Initial Warming Research Articles

Roles of Earth’s Albedo Variations and Top-of-the-Atmosphere Energy Imbalance in Recent Warming: New Insights from Satellite and Surface Observations

Past studies have reported a decreasing planetary albedo and an increasing absorption of solar radiation by Earth since the early 1980s, and especially since 2000. This should have contributed to the observed surface warming. However, the magnitude of such solar contribution is presently unknown, and the question of whether or not an enhanced uptake of shortwave energy by the planet represents positive feedback to an initial warming induced by rising greenhouse-gas concentrations has not conclusively been answered. The IPCC 6th Assessment Report also did not properly assess this issue. Here, we quantify the effect of the observed albedo decrease on Earth’s Global Surface Air Temperature (GSAT) since 2000 using measurements by the Clouds and the Earth’s Radiant Energy System (CERES) project and a novel climate-sensitivity model derived from independent NASA planetary data by employing objective rules of calculus. Our analysis revealed that the observed decrease of planetary albedo along with reported variations of the Total Solar Irradiance (TSI) explain 100% of the global warming trend and 83% of the GSAT interannual variability as documented by six satellite- and ground-based monitoring systems over the past 24 years. Changes in Earth’s cloud albedo emerged as the dominant driver of GSAT, while TSI only played a marginal role. The new climate sensitivity model also helped us analyze the physical nature of the Earth’s Energy Imbalance (EEI) calculated as a difference between absorbed shortwave and outgoing longwave radiation at the top of the atmosphere. Observations and model calculations revealed that EEI results from a quasi-adiabatic attenuation of surface energy fluxes traveling through a field of decreasing air pressure with altitude. In other words, the adiabatic dissipation of thermal kinetic energy in ascending air parcels gives rise to an apparent EEI, which does not represent “heat trapping” by increasing atmospheric greenhouse gases as currently assumed. We provide numerical evidence that the observed EEI has been misinterpreted as a source of energy gain by the Earth system on multidecadal time scales.

Reducing the Energy Consumption during Microwave Drying of Coal Slime Dough by Optimizing Parameters: Experiment and Modeling.

Reducing the energy consumption in microwave drying processes is essential for the sustainable management of coal slime. Utilizing a self-constructed microwave thermogravimetric apparatus, the research investigates critical parameters, including microwave power, spherical diameter, and granule size, affecting drying kinetics and energy efficiency. The results show that it was observed that the drying process progresses through three distinct stages, marked by variations in temperature and moisture content: the initial warming phase, a steady drying stage, and a final phase where the drying rate decreases; optimal pellet sizes for efficient moisture evaporation and diffusion were identified, with smaller particles enhancing heat transfer and drying efficiency; and the Nadhari model was determined to best represent the drying kinetics of coal slime under microwave radiation. The findings indicate a positive correlation between drying efficiency and particle size while being inversely related to increased microwave power for smaller granules. A direct positive relationship between moisture migration and increased power levels was established, while an inverse relationship with the enlargement of particle sizes was observed, negatively affecting the efficiency. For granule sizes of 30, 40, and 50 mm, a decrease in activation power was recorded, with values of 8.215 ± 2.301, 7.936 ± 1.547, and 3.393 ± 0.248 W·g-1, respectively; and through the comparative analysis of energy consumption, it was demonstrated that for coal slurry particles sized 0.15-0.18 mm subjected to a drying duration of 600 s, an increase in power leads to a reduction in drying efficiency, whereas larger diameter contributes to improved efficiency.

Change of El Niño onset location around 1970

A shift of El Niño onset location from eastern Pacific (EP) to western Pacific (WP) occurred around 1970. It was accompanied by a faster mean sea surface temperature (SST) warming in WP and a change of precursory SST and wind anomaly patterns. The eigenvalue analysis of a simple coupled model shows that an SST anomaly (SSTA) in WP may grow under the post-1970 mean condition but cannot under the pre-1970 mean condition. As a result, a warm SSTA appeared in WP accompanying to a preceding La Niña condition in EP after 1970, whereas such a warming was rarely seen before 1970. The preceding SSTA patterns led to distinctive zonal wind responses in EP, favoring El Niño onset in EP prior to 1970. For the post-1970 El Niño onset, an initial warming in WP was induced by anomalous downward solar radiation in association with atmospheric meridional overturning circulation or anomalous horizontal advection associated with thermocline induced eastward geostrophic currents.

