously cooling in the future, and the rest will probably warm up in 2114, 2041, 2096, 2099, 2119, 2073, 2048, and 2101, respectively. The study will help us to further understand the essential characteristics of global climate change, and to find more theoretical bases for mitigating global warming and exploring surface cooling mechanisms. [ABSTRACT FROM AUTHOR]

As the second largest dust source on the globe, the tectonic and climatic evolution of continental Asia has an important impact on regional and global climate change. The West Pacific is the main sediment sink for eolian dust transported eastward from the Asian interior. Clay minerals, as the major fine-grained weathering products of continental rocks, can be readily transported by wind or currents over long distances and thus have been widely used in the reconstruction of paleoclimate and weathering history. However, the overall evolutionary tendency and response mechanism of clay mineral records over large spatial and long timescales across Asia remain unclear. Here, two continuous and high-resolution clay mineral records since 30 Ma were reconstructed from sediments at Deep Sea Drilling Program (DSDP) Sites 292 and 296 in the Philippine Sea. Clay minerals and Sr-Nd isotope compositions were used to constrain provenance and reconstruct the drying history of the dust source region since the Oligocene. The results show that the clay-sized detrital sediments in the Philippine Sea are a mixture of Asian eolian dust and volcanic materials from the West Pacific arcs. Based on the clay mineral compositions and eolian flux, we reveal that the Asian interior has been continuously drying since the late Oligocene and that stepwise enhanced aridification occurred at approximately 20, 14, 7, and 3 Ma. Compared with other regions of the world, the relative contents of illite and chlorite increased more dramatically in Asia during the late Cenozoic, and the inconsistency became more obvious at approximately 20 Ma. Since 3 Ma, illite and chlorite have increased consistently across the globe. Combined with the Asian tectonic and climatic history, we suggest that the increase in illite and chlorite from Asia between 20 and 3 Ma was mainly in response to the uplift of the Himalayan-Tibetan Plateau, whereas after 3 Ma, it was primarily controlled by global cooling driven by the expansion of the Arctic ice sheet. [ABSTRACT FROM AUTHOR]

The Eocene-Oligocene Transition (EOT) was one of the most profound climate changes in the Cenozoic era, characterized by global cooling around 34 million years ago. This time period also witnessed major faunal turnovers, such as the "Mongolian Remodeling" of Asia, characterized by the dominance of rodents and lagomorphs after the EOT. Previous studies have primarily focused on overall faunal change across the EOT. Here, we examined one genus, the earliest ctenodactylid Karakoromys, based on rich fossils from continuous sections at Ulantatal, Nei Mongol, magnetostragraphically dated to latest Eocene-Early Oligocene. Based on a systematic paleontological study of these fossils, we recognized four species of Karakoromys (Karakoromys decussus, K. arcanus, K. chelkaris, and K. conjunctus sp. nov.), indicating a relatively high diversity of the most primitive ctenodactylids during the latest Eocene-Early Oligocene (~34.9–30.8 Ma). The turnover of ctenodactylids primarily occurred during a regional aridification event around 31 Ma rather than during the EOT cooling event, suggesting that regional precipitation variation in the semi-arid area may have played a more important role than global temperature change in the evolution of early ctenodactylids. [ABSTRACT FROM AUTHOR]

The climate system responds to changes in the amount of atmospheric greenhouse gases or aerosols through rapid processes, triggered within hours and days, and through slower processes, where the full response may only be seen after centuries. In this paper, we aim to elucidate the mechanisms operating on time scales of hours to years to better understand the response of key climate quantities such as energy fluxes, temperature, and precipitation after a sudden increase in either carbon dioxide (CO2), black carbon (BC), or sulfate (SO4) aerosols. The results are based on idealized simulations from six global climate models. We find that the effect of changing ocean temperatures kicks in after a couple of months. Rapid precipitation reductions start occurring instantly and are established after just a few days. For BC, they constitute most of the equilibrium response. For CO2 and SO4, the magnitude of the precipitation response gradually increases as surface warming/cooling evolves, and for CO2, the sign of the response changes from negative to positive after 2 years. Rapid cloud adjustments are typically established within the first 24 h, and while the magnitude of cloud feedbacks for CO2 and SO4 increases over time, the geographical pattern of the equilibrium cloud change is present already after the first year. While there are model differences, our work underscores the overall similarity of the major time-varying processes and responses simulated by current global models and hence the robustness of key features of simulated responses to historical and future anthropogenic forcing. Significance Statement: How does the climate system respond to a change in the amount of atmospheric greenhouse gases or aerosols? Some processes are rapid, responding within hours and days. Others are slow, and the full response to a forcing of the climate may only be seen after centuries. In this paper, we use six global climate models to investigate the time scales of climate responses to carbon dioxide, black carbon, and sulfate, focusing on key climate quantities, such as temperature, precipitation, and clouds. While there are ample model differences, our work underscores the overall similarity of the major time-varying processes and responses simulated by current global models and hence the robustness of key features of simulated responses to historical and future anthropogenic forcing. [ABSTRACT FROM AUTHOR]

The north temperate region was characterized by a warm climate and a rich thermophilic flora before the Eocene, but early diversifications of the temperate biome under global climate change and biome shift remain uncertain. Moreover, it is becoming clear that hybridization/introgression is an important driving force of speciation in plant diversity. Here, we applied analyses from biogeography and phylogenetic networks to account for both introgression and incomplete lineage sorting based on genomic data from the New World Vitis, a charismatic component of the temperate North American flora with known and suspected gene flow among species. Biogeographic inference and fossil evidence suggest that the grapes were widely distributed from North America to Europe during the Paleocene to the Eocene, followed by widespread extinction and survival of relicts in the tropical New World. During the climate warming in the early Miocene, a Vitis ancestor migrated northward from the refugia with subsequent diversification in the North American region. We found strong evidence for widespread incongruence and reticulate evolution among nuclear genes within both recent and ancient lineages of the New World Vitis. Furthermore, the organellar genomes showed strong conflicts with the inferred species tree from the nuclear genomes. Our phylogenomic analyses provided an important assessment of the wide occurrence of reticulate introgression in the New World Vitis, which potentially represents one of the most important mechanisms for the diversification of Vitis species in temperate North America and even the entire temperate Northern Hemisphere. The scenario we report here may be a common model of temperate diversification of flowering plants adapted to the global climate cooling and fluctuation in the Neogene. [ABSTRACT FROM AUTHOR]

