Interannual Climate Variability Change during the Medieval Climate Anomaly and Little Ice Age in PMIP3 Last Millennium Simulations

In this study, we analyzed numerical experiments undertaken by 10 climate models participating in PMIP3（Paleoclimate Modelling Intercomparison Project Phase 3） to examine the changes in interannual temperature variability and coefficient of variation（CV） of interannual precipitation in the warm period of the Medieval Climate Anomaly（MCA） and the cold period of the Little Ice Age（LIA）. With respect to the past millennium period, the MCA temperature variability decreases by 2.0% on average over the globe, and most of the decreases occur in low latitudes. In the LIA, temperature variability increases by a global average of 0.6%, which occurs primarily in the high latitudes of Eurasia and the western Pacific. For the CV of interannual precipitation, regional-scale changes are more significant than changes at the global scale, with a pattern of increased（decreased） CV in the midlatitudes of Eurasia and the northwestern Pacific in the MCA（LIA）. The CV change ranges from-7.0% to 4.3%（from -6.3% to 5.4%）, with a global average of -0.5%（-0.07%） in the MCA（LIA）.Also, the variability changes are considerably larger in December–January–February with respect to both temperature and precipitation.

The Approaching New Grand Solar Minimum and Little Ice Age Climate Conditions

By about 2030-2040, the Sun will experience a new grand solar minimum. This is evident from multiple studies of quite different characteristics: the phasing of sunspot cycles, the cyclic observations of North Atlantic behaviour over the past millennium, the cyclic pattern of cosmogenic radionuclides in natural terrestrial archives, the motions of the Sun with respect to the centre of mass, the planetary spin-orbit coupling, the planetary conjunction history and the general planetary-solar-terrestrial interaction. During the previous grand solar minima—i.e. the Sporer Minimum (ca 1440-1460), the Maunder Minimum (ca 1687-1703) and the Dalton Minimum (ca 1809-1821)—the climatic conditions deteriorated into Little Ice Age periods.

THE NUMERICAL SIMULATION OF THE ICE AGE CLIMATE

Using the lAP two-level general circulation model,the ice age July climate was simulated through the surface con- ditions of 18 000 years before present assembled by the CLIMAP Project.Comparing with the present July simulation results,the ice age atmosphere is found to have a substantially lower temperature,precipitation,and cloudiness,higher sea-level pressure,especially in the high latitude land region of the Northern Hemisphere and Antarctica.When the CO2 content is set as the modern value the climatic response is very small,which shows that the problems of CO2 sen- sitivity should be studied by means of coupled models.It is also pointed out that there are some common characteristics between CO2-induced climatic changes and the ice age surface condition-induced climatic changes,which may give us some insight into how climate responds to external forcings.

A New Ice Age? None Soon,Snow 2 Miles Deep Implies

冰川学专家认为,全球气候在漫长的地质年代中曾有数次冷暖变化,冰川作用随之重复发生。气候寒冷时,降雪量增加,发育大规模的冰川,巨大的冰盖掩盖地球,称为冰川期(ice age)。地球已经历了四次大冰川期,第五纪冰川期是否即将来临?科学家对此进行了研究。

Habitable Land Will Soon Become the World’s Scarcest Resource: Why Appalachia Should Choose Climate Change Havens over Millionaire Estates and Golf Courses

This research advocates for the construction of Climate Change Haven Communities across the Appalachian Region. The proposed development plan can be extended to the northern tier states across the US and also to the northern and mountainous regions of Europe and Asia. We present an analogy to the earlier climate change period of the Last Glacial Maximum/“Ice Age” in which these same northern regions of the planet were covered in ice sheets making them uninhabitable for most humans and many plant and animal species. In some significant ways, the Ice Age scenario can be a reverse-model for our current climate crisis. We also advocate strongly for the prevention of upscale real estate development projects in these same regions of the globe, as these will foreclose the possibility of safely sheltering the millions of persons who will be displaced by climate change over the next 5 to 10 years.