Short-Term Climatic Oscillations in the Central Region of the East-European Plain at the Beginning of the Holocene Based on Palynological Studies of Lacustrine Deposits

The Preboreal (11.75–10.70 ka BP) is still the least paleogeographically studied time interval in the central part of the East European Plain. High-resolution multi-proxy studies of lacustrine sediments at the Seltso site located in the Desna River floodplain (Dnieper River basin) were conducted. Radiocarbon dating, loss-on-ignition determination, sedimentological and palynological studies and identification of Non-Pollen Palynomorphs in lacustrine sediments allow us to reconstruct changes in vegetation caused by rapid warming at the Younger Dryas–Holocene boundary, short-term climatic fluctuations within the Preboreal and subsequent resumption of warming. Initial Preboreal warming reached its maximum at about 11.5 ka BP when a relatively dry continental climate existed. Between 11.4 and 11.2 ka BP, a short-term cooling corresponding to the Preboreal Oscillation in Greenland occurred, as indicated by a significant reduction of woody vegetation and expansion of open plant communities. In the Late Preboreal, approximately 11.2–10.7 ka BP, warming resumed, which was accompanied by a decrease in the climate continentality. Comparison with high-resolution lithological and palynological data from eight reliably dated sections of the central East European Plain indicates that in northwestern and central Europe, the impact of the Preboreal Oscillation cooling on the vegetation and the lake ecosystems’ development was probably somewhat stronger.

Climate, vegetation, and fire, during the last deglaciation in northwestern Amazonia

The magnitude of change in climatic conditions and vegetation response to the last deglaciation in various parts of tropical Amazonia is poorly understood and controversial. Analysis of a sediment core e.g. fossil pollen, X-ray Fluorescence (XRF) and charcoal from Lake Malachite on the Hill of Six Lakes in northwestern Brazil provided a deglacial history of climate, vegetation change and fire. Pollen revealed a forested landscape throughout, with shifts in composition that were driven by warming and changes in precipitation. The glacial cooling of c. 4–5 °C had brought species characteristic of cooler climates into the Amazon lowlands and was followed by an initial warming that began at least 19.5 thousand calibrated years before the present (cal kyr BP). Temperature oscillations and changes in precipitation between (18–14.6 cal kyr BP) associated with Heinrich Stadial 1 were observed as wet-dry-wet oscillations similar to some of the previous studies, and were evident in both pollen and XRF data. The pollen spectra were consistent that of a mesic forest before and after the peak of the Last Glacial Maximum. Cool-adapted taxa had previously been described from other cores from the Hill of Six Lakes, and persisted in low abundances until c. 14.1 cal kyr BP. No distinct response to the Atlantic Cold Reversal was evident in our proxy data. The early Holocene was marked by pollen, charcoal, and sedimentary changes that could reflect a peak drought stress on the forest. The large occurrence of charcoal indicating an increase in fires coincided with disturbance elements e.g. Cecropia and Alchornea, that could have been consistent with human disturbance of the forest at c. 10.2 cal kyr BP.