It has been proposed that the northeastern Tibetan Plateau (NETP) was the most recent plateau sub-region to gain elevation, leading to profound environmental changes in northern East Asia around the mid-Pliocene (ca. 3.6 Ma). Alternatively, environmental changes in the region have been linked to ongoing global cooling and glacial intensification after 3.3 Ma. Here, we test these hypotheses using Plio-Pleistocene estimates of paleotemperatures and paleoelevations in the NETP derived from oxygen and carbon stable isotopic composition (n = 792) and clumped isotope measurements (n = 32) of carbonates from a Lake Qinghai Basin sediment core, eastern NETP. From 5 to 2 Ma, basinal mean annual air temperatures (MAATs) decreased by 4.9 ± 2.8 °C at rates of 1.6 °C ± 0.5 °C/myr, concurrently with regional and global cooling. However, the largest MAAT decline occurs between ca. 4.8-3.7 Ma (4.1 ± 3.2 °C) and ca. 3.4-2.0 Ma (-0.3 ± 2.8 °C) and may correspond with an elevation change of 1.0 ± 1.0 km at 3.6 Ma, coincident with tectonic activity in the Lake Qinghai Basin and several other basins in the NETP and its foreland. Taken together, these results suggest a combination of global cooling and a small magnitude of surface uplift (<1 km) at ca. 3.6 Ma may have contributed to the regional evolution of climate in the Lake Qinghai Basin. [ABSTRACT FROM AUTHOR]

The global temperature gradually decreased from the Cretaceous Santonian to Campanian, while angiosperms evolved rapidly and gradually became dominant. The Songliao Basin, NE China, contains abundant fossil palynomorphs from the Santonian to Campanian age. A thorough investigation of fossil palynomorphs in borehole ZKY2-1 of the SW Songliao Basin was performed, reconstructing the vegetation and paleoclimate transition from the Santonian–earliest Campanian (lower Nenjiang Formation) to the late Campanian (Sifangtai Formation). Eighty form-genera from borehole ZKY2-1 have been identified. Three palynomorph assemblages were identified: the Schizaeoisporites–Cyathidites–Inaperturopollenites assemblage, Schizaeoisporites–Classopollis–Retitricolporites assemblage, and Schizaeoisporites–Aquilapollenites–Tricolporopollenits assemblage, from bottom to top. Based on palynological analysis from ZKY2-1 and other boreholes in the Songliao Basin, angiosperm pollen proportion in the Sifangtai Formation is significantly higher than in the lower Nenjiang Formation, indicating rapid angiosperm spread from late Santonian to Campanian. Palynological records indicate relatively humid climate during this period; the content of cool palynological types increased from the lower Nenjiang Formation to the Sifangtai Formation, suggesting a transition from warm to cool climate during the late Santonian–earliest Campanian to the late Campanian. The new palynological evidence from the Songliao Basin reveals a global cooling on land and sea during the late Santonian–Campanian period. This climate change may further promote angiosperm spread during the Late Cretaceous period. [ABSTRACT FROM AUTHOR]

Large volcanic eruptions drive significant climate perturbations through major anomalies in radiative fluxes and the resulting widespread cooling of the surface and upper ocean. Recent studies suggest that these eruptions also drive important variability in air‐sea carbon and oxygen fluxes. By simulating the Earth system using two initial‐condition large ensembles, with and without the aerosol forcing associated with the Mt. Pinatubo eruption in June 1991, we isolate the impact of this volcanic event on physical and biogeochemical properties of the ocean. The Mt. Pinatubo eruption forced significant anomalies in surface fluxes and the ocean interior inventories of heat, oxygen, and carbon. Pinatubo‐driven changes persist for multiple years in the upper ocean and permanently modify the ocean's heat, oxygen, and carbon inventories. Positive anomalies in oxygen concentrations emerge immediately post‐eruption and penetrate into the deep ocean. In contrast, carbon anomalies intensify in the upper ocean over several years post‐eruption, and are largely confined to the upper 150 m. In the tropics and northern high latitudes, the change in oxygen is dominated by surface cooling and subsequent ventilation to mid‐depths, while the carbon anomaly is associated with solubility changes and eruption‐generated El Niño—Southern Oscillation variability. We do not find significant impact of Pinatubo on oxygen or carbon fluxes in the Southern Ocean; but this may be due to Southern Hemisphere aerosol forcing being underestimated in Community Earth System Model 1 simulations. Plain Language Summary: The eruption of Pinatubo in June of 1991 produced sunlight‐reflecting aerosols in the upper atmosphere and led to a cooling of the planet for several years. While the global cooling following the eruption is well documented, the impact of the eruption on the ocean oxygen and carbon budgets has received comparably little attention. As the global ocean oxygen concentration is declining in response to climate change, and as the ocean's continued storage of anthropogenic carbon is critical for the climate system, it is of interest to quantify the effect of the eruption on both oxygen and carbon in the global ocean. Here, we use an Earth system model to simulate the historical evolution of the climate system both with and without the Mt. Pinatubo eruption. By comparing the simulations, we are able to quantify the effect of the eruption on ocean properties. We find that the eruption led to cooler surface ocean temperatures, and increases in the ocean oxygen and carbon concentrations that persisted for many years. Our simulations can also be used to study other Earth system changes caused by the eruption. Key Points: Two initial‐condition large ensembles are used to quantify the ocean physical and biogeochemical response to the eruption of Mt. PinatuboOxygen is immediately absorbed into the upper ocean and transits to depth where it permanently increases the interior inventory by 60 TmolMt Pinatubo forced an increase in the ocean carbon sink of −0.29 ± 0.14 Pg C yr−1 in 1992 [ABSTRACT FROM AUTHOR]

Global climate change has led to more extreme thermal events. Plants and animals harbour diverse microbial communities, which may be vital for their physiological performance and help them survive stressful climatic conditions. The extent to which microbiome communities change in response to warming or cooling may be important for predicting host performance under global change. Using a meta‐analysis of 1377 microbiomes from 43 terrestrial and aquatic species, we found a decrease in the amplicon sequence variant‐level microbiome phylogenetic diversity and alteration of microbiome composition under both experimental warming and cooling. Microbiome beta dispersion was not affected by temperature changes. We showed that the host habitat and experimental factors affected microbiome diversity and composition more than host biological traits. In particular, aquatic organisms—especially in marine habitats—experienced a greater depletion in microbiome diversity under cold conditions, compared to terrestrial hosts. Exposure involving a sudden long and static temperature shift was associated with microbiome diversity loss, but this reduction was attenuated by prior‐experimental lab acclimation or when a ramped regime (i.e., warming) was used. Microbial differential abundance and co‐occurrence network analyses revealed several potential indicator bacterial classes for hosts in heated environments and on different biome levels. Overall, our findings improve our understanding on the impact of global temperature changes on animal and plant microbiome structures across a diverse range of habitats. The next step is to link these changes to measures of host fitness, as well as microbial community functions, to determine whether microbiomes can buffer some species against a more thermally variable and extreme world. [ABSTRACT FROM AUTHOR]