The Glacial(MIS 3-2)Outlet Glacier of the Marsyandi Nadi-icestream-network with its Ngadi Khola Tributary Glacier(Manaslu-and Lamjung Himalaya):The Reconstructed Lowering of the Marsyandi Nadi Ice Stream Tongue down in to the Southern Himalaya Foreland

For the reconstruction of past climate variations,investigations on the history of glaciers are necessary.In the Himalaya,investigations like these have a rather short tradition in comparison with other mountains on earth.At the same time,this area on the southern margin of Tibet is of special interest because of the question as to the monsoon-influence that is connected with the climate-development.Anyhow,the climate of High Asia is of global importance.Here for the further and regionally intensifying answer to this question,a glacial glacier reconstruction is submitted from the CentralHimalaya,more exactly from the Manaslu-massif.Going on down-valley from the glacial-historical investigations of 1977 in the upper Marsyandi Khola(Nadi) and the partly already published results of field campaigns in the middle Marsyandi Khola and the Damodar- and Manaslu Himal in the years 1995,2000,2004 and 2007,new geomorphological and geological field- and laboratory data are introduced here from the Ngadi(Nadi) Khola and the lower Marsyandi Nadi from the inflow of the Ngadi(Nadi) Khola down to the southern mountain foreland.There has existed a connected ice-stream-network drained down to the south by a 2,100-2,200 m thick and 120 km long Marsyandi Nadi main valley glacier.At a height of the valley bottom of c.1,000 m a.s.l.the Ngadi Khola glacier joined the still c.1,300 m thick Marsyandi parent glacier from the Himalchuli-massif(Nadi(Ngadi) Chuli) – the south spur of the Manaslu Himal.From here the united glacier tongue flowed down about a further 44 km to the south up to c.400 m a.s.l.(27°57'38 "N/84°24'56" E) into the Himalaya fore-chains and thus reached one of or the lowest past ice margin position of the Himalayas.The glacial(LGP(Last glacial period),LGM(Last glacial maximum) Würm,Stage 0,MIS 3-2) climatic snowline(ELA = equilibrium line altitude) has run at 3,900 to 4,000 m a.s.l.and thus c.1,500 altitude meters below the current ELA(Stage XII) at 5,400-5,500 m a.s.l.The reconstructed,maximum lowering of the climatic snowline(ΔELA = depression of the equilibrium line altitude) about 1,500 m corresponds at a gradient of 0.6°C per 100 altitude meters to a High Glacial decrease in temperature of 9°C(0.6 × 15 = 9).At that time the Tibetan inland ice has caused a stable cold high,so that no summer monsoon can have existed there.Accordingly,during the LGP the precipitation was reduced,so that the cooling must have come to more than only 9°C.

Aeolian activity in the southern Gurbantunggut Desert of China during the last 900 years

The mineral dust emitted from Central Asia has a significant influence on the global climate system.However,the history and mechanisms of aeolian activity in Central Asia remain unclear,due to the lack of well-dated records of aeolian activity and the intense wind erosion in some of the dust source areas(e.g.,deserts).Here,we present the records of aeolian activity from a sedimentary sequence in the southern Gurbantunggut Desert of China using grain size analysis and optically stimulated luminescence(OSL)dating,based on field sampling in 2019.Specifically,we used eight OSL dates to construct chronological frameworks and applied the end-member(EM)analysis for the grain size data to extract the information of aeolian activity in the southern Gurbantunggut Desert during the last 900 a.The results show that the grain size dataset can be subdivided into three EMs(EM1,EM2,and EM3).The primary modal sizes of these EMs(EM1,EM2,and EM3)are 126.00,178.00,and 283.00μm,respectively.EM1 represents a mixture of the suspension components and saltation dust,while EM2 and EM3 show saltation dust transported over a shorter distance via strengthened near-surface winds,which can be used to trace aeolian activity.Combined with the OSL chronology,our results demonstrate that during the last 900 a,more intensive and frequent aeolian activity occurred during 450-100 a BP(Before Present)(i.e.,the Little Ice Age(LIA)),which was reflected by a higher proportion of the coarse-grained components(EM2+EM3).Aeolian activity decreased during 900-450 a BP(i.e.,the Medieval Warm Period(MWP))and 100 a BP-present(i.e.,the Current Warm Period(CWP)).Intensified aeolian activity was associated with the strengthening of the Siberian High and cooling events at high northern latitudes.We propose that the Siberian High,under the influence of temperature changes at high northern latitudes,controlled the frequency and intensity of aeolian activity in Central Asia.Cooling at high northern latitudes would have significantly enhanced the Siberian High,causing its position to shift southward.Subsequently,the incursion of cold air masses from high northern latitudes resulted in stronger wind regimes and increased dust emissions from the southern Gurbantunggut Desert.It is possible that aeolian activity may be weakened in Central Asia under future global warming scenarios,but the impact of human activities on this region must also be considered.