Abrupt warming and alpine glacial retreat through the last deglaciation in Alaska interrupted by modest Northern Hemisphere cooling

Abstract. Alpine glacier-based temperature reconstructions spanning the last deglaciation provide critical constraints on local to regional climate change and have been reported from several formerly glaciated regions around the world yet remain sparse from high-northern-latitude regions. Using newly and previously 10Be-dated moraines, we report paleo-glacier equilibrium line altitudes (ELAs) for 15 time slices spanning the Last Glacial Maximum (LGM) to the Little Ice Age (LIA) for a valley in the western Alaska Range. We translate our ELA reconstructions into a proxy for summer temperature by applying a dry adiabatic lapse rate at each reconstructed ELA relative to the outermost LIA moraine. We observe ∼4 °C warming through the last deglaciation at our site that took place in two steps following initial gradual warming: ∼1.5 °C abrupt warming at 16 ka, ∼2 kyr after the onset of global CO2 rise, and ∼2 °C warming at ∼15 ka, near the start of the Bølling. Moraine deposition and modest summer cooling during Heinrich Stadial 1 and the early Younger Dryas (YD) suggest that despite these events being expressed more strongly in wintertime, the classic blueprint of North Atlantic climate variability extends to the western Arctic region.

The evolution process and degradation model of permafrost in the Source Area of the Yellow River on the Qinghai-Tibet Plateau since the Little Ice Age

Permafrost degradation is currently receiving as much attention as global warming. Permafrost evolution is a particularly slow process, making it impossible to examine the entire process by observation. Based on the heat conduction theory, in this study, a nonlinear numerical model for the entire process of permafrost evolution was developed with consideration of phase transition. The numerical simulation model was used to retrospectively analyse the evolution process and degradation pattern of permafrost in Tangchama beach-land in the Source Area of the Yellow River (SAYR) from 1400 to 2100; this analysis was performed using ice core inversion results obtained from the Qinghai-Tibet Plateau since the Little Ice Age and various future climate change scenarios from the IPCC Fifth Assessment Report. The simulation results showed that: 1) since 1900, permafrost temperatures have substantially increased, exceeding the range of change between 1400 and 1900; under the RCP2.6, RCP6.0 and RCP8.5 scenarios, permafrost will degrade and disappear in the next 100 years, and the degradation rate will subsequently accelerate. 2) The permafrost table steadily goes downward at first, and the onset of fast permafrost degradation is signalled by the appearance of a residual thawed layer at a depth of 3–4 m. The permafrost layer then gradually thins out as the permafrost table rapidly descends and the permafrost base slowly ascends. The permafrost will fully deteriorate and vanish once the permafrost table and the permafrost base bounds overlap. 3) Due to permafrost degradation, the ground temperature curve can be divided into the following stages: uniform gradient stage, C-type stage, zero-gradient type stage and phase transition stage. The four stages of the “permafrost life cycle” are initial temperature warming, continuous temperature rising, residual thawed layer, and final permafrost disappearance.

Biodiversity burdens in Spanish conventional and low-impact single-family homes

Biodiversity loss caused by housing is not a well-defined sector of environmental impact. This research quantifies effects on biodiversity of an average Spanish Single-Family House (SFH) with 180 m2 of built surface. The current Spanish SFH stock GWP amounts to 1.16 Gt CO2eq in a 50-year life cycle, 40 % of which is embodied in the building materials and the 60 % are emissions due to the use of the building. This stock also impacts with 10.2 Gt 1,4-DCB the land, water and human health. SFHs also drive 6052 species extinct in a 50 year life cycle, and account for 3.03 M years of life lost due to premature death or lived with a disability. Divided by the 16 M people living in Spanish SFHs, each one lost 0.19 years of their lives (68.1 days) due to their home's impacts on human health.The article compares a reference conventional building against three low-impact cases, to understand how different building techniques and materials influence environmental outcomes that keep biodiversity loss the lowest possible. Scenarios include a standard brick and concrete house as Scenario 0 (SC0, Base), a timber Passivhaus as Scenario 1 (SC1), a straw-bale house with renewable energies as Scenario 2 (SC2), and an earth bioclimatic house as Scenario 3 (SC3). An initial Global Warming Potential (GWP) analysis was performed to relate previous building Life Cycle Assessment (LCA) studies with biodiversity metrics. Three main biodiversity metrics; ecotoxicity (as midpoint indicator), biodiversity loss and damage to human health (both as endpoint indicators) have been considered.Compared to SC0 with 1292 kgCO2-eq·m−2 (516 embodied) of GWP, we found that SC1 emitted −47.0 % of that, SC2–41.4 % and SC3–80.9 %. Concerning ecotoxicity, where SC0 has 11,399 kg 1,4 DCB, the results are −27.9 % in SC1, −19.2 % in SC2, and −45.6 % in SC3. Regarding biodiversity loss, where SC0 has 7.54 E−06 species.yr·m−2, the impacts are −30.9 % in SC1, −32.6 % in SC2, and −58.6 % in SC3.Human health damage in SC0 being 3.37 E−03 DALY, has been reduced in the timber home (SC1) is −44.2 %, of the Straw SFH (SC2) −39.2 %, and of the earth house (SC3) −67.1 %.This article shows that with current existing technological solutions GWP could be reduced in −80.9 %, ecotoxicity in −45.6 %, biodiversity loss in −58.6 % and human health in −67.1 %. Spanish Single-Family Houses built in timber, earth or straw-bale are real alternatives to current cement traditional building.

