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Sun W, Li J, Yu R, Li N, Zhang Y. Exploring changes of precipitation extremes under climate change through global variable-resolution modeling. Sci Bull (Beijing) 2024; 69:237-247. [PMID: 37993336 DOI: 10.1016/j.scib.2023.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 10/08/2023] [Accepted: 10/12/2023] [Indexed: 11/24/2023]
Abstract
Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems. Here we take the record-breaking precipitation over China in 2021 as an example, and study its changes under three different climate scenarios through a developed pseudo-global-warming (PGW) experimental framework with 60-3 km variable-resolution global ensemble modeling. Compared to the present climate, the precipitation extreme under a warmer (cooler) climate increased (decreased) in intensity, coverage, and total amount at a range of 24.3%-37.8% (18.7%-56.1%). With the help of the proposed PGW experimental framework, we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme. Under the warmer climate, large-scale water vapor transport converged from double typhoons and the subtropical high marched into central China, enhancing the convective energy and instability on the leading edge of the transport belt. As a result, the mesoscale convective system (MCS) that directly contributed to the precipitation extreme became stronger than that in the present climate. On the contrary, the cooler climate displayed opposite changing characteristics relative to the warmer climate, ranging from the large-scale systems to local environments and to the MCS. In summary, our study provides a promising approach to scientifically assess the response of precipitation extremes to climate change, making it feasible to perform ensemble simulations while investigating the multi-scale system interactions over the globe.
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Affiliation(s)
- Wei Sun
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China; Institute of Tibetan Plateau Meteorology, China Meteorological Administration, Chengdu 610072, China
| | - Jian Li
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China; Institute of Tibetan Plateau Meteorology, China Meteorological Administration, Chengdu 610072, China.
| | - Rucong Yu
- Department of Atmospheric Science, Yunnan University, Kunming 650091, China; State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Nina Li
- National Meteorological Center, China Meteorological Administration, Beijing 100081, China
| | - Yi Zhang
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China; 2035 Future Laboratory, PIESAT Information Technology Co., Ltd., Beijing 100105, China
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2
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Yuan S, Chiang HW, Liu G, Bijaksana S, He S, Jiang X, Imran AM, Wicaksono SA, Wang X. The strength, position, and width changes of the intertropical convergence zone since the Last Glacial Maximum. Proc Natl Acad Sci U S A 2023; 120:e2217064120. [PMID: 38033310 PMCID: PMC10666097 DOI: 10.1073/pnas.2217064120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 09/18/2023] [Indexed: 12/02/2023] Open
Abstract
The intertropical convergence zone (ITCZ) plays a key role in regulating tropical hydroclimate and global water cycle through changes in its convection strength, latitudinal position, and width. The long-term variability of the ITCZ, along with the corresponding driving mechanisms, however, remains obscure, mainly because it is difficult to separate different ITCZ variables in paleoclimate proxy records. Here, we report a speleothem oxygen isotope (δ18O) record from southwestern Sulawesi, Indonesia, and compile it with other speleothem records from the Maritime Continent. Using the spatial gradient of speleothem δ18O along a transect across the ITCZ, we constrain ITCZ variabilities over the Maritime Continent during the past 30,000 y. We find that ITCZ convection strength overall intensified from the last glacial period to the Holocene, following changes in climate boundary conditions. The mean position of the regional ITCZ has moved latitudinally no more than 3° in the past 30,000 y, consistent with the deduction from the atmospheric energy framework. However, different from modern observations and model simulations for future warming, the ITCZ appeared narrower during both the late Holocene and most part of the last glacial period, and its expansion occurred during Heinrich stadials and the early-to-mid Holocene. We also find that during the last glacial and deglacial period, prominent millennial-scale ITCZ changes were closely tied to the variability of the Atlantic meridional overturning circulation (AMOC), whereas during the Holocene, they were predominantly modulated by the long-term variability of the Walker circulation.
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Affiliation(s)
- Shufang Yuan
- Earth Observatory of Singapore, Nanyang Technological University, Singapore639798, Singapore
- Asian School of Environment, Nanyang Technological University, 639798, Singapore
| | - Hong-Wei Chiang
- Department of Geosciences, National Taiwan University, Taipei10617, Taiwan
| | - Guangxin Liu
- Department of Atmospheric Science, Yunnan University, Kunming650500, China
| | - Satria Bijaksana
- Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung40132, Indonesia
| | - Shaoneng He
- Earth Observatory of Singapore, Nanyang Technological University, Singapore639798, Singapore
- Asian School of Environment, Nanyang Technological University, 639798, Singapore
| | - Xiuyang Jiang
- School of Geographical Sciences, Fujian Normal University, Fuzhou350007, China
| | - Andi M. Imran
- Department of Geological Engineering, Hasanuddin University, Makassar90245, Indonesia
| | - Satrio A. Wicaksono
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI02912
| | - Xianfeng Wang
- Earth Observatory of Singapore, Nanyang Technological University, Singapore639798, Singapore
- Asian School of Environment, Nanyang Technological University, 639798, Singapore
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3
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Wang P, Yang Y, Xue D, Ren L, Tang J, Leung LR, Liao H. Aerosols overtake greenhouse gases causing a warmer climate and more weather extremes toward carbon neutrality. Nat Commun 2023; 14:7257. [PMID: 37945564 PMCID: PMC10636203 DOI: 10.1038/s41467-023-42891-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023] Open
Abstract
To mitigate climate warming, many countries have committed to achieve carbon neutrality in the mid-21st century. Here, we assess the global impacts of changing greenhouse gases (GHGs), aerosols, and tropospheric ozone (O3) following a carbon neutrality pathway on climate and extreme weather events individually using the Community Earth System Model version 1 (CESM1). The results suggest that the future aerosol reductions significantly contribute to climate warming and increase the frequency and intensity of extreme weathers toward carbon neutrality and aerosol impacts far outweigh those of GHGs and tropospheric O3. It reverses the knowledge that the changing GHGs dominate the future climate changes as predicted in the middle of the road pathway. Therefore, substantial reductions in GHGs and tropospheric O3 are necessary to reach the 1.5 °C warming target and mitigate the harmful effects of concomitant aerosol reductions on climate and extreme weather events under carbon neutrality in the future.
