avogadros_number

avogadros_number OP t1_jec92vl wrote

Study (open access): Universal and efficient extraction of lithium for lithium-ion battery recycling using mechanochemistry


>Abstract

>The increasing lithium-ion battery production calls for profitable and ecologically benign technologies for their recycling. Unfortunately, all used recycling technologies are always associated with large energy consumption and utilization of corrosive reagents, which creates a risk to the environment. Herein we report a highly efficient mechanochemically induced acid-free process for recycling Li from cathode materials of different chemistries such as LiCoO2, LiMn2O4, Li(CoNiMn)O2, and LiFePO4. The introduced technology uses Al as a reducing agent in the mechanochemical reaction. Two different processes have been developed to regenerate lithium and transform it into pure Li2CO3. The mechanisms of mechanochemical transformation, aqueous leaching, and lithium purification were investigated. The presented technology achieves a recovery rate for Li of up to 70% without applying any corrosive leachates or utilizing high temperatures. The key innovation is that the regeneration of lithium was successfully performed for all relevant cathode chemistries, including their mixture.

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avogadros_number OP t1_j9hocdi wrote

Study (open access): Methane Venting at Cold Heavy Oil Production with Sand (CHOPS) Facilities Is Significantly Underreported and Led by High-Emitting Wells with Low or Negative Value


>Abstract

>Cold Heavy Oil Production with or without Sand, CHOP(S), facilities produce a significant portion of Canada’s conventional oil. Methane venting from single-well CHOPS facilities in Saskatchewan, Canada was measured (i) using Bridger Photonics’ airborne Gas Mapping LiDAR (GML) at 962 sites and (ii) on-site using an optical mass flux meter (VentX), ultrasonic flow meter, and QOGI camera at 11 sites. The strong correlation between ground measurements and airborne GML supported subsequent detailed analysis of the aerial data and to our knowledge is the first study to directly test the ability of airplane surveys to accurately reproduce mean emission rates of unsteady sources. Actual methane venting was found to be nearly four times greater than the industry-reported levels used in emission inventories, with ∼80% of all emissions attributed to casing gas venting. Further analysis of site-total emissions revealed potential gaps in regulations, with 14% of sites appearing to exceed regulated limits while accounting for 61% of measured methane emissions. Finally, the concept of marginal wells was adapted to consider the inferred cost of methane emissions under current carbon pricing. Results suggest that almost a third of all methane is emitted from environmentally marginal wells, where the inferred methane cost negates the value of the oil produced. Overall, the present results illustrate the importance of independent monitoring, reporting, and verification (MRV) to ensure accuracy in reporting and regulatory compliance, and to ensure mitigation targets are not foiled by a collection of disproportionately high-emitting sites.

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avogadros_number OP t1_j8ltl1b wrote

>During the Jurassic and Cretaceous, global events of widespread low-oxygen conditions (Oceanic Anoxic Events) were recorded in marine strata associated to major perturbations in the carbon cycle. These disturbances were linked to rapid global warming, probably caused by a release of carbon dioxide in the atmosphere due to degassing related to large-scale volcanism, dissociation of methane hydrates and thermogenic methane.

>Many authors have studied the Oceanic Anoxic Events (OAEs) following the original definition by Schlanger and Jenkyns (1976). Nine OAEs are recognized as of global significance and three of them are considered as major events: T-OAE, OAE1a and OAE2. The first, also called Toarcian OAE or Posidonienschiefer event, occurred in the Early Jurassic (~183 Ma) and was first identified by Jenkyns (1980) in northern Europe. The second, also called early Aptian OAE or Selli Event, occurred in the late Early Cretaceous (~120 Ma) and was first observed by Coccioni et al. (1987) in Italy. The third global event, also called Cenomanian – Turonian OAE or Bonarelli Event, occurred in the early Late Cretaceous (~93 Ma) and was noticed by Schlanger and Jenkyns (1976) when comparing subsurface data from the Deep Sea Drilling Project to outcrops; with the most famous being the Livello Bonarelli in the Umbrian Apennines of Italy.