Tropical ocean temperatures and changes in terrigenous flux during the Paleocene-Eocene Thermal Maximum in southern Tibet

The Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma) was an extreme climate warming event of the early Cenozoic. The development and ecology of carbonate platforms are highly sensitive to changes in SSTs, sea level and terrestrial detrital input. However, no record of SST changes during the PETM has yet been reported from a shallow marine carbonate platform. Here, we reconstruct SSTs for two shallow marine carbonate PETM sections in present-day southern Tibet from the distribution of isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGT). Our dataset demonstrates that the temperature of the tropical eastern Tethys likely increased 3 to 5 °C during the PETM (depending on the TEX86 calibration used), and it supports a reduction of 2 °C in the meridional gradient between middle and low latitudes. Elemental data and quartz content imply an increase in terrigenous flux prior to the onset of the CIE, possibly linked to initial PETM warming. However, inconsistent changes in terrigenous flux at other PETM sections in the eastern Tethys suggest a variable response modulated by sea-level change and hinterland weathering, erosion and sediment delivery.

Detection and Prediction of the Early Thermal Runaway and Control of the Li-Ion Battery by the Embedded Temperature Sensor Array.

Sorts of Li-ion batteries (LIB) have been becoming important energy supply and storage devices. As a long-standing obstacle, safety issues are limiting the large-scale adoption of high-energy-density batteries. Strategies covering materials, cell, and package processing have been paid much attention to. Here, we report a flexible sensor array with fast and reversible temperature switching that can be incorporated inside batteries to prevent thermal runaway. This flexible sensor array consists of PTCR ceramic sensors combined with printed PI sheets for electrodes and circuits. Compared to room temperature, the resistance of the sensors soars nonlinearly by more than three orders of magnitude at around 67 °C with a 1 °C/s rate. This temperature aligns with the decomposition temperature of SEI. Subsequently, the resistance returns to normal at room temperature, demonstrating a negative thermal hysteresis effect. This characteristic proves advantageous for the battery, as it enables a lower-temperature restart after an initial warming phase. The batteries with an embedded sensor array could resume their normal function without performance compromise or detrimental thermal runaway.

Late-Glacial palaeotemperatures and palaeoprecipitations in the Aubrac Mountains (French Massif Central) reconstructed from multiproxy analyses (Coleoptera, chironomids and pollen)