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Affiliation(s)
- Pinya Wang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Joint International Research Laboratory of Climate and Environment Change, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, China
| | - Yang Yang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Joint International Research Laboratory of Climate and Environment Change, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, China.
| | - Daokai Xue
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Lili Ren
- College of Environment and Ecology, Jiangsu Open University, Nanjing, Jiangsu, China
| | - Jianping Tang
- School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - L Ruby Leung
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Hong Liao
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Joint International Research Laboratory of Climate and Environment Change, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, China
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4
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Rafalska A, Walkiewicz A, Osborne B, Klumpp K, Bieganowski A. Variation in methane uptake by grassland soils in the context of climate change - A review of effects and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 871:162127. [PMID: 36764535 DOI: 10.1016/j.scitotenv.2023.162127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/19/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
Grassland soils are climate-dependent ecosystems that have a significant greenhouse gas mitigating function through their ability to store large amounts of carbon (C). However, what is often not recognized is that they can also exhibit a high methane (CH4) uptake capacity that could be influenced by future increases in atmospheric carbon dioxide (CO2) concentration and variations in temperature and water availability. While there is a wealth of information on C sequestration in grasslands there is less consensus on how climate change impacts on CH4 uptake or the underlying mechanisms involved. To address this, we assessed existing knowledge on the impact of climate change components on CH4 uptake by grassland soils. Increases in precipitation associated with soils with a high background soil moisture content generally resulted in a reduction in CH4 uptake or even net emissions, while the effect was opposite in soils with a relatively low background moisture content. Initially wet grasslands subject to the combined effects of warming and water deficits may absorb more CH4, mainly due to increased gas diffusivity. However, in the longer-term heat and drought stress may reduce the activity of methanotrophs when the mean soil moisture content is below the optimum for their survival. Enhanced plant productivity and growth under elevated CO2, increased soil moisture and changed nutrient concentrations, can differentially affect methanotrophic activity, which is often reduced by increasing N deposition. Our estimations showed that CH4 uptake in grassland soils can change from -57.7 % to +6.1 % by increased precipitation, from -37.3 % to +85.3 % by elevated temperatures, from +0.87 % to +92.4 % by decreased precipitation, and from -66.7 % to +27.3 % by elevated CO2. In conclusion, the analysis suggests that grasslands under the influence of warming and drought may absorb even more CH4, mainly because of reduced soil water contents and increased gas diffusivity.
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Affiliation(s)
- Adrianna Rafalska
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Anna Walkiewicz
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland.
| | - Bruce Osborne
- UCD School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, 4 Dublin, Ireland
| | - Katja Klumpp
- INRAE, University of Clermont Auvergne, VetAgro Sup, UREP Unité de Recherche sur l'Ecosystème Prairial, 63000 Clermont-Ferrand, France
| | - Andrzej Bieganowski
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
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5
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Khoie MMM, Nasseri M, Banihashemi MA. Determining the spatial contributions of land use changes on the streamflow and sediment transport regimes: a case study of the Gorganroud watershed in Iran. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:45029-45045. [PMID: 36697980 DOI: 10.1007/s11356-023-25478-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/18/2023] [Indexed: 06/17/2023]
Abstract
Human activities and climate change are recognized as two of the most important drivers of hydrologic variability and have attracted the interest of researchers over the past decade. Changes in land use, dam construction, agricultural development, and global warming are forces that directly or indirectly impact the global and local hydrologic regime. This study examines the effects of these drivers on streamflow and sediment transport in the Gorganroud watershed, located in the north of Iran. In addition, the most sensitive land use patterns are detected using statistical approaches and a hydrologic model. The current study's principal argument is based on the variability of land use patterns during the modeling procedure (2007-2019). The Soil and Water Assessment Tool (SWAT) model is used to consider the land use dynamics during the simulation period based on the hydrological regime of the reference period. The Simple Differential Method (SDM) and Climate Elasticity Method (CEM) are utilized to estimate the contribution rates of land use and climate change in streamflow and sediment transport changes. The results indicate that changes in land use have contributed more than 60% to streamflow and sediment regime changes in all subbasins. A sensitivity analysis of land uses and the spatial distribution of the Human Contribution Rate (HCR) over the study area reveal that an increase in orchard land use (8.7% during the computational period) is primarily responsible for these significant changes.
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Affiliation(s)
| | - Mohsen Nasseri
- School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.
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6
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Seltzer AM, Blard PH, Sherwood SC, Kageyama M. Terrestrial amplification of past, present, and future climate change. SCIENCE ADVANCES 2023; 9:eadf8119. [PMID: 36753551 PMCID: PMC9908018 DOI: 10.1126/sciadv.adf8119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/10/2023] [Indexed: 06/18/2023]
Abstract
Terrestrial amplification (TA) of land warming relative to oceans is apparent in recent climatic observations. TA results from land-sea coupling of moisture and heat and is therefore important for predicting future warming and water availability. However, the theoretical basis for TA has never been tested outside the short instrumental period, and the spatial pattern and amplitude of TA remain uncertain. Here, we investigate TA during the Last Glacial Maximum (LGM; ~20 thousand years) in the low latitudes, where the theory is most applicable. We find remarkable consistency between paleotemperature proxies, theory, and climate model simulations of both LGM and future climates. Paleoclimate data thus provide crucial new support for TA, refining the range of future low-latitude, low-elevation TA to [Formula: see text] (95% confidence interval), i.e., land warming ~40% more than oceans. The observed data model theory agreement helps reconcile LGM marine and terrestrial paleotemperature proxies, with implications for equilibrium climate sensitivity.
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Affiliation(s)
- Alan M. Seltzer
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Pierre-Henri Blard
- Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, Vandoeuvre-lès-Nancy, France
- Laboratoire de Glaciologie, Université Libre de Bruxelles, Brussels, Belgium
| | - Steven C. Sherwood
- Climate Change Research Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Masa Kageyama
- Laboratoire des Sciences du Climat et de l’Environnement/Institut Pierre-Simon Laplace (LSCE/IPSL), UMR CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
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7
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Yang Q, Veen GF(C, Wagenaar R, Manrubia M, ten Hooven FC, van der Putten WH. Temporal dynamics of range expander and congeneric native plant responses during and after extreme drought events. ECOL MONOGR 2022; 92:e1529. [PMID: 36590329 PMCID: PMC9787952 DOI: 10.1002/ecm.1529] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/01/2021] [Accepted: 01/14/2022] [Indexed: 01/04/2023]
Abstract
Climate change is causing range shifts of many species to higher latitudes and altitudes and increasing their exposure to extreme weather events. It has been shown that range-shifting plant species may perform differently in new soil than related natives; however, little is known about how extreme weather events affect range-expanding plants compared to related natives. In this study we used outdoor mesocosms to study how range-expanding plant species responded to extreme drought in live soil from a habitat in a new range with and without live soil from a habitat in the original range (Hungary). During summer drought, the shoot biomass of the range-expanding plant community declined. In spite of this, in the mixed community, range expanders produced more shoot biomass than congeneric natives. In mesocosms with a history of range expanders in the previous year, native plants produced less biomass. Plant legacy or soil origin effects did not change the response of natives or range expanders to summer drought. During rewetting, range expanders had less biomass than congeneric natives but higher drought resilience (survival) in soils from the new range where in the previous year native plant species had grown. The biomass patterns of the mixed plant communities were dominated by Centaurea spp.; however, not all plant species within the groups of natives and of range expanders showed the general pattern. Drought reduced the litter decomposition, microbial biomass, and abundances of bacterivorous, fungivorous, and carnivorous nematodes. Their abundances recovered during rewetting. There was less microbial and fungal biomass, and there were fewer fungivorous nematodes in soils from the original range where range expanders had grown in the previous year. We concluded that in mixed plant communities of range expanders and congeneric natives, range expanders performed better, under both ambient and drought conditions, than congeneric natives. However, when considering the responses of individual species, we observed variations among pairs of congenerics, so that under the present mixed-community conditions there was no uniformity in responses to drought of range expanders versus congeneric natives. Range-expanding plant species reduced soil fungal biomass and the numbers of soil fungivorous nematodes, suggesting that the effects of range-expanding plant species can trickle up in the soil food web.
