Heterogeneous glacier mass loss has occurred across High Mountain Asia on a multi-decadal timescale. Contrasting climatic settings influence glacier behaviour at the regional scale, but high ...intra-regional variability in mass loss rates points to factors capable of amplifying glacier recession in addition to climatic change along the Himalaya. Here we examine the influence of surface debris cover and glacial lakes on glacier mass loss across the Himalaya since the 1970s. We find no substantial difference in the mass loss of debris-covered and clean-ice glaciers over our study period, but substantially more negative (-0.13 to -0.29 m w.e.a
) mass balances for lake-terminating glaciers, in comparison to land-terminating glaciers, with the largest differences occurring after 2000. Despite representing a minor portion of the total glacier population (~10%), the recession of lake-terminating glaciers accounted for up to 32% of mass loss in different sub-regions. The continued expansion of established glacial lakes, and the preconditioning of land-terminating glaciers for new lake development increases the likelihood of enhanced ice mass loss from the region in coming decades; a scenario not currently considered in regional ice mass loss projections.
The impact of glacial lake development on the evolution of glaciers in the Himalaya is poorly quantified, despite the increasing prevalence of supraglacial and proglacial water bodies throughout the ...region. In this study we examine changes in the geometry, velocity and surface elevation of nine lake-terminating and nine land-terminating glaciers in the Everest region of the central Himalaya over the time period 2000 to 2015. The land-terminating glaciers we examined all decelerated (mean velocity change of −0.16 to −5.60 m a−1 for different glaciers), thinned most in their middle reaches, and developed a more gently sloping surface (−0.02 to −0.37° change) down-glacier over the period 2000–2015. The lake-terminating glaciers we examined all retreated (0.46 to 1.42 km), became steeper (0.04 to 8.68° change), and showed maximum thinning towards their termini, but differed in terms of their dynamics, with one group of glaciers accelerating (mean speed-up of 0.18 to 8.04 m a−1) and the other decelerating (mean slow-down of −0.36 m a−1 to −8.68 m a−1). We suggest that these two scenarios of glacier evolution each represent a different phase of glacial lake expansion; one that is accompanied by increasingly dynamic glacier behaviour and retreat, and a phase where glacial lakes have little impact on glacier behaviour that may precede or follow the phase of active retreat. Our observations are important because they quantify the interaction of glacial lake expansion with glacier ice mass loss, and show that increased glacier recession should be expected where a glacial lake has begun to develop.
•Himalayan glaciers hosting glacial lakes show divergent velocity evolution.•Land-terminating glacier velocity & geometry change consistent within sample.•Glaciers hosting lakes may experience a phase of dynamic retreat and ice loss.
Abstract
Knowledge about the long-term response of High Mountain Asian glaciers to climatic variations is paramount because of their important role in sustaining Asian river flow. Here, a ...satellite-based time series of glacier mass balance for seven climatically different regions across High Mountain Asia since the 1960s shows that glacier mass loss rates have persistently increased at most sites. Regional glacier mass budgets ranged from −0.40 ± 0.07 m w.e.a
−1
in Central and Northern Tien Shan to −0.06 ± 0.07 m w.e.a
−1
in Eastern Pamir, with considerable temporal and spatial variability. Highest rates of mass loss occurred in Central Himalaya and Northern Tien Shan after 2015 and even in regions where glaciers were previously in balance with climate, such as Eastern Pamir, mass losses prevailed in recent years. An increase in summer temperature explains the long-term trend in mass loss and now appears to drive mass loss even in regions formerly sensitive to both temperature and precipitation.
Imagine you are casually browsing an online bookstore, looking for an interesting novel. Suppose the store predicts you will want to buy a particular novel: the one most chosen by people of your same ...age, gender, location, and occupational status. The store recommends the book, it appeals to you, and so you choose it. Central to this scenario is an automated prediction of what you desire. This article raises moral concerns about such predictions. More generally, this article examines the
ethics of artificial social cognition
—the ethical dimensions of attribution of mental states to humans by artificial systems. The focus is
presumptuous
aim attributions, which are defined here as aim attributions based crucially on the premise that the person in question will have aims like superficially similar people. Several everyday examples demonstrate that this sort of presumptuousness is already a familiar moral concern. The scope of this moral concern is extended by new technologies. In particular, recommender systems based on collaborative filtering are now commonly used to automatically recommend products and information to humans. Examination of these systems demonstrates that they naturally attribute aims presumptuously. This article presents two reservations about the widespread adoption of such systems. First, the severity of our antecedent moral concern about presumptuousness increases when aim attribution processes are automated and accelerated. Second, a foreseeable consequence of reliance on these systems is an unwarranted inducement of interpersonal conformity.