Evolution of permafrost in Northeast Chinasince the Late Pleistocene

In Northeast China, permafrost advanced and retreated several times under the influences of fluctuating paleo-climatesand paleo-environments since the Late Pleistocene. During the last 60 years, many new data were obtained and studies wereconducted on the evolution of permafrost in Northeast China, but so far no systematic summary and review have been made.Based on sedimentary sequences, remains of past permafrost, paleo-flora and -fauna records, and dating data, permafrostevolution since the Late Pleistocene has been analyzed and reconstructed in this paper. Paleo-temperatures reconstructedfrom the remains of past permafrost and those from paleo-flora and -fauna are compared, and thus the southern limitof permafrost （SLP） in each climate period is inferred by the relationship of the permafrost distribution and the meanannual air/ground temperatures （MAAT/MAGT）. Thus, the evolutionary history of permafrost is here divided into fivestages： （1） the Late Pleistocene （Last Glaciation, or LG） （65 to 10–8.5 ka）, the Last Glaciation Maximum （LGM, 21–13 ka）in particular, the coldest period in the latest history with a cooling of about 6~10 °C, characterized by extensive occurrencesof glaciation, flourishing Mammathas-Coelodonta Faunal Complex （MCFC）, widespread aeolian deposits, and significantsea level lowering, and permafrost greatly expanded southwards almost to the coastal plains （37°N–41°N）; （2） the HoloceneMegathermal Period （HMP, 8.5–7.0 to 4.0–3.0 ka）, 3~5 °C warmer than today, permafrost retreated to about 52°N; （3） theLate Holocene Cold Period （Neoglaciation） （4.0–3.0 to 1.0–0.5 ka）, a cooling of 1~3 °C, some earlier thawed permafrost wasrefrozen or attached, and the SLP invaded southwards to 46°N; （4） the Little Ice Age （LIA, 500 to 100–150 a）, the latestcold period with significant permafrost expansion; and （5） climate warming since the last century, during which NortheastChina has undergone extensive permafrost degradation. The frequent and substantial expansions and retreats of permafrosthave greatly impacted cold-region environments in Northeast China. North of the SLP during the HMP, or in the presentcontinuous permafrost zone, the existing permafrost was largely formed during the LG and was later overlapped by thepermafrost formed in the Neoglaciation. To the south, it was formed in the Neoglaciation. However, many aspects ofpermafrost evolution still await further investigations, such as data integration, numerical reconstruction, and merging ofChinese permafrost history with those of bordering regions as well as collaboration with related disciplines. Of these, studies on the evolution and degradation of permafrost during the past 150 years and its hydrological, ecological, and environmentalimpacts should be prioritized.