A large‐scale nuclear war could inject massive amounts of soot into the stratosphere, triggering rapid global climate change. In climate model simulations of nuclear war, global cooling contributes to an expansion of sea ice in the Northern Hemisphere. However, in the Southern Hemisphere (SH), an initial expansion of sea ice shifts suddenly to a 30% loss of sea ice volume over the course of a single melting season in the largest nuclear war simulation. In smaller nuclear war simulations an expansion in sea ice is instead observed which lasts for approximately 15 years. In contrast, in the largest nuclear war simulation, Antarctic sea ice remains below the long term control mean for 15 years, indicating a threshold that must be crossed to cause the response. Declining sea ice in the SH following a global cooling event has been previously attributed to shifts in the zonal winds around Antarctica, which can reduce the strength of the Weddell Gyre. In climate model simulations of nuclear war, the primary mechanisms responsible for Antarctic sea ice loss are: (a) enhanced atmospheric poleward heat transport through teleconnections with a strong nuclear war‐driven El Niño, (b) increased upwelling of warm subsurface waters in the Weddell Sea due to changes in wind stress curl, and (c) decreased equatorward Ekman transport due to weakened Southern Ocean westerlies. The prospect of sudden Antarctic sea ice loss after an episode of global cooling may have implications for solar geoengineering and further motivates this study of the underlying mechanisms of change. Plain Language Summary: Firestorms from a global nuclear war would generate large amounts of smoke that could enter the Earth's atmosphere and block sunlight. Climate model simulations that inject smoke into the upper atmosphere confirm that this smoke causes rapid global cooling leading to increased sea ice in the Northern Hemisphere. However, sea ice in the Southern Hemisphere actually shrinks in the 2–6 years after a very large nuclear war, mainly caused by a change in the winds around Antarctica. Smoke heats the upper atmosphere and the westerly winds around Antarctica shift closer to the coast. The wind shift causes Ekman transport of the top layer of the ocean away from the coast, which brings up relatively warm water from below, melting sea ice during summer and inhibiting sea ice growth during the winter. A similar response has been found in simulations of supervolcano eruptions. As greenhouse gasses continue to warm up the Earth's oceans, a global cooling event that triggers a similar wind shift may lead to greater reductions in Antarctic sea ice. Key Points: A sudden reduction in Antarctic sea ice occurs despite global cooling after nuclear war in climate model simulationsThe sea ice changes in response to dynamic changes in atmospheric and oceanic circulationEven in a nuclear winter, Antarctic sea ice is vulnerable to wind shifts that cause upwelling of water onto the continental shelf [ABSTRACT FROM AUTHOR]

The Indian Monsoon profoundly impacts the climate, agriculture, and economy of the Indian subcontinent and southwestern China. However, the long-term variability of the Indian summer monsoon (ISM) and its forcing mechanism in the context of the stepwise Pleistocene cooling trend are poorly understood, due to the lack of high-quality terrestrial paleoclimate records. Quaternary loess and paleosol deposits in SW China provide the opportunity to study the long-term evolution of the ISM. Based on analyses of magnetic properties and chemical weathering indices, we found that decreased chemical weathering and pedogenic intensity occurred in SW China since the Middle Pleistocene. Comparison of our results with published paleoclimate records from the Indian Ocean and SW China suggest that substantial ISM weakening occurred after ∼0.7–0.6 Ma, coincident with the Mid-Pleistocene climatic transition. We conclude that decreasing global surface temperatures associated with the major growth of Northern Hemisphere ice sheets caused the Middle Pleistocene weakening of the ISM, leading to changes in precipitation regimes in the southern Asian continent and SW China. Our results suggest that global cooling is strongly linked with the South Asian monsoon climate system, and they provide clues for predicting future climate changes in its area of influence. • Decreased chemical weathering and pedogenic intensity occurred in SW China since the Middle Pleistocene. • A weakened Indian summer monsoon led to the decreased chemical weathering and pedogenic intensity. • Intensified glacial conditions drove the Middle Pleistocene weakening of the Indian summer monsoon. [ABSTRACT FROM AUTHOR]

To produce food for a growing world population, irrigated areas have increased from approximately 0.63 million km2 of land in 1900 to 3.1 million km2 of land in 2005. Despite this massive expansion, irrigation is still overlooked in most state‐of‐the‐art Earth system models (ESMs) involved in the Coupled Model Intercomparison Project phase 6 (CMIP6). To our knowledge, only three CMIP6 models represent irrigation activities: CESM2, GISS‐E2‐1‐G, and NorESM2‐LM. Here, we investigate the role of irrigation on historical climate at global and regional scales by analyzing trends of key surface climate variables in CMIP6 simulations during 1900–2014. The three models including irrigation show distinct behavior from the 15 models without irrigation over intensively irrigated areas (i.e., >50% of grid cell area is equipped by irrigation): both annual (months that correspond to monthly air temperature higher than 274 K) mean latent heat flux (LHF) and soil moisture increase over time, in contrast to the models without irrigation that show no trend or even a negative trend. The positive LHF trend over intensively irrigated areas in the irrigation‐on models is consistent with three satellite‐based LHF products. While annual (considering the warmest month in a year) warming trends are found in these regions for most of the no‐irrigation models, the increase in LHF induces a cooling trend for the models with irrigation, which was not confirmed by observational air temperature data sets. These findings, supported by satellite data, indicate the importance of improved representation of land management in the next generation of ESM. Plain Language Summary: Expansion of irrigated areas influences long‐term terrestrial water and energy cycles, primarily via enhanced evapotranspiration from irrigated surfaces. Here, we analyze long‐term (1900–2014) trends of latent heat flux (LHF), soil moisture, precipitation, net radiation, and air temperature from the latest generation of Earth system models (ESMs) involved in the Coupled Model Intercomparison Project phase 6 (CMIP6). Only three CMIP6 models account for irrigation activities, while all others omit irrigation. Based on the trend results, a distinct behavior of the three models is observed, with the annual mean LHF and soil moisture generally increasing over heavily irrigated regions, with a corresponding cooling trend in the annual maximum of monthly air temperature. We find that neglecting irrigation reduces the accuracy of LHF trend estimates over heavily irrigated regions, as the performance of models without irrigation was poor when compared to observation‐based data sets. Our study overall highlights the importance of irrigation as a historical climate forcing and underlines the benefit of incorporating irrigation in the next generation of ESM to reduce uncertainties in historical climate simulations and enhance the reliability of future projections. Key Points: Trends of six essential climate variables were compared between Coupled Model Intercomparison Project phase 6 (CMIP6) simulations with (CMIP6.irr) and without (CMIP6.noirr) irrigationCMIP6.irr exhibits a distinct behavior in better capturing the upward trend of observed latent heat flux over heavily irrigated regionsOver the same regions, while CMIP6.irr exhibits a cooling trend, CMIP6.noirr exhibits a warming trend [ABSTRACT FROM AUTHOR]