A self-fulfilling prophecy is, roughly, a prediction that brings about its own truth. Although true predictions are hard to fault, self-fulfilling prophecies are often regarded with suspicion. In ...this article, we vindicate this suspicion by explaining what self-fulfilling prophecies are and what is problematic about them, paying special attention to how their problems are exacerbated through automated prediction. Our descriptive account of self-fulfilling prophecies articulates the four elements that define them. Based on this account, we begin our critique by showing that typical self-fulfilling prophecies arise due to mistakes about the relationship between a prediction and its object. Such mistakes—along with other mistakes in predicting or in the larger practical endeavor—are easily overlooked when the predictions turn out true. Thus we note that self-fulfilling prophecies prompt no error signals; truth shrouds their mistakes from humans and machines alike. Consequently, self-fulfilling prophecies create several obstacles to accountability for the outcomes they produce. We conclude our critique by showing how failures of accountability, and the associated failures to make corrections, explain the connection between self-fulfilling prophecies and feedback loops. By analyzing the complex relationships between accuracy and other evaluatively significant features of predictions, this article sheds light both on the special case of self-fulfilling prophecies and on the ethics of prediction more generally.
Despite their extreme elevation, glaciers on the Tibetan Plateau are losing mass in response to atmospheric warming, the pattern of which purportedly reflects regional contrasts in climate. Here we ...examine the evolution of glaciers along ~500 km of the Tanggula Shan, Central-Eastern Tibetan Plateau. Using remotely sensed datasets, we quantified changes in glacier mass, area and surface velocity, and compared these results to time series of meteorological observations, in order to disentangle drivers of glacier mass loss since the 1960s. Glacier mass loss has increased (from −0.21 ± 0.12 m w.e. a−1 in 1960s–2000s, to −0.52 ± 0.18 m w.e. a−1 in 2000s–2015/18) in association with pervasive positive temperature anomalies (up to 1.85°C), which are pronounced at the end of the now lengthened ablation season. However, glacier mass budget perturbations do not mirror the magnitude of temperature anomalies in sub-regions, thus additional factors have heightened glacier recession. We show how proglacial lake expansion and glacier surging have compounded glacier recession over decadal/multi-decadal time periods, and exert similar influence on glacier mass budgets as temperature changes. Our results demonstrate the importance of ice loss mechanisms not often incorporated into broad-scale glacier projections, which need to be better considered to refine future glacier runoff estimates.
Meltwater from Himalayan glaciers sustains the flow of rivers such
as the Ganges and Brahmaputra on which over half a billion people depend for
day-to-day needs. Upstream areas are likely to be ...affected substantially by
climate change, and changes in the magnitude and timing of meltwater supply
are expected to occur in coming decades. About 10 % of the Himalayan
glacier population terminates into proglacial lakes, and such
lake-terminating glaciers are known to exhibit higher-than-average total
mass losses. However, relatively little is known about the mechanisms
driving exacerbated ice loss from lake-terminating glaciers in the Himalaya.
Here we examine a composite (2017–2019) glacier surface velocity dataset,
derived from Sentinel 2 imagery, covering central and eastern Himalayan
glaciers larger than 3 km2. We find that centre flow line velocities of
lake-terminating glaciers (N = 70; umedian: 18.83 m yr−1; IQR – interquartile range – uncertainty estimate: 18.55–19.06 m yr−1) are on average more than double those of land-terminating
glaciers (N = 249; umedian: 8.24 m yr−1; IQR uncertainty estimate: 8.17–8.35 m yr−1) and
show substantially more heterogeneity than land-terminating glaciers around
glacier termini. We attribute this large heterogeneity to the varying
influence of lakes on glacier dynamics, resulting in differential rates of
dynamic thinning, which causes about half of the lake-terminating glacier
population to accelerate towards the glacier termini. Numerical ice-flow
model experiments show that changes in the force balance at the glacier
termini are likely to play a key role in accelerating the glacier flow at
the front, with variations in basal friction only being of modest
importance. The expansion of current glacial lakes and the formation of new
meltwater bodies will influence the dynamics of an increasing number of
Himalayan glaciers in the future, and these factors should be carefully
considered in regional projections.