Glacial-Interglacial Atmospheric CO_2 Change——The Glacial Burial Hypothesis

Organic carbon buried under the great ice sheets of the Northern Hemisphere is suggested to be the missing link in the atmospheric CO2 change over the glacial-interglacial cycles. At glaciation, the advancement of continental ice sheets buries vegetation and soil carbon accumulated during warmer periods. At deglaciation, this burial carbon is released back into the atmosphere. In a simulation over two glacial-interglacial cycles using a synchronously coupled atmosphere-land-ocean carbon model forced by reconstructed climate change, it is found that there is a 547-Gt terrestrial carbon release from glacial maximum to interglacial, resulting in a 60-Gt (about 30-ppmv) increase in the atmospheric CO2, with the remainder absorbed by the ocean in a scenario in which ocean acts as a passive buffer. This is in contrast to previous estimates of a land uptake at deglaciation. This carbon source originates from glacial burial, continental shelf, and other land areas in response to changes in ice cover, sea level, and climate. The input of light isotope enriched terrestrial carbon causes atmospheric δ13C to drop by about 0.3‰ at deglaciation, followed by a rapid rise towards a high interglacial value in response to oceanic warming and regrowth on land. Together with other ocean based mechanisms such as change in ocean temperature, the glacial burial hypothesis may offer a full explanation of the observed 80–100-ppmv atmospheric CO2 change.

Coastal environment of the past millennium recorded by a coastal dune in Fujian,China

Coastal dune is a common aeolian geomorphology in a sandy coast,which records the evolution process of the aeolian landscape system and reflects the complex interaction among land surface,atmosphere and ocean.Coast is a sensitive area to global climate change.Restricted by chronology,most previous researches in China focused only on the cause of formation of coastal dunes.In recent years,the development of optically stimulated luminescence （OSL） dating provides a good method and acts as a carrier for coastal dunes to paleoclimate and paleoenvironmental studies.In this study,we selected an aeolian dune at the Anshan archaeological site,Fujian,China as the research object based on field observations.For determining their sedimentary stages and the primary influencing factors,we used the OSL dating method to construct a chronological framework for the aeolian dune.In addition,the sizes of grains were analyzed for identifying factors influencing the winter monsoon during the Medieval Warm Period （MWP） and the Little Ice Age （LIA） in this area.The results showed that the deposition of the aeolian dune was closely related to variations in the winter monsoon intensity.The changes of the winter monsoon were similar to the tendency of the East Asian winter monsoon,although there were several sub-fluctuations.From an overall perspective,the winter monsoon was strengthened during the MWP （1050–1300） .The results of a power spectrum analysis showed that the intensity of the East Asian winter monsoon is correlated with sunspot activity.

The past,present,and future of the Siberian Grouse(Falcipennis falcipennis)under glacial oscillations and global warming

Global climate change has a significant effect on species,as environment conditions change,causing many species'distributions to shift.During the last three million years,the earth has experienced glacial oscillations,forcing some species to survive in ice-free refugia during glacial periods and then disperse postglacially.In this study,by assessing the potential distribution of Siberian Grouse(Falcipennis falcipennis),we used Global Circular Models and Representative Concentration Pathways to model their pattern of range changes during glacial oscillations and the potential impact of present global warming.We used 158 location records of Siberian Grouse to generate a full climate model using 19 bioclimate variables in MaxEnt.We discarded variables with a correlation coefficient larger than 0.8 and relatively lower modeling contributions between each pair of correlated variables.Using the remaining variables,we created a normally uncorrelated simple climate model to predict the possible distribution of Siberian Grouse from the most recent Ice Age to present and to 2070.Then we added geographical data and the human interference index to construct a multiple factor full model to evaluate which were important in explaining the distribution of Siberian Grouse.The Total Suitability Zone(P≥0.33)of Siberian Grouse is about 243,000km^(2) and the Maximum Suitability Zone(P≥0.66)is 36,000km^(2) and is confined to the Russian Far East.Potential habitat modeling suggested that annual precipitation,annual mean temperature,and the distance from lakes are the most explanatory variables for the current distribution of Siberian Grouse.The distribution center moved to the southeast during the Last Glacial Maximum and spread back to the northwest after the ice melted and temperatures rose.The total area range of Siberian Grouse experienced a dramatic loss during the Last Glacial Maximum.Global warming is presently forcing the Siberian Grouse to migrate northward with a contraction of its range.There is an urgent need to protect its habitat,because little of its Maximum Sustainable Zone is protected,although there are some large reserves in that area.

