Global and Planetary Change最新文献

{"title":"The presence of the Tibetan Plateau lowers atmospheric CO2 levels via the Atlantic-Pacific carbon seesaw","authors":"Jinlong Du, Jun Tian, Aixue Hu, Yongqiang Yu, Baohuang Su, Dabang Jiang","doi":"10.1016/j.gloplacha.2024.104681","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104681","url":null,"abstract":"The presence of the Tibetan Plateau is believed to lower <ce:italic>p</ce:italic>CO<ce:inf loc=\"post\">2</ce:inf><ce:sup loc=\"post\">atm</ce:sup> by stimulating weathering carbon sink, during which the global ocean is considered a passive carbon reservoir despite the tremendous marine carbon inventory. Yet, recent studies reveal that the orographic forcing of the Tibetan Plateau could lead to drastic changes in ocean circulation, which would substantially affect basin-scale carbon storage and hence <ce:italic>p</ce:italic>CO<ce:inf loc=\"post\">2</ce:inf><ce:sup loc=\"post\">atm</ce:sup>. However, this connection between the presence of the Tibetan Plateau and changes in the oceanic carbon inventory remains insufficiently investigated. Here, by employing a state-of-the-art ocean-biogeochemical model, we explore the role of the Tibetan Plateau in determining basin-scale carbon storage patterns based on an idealized experimental design. We find that the presence of the Tibetan Plateau substantially enhances deep Pacific carbon storage and hence lowers <ce:italic>p</ce:italic>CO<ce:inf loc=\"post\">2</ce:inf><ce:sup loc=\"post\">atm</ce:sup> via essential reorganization of the meridional overturning circulation, particularly associated with the development of the Pacific halocline. Moreover, the presence of the Tibetan Plateau greatly affects the oceanic carbon uptake in the Northern Hemisphere, which is likely controlled by the variations in surface alkalinity.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"132 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of the Asian summer monsoon during the Heinrich events 1–6","authors":"Yan-Xia Xue, Yao Wu, Chao-Jun Chen, Jun-Yun Li, Hai Cheng, Chuan-Chou Shen, Jian Zhang, Ting-Yong Li","doi":"10.1016/j.gloplacha.2024.104680","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104680","url":null,"abstract":"There are still a series of controversies about the variation patterns and spatial differences of the Asian summer monsoon (ASM) during the Heinrich Stadials (HSs). Using stalagmite δ<ce:sup loc=\"post\">18</ce:sup>O records from Yangkou Cave, Southwest China, this study revealed the climate dynamics of 6 weak ASM events corresponding to Heinrich events since the last glacial period. During the Asian Heinrich Stadial (AHS) 1–6, the ASM intensity in northern China responded rapidly to climate change in the North Atlantic, whereas the response in southern China was gradual. Ocean-atmosphere interactions under the bipolar “see-saw” mechanism dominated the ASM dynamics during the HSs. The ASM strengthening in the south of the Asian monsoon region was earlier and more gradual than in the north during the termination of the AHS, implying that the Southern Hemisphere high latitudes and tropical oceans played a critical role in the termination of millennial-scale abrupt climatic events. According to our observations, variations in moisture transport distances resulted in spatial differences in amplitude of stalagmite δ<ce:sup loc=\"post\">18</ce:sup>O during the AHSs, implying that δ<ce:sup loc=\"post\">18</ce:sup>O can reflect the hydrological imprint of variation in the ASM circulation.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined impacts of land change and climate variability on ecosystem net primary productivity in arid regions","authors":"Emeka Edwin Igboeli, Ogbue Chukwuka, Friday Uchenna Ochege, Chukwuemeka Anthony Onyekwelu, Qing Ling, Chukwuedozie Ajaero, Rafiq Hamdi, Mijanur Rahman, Alphonse Kayiranga, Geping Luo","doi":"10.1016/j.gloplacha.2024.104682","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104682","url":null,"abstract":"Net Primary Productivity (NPP) is an index for assessing ecosystem services and productivity on land. However, previous studies focused solely on NPP changes across ecological regions, overlooking the comparative advantage of the impacts of land changes and climatic variations on various forms of NPP as indicators of ecosystem degradation and restoration across different eco-political milieux. This study comparatively analyzed land cover changes and examined NPP trends and their effects using Mann-Kendall Theil-Sen slopes, the Pearson correlation, and advanced geostatistical methods in the Lake Chad Basin (LCB) and the Aral Sea Basin (ASB). We found that from 2000 to the present and projected to 2030, cropland is expected to expand by 2.20 %, leading to a reduction of shrubland by −2.40 % in LCB. Likewise, a probable increase of 1.1 % in grassland is expected to further reduce waterbodies in ASB by −1.5 %. These potential changes are the resultant effect of the present human-induced NPP (HNPP) reduction of −5.92gC/m<ce:sup loc=\"post\">2</ce:sup>/yr across 2.44 × 10<ce:sup loc=\"post\">3</ce:sup> km<ce:sup loc=\"post\">2</ce:sup> and 29.84gC/m<ce:sup