This review explores the question: should the world rely wholly or partially on solar geoengineering (SG) to mitigate climate change (CC), or on renewable energy, together with deep energy reductions? Recent thinking is for SG to only supplement more conventional climate change mitigation methods. However, we first show that conventional mitigation methods are not working., given that global annual CO2 emissions are still rising, so it is far more likely that SG will be called upon to counter most anthropogenic CC, as early research proposed. The paper next examines the various SG proposals that have been considered and their objectives. Future choices could be between an increasingly unpredictable climate, and SG, with its own risks and unknowns, or deep energy reductions and RE. The claim is that SG has far lower costs for a given climate forcing reduction compared with more conventional methods, and equally important, could be quickly implemented, producing temperature reductions in a year or so, compared with decades needed for more conventional mitigation approaches. SG implementation would affect not only the technical potential for key RE sources but also the actual uptake of RE and energy reductions. However, a fair comparison of RE and SG must recognise that the SG option also requires a solution to rising ocean acidification (OA). Because the material quantities needed annually to counter OA are orders of magnitude larger than for SG, its costs and energetic requirements will also be far higher, as will the time for implementation. [ABSTRACT FROM AUTHOR]

Long transient simulations of the last deglaciation are increasingly being performed to identify the drivers of multiple rapid Earth system changes that occurred in this period. Such simulations frequently prescribe temporal variations in ice sheet properties, which can play an important role in controlling atmospheric and surface climate. To preserve a model's standard performance in simulating climate, it is common to apply time dependent orographic variations, including parameterised sub-grid scale orographic variances, as anomalies from the pre-industrial state. This study investigates the causes of two abrupt climate change events in the Northern Hemisphere extratropics occurring between 16 and 14 thousand years ago in transient simulations of the last deglaciation from the Hadley Centre coupled general circulation model (HadCM3). One event is characterized by regional Northern Hemisphere changes comprising a centennial scale cooling of ~ 10 °C across Fennoscandia followed by rapid warming in less than 50 years as well as synchronous shifts in the Northern Annular Mode. The second event has comparable but temporally reversed characteristics. Sensitivity experiments reveal the climate anomalies are exclusively caused by artificially large values of orographic gravity wave drag, resulting from the combined use of the orographic anomaly method along with a unique inclusion of transient orography that linearly interpolates between timesteps in the ice sheet reconstruction. Palaeoclimate modelling groups should therefore carefully check the effects of their sub-grid scale orographic terms in transient palaeoclimate simulations with prescribed topographic evolution. [ABSTRACT FROM AUTHOR]

This is a review of Soil Grown Tall: The Epic Saga of Life from Earth, by Gregory J. Retallack. In this book, Retallack shows how soils and life have coevolved over the last 3.5 billion years, and what soils tell us about the environments in which various terrestrial organisms have evolved and flourished. A theme of the book is the Proserpina Principle: producers consume CO2, consumers exhale it, and alternating dominance of producers and consumers alternates global warming and cooling, while keeping temperature within life-permitting limits. [ABSTRACT FROM AUTHOR]

Simple Summary: The deciduous shrub Comptonia is a monotypic genus of Myricaceae, which currently is distributed only in eastern North America, with a smaller range than that in other periods of the Cenozoic. By analyzing the macroscopic and microscopic characteristics of the leaves, we describe a new species of Comptonia (i.e., Comptonia hirsuta) from the Hannuoba Formation in Zhuozi, Inner Mongolia, North China. The co-occurring fruits were also studied based on their morphological characteristics, which were assigned to Comptonia tymensis. Variation in the distribution range of Comptonia indicates the influence of global cooling on the expansion of this plant. Furthermore, the Bering Land Bridge played an important role in the migration from North America to East Asia. The Thulean route may have provided an opportunity for plant exchange between western Europe and eastern North America. Moreover, the reason for the disappearance of Comptonia from China according to the analysis of the changes in both the global climate and the distribution of Comptonia fossils is also discussed. It is suggested that the climatic changes after the late Miocene and the progenitive pattern of Comptonia together caused the disappearance of Comptonia in China. Comptonia (Myricaceae) is well known as a monotypic genus living only in eastern North America; however, fossils show that the genus occurred extensively in the Northern Hemisphere during the Cenozoic. We observed dozens of Comptonia leaf fossils from the early Miocene in Zhuozi, China. The leaf architecture characteristics and epidermal features of the fossil specimens are described in detail here for the first time, and they were assigned to a new species: Comptonia hirsuta. The fruit fossils collected simultaneously from the same layer were assigned to Comptonia tymensis. The global fossil records indicate that the spatial distribution range of Comptonia reached its peak in both the Eocene and Miocene as two warm periods and then gradually decreased in the Oligocene, as well as after the late Miocene, because of the cooling global climate. Furthermore, the Comptonia taxon in East Asia may have migrated from North America via the Bering route in the late Paleocene or Eocene. Plant exchange between western Europe and eastern North America possibly occurred during the Eocene via the Thulean route. Phytogeographic variation in the Comptonia fossils from China also indicates that the reason for the disappearance of Comptonia from China may not only be due to the prolonged cooling and drying after the late Miocene, but also due to its progenitive pattern. [ABSTRACT FROM AUTHOR]

Frost cracking is a dominant mechanical weathering phenomenon facilitating the breakdown of bedrock in periglacial regions. Despite recent advances in understanding frost cracking processes, few studies have addressed how global climate change over the late Cenozoic may have impacted spatial variations in frost cracking intensity. In this study, we estimate global changes in frost cracking intensity (FCI) by segregation ice growth. Existing process-based models of FCI are applied in combination with soil thickness data from the Harmonized World Soil Database. Temporal and spatial variations in FCI are predicted using surface temperature changes obtained from ECHAM5 general circulation model simulations conducted for four different paleoclimate time slices. Time slices considered include pre-industrial (∼ 1850 CE, PI), mid-Holocene (∼ 6 ka, MH), Last Glacial Maximum (∼ 21 ka, LGM), and Pliocene (∼ 3 Ma, PLIO) times. Results indicate for all paleoclimate time slices that frost cracking was most prevalent (relative to PI times) in the middle- to high-latitude regions, as well as high-elevation lower-latitude areas such the Himalayas, Tibet, the European Alps, the Japanese Alps, the US Rocky Mountains, and the Andes Mountains. The smallest deviations in frost cracking (relative to PI conditions) were observed in the MH simulation, which yielded slightly higher FCI values in most of the areas. In contrast, larger deviations were observed in the simulations of the colder climate (LGM) and warmer climate (PLIO). Our results indicate that the impact of climate change on frost cracking was most severe during the PI–LGM period due to higher differences in temperatures and glaciation at higher latitudes. The PLIO results indicate low FCI in the Andes and higher values of FCI in Greenland and Canada due to the diminished extent of glaciation in the warmer PLIO climate. [ABSTRACT FROM AUTHOR]