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Affiliation(s)
- Qiang Yang
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands,State Key Laboratory of Grassland Agro‐ecosystems, School of Life SciencesLanzhou UniversityLanzhouChina
| | - G. F. (Ciska) Veen
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
| | - Roel Wagenaar
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
| | - Marta Manrubia
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
| | - Freddy C. ten Hooven
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
| | - Wim H. van der Putten
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands,Laboratory of Nematology, Department of Plant SciencesWageningen University (WUR)WageningenThe Netherlands
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8
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Zhang Z, Bao T, Hautier Y, Yang J, Liu Z, Qing H. Intra-annual growing season climate variability drives the community intra-annual stability of a temperate grassland by altering intra-annual species asynchrony and richness in Inner Mongolia, China. Ecol Evol 2022; 12:e9385. [PMID: 36225823 PMCID: PMC9532246 DOI: 10.1002/ece3.9385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/04/2022] [Accepted: 09/19/2022] [Indexed: 11/14/2022] Open
Abstract
Understanding the factors that regulate the functioning of our ecosystems in response to environmental changes can help to maintain the stable provisioning of ecosystem services to mankind. This is especially relevant given the increased variability of environmental conditions due to human activities. In particular, maintaining a stable production and plant biomass during the growing season (intra‐annual stability) despite pervasive and directional changes in temperature and precipitation through time can help to secure food supply to wild animals, livestock, and humans. Here, we conducted a 29‐year field observational study in a temperate grassland to explore how the intra‐annual stability of primary productivity is influenced by biotic and abiotic variables through time. We found that intra‐annual precipitation variability in the growing season indirectly influenced the community intra‐annual biomass stability by its negative effect on intra‐annual species asynchrony. While the intra‐annual temperature variability in the growing season indirectly altered community intra‐annual biomass stability through affecting the intra‐annual species richness. At the same time, although the intra‐annual biomass stability of the dominant species and the dominant functional group were insensitive to climate variability, they also promoted the stable community biomass to a certain extent. Our results indicate that ongoing intra‐annual climate variability affects community intra‐annual biomass stability in the temperate grassland, which has important theoretical significance for us to take active measures to deal with climate change.
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Affiliation(s)
- Ze Zhang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau Inner Mongolia University Hohhot China.,Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and Environment, Inner Mongolia University Hohhot China
| | - Tiejun Bao
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau Inner Mongolia University Hohhot China.,Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and Environment, Inner Mongolia University Hohhot China
| | - Yann Hautier
- Ecology and Biodiversity Group, Department of Biology Utrecht University Utrecht Netherlands
| | - Jie Yang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau Inner Mongolia University Hohhot China.,Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and Environment, Inner Mongolia University Hohhot China
| | - Zhongling Liu
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau Inner Mongolia University Hohhot China.,Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and Environment, Inner Mongolia University Hohhot China
| | - Hua Qing
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau Inner Mongolia University Hohhot China.,Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and Environment, Inner Mongolia University Hohhot China
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9
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Yuan S, Chen J, Hintelmann H, Cai H, Yuan W, He S, Zhang K, Zhang Y, Liu Y. Event-Based Atmospheric Precipitation Uncovers Significant Even and Odd Hg Isotope Anomalies Associated with the Circumpolar Vortex. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12713-12722. [PMID: 35978561 DOI: 10.1021/acs.est.2c02613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The determination of the mass-independent fractionation of even Hg isotopes (even-MIF, Δ200Hg) in atmospheric samples adds another intriguing feature to the Hg isotope system. Despite our lack of sufficient experimental verification and the momentary absence of a valid mechanism to explain its occurrence, even-MIF could be instrumental in understanding the cycle and deposition of atmospheric Hg. In contrast to slightly positive Δ200Hg values (<0.30‰) frequently observed in most atmospheric samples, large Δ200Hg values (up to 1.24‰) determined in precipitation from Peterborough (Ontario, Canada) stand out and could provide valuable information for the origin of the even-MIF mystery. We now report a systematic analysis of high-resolution rainfall and snowfall samples collected in winter during cold weather at Peterborough, Canada. Dissolved and particulate Hg both displayed large variations of odd-MIF (from -0.93‰ to 2.02‰ for Δ199Hg), which may result from long-range transportation, as the negative odd-MIF in particulate Hg is likely a result of long-distance transport of arctic atmospheric Hg(II). Dissolved Hg revealed significant even-MIF values (from 0.25‰ to 1.19‰ for Δ200Hg) and a negative relationship between Δ200Hg and Δ204Hg, which provide further evidence for the previously proposed conceptual model of Δ200Hg. Disconnected odd-MIF and even-MIF trends were detected in sequentially collected precipitation samples, which further suggests different sources or mechanisms for Δ199Hg and Δ200Hg. Particularly, the high Δ200Hg values highlight the transport of stratospheric Hg through a polar vortex to the sampling region, stimulating further systematic investigation. The new Δ200Hg data for particulate Hg add to existing information on atmospheric Hg(II) worldwide, suggesting a global distribution of Hg characterized by even-MIF in the atmosphere, and further constrain the model of atmospheric Hg deposition.