loc=\"post\">2</ce:sup>/yr across 14.32× 10<ce:sup loc=\"post\">3</ce:sup> km<ce:sup loc=\"post\">2</ce:sup>, indicating human-dominated degradation (HDD) in LCB. Whereas, in ASB, the influence of HNPP by −8.12 gC/m<ce:sup loc=\"post\">2</ce:sup>/yr across 14.32 × 10<ce:sup loc=\"post\">3</ce:sup> km<ce:sup loc=\"post\">2</ce:sup> and by 4.00gC/m<ce:sup loc=\"post\">2</ce:sup>/yr across 7.24× 10<ce:sup loc=\"post\">3</ce:sup> km<ce:sup loc=\"post\">2</ce:sup> indicate incipient human-dominated restoration scenarios. Consequent to the warming temperature, climate fluctuations are characterized by HDD in LCB, whereas in ASB, they are characterized by climate-induced degradation. Apprehending these evolving dynamics in endorheic lakes can provide insight into potential restoration trajectories for future land degradations.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"65 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal and spatial changes of glacial lakes in the central Himalayas and their response to climate change based on multi-source remote sensing data","authors":"Xiaoqiang Cheng, Donghui Shangguan, Chengsheng Yang, Wangping Li, Zhaoye Zhou, Xiaojie Liu, Da Li, Xiuxia Zhang, Huilan Ding, Zewei Liu, Yi Yu, Xiaoxian Wang, Beibei He, Qin Yang, Yaojun Li, Rongjun Wang, Yadong Liu, Lingzhi Deng, Yanzi Shi","doi":"10.1016/j.gloplacha.2024.104675","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104675","url":null,"abstract":"Global warming has significantly accelerated the retreat of glaciers and expansion of glacial lakes in the central Himalayas, thereby heightening the risks of various disasters, including ice avalanches, rock avalanches, and glacial lake outburst floods (GLOFs). These events pose considerable threats to the lives and properties of individuals residing in downstream areas. Consequently, conducting comprehensive research into the geographical distribution, formation, and evolutionary processes of glacial lakes, along with assessments of the potential impacts of GLOFs on climate change, is critically important for developing strategies to mitigate associated risks. To address this need, we propose a dynamic threshold method (known as OTSU) to facilitate the automatic and precise extraction of glacial lake boundaries in the central Himalayas. This innovative approach leverages the enhanced normalized difference water index (ENDWI), derived from multi-temporal Landsat series remote sensing imagery and Sentinel-2A /2B datasets, which were sourced from the Google Earth Engine (GEE) platform for the years 1990–2022. In addition to extracting lake boundaries, we examined the spatiotemporal evolution characteristics of glacial lakes in the region. Moreover, mathematical statistics were employed to systematically organize and analyse the GLOF disaster events in the central Himalayas. Finally, thoroughly investigate the interplay between glacial lake evolution and climate change, we incorporated relevant meteorological data. The present findings reveal that: 1) Glacial lakes are primarily distributed in the border area between China and Nepal in the central Himalayas, composed of non-contact lakes with glaciers, and concentrated in the altitude range of 3600–5900 m. 2) Since the 1990s, the expansion of glacial lakes is predominated by small glacial lakes in the central Himalayas; there have been 847 new glacial lakes, and the area and volume of glacial lakes has increased by 88.61 ± 4.64 km<ce:sup loc=\"post\">2</ce:sup> and 24.72 ± 2.59 km<ce:sup loc=\"post\">3</ce:sup>, respectively. 3) Global warming, coupled with the escalating rates of glacial meltwater, serves as the primary catalyst for the proliferation of glacial lakes. This multifaceted approach aims to provide a clearer understanding of the dynamics at play in this vulnerable region and to inform effective risk management strategies. Since 1950, there has been a significant increase in the frequency of GLOFs, with the month of June demonstrating the highest incidence, followed closely by August. These glacial lake outbursts are predominantly instigated by ice avalanches. The present findings provide valuable scientific insights that could contribute to the mitigation of regional natural disasters.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"115 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulation and response of heterotrophic bacterial production to environmental changes in marginal seas of the Western Pacific Ocean","authors":"Qiao Liu, Jinyan Wang, Xiao-Jun Li, Ni Meng, Gui-Peng Yang, Guiling Zhang, Guang-Chao Zhuang","doi":"10.1016/j.gloplacha.2024.104678","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104678","url":null,"abstract":"Heterotrophic bacterial production represents an important part of microbial food web processes in marine ecosystems and plays a significant role in biogeochemical carbon cycle. As environmental factors have changed in marginal seas of the Western Pacific Ocean over the past 20 years, the response and regulation of bacterial production remain poorly understood. In this study, we quantified bacterial production rates using the <ce:sup loc=\"post\">3</ce:sup>H-leucine