>- The expression of the Oceanic Anoxic Event 2 (OAE2) in the northeast of Brazil (Sergipe-Alagoas Basin)

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avogadros_number OP t1_j8lt3mi wrote

They absolutely are. Of all of the mass extinction events and minor extinction events, one of them (the end-Cretaceous) is more commonly attributed to bolide impact, though not without prior effects from the Deccan Traps. The End-Permian (Siberian Traps), and End-Triassic (Central Atlantic Volcanic Province - CAMP) are certainly attributed to volcanism, as are a number of other extinction events such as AOE 2 and others. Not all large impact events lead to extinctions or mass extinctions (> 75% of all species go extinct within a relatively short geological time span). For example, the Manicouagan Impact Crater, located in Quebec, Canada has a diameter of ~100 km and occurred more than 12 million years before the end of the Triassic with no extinctions associated with the event.

The greatest cause of extinction events - mass or otherwise, whether from volcanism, impact events, orbital cycles, etc. results from the subsequent changes in atmospheric and ocean chemistry. This doesn't bode well for our current climate trajectory.

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avogadros_number OP t1_j2mszev wrote

That's not really what your linked article says. From the article:

>By about 16,000 years ago, the North Pacific Coast offered a linear migration route, essentially unobstructed and entirely at sea level, from northeast Asia into the Americas. Recent reconstructions suggest that rising sea levels early in the postglacial created a highly convoluted and island-rich coast along Beringia's southern shore, conditions highly favorable to maritime hunter-gatherers... With reduced wave energy, holdfasts for boats, and productive fishing, these linear kelp forest ecosystems may have provided a kind of “kelp highway” for early maritime peoples colonizing the New World.

If you examine some maps for the coastal migration / kelp highway you'll notice Beringia is fully exposed with a large tongue from the Cordilleran ice sheet extending north along the Alaska and Aleutian Ranges. The oldest footprints along the Pacific coast of Canada date to 13,000 years ago on Calvert Island: Terminal Pleistocene epoch human footprints from the Pacific coast of Canada

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avogadros_number OP t1_j2jepqh wrote

This study shows the land bridge was open from ~36 ka to ~11 ka which fits with our current, non controversial, understanding and timing for crossing Beringia and travelling south by coastal routes (the Ice Free Corridor didn't open until later). Scientists have traditionally agreed that the earliest dates that humans were found in North America is somewhere between 14,000 to 16,000 years ago, which is supported by recent findings, give or take:

The oldest stemmed points (pre-Clovis) in North America have been dated to ~16,000 cal yr B.P. and are in Cooper's Ferry Idaho. These findings are not controversial and have been widely accepted: Dating of a large tool assemblage at the Cooper’s Ferry site (Idaho, USA) to ~15,785 cal yr B.P. extends the age of stemmed points in the Americas

Other findings, such as the oldest foot prints, located in White Sands National Park in New Mexico, date back to between 23,000 and 21,000 years ago. However, these dates are highly controversial and several authors have called for improved methods to date them: A critical assessment of claims that human footprints in the Lake Otero basin, New Mexico date to the Last Glacial Maximum

The tiny seeds of an aquatic plant (Ruppia cirrhosa) were used to age the footprints last year are at the center of the timeframe debate. Ruppia cirrhosa, grows underwater and gets a lot of its carbon for photosynthesis from dissolved carbon atoms in water. It's possible that carbon in the water came from a much older reservoir than when the foot prints were made:

>"The dating of those footprints is crucial in interpretations of when humans first came to North America from Asia, but the ages have larger uncertainties than has been reported. Some of that uncertainty is related to the possibility of a radiocarbon reservoir in the water in which the dated propagules of Ruppia cirrhosa grew. As a test of that possibility, Ruppia specimens collected in 1947 from nearby Malpais Spring returned a radiocarbon age of ca. 7400 cal yr BP. We think it would be appropriate to devise and implement independent means for dating the footprints, thus lowering the uncertainty in the proposed age of the footprints and leading to a better understanding of when humans first arrived in the Americas."