Many glaciers and ice caps on the Tibetan Plateau have retreated and lost mass in recent years in response to temperature increases, providing clear evidence of the impact of climate change on the ...region. There is increasing evidence that many of the glaciers on the Tibetan Plateau have also shown periodically dynamic behaviour in the form of glacier surging and some even catastrophic collapse events. In this study, we examine the prevalence of glacier surging at the Geladandong ice caps, North East Tibetan Plateau, to better understand the role of surge events in the evolution of glacier mass loss budgets. Using glacier surface elevation change data over the period 1969–2018 and glacier surface velocity data from the ITS_LIVE dataset, we find that 19 outlet glaciers of the ice caps are of surge-type. Our multi-temporal measurements of glacier mass balance show that surge-type glacier mass budgets vary depending on the portion of the surge-cycle captured by geodetic data. At the regional level, pre- and post-surge glacier mass loss variability does not bias regional mass budget estimates, but enhanced, or suppressed, mass loss estimates are likely when small groups of glaciers are examined. Our results emphasise the importance of accurate surge-type glacier inventories and the need to maximise geodetic data coverage over glacierised regions known to contain surge-type glaciers.
Worker well-being is a hot topic in organizations, consultancy and academia. However, too often, the buzz about worker well-being, enthusiasm for new programs to promote it and interest to research ...it, have not been accompanied by universal enthusiasm for scientific measurement. Aim to bridge this gap, we address three questions. To address the question ‘What is worker well-being?’, we explain that worker well-being is a multi-facetted concept and that it can be operationalized in a variety of constructs. We propose a four-dimensional taxonomy of worker well-being constructs to illustrate the concept’s complexity and classify ten constructs within this taxonomy. To answer the question ‘How can worker well-being constructs be measured?’, we present two aspects of measures: measure obtrusiveness (i.e., the extent to which obtaining a measure interferes with workers’ experiences) and measure type (i.e., closed question survey, word, behavioral and physiological). We illustrate the diversity of measures across our taxonomy and uncover some hitherto under-appreciated avenues for measuring worker well-being. Finally, we address the question ‘How should a worker well-being measure be selected?’ by discussing conceptual, methodological, practical and ethical considerations when selecting a measure. We summarize these considerations in a short checklist. It is our hope that with this study researchers – working in organizations, in academia or both – will feel more competent to find effective strategies for the measurement worker well-being and eventually make policies and choices with a better understanding of what drives worker well-being.
Region-wide averaging of Himalayan glacier mass change has masked any catchment or glacier-scale variability in glacier recession; thus the role of a number of glaciological processes in glacier ...wastage remains poorly understood. In this study, we quantify mass loss rates over the period 2000–2015 for 32 glaciers across the Everest region and assess how future ice loss is likely to differ depending on glacier hypsometry. The mean mass balance of all 32 glaciers in our sample was −0.52 ± 0.22 m water equivalent (w.e.) a−1. The mean mass balance of nine lacustrine-terminating glaciers (−0.70 ± 0.26 m w.e. a−1) was 32 % more negative than land-terminating, debris-covered glaciers (−0.53 ± 0.21 m w.e. a−1). The mass balance of lacustrine-terminating glaciers is highly variable (−0.45 ± 0.13 to −0.91 ± 0.22 m w.e. a−1), perhaps reflecting glacial lakes at different stages of development. To assess the importance of hypsometry on glacier response to future temperature increases, we calculated current (Dudh Koshi – 0.41, Tama Koshi – 0.43, Pumqu – 0.37) and prospective future glacier accumulation area Ratios (AARs). IPCC AR5 RCP 4.5 warming (0.9–2.3 °C by 2100) could reduce AARs to 0.29 or 0.08 in the Tama Koshi catchment, 0.27 or 0.17 in the Dudh Koshi catchment and 0.29 or 0.18 in the Pumqu catchment. Our results suggest that glacial lake expansion across the Himalayas could expedite ice mass loss and the prediction of future contributions of glacial meltwater to river flow will be complicated by spatially variable glacier responses to climate change.
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