incorporation method and investigated the factors influencing bacterial production distributions in the East China Sea and the Yellow Sea. Our data revealed that bacterial production varied largely (1.6–24.4 mg C m<ce:sup loc=\"post\">−3</ce:sup> d<ce:sup loc=\"post\">−1</ce:sup>) in the surface waters, and higher rates were observed at temperate sites in the East China Sea. Incubation experiments under different temperature or nutrient conditions demonstrated that elevated temperature or the addition of silicate, DIN and phosphate could simulate heterotrophic activity. The decadal increases of BP could be a result of microbial response to the variations in temperature, nutrient levels, and dissolved oxygen that are closely linked to food-web dynamics and biogeochemical processes. High ratios of integrated bacterial production to primary production suggested bacterial production could be supported by non-phytoplanktonic carbon sources, while the low bacterial growth efficiency indicated that a large fraction of carbon was respired in the offshore waters. These results provided insights into the regulations of BP and heterotrophic response to environmental evolution in marginal seas of the Western Pacific Ocean.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"294 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Astronomically forced dynamics of Late Devonian (Famennian) sea level and biotic recovery in western Junggar, Northwest China","authors":"Kunyuan Ma, Linda Hinnov, Zhihong Wang, Kai Wang, Ruiwen Zong, Xinsong Zhang, Junjun Song, Yang Bai, Yiming Gong","doi":"10.1016/j.gloplacha.2024.104677","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104677","url":null,"abstract":"The Hongguleleng Formation in western Junggar, northwest China preserves a rich variety of fossils and was previously regarded as a “refugium” during the Late Devonian biotic crisis. Uncertainty in the age of the Hongguleleng Formation has persisted for a considerable time. In this study, cyclostratigraphic analysis was carried out on the Upper Devonian Bulongguoer and Wulankeshun sections from western Junggar, northwest China. Time series analysis and modeling of iron (Fe) concentration proxy data reveal variations with frequencies comparable to those of the Earth's long and short orbital eccentricity, obliquity, and precession index in both successions. Interpreted 405-kyr long orbital eccentricity cycles were used to establish floating astronomical time scales (FATs) for the two successions. From these FATs the depositional duration of the Hongguleleng Formation is calculated as 11.5 ± 0.58 Myr. The Devonian-Carboniferous boundary age of 359.3 ± 0.3 Ma was chosen as a time “anchor”, resulting in an astronomically determined age of 370.2 ± 0.66 Ma for the base of the Hongguleleng Formation. Combined with conodont biostratigraphy, this age indicates that the Hongguleleng Formation in western Junggar does not reach down to the Frasnian-Famennian boundary. Sedimentary noise modeling of the reconstructed Fe concentration time series provides an interpretation of sea-level variations in the Paleo-Asian Ocean controlled by astronomical forcing from very long orbital eccentricity cycles (<ce:italic>g</ce:italic><ce:inf loc=\"post\">4</ce:inf>–<ce:italic>g</ce:italic><ce:inf loc=\"post\">3</ce:inf>) throughout the Late Devonian period. Intensified monsoonal climates during these orbital eccentricity cycle maxima led to elevated terrigenous input and strengthened upwelling, which enhanced primary productivity in the western Junggar. We propose an “astronomical climate change” model as a driving mechanism that led to biotic recovery in the Famennian Hongguleleng Formation.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"172 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"U-series isotope constraints on the rates of aeolian-impacted basaltic weathering under tropical climate","authors":"Guodong Ming, Jingyi Huang, Jiaru Sheng, Yingzeng Gong, Jiye Guo, Huimin Yu, Wenhan Cheng, Craig C. Lundstrom, Fang Huang","doi":"10.1016/j.gloplacha.2024.104673","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104673","url":null,"abstract":"The chemical weathering of basalt rocks is crucial for stabilizing Earth's habitability and carbon cycle. Currently, the soil chemistry and weathering rates of basalt under significant aeolian influence are not fully understood. This study addresses this gap by investigating the U geochemistry and regolith production rates in a highly weathered basalt profile in Southern China. The ε<ce:inf loc=\"post\">Nd(0)</ce:inf> values decrease from the bedrock sample (4.68) to the top soils (0.94), indicating aerosol input from the top. Dust accretion decrease downward and significantly affects the vertical distribution of U (R<ce:sup loc=\"post\">2</ce:sup> = 0.86), while the chemical mobilization of U is controlled by binding with Fe oxides-organic matter complexes (R<ce:sup loc=\"post\">2</ce:sup> = 0.33).","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"54 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triggering of a 2500-year coral shutdown in northern South China Sea by