Other sites such as those at Bluefish Caves (controversial) and Old Crow river basin (was controversial not sure if it still is) fit with the timing of the land bridge being exposed and flooded. While other foot prints found on Calvert Island along the coast of British Columbia date to 13,000 years old: Terminal Pleistocene epoch human footprints from the Pacific coast of Canada

What's rather surprising here is the rapid growth of the ice sheets, and the resulting drop in sea level, occurring surprisingly quickly and much later in the glacial cycle than previous studies had suggested.

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avogadros_number OP t1_j2jczd3 wrote

Study (open access): The Bering Strait was flooded 10,000 years before the Last Glacial Maximum


>Significance

>The Bering Strait was a land bridge during the peak of the last ice age (the Last Glacial Maximum, LGM), when sea level was ~130 m lower than today. This study reconstructs the history of sea level at the Bering Strait by tracing the influence of Pacific waters in the Arctic Ocean. We find that the Bering Strait was open from at least 46,000 until 35,700 y ago, thus dating the last formation of the land bridge to within 10,000 y of the LGM. This history requires that ice volume increased rapidly into the LGM. In addition, it appears that humans migrated to the Americas as soon as the formation of the land bridge allowed for their passage.

>Abstract

>The cyclic growth and decay of continental ice sheets can be reconstructed from the history of global sea level. Sea level is relatively well constrained for the Last Glacial Maximum (LGM, 26,500 to 19,000 y ago, 26.5 to 19 ka) and the ensuing deglaciation. However, sea-level estimates for the period of ice-sheet growth before the LGM vary by > 60 m, an uncertainty comparable to the sea-level equivalent of the contemporary Antarctic Ice Sheet. Here, we constrain sea level prior to the LGM by reconstructing the flooding history of the shallow Bering Strait since 46 ka. Using a geochemical proxy of Pacific nutrient input to the Arctic Ocean, we find that the Bering Strait was flooded from the beginning of our records at 46 ka until 35.7 (+3.3 / −2.4 ka). To match this flooding history, our sea-level model requires an ice history in which over 50% of the LGM’s global peak ice volume grew after 46 ka. This finding implies that global ice volume and climate were not linearly coupled during the last ice age, with implications for the controls on each. Moreover, our results shorten the time window between the opening of the Bering Land Bridge and the arrival of humans in the Americas.

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avogadros_number OP t1_j08wpsg wrote

Study: Following the money: trade associations, political activity and climate change


>Abstract

>The political activities of industries associated with the production and consumption of fossil fuels have thwarted state efforts to advance climate policy. Yet research on the role of trade associations that firms use to coordinate their activities remains sparse. Studies of business political activity are generally focussed on the firm level with trade associations typically considered only as part of wider advocacy coalitions. Scholars are still to examine the full range of political activities of trade associations. Using an original dataset built from trade associations’ IRS filings, we find that trade associations engaged on climate change spent $3.4 billion in 10 years on political activities, with the largest expenditure on advertising and promotion, followed by lobbying, grants and political contributions. Our data challenges the prevailing assumptions about the primary political activities of business actors. To explain the variation in spending, we present the findings from a regression analysis and semi-structured interviews. We argue that scholars have for too long failed to account for the political activities of trade associations, which are also one of the most important opponents of climate policies.

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avogadros_number OP t1_iy33f51 wrote

Picture a straight trend line going from the bottom left of a graph to the upper right. That's a pretty clear trend. But the climate system has a lot of internal variability which makes that trend line actually look like a very squiggly line, so much so that the initial straight trend line isn't really apparent anymore. The data has become quite noisy. That internal variability includes processes intrinsic to the atmosphere, ocean, land, and cryosphere and their interactions, and it takes a lot of effort to be able to pick out certain trends caused by specific phenomena; however, as certain signals become stronger they become more clear, more evident and apparent, the data becomes less noisy with respect to the stronger signal, that straight line trend begins to emerge again. So right now the signal isn't obvious, but it will be by ~2030.