New investigations performed with a multi-proxy approach provide a robust climate reconstruction for the Late-Glacial in the Massif Central, France. The temperature reconstruction from Coleoptera is obtained from the Mutual Climatic Range Method, or “MCR” method, based on the range of climates corresponding to the area occupied today by the species identified in fossil assemblages. The Weighthed Averaging Partial Least Squared (WA-PLS) method is used to produce mean July temperature estimates from Chironomid assemblages. Climate reconstruction from pollen data is performed using an assemblage approach, the Modern Analogue Technique. During the Late-Glacial the July temperature (Tmax) reconstructed from beetles (Coleoptera) was lower than the current Tmax of 18.9 °C. Summer conditions were close to the present at the beginning of the Oldest Dryas (17400–14600 cal. BP), and during most of the Allerød (13900–12800 cal. BP). During the Younger Dryas (12800–11700 cal. BP) Tmax estimates ranged from 12 to 13 °C, much lower than today. The Tmax increased at the onset of the Holocene (11700 cal. BP), reaching values close to the modern conditions from the beginning of the period. Tmax reconstructed from chironomids shows an initial warming around 15000 cal. BP, with a Tmax rise from 7 °C to 11 °C. A maximum (13.5 °C) was reached around 13800 cal. BP. A second optimum of 16 °C occurred after 10800 cal. BP. The Late-Glacial Interstadial (LGI) is marked by temperature decreases (from 13 to 12 to 10–9 °C) around 13200–12900 cal. BP. A second climate minimum was reached around 12600 cal. BP, during the Younger Dryas (Tmax about 10 °C). The end of the Younger Dryas seems to have been warmer, with a Tmax of about 13 °C, just before the early Holocene climate improvement. Pollen-inferred results showed that the Late-Glacial climate at Roustières was characterized by colder and drier winter and summer seasons than today, and by conditions close to the modern ones around 11700 cal. BP, at the onset of the Holocene. Climate conditions comparable to the modern ones were also evidenced at the end of the Allerød, with colder than today conditions evidenced from both Tmax and Tmin (January temperature). During the Oldest and Younger Dryas the coldest month showed a temperature of −13 °C, while summers appeared more moderate (warmest month around 16 °C). Cold conditions were also reconstructed during the Bølling, while temperatures comparable to present-day values were reached during the Allerød. A cold oscillation occurred around 13400 cal. BP. Particularly dry conditions were reconstructed during the Oldest Dryas (17000–15800 cal. BP). From 15800 to the end of the Younger Dryas, the precipitation oscillated around 750 mm, but increased during the Allerød and the Holocene periods. These climatic trends reconstructed by the three proxies allowed identifying the temperate periods (LGI and the Holocene) and the cold events (Younger Dryas) of the Late-Glacial period. However, difficulties due to different sampling resolutions emerged, and several discrepancies linked to the proxy or the methods used are discussed.

Optimum growth temperature declines with body size within fish species.

According to the temperature-size rule, warming of aquatic ecosystems is generally predicted to increase individual growth rates but reduce asymptotic body sizes of ectotherms. However, we lack a comprehensive understanding of how growth and key processes affecting it, such as consumption and metabolism, depend on both temperature and body mass within species. This limits our ability to inform growth models, link experimental data to observed growth patterns, and advance mechanistic food web models. To examine the combined effects of body size and temperature on individual growth, as well as the link between maximum consumption, metabolism, and body growth, we conducted a systematic review and compiled experimental data on fishes from 52studies that combined body mass and temperature treatments. By fitting hierarchical models accounting for variation between species, we estimated how maximum consumption and metabolic rate scale jointly with temperature and body mass within species. We found that whole-organism maximum consumption increases more slowly with body mass than metabolism, and is unimodal over the full temperature range, which leads to the prediction that optimum growth temperatures decline with body size. Using an independent dataset, we confirmed this negative relationship between optimum growth temperature and body size. Small individuals of a given population may, therefore, exhibit increased growth with initial warming, whereas larger conspecifics could be the first to experience negative impacts of warming on growth. These findings help advance mechanistic models of individual growth and food web dynamics and improve our understanding of how climate warming affects the growth and size structure of aquatic ectotherms.