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Affiliation(s)
- Shengliu Yuan
- Chemistry Department, Trent University, Peterborough, Ontario K9J 7B8, Canada
| | - Jiubin Chen
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, People's Republic of China
| | - Holger Hintelmann
- Chemistry Department, Trent University, Peterborough, Ontario K9J 7B8, Canada
| | - Hongming Cai
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, People's Republic of China
| | - Wei Yuan
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, People's Republic of China
| | - Sheng He
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, People's Republic of China
| | - Ke Zhang
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, People's Republic of China
| | - Yuanyuan Zhang
- Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550002, People's Republic of China
| | - Yulong Liu
- Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550002, People's Republic of China
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10
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Wang P, Asare E, Pitzer VE, Dubrow R, Chen K. Associations between long-term drought and diarrhea among children under five in low- and middle-income countries. Nat Commun 2022; 13:3661. [PMID: 35773263 PMCID: PMC9247069 DOI: 10.1038/s41467-022-31291-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 06/13/2022] [Indexed: 11/30/2022] Open
Abstract
Climate change is projected to intensify drought conditions, which may increase the risk of diarrheal diseases in children. We constructed log-binomial generalized linear mixed models to examine the association between diarrhea risk, ascertained from global-scale nationally representative Demographic and Health Surveys, and drought, represented by the standardized precipitation evapotranspiration index, among children under five in 51 low- and middle-income countries (LMICs). Exposure to 6-month mild or severe drought was associated with an increased diarrhea risk of 5% (95% confidence interval 3-7%) or 8% (5-11%), respectively. The association was stronger among children living in a household that needed longer time to collect water or had no access to water or soap/detergent for handwashing. The association for 24-month drought was strong in dry zones but weak or null in tropical or temperate zones, whereas that for 6-month drought was only observed in tropical or temperate zones. In this work we quantify the associations between exposure to long-term drought and elevated diarrhea risk among children under five in LMICs and suggest that the risk could be reduced through improved water, sanitation, and hygiene practices, made more urgent by the likely increase in drought due to climate change.
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Affiliation(s)
- Pin Wang
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA.
- Yale Center on Climate Change and Health, Yale School of Public Health, New Haven, CT, USA.
| | - Ernest Asare
- Department of Epidemiology of Microbial Diseases and the Public Health Modeling Unit, Yale School of Public Health, New Haven, CT, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases and the Public Health Modeling Unit, Yale School of Public Health, New Haven, CT, USA
| | - Robert Dubrow
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA
- Yale Center on Climate Change and Health, Yale School of Public Health, New Haven, CT, USA
| | - Kai Chen
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA
- Yale Center on Climate Change and Health, Yale School of Public Health, New Haven, CT, USA
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11
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Interhemispheric antiphasing of neotropical precipitation during the past millennium. Proc Natl Acad Sci U S A 2022; 119:e2120015119. [PMID: 35446705 PMCID: PMC9169948 DOI: 10.1073/pnas.2120015119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Understanding Intertropical Convergence Zone (ITCZ) responses to external forcing is critical for predicting climate change in a warming world. We analyzed paleoclimate records of precipitation change in the neotropics and climate model simulations that span the preindustrial last millennium to assess ITCZ behavior on multicentury timescales. Our results demonstrate that the ITCZ shifted southward during the Little Ice Age in the Atlantic basin in response to relative cooling of the Northern Hemisphere driven by volcanic forcing. This finding contrasts with studies suggesting that changes in ITCZ width and/or strength, rather than a change in mean position, occurred during the Little Ice Age. This reinforces the idea that ITCZ responses to external forcing are region specific. Uncertainty about the influence of anthropogenic radiative forcing on the position and strength of convective rainfall in the Intertropical Convergence Zone (ITCZ) inhibits our ability to project future tropical hydroclimate change in a warmer world. Paleoclimatic and modeling data inform on the timescales and mechanisms of ITCZ variability; yet a comprehensive, long-term perspective remains elusive. Here, we quantify the evolution of neotropical hydroclimate over the preindustrial past millennium (850 to 1850 CE) using a synthesis of 48 paleo-records, accounting for uncertainties in paleo-archive age models. We show that an interhemispheric pattern of precipitation antiphasing occurred on multicentury timescales in response to changes in natural radiative forcing. The conventionally defined “Little Ice Age” (1450 to 1850 CE) was marked by a clear shift toward wetter conditions in the southern neotropics and a less distinct and spatiotemporally complex transition toward drier conditions in the northern neotropics. This pattern of hydroclimatic change is consistent with results from climate model simulations indicating that a relative cooling of the Northern Hemisphere caused a southward shift in the thermal equator across the Atlantic basin and a southerly displacement of the ITCZ in the tropical Americas, with volcanic forcing as the principal driver. These findings are at odds with proxy-based reconstructions of ITCZ behavior in the western Pacific basin, where changes in ITCZ width and intensity, rather than mean position, appear to have driven hydroclimate transitions over the last millennium. This reinforces the idea that ITCZ responses to external forcing are region specific, complicating projections of the tropical precipitation response to global warming.
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Zhang Z, Hautier Y, Bao T, Yang J, Qing H, Liu Z, Wang M, Li T, Yan M, Zhang G. Species richness and asynchrony maintain the stability of primary productivity against seasonal climatic variability. FRONTIERS IN PLANT SCIENCE 2022; 13:1014049. [PMID: 36388500 PMCID: PMC9650401 DOI: 10.3389/fpls.2022.1014049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/12/2022] [Indexed: 05/14/2023]
Abstract
The stability of grassland communities informs us about the ability of grasslands to provide reliable services despite environmental fluctuations. There is large evidence that higher plant diversity and asynchrony among species stabilizes grassland primary productivity against interannual climate variability. Whether biodiversity and asynchrony among species and functional groups stabilize grassland productivity against seasonal climate variability remains unknown. Here, using 29-year monitoring of a temperate grassland, we found lower community temporal stability with higher seasonal climate variability (temperature and precipitation). This was due to a combination of processes including related species richness, species asynchrony, functional group asynchrony and dominant species stability. Among those processes, functional group asynchrony had the strongest contribution to community compensatory dynamics and community stability. Based on a long-term study spanning 29 years, our results indicate that biodiversity and compensatory dynamics a key for the stable provision of grassland function against increasing seasonal climate variability.
