Reconstructing climates of the past relies on a variety of evidence from a large number of sites to capture the varied features of climate and the spatial heterogeneity of climate 32 change. This review summarizes available information from diverse Holocene paleoenvironmental records across eastern Beringia (Alaska, westernmost Canada and adjacent 34 seas), and it quantifies the primary trends of temperature-and moisture-sensitive records based in part on midges, pollen, and biogeochemical indicators (compiled in the recently published Arctic 36Holocene database, and updated here to v2.1). The composite time series from these proxy records are compared with new summaries of mountain-glacier and lake-level fluctuations, 38 terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies to clarify multi-centennial-to millennial-scale trends in 40Holocene climate change. To focus the synthesis, the paleo data are used to frame specific questions that can be addressed with simulations by Earth system models to investigate the 42 causes and dynamics of past and future climate change. This systematic review shows that, during the early Holocene (11.7-8.2 ka), rather than a prominent thermal maximum as suggested 44 previously, temperatures were highly variable, at times both higher and lower than present (approximate mid-20 th -century average), with no clear spatial pattern. Composited pollen, midge 46 and other proxy records average out the variability and show the overall lowest summer and mean-annual temperatures across the study region during the earliest Holocene, followed by 48 warming over the early Holocene. The sparse data available on early Holocene glaciation show that glaciers in southern Alaska were as extensive then as they were during the late Holocene. 50Early Holocene lake levels were low in interior Alaska, but moisture indicators show pronounced differences across the region. The highest frequency of both peatland and thaw-lake initiation 52 ages also occurred during the early Holocene. During the middle Holocene (8.2-4.2 ka), glaciers 3 retreated as the regional average temperature increased to a maximum between 7 and 5 ka, as 54 reflected in most proxy types. Following the middle Holocene thermal maximum, temperatures decreased starting between 4 and 3 ka, signaling the onset of Neoglacial cooling. Glaciers in the 56 Brooks and Alaska Ranges advanced to their maximum Holocene extent as lakes generally rose to modern levels. Temperature differences for averaged 500-year time steps typically ranged by 58 1-2°C for individual records in the Arctic Holocene database, with a transition to a cooler late Holocene that was neither abrupt nor spatially coherent. The longest and highest-resolution 60 terrestrial water isotope records previously interpreted to represent changes in the Aleutian lowpressure system around this time are here shown to be largely contradictory. Furthermore, there 62 are too few records with sufficient resolution to ...

Magnesium sulphate has been demonstrated to be an effective neuroprotectant for babies delivered prematurely (under 37 weeks’ gestational age). Antenatal administration reduces infant mortality and cerebral palsy (CP); however, uptake in the UK has been significantly lower than other countries. A quality improvement (QI) project (PReventing Cerebral palsy in Pre Term labour (PReCePT)) was carried out in the West of England, UK, to raise awareness of evidence and to improve the uptake of magnesium sulphate as neuroprotectant in preterm deliveries. Five National Health Service (NHS) Trusts and the West of England Academic Health Science Network participated in the QI project. The project was underpinned by a multifaceted QI approach that included: patient and clinical coproduction of resources; recruitment of clinical champions to support the local microsystems and create a stimulating/supporting environment for change; Plan, Do, Study, Act cycles; training for over 600 NHS staff and awareness raising and strategic influencing of key leaders. A baseline audit and regular measurement of the number of eligible women receiving magnesium sulphate was undertaken at each hospital site, and the overall programme was evaluated using data from an international benchmarking organisation for neonatal care outcomes—the Vermont Oxford Network. During the project 664 staff received magnesium sulphate training. The use of magnesium sulphate increased across the West of England from an average baseline of 21% over the 2 years preceding the project to 88% by the conclusion of the project. The project was also able to influence the development of a national data collection process for benchmarking the use of magnesium sulphate for neuroprotection in preterm deliveries in the U.K. PReCePT appears to have had a favourable effect on the uptake of magnesium sulphate across the West of England. The project has also provided learning about how to stimulate adoption and spread of evidence using a QI approach across a network.

Abstract. It has been argued that the infiltration and retention of meltwater within firn across the percolation zone of the Greenland ice sheet has the potential to buffer up to  ∼  3.6 mm of global sea-level rise (Harper et al., 2012). Despite evidence confirming active refreezing processes above the equilibrium line, their impact on runoff and proglacial discharge has yet to be assessed. Here, we compare meteorological, melt, firn stratigraphy and discharge data from the extreme 2010 and 2012 summers to determine the relationship between atmospheric forcing and melt runoff at the land-terminating Kangerlussuaq sector of the Greenland ice sheet, which drains into the Watson River. The 6.8 km3 bulk discharge in 2012 exceeded that in 2010 by 28 %, despite only a 3 % difference in net incoming melt energy between the two years. This large disparity can be explained by a 10 % contribution of runoff originating from above the long-term equilibrium line in 2012 caused by diminished firn retention. The amplified 2012 response was compounded by catchment hypsometry; the disproportionate increase in area contributing to runoff as the melt-level rose high into the accumulation area.Satellite imagery and aerial photographs reveal an extensive supraglacial network extending 140 km from the ice margin that confirms active meltwater runoff originating well above the equilibrium line. This runoff culminated in three days with record discharge of 3100 m3 s−1 (0.27 Gt d−1) that peaked on 11 July and washed out the Watson River Bridge. Our findings corroborate melt infiltration processes in the percolation zone, though the resulting patterns of refreezing are complex and can lead to spatially extensive, perched superimposed ice layers within the firn. In 2012, such layers extended to an elevation of at least 1840 m and provided a semi-impermeable barrier to further meltwater storage, thereby promoting widespread runoff from the accumulation area of the Greenland ice sheet that contributed directly to proglacial discharge and global sea-level rise.

Measurements of oxygen and hydrogen stable isotopes in precipitation (δ18OP and δ2HP) provide a valuable tool for understanding modern hydrological processes and the empirical foundation for interpreting paleoisotope archives. However, long‐term data sets of modern δ18OP and δ2HP in southern Alaska are entirely absent, thus limiting our insight and application of regionally defined climate‐isotope relationships in this proxy‐rich region. We present and utilize a 13‐year‐long record of event‐based δ18OP and δ2HP data from Anchorage, Alaska (2005–2018, n = 332), to determine the mechanisms controlling precipitation isotopes. Local surface air temperature explains ~30% of variability in the δ18OP data with a temperature‐δ18O slope of 0.31 ‰/°C, indicating that δ18OP archives may not be suitable paleo‐thermometers in this region. Instead, back‐trajectory modeling reveals how winter δ18OP/δ2HP reflects synoptic and mesoscale processes in atmospheric circulation that drive changes in the passage of air masses with different moisture sources, transport, and rainout histories. Specifically, meridional systems—with either northerly flow from the Arctic or southerly flow from the Gulf of Alaska—have relatively low δ18OP/δ2HP due to progressive cooling and removal of precipitation as it condenses with altitude over Alaska's southern mountain ranges. To the contrary, zonally derived moisture from either the North Pacific and/or Bering Sea retains relatively high δ18OP/δ2HP values. These new data contribute a better understanding of the modern Alaska water isotope cycle and provide an empirical basis for interpreting paleoisotope archives in context of regional atmospheric circulation.