Large-scale climate response to the spatial and temporal changes of anthropogenic aerosols are investigated in comparison with greenhouse gas (GHG) forcing using Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations during 1930–2010. Globally, increasing anthropogenic aerosols in the Northern Hemisphere (NH) since the industrial revolution generates a North–South interhemispherically asymmetric climate response pattern. But this feature only dominates the historical climate change early in the twentieth century. In the second half of the twentieth century, anthropogenic aerosol emissions increase monotonically in Asia, but increase first and then decrease rapidly over Europe and North America. The shift of aerosol emissions from the western mid-latitude NH to the eastern low-latitude NH induces distinct climate response patterns compared with its global increase effect, anchoring an equatorial symmetric tropical sea surface temperature (SST) cooling and precipitation decrease, which resembles that in the GHG-induced response patterns with sign reversed. After the mid-1970s, with declining aerosol emissions over Europe and North America and increasing emissions in Asia, anthropogenic aerosol forcing generates a northward recovery of the tropical rainfall with little response in the tropical SST anomalies due to the cancellation effect of the distinct aerosol emissions conditions between the western and the eastern NH. While GHG forcing dominates observed climate change in the twentieth century, the distinct climate response patterns to the spatial and temporal evolutions of anthropogenic aerosol forcing highlight its important role in shaping the regional climate changes. [ABSTRACT FROM AUTHOR]

Molecular phylogenetic studies that have included sirenians from the genera Trichechus, Dugong, and Hydrodamalis have resolved their interrelationships but have yielded divergence age estimates that are problematically discordant. The ages of these lineage splits have profound implications for how to interpret the sirenian fossil record--including clade membership, biogeographic patterns, and correlations with Earth history events. In an effort to address these issues, here we present a total evidence phylogenetic analysis of Sirenia that includes living and fossil species and applies Bayesian tip-dating methods to estimate their interrelationships and divergence times. In addition to extant sirenians, our dataset includes 56 fossil species from 106 dated localities and numerous afrotherian outgroup taxa. Genetic, morphological, temporal, and biogeographic data are assessed simultaneously to bring all available evidence to bear on sirenian phylogeny. The resulting time-tree is then used for Bayesian geocoordinates reconstruction analysis, which models ancestral geographic areas at splits throughout the phylogeny, thereby allowing us to infer the direction and timing of dispersals. Our results suggest that Pan-Sirenia arose in North Africa during the latest Paleocene and that the Eocene evolution of stem sirenians was primarily situated in the Tethyan realm. In the late Eocene, some lineages moved into more northern European latitudes, an area that became the source region for a key trans-Atlantic dispersal towards the Caribbean and northern-adjacent west Atlantic. This event led to the phylogenetic and biogeographic founding of crown Sirenia with the Dugongidae-Trichechidae split occurring at the Eocene-Oligocene boundary (~33.9 Ma), temporally coincident with the onset of dropping global sea levels and temperatures. This region became the nexus of sirenian diversification and supported taxonomically-rich dugongid communities until the earliest Pliocene. The Dugonginae-Hydrodamalinae split occurred near Florida during the early Miocene (~21.2 Ma) and was followed by a west-bound dispersal that gave rise to the Pacific hydrodamalines. The late middle Miocene (~12.2 Ma) split of Dugong from all other dugongines also occurred near Florida and our analyses suggest that the Indo-Pacific distribution of modern dugongs is the result of a trans-Pacific dispersal. From at least the early Miocene, trichechid evolution was based entirely in South America, presumably within the Pebas Wetlands System. We infer that the eventual establishment of Amazon drainage into the South Atlantic allowed the dispersal of Trichechus out of South America no earlier than the mid-Pliocene. Our analyses provide a new temporal and biogeographic framework for understanding major events in sirenian evolution and their possible relationships to oceanographic and climatic changes. These hypotheses can be further tested with the recovery and integration of new fossil evidence. [ABSTRACT FROM AUTHOR]

Major mass extinctions in the Phanerozoic Eon occurred during abrupt global climate changes accompanied by environmental destruction driven by large volcanic eruptions and projectile impacts. Relationships between land temperature anomalies and terrestrial animal extinctions, as well as the difference in response between marine and terrestrial animals to abrupt climate changes in the Phanerozoic, have not been quantitatively evaluated. My analyses show that the magnitude of major extinctions in marine invertebrates and that of terrestrial tetrapods correlate well with the coincidental anomaly of global and habitat surface temperatures during biotic crises, respectively, regardless of the difference between warming and cooling (correlation coefficient R=0.92 –0.95). The loss of more than 35 % of marine genera and 60 % of marine species corresponding to the so-called "big five" major mass extinctions correlates with a >7 ∘ C global cooling and a 7–9 ∘ C global warming for marine animals and a >7 ∘ C global cooling and a >∼7 ∘ C global warming for terrestrial tetrapods, accompanied by ±1 ∘ C error in the temperature anomalies as the global average, although the amount of terrestrial data is small. These relationships indicate that (i) abrupt changes in climate and environment associated with high-energy input by volcanism and impact relate to the magnitude of mass extinctions and (ii) the future anthropogenic extinction magnitude will not reach the major mass extinction magnitude when the extinction magnitude parallelly changes with the global surface temperature anomaly. In the linear relationship, I found lower tolerance in terrestrial tetrapods than in marine animals for the same global warming events and a higher sensitivity of marine animals to the same habitat temperature change than terrestrial animals. These phenomena fit with the ongoing extinctions. [ABSTRACT FROM AUTHOR]

The growth of the Qinghai-Tibetan Plateau (QTP) during the Cenozoic drove dramatic climate and environmental change in this region. However, there has been limited comprehensive research into evolution of climate during this interval. Here we present a quantitative reconstruction using Bioclimatic Analysis (BA) and Joint Probability Density Functions (JPDFs) based on data available for 48 fossil floras, including macrofossils and palynological fossils collected in the QTP area from the Paleogene to Neogene (66–2.58 Ma). Both methods indicate that there was an overall decline in temperature and precipitation. Paleoclimatic simulations using Hadley Centre Coupled Model version3 (HadCM3) show that the most prominent climate change was very likely driven by QTP orographic evolution from the late Eocene, which was accompanied by a shift in temperature from a latitudinal distribution to a topographically controlled pattern. In addition, with the growth of the QTP, temperature and precipitation decreased gradually in the northeastern part of the plateau. Different sources of evidence, including plant fossil records, climate simulations and other proxies, indicate that the topographic evolution of the QTP and other geological events, in conjunction with global cooling, may have been the main factors driving climate change in this region. This research can provide insights into Cenozoic environmental change and ecosystem evolution. [ABSTRACT FROM AUTHOR]