Land-sea ecological connectivity during a Jurassic warming event

Knowledge on how climate change affects land-sea ecological connectivity in deep time is scarce. To fill this knowledge gap we have assembled a unique dataset through a Jurassic (early Toarcian) warming event that includes quantitative abundance data from pollen and spores, organic-walled marine plankton and benthic macro-invertebrates, in association with geochemical data derived from the same sampled horizons, from the Cleveland Basin, UK. Using this dataset we: (i) reconstruct the timing of degradation and recovery of land-plants, marine primary producers and benthic fauna in response to this event, and (ii) test for connectivity between changes in land and marine ecosystems. We find a discrepancy between the timing of the response of land-plant and marine ecosystems to the event. Land-plants were the first to be affected by initial warming, but also recovered relatively quickly after the peak of warmth to return to pre-event levels of richness and diversity. Plankton and benthic fauna instead experienced a delayed response to initial warming, but as warming peaked, they suffered a rapid and extreme turnover. Recovery in the shelf sea was also delayed (particularly for the benthos) compared to the vegetation. Ecological connectivity analyses show a strong link between changes in terrestrial and marine ecosystems. The loss of large trees on land contributed to changes in marine plankton, from dinoflagellate- to prasinophyte algal-dominated communities, by enhancing erosion, runoff and nutrient-supply into shallow seas. Eutrophication and changes in primary productivity contributed to the decrease of dissolved oxygen in the water column and in bottom waters, which in turn affected benthic communities. Such cause-effect mechanisms observed in the Cleveland Basin are likely to have occurred in other basins of the Boreal Realm, and in part also in basins of the Sub-Boreal and Tethyan realms. Although palaeolatitudinal and palaeoceanographic gradients may have controlled local and regional changes in land-plants and marine ecosystems during the Early Jurassic, the main climatic and environmental changes linked to rapid global warming, enhanced weathering and high primary productivity, are shared among all the examined realms.

Paleocene/Eocene carbon feedbacks triggered by volcanic activity

The Paleocene–Eocene Thermal Maximum (PETM) was a period of geologically-rapid carbon release and global warming ~56 million years ago. Although modelling, outcrop and proxy records suggest volcanic carbon release occurred, it has not yet been possible to identify the PETM trigger, or if multiple reservoirs of carbon were involved. Here we report elevated levels of mercury relative to organic carbon—a proxy for volcanism—directly preceding and within the early PETM from two North Sea sedimentary cores, signifying pulsed volcanism from the North Atlantic Igneous Province likely provided the trigger and subsequently sustained elevated CO2. However, the PETM onset coincides with a mercury low, suggesting at least one other carbon reservoir released significant greenhouse gases in response to initial warming. Our results support the existence of ‘tipping points’ in the Earth system, which can trigger release of additional carbon reservoirs and drive Earth’s climate into a hotter state.

Lagged Responses of the Tropical Pacific to the 11-yr Solar Cycle Forcing and Possible Mechanisms

This paper uses two subsets of ensemble historical-Nat simulations and pi-Control simulations from CMIP5 as well as observational/reanalysis datasets to investigate responses of the tropical Pacific to the 11-yr solar cycle. A statistically significant 11-yr solar signal is found in the upper-ocean layers above the thermocline and tropospheric circulations. A warming response initially appears in the upper layers of the central equatorial Pacific in the solar maximum years in observations, then increases and shifts into the eastern Pacific at lags 1–3 years. Meanwhile, an anomalous updraft arises over the western equatorial Pacific and shifts eastwards in the following years with anomalous subsidence over the Maritime Continent. These lagged responses are confirmed by the historical-Nat simulations, except that the initial signal is located more to the west and all the responses are weaker than the observed. A simplified mixed-layer heat budget analysis based on the historical-Nat simulations suggests that the atmospheric forcing, especially the shortwave radiation, is the major contributor to the initial warming response, and the ocean heat transport effect is responsible for the eastward displacement of the lagged warming responses. In the solar maximum years, the zonal ocean temperature gradient in the western-central Pacific is reduced by the initial warming, and anomalous westerly winds appear over the western equatorial Pacific and extend into the eastern Pacific during the lagged years. These anomalous westerly winds reduce the wind-driven ocean dynamical transport, resulting in the initial warming in the central equatorial Pacific being amplified and the surface warming shifting eastward during the lagged 1–3 years.