Absence of the Impact of the Flux of Cosmic Rays and the Cloud Cover on the Energy Balance of the Earth

The energy of solar radiation absorbed by the Earth,as well as the thermal radiation of the Earth’s surface,which is released to the space through the atmospheric transparency window,depends on variations of the area of the cloud cover.Svensmark et al.suggest that the increase in the area of the cloud cover in the lower atmosphere,presumably caused by an increase in the flux of galactic cosmic rays during the quasi-bicentennial minimum of solar activity,results only in an increase in the fraction of the solar radiation reflected back to the space and weakens the flux of the solar radiation that reached the Earth surface.It is suggested,without any corresponding calculations of the variations of the average annual energy balance of the EarthЕ,that the consequences will include only a deficit of the solar energy absorbed by the Earth and a cooling of the climate up to the onset of the Little Ice Age.These suggestions ignore simultaneous impact of the opposite aspects of the increase in the area of the cloud cover on the climate warming.The latter will result from a decrease in the power of thermal radiation of the Earth’s surface released to the space,and also in the power of the solar radiation reflected from the Earth’s surface,due to the increase in their absorption and reflection back to the surface.A substantial strengthening in the greenhouse effect and the narrowing of the atmospheric transparency window will also occur.Here,we estimate the impact of all aspects of possible long-term 2%growth of the cloud cover area in the lower atmosphere byЕ.We found that an increase in the cloud cover area in the lower atmosphere will result simultaneously both in the decrease and in the increase in the temperature,which will virtually compensate each other,while the energy balance of the Earth E before and after the increase in the cloud cover area by 2%will stay essentially the same:E1-E0≈0.

New Long-Term Climate Oscillations

The astronomical theory of climate change is based on the solution of differential equations describing Earth’s orbital and rotational motions. The equations are used to calculate the change in insolation over the Earth’s surface. As a result of the author’s solution of the orbital problem, the periods and amplitudes of Earth-orbit variations and their evolution have been refined. Unlike previous studies, the equations of Earth’s rotational motion are solved completely. The Earth’s rotational axis precesses relative to a direction different from the direction of the orbit’s axial precession, and oscillates with periods of half a month, half a year and 18.6 years. Also, its oscillations occur with irregular periods of several tens of thousands of years and more. All these motions lead to oscillations of the obliquity in the range of 14.7° to 32.1°, which prove to be 7 - 8 times larger than obtained by a previous theory. In the same proportion, the Earth’s insolation oscillations increase in amplitude, with insolation extremes occurring in other epochs than those in the previous theory. The amplitudes and the onset times of the extremes correlate with known paleoclimate changes. Thirteen insolation periods of paleoclimate variation over an interval of 200 thousand years are identified. From the insolation evolution calculated over a time interval of 1 million years, 6 climate gradations from very cold to very warm are identified.

Quantifying temporal changes in Tornionjoki river ice breakup dates and spring temperatures in Lapland since 1802

Cryophenological records （i.e. observational series of freeze and breakup dates of ice） are of great importance when assessing the environmental variations in cold regions. Here we employed the extraordinarily long observational records of river ice breakup dates and air temperatures in northern Fennoscandia to examine their interrelations since 1802. Historical observations, along with modern data, comprise the informational setting for this analysis carried out using t-test. Temperature history of April-May season was used as cli- matic counterpart for the breakup timings. Both records （temperature and breakup） showed seven sub-periods during which their local means were distinctly different relative to preced- ing and subsequent sub-periods. The starting and ending years of these sub-periods oc- curred in temporal agreement. The main findings of this study are summarized as follows： （1） the synchrony between the temperature and river ice breakup records ruled out the possibility that the changes would have occurred due to quality of the historical series （i.e. inhomoge- neity problems often linked to historical time-series）; （2） the studied records agreed to show lower spring temperatures and later river ice breakups during the 19th century, in comparison to the 20th century conditions, evidencing the prevalence of cooler spring temperatures in the study region, in agreement with the concept of the Little Ice Age （1570-1900） climate in North-West Europe; （3） the most recent sub-period demonstrate the highest spring tem- peratures with concomitantly earliest river ice breakups, showing the relative warmth of the current springtime climate in the study region in the context of the past two centuries; （4） the effects of anthropogenic changes in the river environment （e.g. construction and demolition of dams） during the 20th century should be considered for non-climatic variations in the breakup records; （5） this study emphasizes the importance of multi-centurial （i.e. historical） cryo- phenological information for highly interesting viewpoints of climate and environmental his- tory.