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Affiliation(s)
- Ze Zhang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Yann Hautier
- Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan, Utrecht, Netherlands
| | - Tiejun Bao
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Jie Yang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Hua Qing
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
- *Correspondence: Hua Qing,
| | - Zhongling Liu
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Min Wang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Taoke Li
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Mei Yan
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Guanglin Zhang
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Inner Mongolia University, Hohhot, China
- Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
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Resilience of the Central Indian Forest Ecosystem to Rainfall Variability in the Context of a Changing Climate. REMOTE SENSING 2021. [DOI: 10.3390/rs13214474] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding the spatio-temporal pattern of natural vegetation helps decoding the responses to climate change and interpretation on forest resilience. Satellite remote sensing based data products, by virtue of their synoptic and repetitive coverage, offer to study the correlation and lag effects of rainfall on forest growth in a relatively longer time scale. We selected central India as the study site. It accommodates tropical natural vegetation of varied forest types such as moist and dry deciduous and evergreen and semi-evergreen forests that largely depend on the southwest monsoon. We used the MODIS derived NDVI and CHIRPS based rainfall datasets from 2001 to 2018 in order to analyze NDVI and rainfall trend by using Sen’s slope and standard anomalies. The study observed a decreasing rainfall trend over 41% of the forests, while the rest of the forest area (59%) demonstrated an increase in rainfall. Furthermore, the study estimated drought conditions during 2002, 2004, 2009, 2014 and 2015 for 98.2%, 92.8%, 89.6%, 90.1% and 95.8% of the forest area, respectively; and surplus rainfall during 2003, 2005, 2007, 2011, 2013 and 2016 for 69.5%, 63.9%, 71.97%, 70.35%, 94.79% and 69.86% of the forest area, respectively. Hence, in the extreme dry year (2002), 93% of the forest area showed a negative anomaly, while in the extreme wet year (2013), 89% of forest cover demonstrated a positive anomaly in central India. The long-term vegetation trend analysis revealed that most of the forested area (>80%) has a greening trend in central India. When we considered annual mean NDVI, the greening and browning trends were observed over at 88.65% and 11.35% of the forested area at 250 m resolution and over 93.01% and 6.99% of the area at 5 km resolution. When we considered the peak-growth period mean NDVI, the greening and browning trends were as follows: 81.97% and 18.03% at 250 m and 88.90% and 11.10% at 5 km, respectively. The relative variability in rainfall and vegetation growth at five yearly epochs revealed that the first epoch (2001–2005) was the driest, while the third epoch (2011–2015) was the wettest, corresponding to the lowest vegetation vigour in the first epoch and the highest in the third epoch during the past two decades. The study reaffirms that rainfall is the key climate variable in the tropics regulating the growth of natural vegetation, and the central Indian forests are dominantly resilient to rainfall variation.
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Lesser MP. Eutrophication on Coral Reefs: What Is the Evidence for Phase Shifts, Nutrient Limitation and Coral Bleaching. Bioscience 2021. [DOI: 10.1093/biosci/biab101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Coral reefs continue to experience extreme environmental pressure from climate change stressors, but many coral reefs are also exposed to eutrophication. It has been proposed that changes in the stoichiometry of ambient nutrients increase the mortality of corals, whereas eutrophication may facilitate phase shifts to macroalgae-dominated coral reefs when herbivory is low or absent. But are corals ever nutrient limited, and can eutrophication destabilize the coral symbiosis making it more sensitive to environmental stress because of climate change? The effects of eutrophication are confounded not just by the effects of climate change but by the presence of chemical pollutants in industrial, urban, and agricultural wastes. Because of these confounding effects, the increases in nutrients or changes in their stoichiometry in coastal environments, although they are important at the organismal and community level, cannot currently be disentangled from each other or from the more significant effects of climate change stressors on coral reefs.
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Affiliation(s)
- Michael P Lesser
- University of New Hampshire, Durham, New Hampshire, United States
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Ketabchi H, Jahangir MS. Influence of aquifer heterogeneity on sea level rise-induced seawater intrusion: A probabilistic approach. JOURNAL OF CONTAMINANT HYDROLOGY 2021; 236:103753. [PMID: 33307334 DOI: 10.1016/j.jconhyd.2020.103753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 11/19/2020] [Accepted: 11/28/2020] [Indexed: 06/12/2023]
Abstract
Seawater intrusion (SWI) is influenced by a variety of coastal phenomena, such as sea level rise (SLR), inundation of low-lying coastal regions, coastal storms, recharge rate variations, and pumping-induced saltwater upconing. Quantification of the influence of heterogeneity in the hydraulic conductivity field on SWI combined with SLR, land-surface inundation, and recharge rate variations in an unconfined aquifer is the main objective of the present study. The principal SWI indicators used in this study are length of the SWI wedge, seawater volume, and weighted average transition zone width. Characterized by the hydraulic conductivity field variance (σlnk2), the longitudinal correlation length (λx), the type of SLR (gradual or instantaneous SLR), the land-surface inundation consideration, and the recharge rate variations, 72 scenarios have been introduced, and for each of them, 50 sets of heterogeneous hydraulic conductivity fields have been generated. Based on two approaches, namely ensemble Monte-Carlo and a Bayesian framework, it is demonstrated that: (1) the land-surface inundation consideration increases the SWI wedge length and the seawater volume regardless of the type of SLR, while it decreases the weighted average transition zone width in gradual SLR scenarios; (2) λx has a more significant impact on SWI characteristics compared to σlnk2; (3) increasing the degree of aquifer heterogeneity results in larger effective dispersion values; (4) Numerical bootstrapping suggests that the introduced Bayesian framework could be adopted as an alternative to computationally demanding methods such as bootstrapping for stochastic analysis of SWI; (5) Reliability analysis indicates the general belief that considering the heterogeneity decreases the SWI wedge length and the seawater volume, while increases the transition zone width compared to the homogeneous modeling is associated with huge amounts of uncertainty proportional to the aquifer heterogeneity itself; and (6) the results show that the impact of heterogeneity on the SWI indicators is similar under different recharge rates.
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Affiliation(s)
- Hamed Ketabchi
- Department of Water Engineering and Management, Tarbiat Modares University, P.O. Box 14115-336, Tehran, Iran.
| | - Mohammad Sina Jahangir
- Water Engineering and Management Research Institute, Tarbiat Modares University, P.O. Box 14115-111, Tehran, Iran
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Elevation Dependence of the Impact of Global Warming on Rainfall Variations in a Tropical Island. WATER 2020. [DOI: 10.3390/w12123582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Due to their vulnerability, understanding the impacts of global warming on rainfall is important for a tropical country and islands. This research aimed to assess the impact of global warming on rainfall in Madagascar, using the Mann-Kendall test, continuous wavelet transform, and polynomial regression. The result showed that the annual, seasonal maximum, and minimum temperature increased, while elevation amplified the increase of maximum temperature. Different trends in rainfall were found in the 22 regions of Madagascar but in general, the increasing trend in rainfall was prominent at a higher elevation than lower elevation. The annual rainfall decreased up to −5 mm per year for the regions located below 450 m of altitude while increased up to +5 mm per year above 500 m. We found that the wet becomes wetter with an important increase in rainfall in summer and the increase in temperature influenced the rainfall. The annual rainfall increased with temperature and elevation. However, if the increase in temperature was more than 0.03 °C per year, the annual rainfall increased regardless of elevation. The knowledge of the elevation dependence of the impact of warming on rainfall is important for water resources management and climate change adaptation strategies, especially for island nations and African countries.