Background and Aims Ongoing global warming is a challenge for humankind. A series of drastic climatic changes have been proven to have occurred throughout the Cenozoic based on a variety of geological evidence, which helps to better understand our planet's future climate. Notably, extant biomes have recorded drastic environmental shifts. The climate in southern Asia, which hosts high biodiversity, is deeply impacted by the Asian monsoon. The origins and evolutionary dynamics of biomes occurring between the tropics and sub-tropics in southern Asia have probably been deeply impacted by climatic changes; however, these aspects remain poorly studied. We tested whether the evolutionary dynamics of the above biomes have recorded the drastic, late Cenozoic environmental shifts, by focusing on Magnolia section Michelia of the family Magnoliaceae. Methods We established a fine time-calibrated phylogeny of M. section Michelia based on complete plastid genomes and inferred its ancestral ranges. Finally, we estimated the evolutionary dynamics of this section through time, determining its diversification rate and the dispersal events that occurred between tropical and sub-tropical areas. Key Results The tropical origin of M. section Michelia was dated to the late Oligocene; however, the diversification of its core group (i.e. M. section Michelia subsection Michelia) has occurred mainly from the late Miocene onward. Two key evolutionary shifts (dated approx. 8 and approx. 3 million years ago, respectively) were identified, each of them probably in response to drastic climatic changes. Conclusion Here, we inferred the underlying evolutionary dynamics of biomes in southern Asia, which probably reflect late Cenozoic climatic changes. The occurrence of modern Asian monsoons was probably fundamental for the origin of M. section Michelia ; moreover, the occurrence of asymmetric dispersal events between the tropics and sub-tropics hint at an adaptation strategy of M. section Michelia to global cooling, in agreement with the tropical conservatism hypothesis. [ABSTRACT FROM AUTHOR]

The Eocene–Oligocene Transition (EOT) marks the onset of a major phase of global cooling with significant consequences to the vegetation worldwide. Here, we present palynological analyses from a site in southern São Paulo basin, southeastern Brazil (23.67°S; 46.58°W). An Oligocene age was constrained by the abundance of Dacrydiumites florinii and Podocarpidites spp., alongside the presence of taxa such as Cicatrocosisporites dorogensis and Polypodiisporites usmensis. Autochthonous elements including Paleoazolla, Corsinipollenites spp. , Monoporopollenites annulatus, and Zygnemataceae algae spores are indicative of a low-energy freshwater depositional environment. In addition, we performed a comparison of Eocene and Oligocene temperature and precipitation estimates from records in southeastern Brazil using the weighted Mutual Climate Range approach. Results support global trends with a cooling of ca. 3–4 °C from the Eocene to the Oligocene accompanied by slightly drier regional conditions. Oligocene environmental changes drove a vegetation turnover by local extinction of warm-tropical taxa or a significant retreat of species unable to stand comparatively colder and drier climates under lower CO 2atm concentrations. Our data are consistent with previous estimates and verify the impact of global cooling on the vegetation of mid-low latitudes of the Southern Hemisphere. • The Eocene–Oligocene transition led to a mean annual temperature drop of ca. 3–4 °C. • Southeastern Brazil is marked by slightly drier conditions during the Oligocene. • Vegetation shifts were led by local extinction of taxa due to changes in climate. • The Oligocene palynoflora featured a significantly higher abundance of gymnosperms. [ABSTRACT FROM AUTHOR]

Interactions among late Cenozoic global cooling, tectonic activity and regional climate evolution of the northeastern Tibetan Plateau remain elusive. To further understand the relative contributions of global climate change and tectonism, we conducted a comprehensive study of heavy minerals, rock magnetism, and branched glycerol dialkyl glycerol tetraethers (brGDGTs) in late Cenozoic sediments of the Laojunmiao section (ca. 12.7 Ma to 5 Ma) in the Jiuxi Basin. Our results reveal a notable increase in magnetic susceptibility (χ) and saturation isothermal remanent magnetization (SIRM) at 8.5 Ma, aligning with an accelerated decrease in temperature captured by brGDGTs. Combined with heavy mineral analysis, we propose that the profound changes in magnetic parameters and temperature are closely linked to the intensive uplift of the northern Qilian Shan since 8.5 Ma. Furthermore, this ongoing uplift has occurred simultaneously with persistent aridification in the Jiuxi Basin and its adjacent regions. The Qilian Shan might have reached a threshold elevation and began to act as a moisture barrier to northwestward moisture since 8.5 Ma. By synthesizing hydroclimate evolution records from the northeastern Tibetan Plateau, we deduce that changing topography resulting from tectonic uplift may have exerted a significant influence on regulating the moisture distribution in this region during the mid- to late Miocene. • Temperature reconstructed using brGDGTs declined at an accelerated rate at 8.5 Ma • Magnetic enhancement of lacustrine-delta fan sediments occurred at 8.5 Ma. • The northern Qilian Shan was uplifted at 8.5 Ma, simultaneous with regional drying. • Tectonic uplift was the primary driver of this climate transition at 8.5 Ma. [ABSTRACT FROM AUTHOR]

Climate changes have substantial impacts on the geographic distribution of montane lakes and evolutionary dynamics of cold-adapted species. Past climate cooling is hypothesized to have promoted the dispersal of cold-adapted species via montane lakes, while future climate warming is thought to constrain their distributions. We test this hypothesis by using phylogeographic analysis and niche modeling of the Holarctic crustacean Gammarus lacustris with global sampling comprised of 567 sequenced individuals and 3180 occurrence records. We found that the species arose in Tian Shan in Central Asia and dispersed into montane lakes along the Alps, Himalayas, Tibet, East Asia, and the North American Rocky Mountain ranges, with accelerated diversification rates outside Tian Shan. Climatically suitable regions for geographic lineages of G. lacustris were larger during cooling periods (LGM), but smaller during warming periods (Mid-Holocene). In the future (2070) scenario, potential distributions in the Himalayas, North Tibet, South Tibet and North America are predicted to expand, whereas ranges in East Asia, Europe and Tian Shan will decline. Our results suggest that Mid-Mioceneto-Pleistocene continuous cooling promoted multiple independent dispersal events out of Tian Shan due to increased availability of montane lakes via "budding" of lineages. Montane lakes are conduits through which cold-adapted amphipods globally dispersed, dominating circumboreal lakes. However, future climate warming is likely to force organisms to shift upward in altitude and northward in latitude, leading to a future change in local populations. These findings highlight the importance of conservation of montane lakes, especially in the context of climate change. [ABSTRACT FROM AUTHOR]

The theory of anthropogenic global warming (AGW) enjoys considerable consensus among experts. It is widely recognized that global industrialization is producing an increase in the planet’s temperatures and causing environmental disasters. Still, there are scholars – although a minority – who consider groundless either the idea of global warming itself or the idea that it constitutes an existential threat for humanity. This lack of scientific unanimity (as well as differing political ideologies) ignites controversies in the political world, the mass media, and public opinion as well. Sociologists have been dealing with this issue for some time, producing researches and studies based on their specific competencies. Using scientometric tools, this article tries to establish to what extent and in which capacity sociologists are studying the phenomenon of climate change. Particular attention is paid to meta-analytical aspects such as consensus, thematic trends, and the impact of scientific works.