Temperature variations along the Silk Road over the past 2000 years:Integration and perspectives

Reconstructing temperature changes along the Silk Road(SR)over the last two millennia can provide insights into past global changes and their impact on the rise and fall of ancient civilizations in this region.Numerous high-quality single-site paleotemperature records have been produced for the eastern part of the SR(mainly for the Xinjiang region and its surrounding areas),which provide the data basis for a comprehensive synthesis.In this study,we used objective criteria to select 10 highquality ones from 30 temperature reconstructions derived from various geological archives including lacustrine sediments,ice cores,and tree rings in this region.Our aims are to summarize the pattern of temperature change over the past 2000 years,to provide a long-term viewpoint on the present warming,and to evaluate the impact of climate change on civilizations along the SR.The principal results are as follows:(1)The temperature variations over the last millennium are mutually consistent within these records.The study area experienced typical climate anomalies during the Medieval Warm Period(MWP,AD 1000-1250),the Little Ice Age(LIA,AD 1450-1850),and the Current Warm Period(CWP,AD 1850 to present);however,contrary to previous knowledge,the amplitude of climatic warming during the CWP did not exceed that during the MWP.(2)Fewer temperature records were available for the interval AD 1–1000,and there were large differences between them.For example,the reconstructed climate during both the Han Dynasty and the Sui-Tang Dynasties was either warm or cold,without prevailing consensus.(3)The warming during the MWP favored the rapid development of the SR route along the northern slopes of the Tianshan Mountains,and the cooling during the LIA contributed to the decline of the SR marked by the closure of the Jiayuguan Pass.Notably,the scarcity of temperature records and the discrepancies between them during AD 1-1000 in the eastern part of the SR have hindered our understanding of the hydroclimatic changes and their influence on the development of civilizations along the SR.Thus,it is important to obtain an increased number of high-quality reliable records spanning the past 2000 year,and to examine the occurrence of local signals of temperature changes during the period of AD 1-1000.On the other hand,the paleotemperature investigation on the western part of the SR over the last two millennia is wholly insufficient,and thus more high-quality single-site and integrated studies are needed,to facilitate more comprehensive insights into the coupled relationship between climate change and the rise and fall of civilizations along the entire length of the Silk Road.

Glaciation-induced features or sediment gravity flows——An analytic review

For more than 150 years, geologic characteristics claimed to be evidence for pre-Pleistocene glaciations have been debated. Advancements in recent decades, in understanding features generated by mainly glacial and mass flow processes, are here reviewed. Detailed studies of data offered in support of prePleistocene glaciations have led to revisions that involve environments of mass movements. Similarities and differences between Quaternary glaciogenic and mass movement features are examined, to provide a more systematic methodology for analysing the origins of more ancient deposits. Analyses and evaluation of data are from a) Quaternary glaciogenic sediments, b) formations which have been assigned to pre-Pleistocene glaciations, and c) formations with comparable features associated with mass movements(and occasionally tectonics). Multiple proxies are assembled to develop correct interpretations of ancient strata. The aim is not per se to reinterpret specific formations and past climate changes, but to enable data to be evaluated using a broader and more inclusive conceptual framework.Regularly occurring pre-Pleistocene features interpreted to be glaciogenic, have often been shown to have few or no Quaternary glaciogenic equivalents. These same features commonly form by sediment gravity flows or other non-glacial processes, which may have led to misinterpretations of ancient deposits. These features include, for example, environmental affinity of fossils, grading, bedding, fabrics, size and appearance of erratics, polished and striated clasts and surfaces(“pavements”), dropstones, and surface microtextures.Recent decades of progress in research relating to glacial and sediment gravity flow processes have resulted in proposals by geologists, based on more detailed field data, more often of an origin by mass movements and tectonism than glaciation.The most coherent data of this review, i.e., appearances of features produced by glaciation, sediment gravity flows and a few other geological processes, are summarized in a Diamict Origin Table.