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Yang F, Ma Y, Liu F, Zhao X, Fan C, Hu Y, Hu K, Chang Z, Xiao X. Short-term effects of rainfall on childhood hand, foot and mouth disease and related spatial heterogeneity: evidence from 143 cities in mainland China. BMC Public Health 2020; 20:1528. [PMID: 33036602 PMCID: PMC7545871 DOI: 10.1186/s12889-020-09633-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/29/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Numerous studies have demonstrated the potential association between rainfall and hand, foot and mouth disease (HFMD), but the results are inconsistent. This study aimed to quantify the relationship between rainfall and HFMD based on a multicity study and explore the potential sources of spatial heterogeneity. METHODS We retrieved the daily counts of childhood HFMD and the meteorological variables of the 143 cities in mainland China between 2009 and 2014. A common time series regression model was applied to quantify the association between rainfall and HFMD for each of the 143 cities. Then, we adopted the meta-regression model to pool the city-specific estimates and explore the sources of heterogeneity by incorporating city-specific characteristics. RESULTS The overall pooled estimation suggested a nonlinear exposure-response relationship between rainfall and HFMD. Once rainfall exceeded 15 mm, the HFMD risk stopped increasing linearly and began to plateau with the excessive risk ratio (ERR) peaking at 21 mm of rainfall (ERR = 3.46, 95% CI: 2.05, 4.88). We also found significant heterogeneity in the rainfall-HFMD relationships (I2 = 52.75%, P < 0.001). By incorporating the city-specific characteristics into the meta-regression model, temperature and student density can explain a substantial proportion of spatial heterogeneity with I2 statistics that decreased by 5.29 and 6.80% at most, respectively. CONCLUSIONS Our findings verified the nonlinear association between rainfall and HFMD. The rainfall-HFMD relationship also varies depending on locations. Therefore, the estimation of the rain-HFMD relationship of one location should not be generalized to another location.
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Affiliation(s)
- Fan Yang
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16, Section 3, South Renmin Road, Chengdu, Sichuan, 610041, PR China
| | - Yue Ma
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16, Section 3, South Renmin Road, Chengdu, Sichuan, 610041, PR China
| | - Fengfeng Liu
- Division of Infectious Disease & Key Laboratory of Surveillance and Early Warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, PR China
| | - Xing Zhao
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16, Section 3, South Renmin Road, Chengdu, Sichuan, 610041, PR China
| | - Chaonan Fan
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16, Section 3, South Renmin Road, Chengdu, Sichuan, 610041, PR China
| | - Yifan Hu
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16, Section 3, South Renmin Road, Chengdu, Sichuan, 610041, PR China
| | - Kuiru Hu
- Institute of Basic Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Zhaorui Chang
- Division of Infectious Disease & Key Laboratory of Surveillance and Early Warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, PR China.
| | - Xiong Xiao
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16, Section 3, South Renmin Road, Chengdu, Sichuan, 610041, PR China.
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Wall DP, Delgado A, O'Sullivan L, Creamer RE, Trajanov A, Kuzmanovski V, Bugge Henriksen C, Debeljak M. A Decision Support Model for Assessing the Water Regulation and Purification Potential of Agricultural Soils Across Europe. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.00115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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19
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Boyle WA, Shogren EH, Brawn JD. Hygric Niches for Tropical Endotherms. Trends Ecol Evol 2020; 35:938-952. [PMID: 32693967 DOI: 10.1016/j.tree.2020.06.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/17/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022]
Abstract
Biotic selective pressures dominate explanations for the evolutionary ecology of tropical endotherms. Yet, abiotic factors, principally precipitation regimes, shape biogeographical and phenological patterns in tropical regions. Despite its importance, we lack a framework for understanding when, why, and how rain affects endotherms. Here, we review how tropical birds and mammals respond to rain at individual, population, and community levels, and propose a conceptual framework to interpret divergent responses. Diverse direct and indirect mechanisms underlie responses to rainfall, including physiological, top-down, and food-related drivers. Our framework constitutes a roadmap for the empirical studies required to understand the consequences of rainfall variability. Identifying the patterns and mechanisms underpinning responses to temporal variation in precipitation is crucial to anticipate consequences of anthropogenic climate change.
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Affiliation(s)
- W Alice Boyle
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA.
| | - Elsie H Shogren
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Jeffrey D Brawn
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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20
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Koffi EN, Bergamaschi P, Alkama R, Cescatti A. An observation-constrained assessment of the climate sensitivity and future trajectories of wetland methane emissions. SCIENCE ADVANCES 2020; 6:eaay4444. [PMID: 32300649 PMCID: PMC7148105 DOI: 10.1126/sciadv.aay4444] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 01/16/2020] [Indexed: 05/09/2023]
Abstract
Wetlands are a major source of methane (CH4) and contribute between 30 and 40% to the total CH4 emissions. Wetland CH4 emissions depend on temperature, water table depth, and both the quantity and quality of organic matter. Global warming will affect these three drivers of methanogenesis, raising questions about the feedbacks between natural methane production and climate change. Until present the large-scale response of wetland CH4 emissions to climate has been investigated with land-surface models that have produced contrasting results. Here, we produce a novel global estimate of wetland methane emissions based on atmospheric inverse modeling of CH4 fluxes and observed temperature and precipitation. Our data-driven model suggests that by 2100, current emissions may increase by 50% to 80%, which is within the range of 50% and 150% reported in previous studies. This finding highlights the importance of limiting global warming below 2°C to avoid substantial climate feedbacks driven by methane emissions from natural wetlands.
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He P, Gleason SM, Wright IJ, Weng E, Liu H, Zhu S, Lu M, Luo Q, Li R, Wu G, Yan E, Song Y, Mi X, Hao G, Reich PB, Wang Y, Ellsworth DS, Ye Q. Growing-season temperature and precipitation are independent drivers of global variation in xylem hydraulic conductivity. GLOBAL CHANGE BIOLOGY 2020; 26:1833-1841. [PMID: 31749261 DOI: 10.1111/gcb.14929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Stem xylem-specific hydraulic conductivity (KS ) represents the potential for plant water transport normalized by xylem cross section, length, and driving force. Variation in KS has implications for plant transpiration and photosynthesis, growth and survival, and also the geographic distribution of species. Clarifying the global-scale patterns of KS and its major drivers is needed to achieve a better understanding of how plants adapt to different environmental conditions, particularly under climate change scenarios. Here, we compiled a xylem hydraulics dataset with 1,186 species-at-site combinations (975 woody species representing 146 families, from 199 sites worldwide), and investigated how KS varied with climatic variables, plant functional types, and biomes. Growing-season temperature and growing-season precipitation drove global variation in KS independently. Both the mean and the variation in KS were highest in the warm and wet tropical regions, and lower in cold and dry regions, such as tundra and desert biomes. Our results suggest that future warming and redistribution of seasonal precipitation may have a significant impact on species functional diversity, and is likely to be particularly important in regions becoming warmer or drier, such as high latitudes. This highlights an important role for KS in predicting shifts in community composition in the face of climate change.