Global climate changes during the Miocene may have created ample opportunities for hybridization between members of tropical and subtropical biomes at the boundary between these zones. Yet, very few studies have explored this possibility. The Yunnan‐Guizhou Plateau (YGP) in Southwest China is a biodiversity hotspot for vascular plants, located in a transitional area between the floristic regions of tropical Southeast Asia and subtropical East Asia. The genus Eriobotrya (Rosaceae) comprises both tropical and subtropical taxa, with 12 species recorded in the YGP, making it a suitable basis for testing the hypothesis of between‐biome hybridization. Therefore, we surveyed the evolutionary history of Eriobotrya by examining three chloroplast regions and five nuclear genes for 817 individuals (47 populations) of 23 Eriobotrya species (including 19 populations of 12 species in the YGP), plus genome re‐sequencing of 33 representative samples. We concluded that: (1) phylogenetic positions for 16 species exhibited strong cytonuclear conflicts, most probably due to ancient hybridization; (2) the YGP is a hotspot for hybridization, with 11 species showing clear evidence of chloroplast capture; and (3) Eriobotrya probably originated in tropical Asia during the Eocene. From the Miocene onwards, the intensification of the Eastern Asia monsoon and global cooling may have shifted the tropical‐subtropical boundary and caused secondary contact between species, thus providing ample opportunity for hybridization and diversification of Eriobotrya, especially in the YGP. Our study highlights the significant role that paleoclimate changes probably played in driving hybridization and generating rich species diversity in climate transition zones. [ABSTRACT FROM AUTHOR]

Palaeogene environmental evolution in East Asia remains ambiguous. Here we present integrative work including magnetostratigraphy, grain‐size, geochemistry, and clay mineralalogy from a 1609 m‐thick fluviolacustrine sequence in eastern China. The results reveal two periods of tectonic control alternating with three periods of climatic control on the sedimentary evolution. Tectonic activity in the study area, as revealed by particle coarsening and reduced weathering, occurred during 65.6–59 Ma and strengthened in Asia during 55–54 Ma in response to the India‐Eurasia collision. Weathering gradually enhanced in East Asia during 59–55 Ma, probably caused by global warming. Continuous global warming during 54–50.5 Ma is responsible for enhanced aridification in East Asia. From 50.5 to 37.6 Ma, global cooling weakened evapotranspiration and increased westerlies‐derived moisture. Both aspects increased effective moisture and chemical weathering in East Asia. These results shed light on how alternating tectonism and climate change impacted environmental evolution in Asia during the Palaeogene. Plain Language Summary: Most investigations in sedimentary basins generally focus exclusively on climatic signals at the expense of tectonic inputs. In this study, we extract both climatic and tectonic signals from long fluviolacustrine sediment records in eastern China comprehensively and objectively. We find that environmental evolution during the Paleogene of East Asia was dominated by tectonism during 65.6–59 and 55–54 Ma, and by climatic changes during 59–55 and 54–37.6 Ma. This work not only constrains the India‐Asia collision to a short 55–54 Ma interval for the first time, but also offers a sound explanation for one of the most important but disputed issues of eolian sediments in the North Pacific Ocean. Key Points: Tectonic activity occurred during 65.6–59 Ma in East Asia and strengthened during 55–54 Ma in response to the India‐Eurasia collisionIn East Asia, global warming led to enhanced weathering during 59–55 Ma and aridification during 54–50.5 MaGlobal cooling between 50.5 and 37.6 Ma increased westerlies‐derived moisture and enhanced chemical weathering in East Asia [ABSTRACT FROM AUTHOR]

Climate research has been presented as a largely Anglophone and European affair, while other regional contributions and concerns have been left largely unexamined. An investigation of the Japan Meteorological Agency's 'Abnormal Weather Reports' and related literature instead reveals the concerns of an island nation anxious about immediate weather abnormalities, causes of climate variability, and predicting the consequences of global warming within a geographically vulnerable Japan. Researchers initially focused on the topic of global cooling in the 1970s, sparking fears about Japan's self-sustainability in the event of a long-term decline in temperatures. By the 1980s, though cooling fears persisted, focus also turned to how El Nino cycles provoked climatic variability, even as initial concern with global warming resulting from human activities, carbon dioxide (CO2) emissions, and ozone depletion grew. Following the Kyoto Protocol's recognition of anthropogenic climate change and creation of a global cooperative framework, research has begun to focus on the consequences of global warming in exacerbating Japan's meteorological risks and on mitigating further anthropogenic temperature increases. [ABSTRACT FROM AUTHOR]

Aim: Past pollen records reveal the changes in latitudinal distribution of plants in relation to climate, particularly their expansion in response to global warming. The maximum northward expansion of the mangrove genus Avicennia since the Early Eocene is known, but this information is missing for other mangrove taxa. Here, we evaluate the diversity of past mangroves with respect to latitude during three Cenozoic thermal maxima (PETM: 56 Ma; EECO: 54–49 Ma; MMCO: 17–14 Ma). Location: North Atlantic, Mediterranean. Taxa: Avicennia, other mangrove taxa (Rhizophoraceae, Nypa, Xylocarpus, Pelliciera, etc.). Method: We collected well‐dated marine sediments along a Northern Hemisphere latitudinal transect and we analysed their pollen content in order to compare the past distribution of mangrove taxa with the present. The analysis of 89 samples (PETM: 13; EECO: 31; MMCO: 45) was performed and interpreted using a robust botanical background for identification of pollen grains and their representativeness in marine sediments. Results: During the Early Eocene, two palaeolatitudinal thresholds at 65–70°N and 35°N, respectively, delimited the Avicennia‐only mangrove from a diversified but scrawny mangrove and finally from a diversified and well‐developed mangrove. The Avicennia threshold was selective at 40°N during the Mid‐Miocene. The Avicennia range limit was up to 10–15° poleward of the limit for other mangrove taxa during the Early Eocene and the Mid‐Miocene compared with 9° at present. Main conclusions: A buffer zone characterised by a diversified but scrawny mangrove co‐occurring with a few megathermal plants occurred in the Early Eocene between 35°N and 65–70°N. This finding questions the relative influence of a more 'equable' climate and/or the ability of some taxa to expand towards areas with cooler conditions in the past. Mangrove provincialism, which was established progressively after the Early Eocene, was probably forced by plate tectonics. The taxonomic impoverishment of the Atlantic East Pacific province was probably caused by successive periods of global cooling. These results support the Tethyan origin of the mangroves. [ABSTRACT FROM AUTHOR]