Variabilities of carbonateδ13C signal in response to the late Paleozoic glaciations,Long’an,South China

An integrated study of biostratigraphy,microfacies,and stable carbon isotope stratigraphy was carried out on the late Famennian–early Asselian carbonates of the Long’an section in Guangxi,South China.Stable carbon isotope studies in the Long’an section have revealed four major positive shifts ofδ13C values in the Carboniferous strata in South China.The first shift occurred in the Siphonodella dasaibaensia zone in the Tournaisian,with an amplitude of 4.19‰.The second shift occurred near the Visean/Serpukhovian boundary,with an amplitude of 2.63‰.The third shift occurred in the Serpukhovian,with an amplitude of 3.95‰.The fourth shift occurred in the Kasimovian,with an amplitude of 3.69‰.Furthermore,there were several brief positiveδ13C shifts during the late Famennian to early Tournaisian.All of these shifts can be well correlated globally,and each corresponds to sea-level regressions in South China and Euro-America,indicating increases in ocean primary productivity and global cooling events.Chronologically,the four major positive excursions ofδ13C,together with several brief positiveδ13C shifts that were observed during the late Famennian to the early Tournaisian,correspond to the well-accepted Glacial I,II,and III events.

Innovations and stepwise evolution of CBFs/DREB1s and their regulatory networks in angiosperms

The C-repeat binding factors/dehydrationresponsive element binding protein 1 s(CBFs/DREB1 s)have been identified as major regulators of cold acclimation in many angiosperm plants.However,their origin and evolutionary process associated to cold responsiveness are still lacking.By integrating multi-omics data of genomes,transcriptomes,and CBFs/DREB1 s genome-wide binding profiles,we unveil the origin and evolution of CBFs/DREB1 s and their regulatory network.Gene collinearity and phylogeny analyses show that CBF/DREB1 is an innovation evolved from tandem duplication-derived DREBⅢgene.A subsequent event of e-whole genome duplication led to two CBF/DREB1 archetypes(CladesⅠandⅡ)in ancient angiosperms.In contrast to cold-insensitivity of Clade I and their parent DREBⅢgenes,CladeⅡevolved a further innovation in cold-sensitive response and was stepwise expanded in eudicots and monocots by independent duplications.In geological time,the duplication events were mainly enriched around the Cretaceous-Paleogene(K-Pg)boundary and/or in the Late Cenozoic Ice Age,when the global average temperature significantly decreased.Consequently,the duplicated CBF/DREB1 genes contributed to the rewiring of CBFs/DREB1 s-regulatory network for cold tolerance.Altogether,our results highlight an origin and convergent evolution of CBFs/DREB1 s and their regulatory network probably for angiosperms adaptation to global cooling.

Changes in vegetation and moisture in the northern Tianshan of China over the past 450 years

Knowledge of historical changes in moisture within semi-arid and arid regions is the basis of climatic change predictions and strategies in response to long-term drought.In this study,a multiproxy peat record with highresolution from Sichanghu in the northern Tianshan was used to document the changes in vegetation and climate over the past 450 years in the arid Central Asia.The pollen,grain size,and loss on ignition(LOI)records indicate that the productivity of local peat began to increase at^1730 AD.The vegetation in the Sichanghu area experienced several transitions,from temperate desert to dense desert,marsh meadow,and steppe desert vegetation.The climate in the study area was extremely dry during the early stages of the Little Ice Age(LIA)(before 1730 AD)and relatively wet during the late stages(1730–1880 AD).The inferred changes in the moisture conditions of the Sichanghu peatland since the LIA may have been controlled by the extent of Arctic sea ice,the North Atlantic Oscillation,and the Siberian High via the connections of large-scale atmospheric circulations such as the Westerlies.