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avogadros_number OP t1_iy2wkrn wrote

Study (open access): Emergence of changing Central-Pacific and Eastern-Pacific El Niño-Southern Oscillation in a warming climate


>Abstract

>El Niño-Southern Oscillation (ENSO) features strong warm events in the eastern equatorial Pacific (EP), or mild warm and strong cold events in the central Pacific (CP), with distinct impacts on global climates. Under transient greenhouse warming, models project increased sea surface temperature (SST) variability of both ENSO regimes, but the timing of emergence out of internal variability remains unknown for either regime. Here we find increased EP-ENSO SST variability emerging by around 2030 ± 6, more than a decade earlier than that of CP-ENSO, and approximately four decades earlier than that previously suggested without separating the two regimes. The earlier EP-ENSO emergence results from a stronger increase in EP-ENSO rainfall response, which boosts the signal of increased SST variability, and is enhanced by ENSO non-linear atmospheric feedback. Thus, increased ENSO SST variability under greenhouse warming is likely to emerge first in the eastern than central Pacific, and decades earlier than previously anticipated.

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avogadros_number OP t1_iw0m57u wrote

Let's try to add some reality instead of playing with metaphors. All cumulative scenarios are just that... cumulative, but some are more important than others, and some are fallacious (ie. slippery slope). Here, this leads to 0.000018C of additional warming over a 20-year period and is then reduced as time goes on. You would need over 11,000 of these events to add an additional 0.2C of warming. The reality is that this event has negligible impact on our climate:

>“Such a tiny warming cannot be perceived in ecosystems or human society,” explains Dr. Xiaolong Chen, first author of the study.

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avogadros_number OP t1_ivz0nyv wrote

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avogadros_number OP t1_ivyydv6 wrote

Study: Negligible Warming Caused by Nord Stream Methane Leaks


>Abstract

>Unanticipated sabotage of two underwater pipelines in the Baltic Sea (Nord Stream 1 and 2) happened on 26 September 2022. Massive quantities of natural gas, primarily methane, were released into the atmosphere, which lasted for about one week. As a more powerful greenhouse gas than CO2, the potential climatic impact of methane is a global concern. Using multiple methods and datasets, a recent study reported a relatively accurate magnitude of the leaked methane at 0.22 ± 0.03 million tons (Mt), which was lower than the initial estimate in the immediate aftermath of the event. Under an energy conservation framework used in IPCC AR6, we derived a negligible increase in global surface air temperature of 1.8 × 10^(−5) °C in a 20-year time horizon caused by the methane leaks with an upper limit of 0.25 Mt. Although the resultant warming from this methane leak incident was minor, future carbon release from additional Earth system feedbacks, such as thawing permafrost, and its impact on the methane mitigation pathways of the Paris Agreement, warrants investigation.

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avogadros_number OP t1_ivguecr wrote

Some may be wondering... can this happen today with the rapid retreat of glaciers, ice caps and ice sheets?

Not really, not for the majority of the globe. As an example, the Cordilleran ice sheet, at its maximum extent contained a sea-level equivalent comparable to that of the present-day Greenland Ice Sheet^1, ^2 That amount of mass pushing down the crust simply isn't there anymore to yield the degree of decompression melting required to produce that much melt (magma) and ultimately trigger a volcanic response.

What about Greenland and Antarctica?

As far as Greenland goes, it doesn't seem likely we'll see any activity there as there are no active volcanoes in Greenland, nor are there any known mapped, dormant volcanoes under the Greenland ice sheet that were active during the Pliocene period of geological history that began more than 5.3 million years ago (volcanoes are considered active if they’ve erupted within the past 50,000 years).

Antarctica, however, does have active volcanoes. I suspect that with the rapid deglaciation of the Antarctic Ice Sheet it may be possible to see an increase in volcanic activity regionally. Though due to its location (at the south pole), and the circumpolar winds and currents, any volcanic ash would also be quite limited globally and would likely remain at the poles rather than spreading out and having any major climatic effects.