Although Neogene climate change reconstruction in central Asia is important for understanding global cooling, Asian monsoon evolution, and the Tibetan Plateau stepwise uplift during the Cenozoic, the paleoenvironmental evolution during the Paleogene in this region is still ambiguous due to a lack of corresponding continuous and complete terrestrial records with precise age constraints. Recently, a new fluvial sedimentary sequence with magnetostratigraphic ages spanning from ∼53 to 40 Ma was found in the Linxia Basin, NE Tibetan Plateau, thereby providing a window to understand Eocene climate change in the Asian interior. From this fluvial sedimentary sequence, we present early‐middle Eocene hydroclimate variations based on a combined method of rock magnetism and diffuse reflectance spectroscopy. Our results show magnetic enhancement of fluvial sediments at 51.7 Ma resulted from abundant single‐domain magnetite inputs from the surrounding mountains through strong erosion and transport in a relatively wet environment. Subsequently, at 47.6 Ma, magnetic weakening of floodplain sediments corresponds to an increase in hematite concentrations produced via low‐temperature oxidation in a prolonged dry environment. Comparisons of paleoclimatic proxies, such as organic geochemistry and rock magnetism from neighboring basins, tectonic deformation of the NE Tibetan Plateau, and sea level change in the Paratethys Sea suggest that the hydroclimate variation from relatively wet to dry climate in the early‐middle Eocene in this area was mainly controlled by global climatic change and probably superimposed by the uplift of the Tibetan Plateau. Key Points: The magnetic susceptibility changes show two significant stages in the Linxia Basin between 53 and 40 MaThis changing mechanism was controlled by the exhumation linked with the hydroclimate variationsThe Paleogene hydroclimate evolution was mainly driven by the global climatic change [ABSTRACT FROM AUTHOR]

Biodiversity dynamics are shaped by a complex interplay between current conditions and historic legacy. The interaction of short- and long-term climate change may mask the true relationship of evolutionary responses to climate change if not specifically accounted for. These paleoclimate interactions have been demonstrated for extinction risk and biodiversity change, but their importance for origination dynamics remains untested. Here, we show that origination probability in marine fossil genera is strongly affected by paleoclimate interactions. Overall, origination probability increases by 27.8% [95% CI (27.4%, 28.3%)] when a short-term cooling adds to a long-term cooling trend. This large effect is consistent through time and all studied groups. The mechanisms of the detected effect might be manifold but are likely connected to increased allopatric speciation with eustatic sea level drop caused by sustained global cooling. We tested this potential mechanism through which paleoclimate interactions can act on origination rates by additionally examining a proxy for habitat fragmentation. This proxy, continental fragmentation, has a similar effect on origination rates as paleoclimate interactions, supporting the importance of allopatric speciation through habitat fragmentation in the deep-time fossil record. The identified complex nature of paleoclimate interactions might explain contradictory conclusions on the relationship between temperature and origination in the previous literature. Our results highlight the need to account for complex interactions in evolutionary studies both between and among biotic and abiotic factors. [ABSTRACT FROM AUTHOR]

Arctic Amplification is robustly seen in climate model simulations of future warming and in the paleoclimate record. Here, we focus on the past century of observations. We show that Arctic Amplification is only a recent phenomenon, and that for much of this period the Arctic cooled while the global‐mean temperature rose. To investigate why this occurred, we analyze large ensembles of comprehensive climate model simulations under different forcing scenarios. Our results suggest that the global warming from greenhouse gases was largely offset in the Arctic by regional cooling due to aerosols, with internal climate variability also contributing to Arctic cooling and global warming trends during this period. This suggests that the disruption of Arctic Amplification was due to a combination of factors unique to the 20th century, and that enhanced Arctic warming should be expected to be a consistent feature of climate change over the coming century. Plain Language Summary: Arctic Amplification is the phenomenon by which the Arctic warms at a faster rate than the global average. Evidence for the occurrence of Arctic Amplification is widely found in climate model simulations as well as in paleo proxy reconstructions of past climate changes. In this study, we investigate the extent to which Arctic Amplification has occurred in observations from the past century. We show that Arctic Amplification is only a recent phenomenon, and that for much of the 20th century, the Arctic cooled while the global‐mean temperature rose. We investigate why this happened using a range of climate model simulations, and we find that there were two main causes for these opposing trends. The first is that regional cooling from aerosols counteracted the warming from greenhouse gases in the Arctic. However, this cannot fully explain the observed trends. The second is that natural fluctuations of the climate system manifested in a pattern of Arctic cooling under global warming. This suggests that the disruption of Arctic Amplification was due to a combination of factors unique to the 20th century, implying that enhanced Arctic warming should be expected to be a consistent feature of climate change over the coming century. Key Points: For much of the past century the Arctic cooled while the globe warmed, with Arctic Amplification of warming only emerging more recentlyWithout increases in both aerosols and greenhouse gas emissions, Arctic Amplification would have occurred throughout the past centuryInternal variability also played an important role in setting the observed Arctic cooling and global warming trends [ABSTRACT FROM AUTHOR]

Aim: We investigated the biogeographic pattern of the species‐rich genus Psectrascelis (Coleoptera: Tenebrionidae) in the Central Andes and the Chilean Atacama Desert as an example for insect evolution in such a geologically and climatically highly dynamic arid region. The main aim was to test two alternative hypotheses about the main drivers of diversification of biotas from deserts in the region: Andean uplift versus Pleistocene fragmentation/dispersal. Location: South America, Central Andes, Atacama Desert. Taxon: Psectrascelis (Coleoptera: Tenebrionidae). Methods: A phylogenetic tree based on cytochrome oxidase I, 16S and Wg genes was prepared for multiple individuals from 36 populations of the region representing 14 species or subspecies. Divergence times, ancestral ranges and biogeographic events that may have led to the current distribution and species diversity were estimated. Results: The first split within the genus is not directly related to the Andean uplift but began at the time of global cooling at ~3.5 Ma, when the Andes had already reached their current altitude. Further differentiations of Psectrascelis lineages were mostly caused by common and more global drivers resulting in major clusters of diversifications at ~2.6–2.2 Ma, ~1.3–0.7 Ma and several subsequent events during the mid‐ to late Quaternary. Today, the two main clades of Psectrascelis almost meet each other after presumably synchronous range expansions along the Western Cordillera. Main conclusions: Diversification of Psectrascelis has primarily been affected by global climate changes since the mid‐Pliocene and has involved multiple vicariance and jump dispersal events. We hypothesize that jump dispersal events have occasionally been accompanied by adaptation to stronger aridity, which paved the way for range expansion into previously unsuitable habitats and eventually led to synchronous colonizations without spatial overlap along different isohyets in the Western Cordillera during the late Pleistocene. [ABSTRACT FROM AUTHOR]