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Affiliation(s)
- Pengcheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Sean M Gleason
- USDA-ARS Water Management and Systems Research Unit, Fort Collins, CO, USA
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ensheng Weng
- Center for Climate Systems Research, Columbia University, New York, NY, USA
| | - Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Mingzhen Lu
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Qi Luo
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Ronghua Li
- Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou, China
| | - Guilin Wu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Enrong Yan
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yanjun Song
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xiangcheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Guangyou Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Yingping Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- CSIRO Oceans and Atmosphere, Aspendale, Vic., Australia
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
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Estimated Impacts of Climate Change on Eddy Meridional Moisture Transport in the Atmosphere. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9234992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Research findings suggest that water (hydrological) cycle of the earth intensifies in response to climate change, since the amount of water that evaporates from the ocean and land to the atmosphere and the total water content in the air will increase with temperature. In addition, climate change affects the large-scale atmospheric circulation by, for example, altering the characteristics of extratropical transient eddies (cyclones), which play a dominant role in the meridional transport of heat, moisture, and momentum from tropical to polar latitudes. Thus, climate change also affects the planetary hydrological cycle by redistributing atmospheric moisture around the globe. Baroclinic instability, a specific type of dynamical instability of the zonal atmospheric flow, is the principal mechanism by which extratropical cyclones form and evolve. It is expected that, due to global warming, the two most fundamental dynamical quantities that control the development of baroclinic instability and the overall global atmospheric dynamics—the parameter of static stability and the meridional temperature gradient (MTG)—will undergo certain changes. As a result, climate change can affect the formation and evolution of transient extratropical eddies and, therefore, macro-exchange of heat and moisture between low and high latitudes and the global water cycle as a whole. In this paper, we explore the effect of changes in the static stability parameter and MTG caused by climate change on the annual-mean eddy meridional moisture flux (AMEMF), using the two classical atmospheric models: the mid-latitude f-plane model and the two-layer β-plane model. These models are represented in two versions: “dry,” which considers the static stability of dry air alone, and “moist,” in which effective static stability is considered as a combination of stability of dry and moist air together. Sensitivity functions were derived for these models that enable estimating the influence of infinitesimal perturbations in the parameter of static stability and MTG on the AMEMF and on large-scale eddy dynamics characterized by the growth rate of unstable baroclinic waves of various wavelengths. For the base climate change scenario, in which the surface temperature increases by 1 °C and warming of the upper troposphere outpaces warming of the lower troposphere by 2 °C (this scenario corresponds to the observed warming trend), the response of the mass-weighted vertically averaged annual mean MTG is -0.2 ℃ per 1000 km. The dry static stability increases insignificantly relative to the reference climate state, while on the other hand, the effective static stability decreases by more than 5.4%. Assuming that static stability of the atmosphere and the MTG are independent of each other (using One-factor-at-a-time approach), we estimate that the increase in AMEMF caused by change in MTG is about 4%. Change in dry static stability has little effect on AMEMF, while change in effective static stability leads to an increase in AMEMF of about 5%. Thus, neglecting atmospheric moisture in calculations of the atmospheric static stability leads to tangible differences between the results obtained using the dry and moist models. Moist models predict ~9% increase in AMEMF due to global warming. Dry models predict ~4% increase in AMEMF solely because of the change in MTG. For the base climate change scenario, the average temperature of the lower troposphere (up to ~4 km), in which the atmospheric moisture is concentrated, increases by ~1.5 ℃. This leads to an increase in specific humidity of about 10.5%. Thus, since both AMEMF and atmospheric water vapor content increase due to the influence of climate change, a rather noticeable restructuring of the global water cycle is expected.
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Watras CJ, Michler JR, Lenters JD, Rubsam JL. A low-cost hydrologic observatory for monitoring the water balance of small lakes. ENVIRONMENTAL MONITORING AND ASSESSMENT 2019; 191:548. [PMID: 31392422 DOI: 10.1007/s10661-019-7712-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Global warming portends an accelerated water cycle as increased evaporation feeds atmospheric moisture and precipitation. To monitor effects on surface water levels, we describe a low-cost hydrologic observatory suitable for small to medium size lakes. The observatory comprises sensor platforms that were built in-house to compile continuous, sub-daily water budgets. The variables measured directly are lake stage (S), evaporation (E), and precipitation (P). A net inflow term (Qnet) is estimated as a residual in the continuity equation: ∆S = P - E + Qnet. We describe how to build in-lake stilling wells and floating evaporation pans using readily available materials. We assess their performance in laboratory tests and field trials. A 3-month deployment on a small Wisconsin lake (18 ha, 10 m deep) confirms that continuous estimates of ∆S, E, P, and Qnet can be made with good precision and accuracy at hourly time scales. During that deployment, daily estimates of E from the floating evaporation pans were comparable with estimates made using the more data-intensive Bowen ratio energy balance method and a mass transfer model. Since small lakes are numerically dominant and widely distributed across the globe, a network of hydrologic observatories would enable the calibration and validation of climate models and consumptive use policies at local and regional scales. And since the observatories are inexpensive and relatively simple to maintain, citizen scientists could facilitate the expansion of spatial coverage with minimal training.
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Affiliation(s)
- Carl J Watras
- Bureau of Water Quality, Wisconsin Department of Natural Resources, UW-Trout Lake Research Station, 3110 Trout Lake Station Drive, Boulder Junction, WI, 54512, USA.