coupled East Asian Monsoon and El Niño–Southern Oscillation","authors":"Fei Tan, Yunfeng Zhang, Guowei Fu, Qi Shi, Xiyang Zhang, Shengnan Zhou, Mingzhuang Wang, Guotao Zhang, Xiaoju Liu, Jian-xin Zhao, Hongqiang Yang","doi":"10.1016/j.gloplacha.2024.104672","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104672","url":null,"abstract":"Rapid climate change is reshaping the ecological dynamics of coral reefs, posing significant challenges in understanding the long-term effects of environmental disturbances on reef development. In the current study, we conducted a chronological analysis and regional review of Holocene massive <ce:italic>Porites</ce:italic> corals in the northern South China Sea, revealing a unique episodic growth pattern, including a 2500-year growth hiatus. The findings suggest that this collapse was driven by the coupling of intensified East Asian winter monsoon and broader-scale El Niño–Southern Oscillation variability. Regional environmental drivers significantly influenced spatiotemporal variations in coral growth stagnation across the Pan-Pacific region. While future sea level rise and warming may benefit nearshore corals, the projected intensification of El Niño–Southern Oscillation variability could undermine the potential of the northern South China Sea as a coral refuge. Effective coral management and environmental mitigation measures are crucial to preventing further collapse of regional coral reefs.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"82 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pacific Walker Circulation modulated millennial-scale East Asian summer monsoon rainfall variability over the past 40 kyr","authors":"Yi Zhong, Yuxing Liu, Xiaojing Du, Xiaoxu Shi, Xing Xu, Zhengyao Lu, Stefanie Kaboth-Bahr, Mark J. Dekkers, Juan C. Larrasoaña, Keiji Horikawa, Chijun Sun, Liang Ning, André Bahr, Yanan Zhang, Debo Zhao, Jiabo Liu, Wenyue Xia, Jingyu Zhang, Sheng Yang, Hai Li, Xiaoyue Liang, Chenxi Hong, Zhengyang Dai, Yuanjie Li, Qingsong Liu","doi":"10.1016/j.gloplacha.2024.104676","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104676","url":null,"abstract":"The millennial-scale hydroclimate variability in East Asia has been debated for a long time due to the lack of reliable precipitation records from southern China and inconsistent model simulations. Here, we reconstruct a 40-kyr rainfall record for southern China and Taiwan based on enviro-magnetic and clay mineral proxy parameters from a northern South China Sea marine sediment core. Both proxies suggest reduced East Asian Summer Monsoon (EASM) precipitation in the southern China-Taiwan region during North Atlantic cooling episodes. After integration with other EASM precipitation records and modeling results, we conclude that the spatial precipitation pattern across Southeast Asia is closely related to the strength of the Pacific Walker Circulation. This interpretation is supported by a model simulation that emphasizes the role of the Walker Circulation in transferring North Atlantic climate variability to the East Asian hydroclimate. Our findings contribute to resolving the disparities between precipitation proxies and model simulations in Southeast Asia.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"48 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Miocene-early Pliocene hydroclimate evolution of the western Altiplano, northern Chile: Implications for aridification trends under warming climate conditions","authors":"Carlie Mentzer, Carmala Garzione, Carlos Jaramillo, Luis Felipe Hinojosa, Jaime Escobar, Nataly Glade, Sebastian Gomez, Deepshikha Upadhyay, Aradhna Tripati, Kaustubh Thirumalai","doi":"10.1016/j.gloplacha.2024.104674","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104674","url":null,"abstract":"The Miocene-Pliocene boundary (∼5.3 million years ago, Ma) represents a climate transition, where global warming resulted in a rise in sea surface temperatures from near modern values in the late Miocene, to sustained, warmer than modern values in the early Pliocene. Estimated atmospheric CO<ce:inf loc=\"post\">2</ce:inf> concentrations were within the range of anthropogenic values. Thus, this transition provides an opportunity to evaluate hydroclimate responses to warming, when the Earth system was in equilibrium with near modern atmospheric CO<ce:inf loc=\"post\">2</ce:inf> levels. Here, we utilize lacustrine carbonate stable and clumped isotope methods, and palynology, to investigate hydroclimate trends within the western Altiplano of Chile during the late Miocene and early Pliocene. The results provide observational support for a warmer and wetter-than-modern climate over these timeframes. However, increasing aridity across the Miocene-Pliocene boundary suggests a hydroclimate response to global climate forcing. Given the sensitivity of the region's climate to disturbances in tropical Pacific, ocean-atmospheric processes, we speculate that this aridification may reflect progressive weakening of the Pacific Walker Circulation, in response to global warming.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"70 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}