Mouse oocyte vitrification with and without dimethyl sulfoxide: influence on cryo-survival, development, and maternal imprinted gene expression.

Oocytes and embryos can be vitrified with and without dimethyl sulfoxide (DMSO). Objectives were to compare no vitrification (No-Vitr), vitrification with DMSO (Vitr + DMSO), and vitrification without DMSO (Vitr - DMSO) on fresh/warmed oocyte survival, induced parthenogenetic activation, parthenogenetic embryo development, and embryonic maternal imprinted gene expression. In this prospective controlled laboratory study, mature B6C3F1 female mouse metaphase II oocytes were treated as: i) No-Vitr, ii) Vitr + DMSO/warmed, and iii) Vitr - DMSO/warmed with subsequent parthenogenetic activation and culture to the blastocyst stage. Oocyte cryo-survival, parthenogenetic activation and embryo development, parthenogenetic embryo maternal imprinted gene expression were outcome measures. Oocyte cryo-survival was significantly improved in Vitr + DMSO versus Vitr - DMSO at initial warming and 2h after warming. Induced parthenogenetic activation was similar between all three intervention groups. While early preimplantation parthenogenetic embryo development was similar between control, Vitr + DMSO, Vitr - DMSO oocytes, the development to blastocysts was significantly inferior in the Vitr - DMSO oocytes group compared to the control and Vitr + DMSO oocyte groups. Finally, maternal imprinted gene expression was similar between intervention groups at both the 2-cell and blastocyst parthenogenetic embryo stage. Inclusion of DMSO in oocyte vitrification solutions improved cryo-survival and developmental potential of parthenogenetic embryos to the blastocyst stage without significantly altering maternal imprinted gene expression.

Predicting the Location of Maple Habitat Under Warming Scenarios in Two Regions at the Northern Range in Canada

AbstractAcer saccharum and Acer rubrum, two main maple species in North America, will be affected by ongoing global warming. Several studies predict a southern limit contraction but limited northward expansion of maple distribution for the future. We aimed to understand the main drivers of current maple distribution to quantify potential changes to maple habitat in this context. We identified the local conditions of maple stands and assessed the potential changes under warming scenarios. We selected two regions in Quebec, Canada, at the northern distribution of the species and applied probability distribution function and principal component analysis to identify the factors explaining the occurrence of maple compared with other forest species, croplands, and grasslands. Maple habitat was estimated under warming scenarios up to 2°C. We observed a lower density of maple stands in the north (7.76%), compared to the south (33.01%). Warming increased maple stands by 3.54 and 1.45% in the northernmost and southernmost regions, respectively, with the highest increases being estimated at the initial warming (+1.0°C). We conclude that maple of northern regions can benefit from local warming if precipitation does not become limiting. These changes could increase the potential for the regional maple industry and forest management.

Asymmetric relationship between ENSO and the tropical Indian Ocean summer SST anomalies

AbstractDuring the summer following El Niño, a basin-wide sea surface temperature (SST) warming takes place over the tropical Indian Ocean (TIO), exerting profound influences on the Asian summer monsoon. This is an important source of seasonal predictability for the Asian summer monsoon. Based on observations, however, the present study finds that the relationship between El Niño-Southern Oscillation (ENSO) and the TIO SST anomalies during the decaying summer is asymmetric with a much weaker relationship between La Niña and the TIO SST anomalies relative to El Niño. The analyses show that this asymmetric relationship can be explained by the asymmetries in initial TIO SST, oceanic Rossby wave in the southern Indian Ocean and ENSO decaying rate. In contrast to El Niño events, La Niña events tend to have a stronger initial TIO warming and a less peak intensity with a weaker oceanic Rossby wave response in the southern Indian Ocean. On the other hand, La Niña events tend to decay more slowly with the persistent SST cooling over the central equatorial Pacific in the following summer. The equatorial Pacific SST cooling would induce an anomalous anticyclone via a Gill-type Rossby wave response, weakening the positive feedback between the anomalous cyclone spanning the tropical Northwest Pacific and North Indian oceans and the TIO summer basin-wide SST cooling. These results have important implications for the climate predictability of the Indian Ocean and Asian summer monsoon.