- Center for Limnology, University of Wisconsin-Madison, 180 North Park St., Madison, WI, 53706, USA.
| | - James R Michler
- Bureau of Water Quality, Wisconsin Department of Natural Resources, UW-Trout Lake Research Station, 3110 Trout Lake Station Drive, Boulder Junction, WI, 54512, USA
| | - John D Lenters
- Bureau of Water Quality, Wisconsin Department of Natural Resources, UW-Trout Lake Research Station, 3110 Trout Lake Station Drive, Boulder Junction, WI, 54512, USA
- Center for Limnology, University of Wisconsin-Madison, 180 North Park St., Madison, WI, 53706, USA
| | - Jeff L Rubsam
- Bureau of Water Quality, Wisconsin Department of Natural Resources, UW-Trout Lake Research Station, 3110 Trout Lake Station Drive, Boulder Junction, WI, 54512, USA
- Center for Limnology, University of Wisconsin-Madison, 180 North Park St., Madison, WI, 53706, USA
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24
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McGee D, Moreno-Chamarro E, Marshall J, Galbraith ED. Western U.S. lake expansions during Heinrich stadials linked to Pacific Hadley circulation. SCIENCE ADVANCES 2018; 4:eaav0118. [PMID: 30498784 PMCID: PMC6261653 DOI: 10.1126/sciadv.aav0118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/29/2018] [Indexed: 06/09/2023]
Abstract
Lake and cave records show that winter precipitation in the southwestern United States increased substantially during millennial-scale periods of Northern Hemisphere winter cooling known as Heinrich stadials. However, previous work has not produced a clear picture of the atmospheric circulation changes driving these precipitation increases. Here, we combine data with model simulations to show that maximum winter precipitation anomalies were related to an intensified subtropical jet and a deepened, southeastward-shifted Aleutian Low, which together increased atmospheric river-like transport of subtropical moisture into the western United States. The jet and Aleutian Low changes are tied to the southward displacement of the intertropical convergence zone and the accompanying intensification of the Hadley circulation in the central Pacific. These results refine our understanding of atmospheric changes accompanying Heinrich stadials and highlight the need for accurate representations of tropical-extratropical teleconnections in simulations of past and future precipitation changes in the region.
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Affiliation(s)
- D. McGee
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - E. Moreno-Chamarro
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J. Marshall
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - E. D. Galbraith
- Institut de Ciència i Tecnologia Ambientals (ICTA) and Department of Mathematics, Universitat Autonoma de Barcelona, 08193 Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
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25
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Martin LCP, Blard PH, Lavé J, Condom T, Prémaillon M, Jomelli V, Brunstein D, Lupker M, Charreau J, Mariotti V, Tibari B, Davy E. Lake Tauca highstand (Heinrich Stadial 1a) driven by a southward shift of the Bolivian High. SCIENCE ADVANCES 2018; 4:eaar2514. [PMID: 30167458 PMCID: PMC6114991 DOI: 10.1126/sciadv.aar2514] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
Heinrich events are characterized by worldwide climate modifications. Over the Altiplano endorheic basin (high tropical Andes), the second half of Heinrich Stadial 1 (HS1a) was coeval with the highstand of the giant paleolake Tauca. However, the atmospheric mechanisms underlying this wet event are still unknown at the regional to global scale. We use cosmic-ray exposure ages of glacial landforms to reconstruct the spatial variability in the equilibrium line altitude of the HS1a Altiplano glaciers. By combining glacier and lake modeling, we reconstruct a precipitation map for the HS1a period. Our results show that paleoprecipitation mainly increased along the Eastern Cordillera, whereas the southwestern region of the basin remained relatively dry. This pattern indicates a southward expansion of the easterlies, which is interpreted as being a consequence of a southward shift of the Bolivian High. The results provide a new understanding of atmospheric teleconnections during HS1 and of rainfall redistribution in a changing climate.
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Affiliation(s)
- Léo C. P. Martin
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
- Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway
| | - Pierre-Henri Blard
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
- Laboratoire de Glaciologie, Département Géosciences, Environnement et Société–Institut des Géosciences, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Jérôme Lavé
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
| | - Thomas Condom
- Université de Grenoble Alpes, Institut de Recherche pour le Développement (IRD), CNRS, Institut des Géosciences de l’Environnement, F-38000 Grenoble, France
| | - Mélody Prémaillon
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
| | - Vincent Jomelli
- Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France
| | - Daniel Brunstein
- Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France
| | - Maarten Lupker
- ETH, Geological Institute, Sonneggstrasse 5, 8092 Zurich, Switzerland
| | - Julien Charreau
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
| | - Véronique Mariotti
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
| | - Bouchaïb Tibari
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
| | | | - Emmanuel Davy
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS–Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France
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26
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Zhang Y, Loreau M, He N, Wang J, Pan Q, Bai Y, Han X. Climate variability decreases species richness and community stability in a temperate grassland. Oecologia 2018; 188:183-192. [PMID: 29943096 DOI: 10.1007/s00442-018-4208-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 06/18/2018] [Indexed: 12/15/2022]
Abstract
Climate change involves modifications in both the mean and the variability of temperature and precipitation. According to global warming projections, both the magnitude and the frequency of extreme weather events are increasing, thereby increasing climate variability. The previous studies have reported that climate warming tends to decrease biodiversity and the temporal stability of community primary productivity (i.e., community stability), but the effects of the variability of temperature and precipitation on biodiversity, community stability, and their relationship have not been clearly explored. We used a long-term (from 1982 to 2014) field data set from a temperate grassland in northern China to explore the effects of the variability of mean temperature and total precipitation on species richness, community stability, and their relationship. Results showed that species richness promoted community stability through increases in asynchronous dynamics across species (i.e., species asynchrony). Both species richness and species asynchrony were positively associated with the residuals of community stability after controlling for its dependence on the variability of mean temperature and total precipitation. Furthermore, the variability of mean temperature reduced species richness, while the variability of total precipitation decreased species asynchrony and community stability. Overall, the present study revealed that species richness and species asynchrony promoted community stability, but increased climate variability may erode these positive effects and thereby threaten community stability.
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Affiliation(s)
- Yunhai Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Michel Loreau
- Centre for Biodiversity Theory and Modelling, Theoretical and Experimental Ecology Station, CNRS and Paul Sabatier University, 09200, Moulis, France
| | - Nianpeng He
- Synthesis Research Center of Chinese Ecosystem Research Network, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101, Beijing, China
| | - Junbang Wang
- Synthesis Research Center of Chinese Ecosystem Research Network, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101, Beijing, China
| | - Qingmin Pan
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China
| | - Yongfei Bai
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China.
| | - Xingguo Han
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China.
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South American monsoon response to iceberg discharge in the North Atlantic. Proc Natl Acad Sci U S A 2018; 115:3788-3793. [PMID: 29581293 DOI: 10.1073/pnas.1717784115] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heinrich Stadials significantly affected tropical precipitation through changes in the interhemispheric temperature gradient as a result of abrupt cooling in the North Atlantic. Here, we focus on changes in South American monsoon precipitation during Heinrich Stadials using a suite of speleothem records covering the last 85 ky B.P. from eastern South America. We document the response of South American monsoon precipitation to episodes of extensive iceberg discharge, which is distinct from the response to the cooling episodes that precede the main phase of ice-rafted detritus deposition. Our results demonstrate that iceberg discharge in the western subtropical North Atlantic led to an abrupt increase in monsoon precipitation over eastern South America. Our findings of an enhanced Southern Hemisphere monsoon, coeval with the iceberg discharge into the North Atlantic, are consistent with the observed abrupt increase in atmospheric methane concentrations during Heinrich Stadials.
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