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avogadros_number OP t1_ivgqmwu wrote

Study: Volcanic trigger of ocean deoxygenation during Cordilleran ice sheet retreat


>Abstract

>North Pacific deoxygenation events during the last deglaciation were sustained over millennia by high export productivity, but the triggering mechanisms and their links to deglacial warming remain uncertain. Here we find that initial deoxygenation in the North Pacific immediately after the Cordilleran ice sheet (CIS) retreat was associated with increased volcanic ash in seafloor sediments. Timing of volcanic inputs relative to CIS retreat suggests that regional explosive volcanism was initiated by ice unloading. We posit that iron fertilization by volcanic ash during CIS retreat fuelled ocean productivity in this otherwise iron-limited region, and tipped the marine system towards sustained deoxygenation. We also identify older deoxygenation events linked to CIS retreat over the past approximately 50,000 years. Our findings suggest that the apparent coupling between the atmosphere, ocean, cryosphere and solid-Earth systems occurs on relatively short timescales and can act as an important driver for ocean biogeochemical change.

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avogadros_number OP t1_itoqqw9 wrote

Study: Negligible atmospheric release of methane from decomposing hydrates in mid-latitude oceans


>Abstract

>Naturally occurring gas hydrates may contribute to a positive feedback for global warming because they sequester large amounts of the potent greenhouse gas methane in ice-like deposits that could be destabilized by increasing ocean/atmospheric temperatures. Most hydrates occur within marine sediments; gas liberated during the decomposition of seafloor hydrates or originating with other methane pools can feed methane emissions at cold seeps. Regardless of the origin of seep methane, all previous measurements of methane emitted from seeps have shown it to have a unique fossil radiocarbon signature, contrasting with other sources of marine methane. Here we present the concentration and natural radiocarbon content of methane dissolved in the water column from the seafloor to the sea surface at seep fields along the US Atlantic and Pacific margins. For shallower water columns, where the seafloor is not within the hydrate stability zone, we do document seep CH4 in some surface-water samples. However, measurements in deeper water columns along the US Atlantic margin reveal no evidence of seep CH4 reaching surface waters when the water-column depth is greater than 430 ± 90 m. Gas hydrates exist only at water depths greater than ~550 m in this region, suggesting that the source of methane escaping to the atmosphere is not from hydrate decomposition.

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avogadros_number OP t1_ir7fuzl wrote

Study (open access): Tunnel valley formation beneath deglaciating mid-latitude ice sheets: Observations and modelling


>Highlights

>• Numerical experiments and geophysical data are used to investigate tunnel valley formation beneath deglaciating ice sheets.

>• New high-resolution 3D seismic data reveal abandoned channel systems, slumps, and subglacial landforms inside tunnel valleys.

>• Migrating channels fed by seasonal surface meltwater erode tunnel valleys within 100s to 1000s of years during deglaciation.

>• Modelled tunnel valleys form time-transgressively close to the retreating ice sheet margin.

>• Our results explain the formation of tunnel valleys in most previously glaciated regions.

>Abstract

>The geological record of landforms and sediments produced beneath deglaciating ice sheets offers insights into inaccessible glacial processes. Large subglacial valleys formed by meltwater erosion of sediments (tunnel valleys) are widespread in formerly glaciated regions such as the North Sea. Obtaining a better understanding of these features may help with the parameterisation of basal melt rates and the interplay between basal hydrology and ice dynamics in numerical models of past, present, and future ice-sheet configurations. However, the mechanisms and timescales over which tunnel valleys form remain poorly constrained. Here, we present a series of numerical modelling experiments, informed by new observations from high-resolution 3D seismic data (6.25 m bin size, ∼4 m vertical resolution), which test different hypotheses of tunnel valley formation and calculate subglacial water routing, seasonal water discharges, and the rates at which tunnel valleys are eroded beneath deglaciating ice sheets. Networks of smaller or abandoned channels, pervasive slump deposits, and subglacial landforms are imaged inside and at the base of larger tunnel valleys, indicating that these tunnel valleys were carved through the action of migrating smaller channels within tens of kilometres of the ice margin and were later widened by ice-contact erosion. Our model results imply that the drainage of extensive surface meltwater to the ice-sheet bed is the dominant mechanism responsible for tunnel valley formation; this process can drive rapid incision of networks of regularly spaced subglacial tunnel valleys beneath the fringes of retreating ice sheets within hundreds to thousands of years during deglaciation. Combined, our observations and modelling results identify how tunnel valleys form beneath deglaciating mid-latitude ice sheets and have implications for how the subglacial hydrological systems of contemporary ice sheets may respond to sustained climate warming.

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