Synoptic timescale linkage between midlatitude winter troughs Sahara temperature patterns and northern Congo rainfall: A building block of regional climate variability

AbstractA coherent synoptic sequence, mostly over North Africa, is identified whereby an upper‐level midlatitude trough (in November–March) excites several days of quasi‐stationary near‐surface warming across the Sahara, leading to rainfall events over northern Congo (NC), and perturbed weather more widely. Ahead of NC rainfall events, composite sequences first identify troughs for several days near Iberia, followed by relatively quick transfer to the Central Mediterranean (CMed). Iberia and CMed daily trough‐strength indices reveal that both lead to warming and NC rainfall. Iberia trough linkages develop through West Africa and take longer to reach NC, while CMed linkages reach NC faster (2–3 days), with impact extent focused mostly south and east of CMed. Building up to the rainfall events, initial warming over the central Sahara migrates southeastward close to NC, ultimately with typical magnitude of about 1–2°C at 10–15°N. Such anomalies are statistically predictive for NC daily rainfall and associated nearby atmospheric features: anomalous low‐level southerly wind and increased moisture; anomalous low‐level westerly wind and vertical easterly shear to 600 hPa; increased mid‐level moisture (600 hPa), which along with low‐level moisture, connects northward into midlatitudes. A secondary route identified by which Iberia troughs can impact NC rainfall is through direct atmospheric teleconnection with precipitation to the west of NC, and subsequent migration of that convection eastward into NC. The eastern side of NC generally shows a small lag on western parts, and links more strongly to CMed troughs. Taken together, the lagged synoptic expression of Iberia and CMed troughs is widespread over several days, including much of North Africa (to equatorial latitudes), southwestern Asia, eastern Africa and the western Indian Ocean. Overall, these results can contribute to situational awareness for weather forecasters across the zones influenced by the troughs, while also providing a framework for climate timescale analyses.

Successful vitrification of manually punctured equine embryos.

Successful vitrification of equine expanded blastocysts requires collapse of the blastocoele cavity using a micromanipulator-mounted biopsy pipette on an inverted microscope. Such equipment is expensive and requires user skill. To develop a manual method of blastocoele collapse prior to vitrification using commercial products. In vivo experiment. Seventy-nine Day 7 or 8 embryos were measured and graded. Twenty were vitrified following micromanipulator-assisted puncture and aspiration before being used to validate commercial human vitrification and warming kits containing, respectively, 2-step concentrations of DMSO and ethylene glycol (7.5%-15% v:v) and decreasing concentrations of sucrose. After warming, embryos were transferred to recipient mares. Once validated, the commercial kits were used to vitrify and warm a further 39 embryos which were punctured manually using a microneedle, 2 (5%) were damaged during puncture and excluded; 20 more embryos were vitrified without puncture. Embryos were grouped as follows: non-punctured≤300µm (n=10) and>300 to≤560µm (n=10), punctured small (>300 to≤560µm; n=17) and large (>560µm; n=10) and exposed to the equilibration solution (ES) in the kit for 6min. An additional group of punctured large embryos was exposed to ES for 8min (n=10). For the initial warming step, embryos were exposed for 1min to the thawing solution at 42°C, before being moved to a dilution solution at room temperature. Vitrified, manually punctured embryos≤560µm exposed to ES for 6min resulted in a pregnancy rate of 82% (14/17). Unpunctured embryos≤300µm gave an 80% (8/10) pregnancy rate. Larger unpunctured embryos, punctured embryos>560µm and embryos exposed to ES for 8min gave significantly reduced pregnancy rates. Limited group sizes. High pregnancy rates can be achieved by manually puncturing≤560µm equine embryos prior to their vitrification and subsequent warming in commercial media.