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We present climate and surface mass balance (SMB) of the Antarctic ice sheet (AIS) as simulated by the global, coupled ocean-atmosphere-land Community Earth System Model (CESM) with a horizontal resolution of $${\sim }1^\circ$$ in the past, present and future (1850-2100). CESM correctly simulates present-day Antarctic sea ice extent, large-scale atmospheric circulation and near-surface climate, but fails to simulate the recent expansion of Antarctic sea ice. The present-day Antarctic ice sheet SMB equals $$2280 \pm 131$$ $$\mathrm {Gt\,year^{-1}}$$ , which concurs with existing independent estimates of AIS SMB. When forced by two CMIP5 climate change scenarios (high mitigation scenario RCP2.6 and high-emission scenario RCP8.5), CESM projects an increase of Antarctic ice sheet SMB of about 70 $$\mathrm {Gt\,year^{-1}}$$ per degree warming. This increase is driven by enhanced snowfall, which is partially counteracted by more surface melt and runoff along the ice sheet's edges. This intensifying hydrological cycle is predominantly driven by atmospheric warming, which increases (1) the moisture-carrying capacity of the atmosphere, (2) oceanic source region evaporation, and (3) summer AIS cloud liquid water content. [ABSTRACT FROM AUTHOR]

Within the framework of sea-level rise projections, there is a strong need for hindcast validation of the evolution of polar ice sheets in a way that tightly matches observational records (from radar and altimetry observations mainly). However, the computational requirements for making hindcast reconstructions possible are severe and rely mainly on the evaluation of the adjoint state of transient ice-flow models. Here, we look at the computation of adjoints in the context of the NASA/JPL/UCI Ice Sheet System Model, written in C++ and designed for parallel execution with MPI. We present the adaptations required in the way the software is designed and written but also generic adaptations in the tools facilitating the adjoint computations. We concentrate on the use of operator overloading coupled with the AdjoinableMPI library to achieve the adjoint computation of ISSM. We present a comprehensive approach to 1) carry out type changing through ISSM, hence facilitating operator overloading, 2) bind to external solvers such as MUMPS and GSL-LU and 3) handle MPI-based parallelism to scale the capability. We demonstrate the success of the approach by computing sensitivities of hindcast metrics such as the misfit to observed records of surface altimetry on the North-East Greenland Ice Stream, or the misfit to observed records of surface velocities on Upernavik Glacier, Central West Greenland. We also provide metrics for the scalability of the approach, and the expected performance. This approach has the potential of enabling a new generation of hindcast-validated projections that make full use of the wealth of datasets currently being collected, or already collected in Greenland and Antarctica, such as surface altimetry, surface velocities, and/or gravity measurements. [ABSTRACT FROM AUTHOR]

Local sea level can deviate from mean global sea level because of both dynamic sea level (DSL) effects, resulting from oceanic and atmospheric circulation and temperature and salinity distributions, and changes in the static equilibrium (SE) sea level configuration, produced by the gravitational, elastic, and rotational effects of mass redistribution. Both effects will contribute to future sea level change. To compare their magnitude, we simulated the effects of Greenland Ice Sheet (GIS) melt by conducting idealized North Atlantic 'water-hosing' experiments in a climate model unidirectionally coupled to a SE sea level model. At current rates of GIS melt, we find that geographic SE patterns should be challenging but possible to detect above dynamic variability. At higher melt rates, we find that DSL trends are strongest in the western North Atlantic, while SE effects will dominate in most of the ocean when melt exceeds ~20 cm equivalent sea level. [ABSTRACT FROM AUTHOR]

This article discusses global warming as a disaster management issue. The measurement of natural disasters in terms of duration and severity is framed in terms of the social aspects of emergency management and preparedness. The lack of relationship between scientific metrics determining the magnitude of disasters and the public perception of the disastrous is explored. While the melting of ice sheets in Antarctica and Greenland will meet the scientific definition of a disaster, they author believes that public perception may be muted by the slow onset of this change. Events that scientists think of as normal, such as wildfires, are perceived by the public as a disaster.

With the warming of the global climate, the mass loss of the Greenland ice sheet is intensifying, having a profound impact on the rising of the global sea level. Here, we used Gravity Recovery and Climate Experiment (GRACE) RL06 data to retrieve the time series variations of ice sheet mass in Greenland from January 2003 to December 2015. Meanwhile, the spatial changes of ice sheet mass and its relationship with land surface temperature are studied by means of Theil–Sen median trend analysis, the Mann–Kendall (MK) test, empirical orthogonal function (EOF) analysis, and wavelet transform analysis. The results showed: (1) in terms of time, we found that the total mass of ice sheet decreases steadily at a speed of −195 ± 21 Gt/yr and an acceleration of −11 ± 2 Gt/yr2 from 2003 to 2015. This mass loss was relatively stable in the two years after 2012, and then continued a decreasing trend; (2) in terms of space, the mass loss areas of the Greenland ice sheet mainly concentrates in the southeastern, southwestern, and northwestern regions, and the southeastern region mass losses have a maximum rate of more than 27 cm/yr (equivalent water height), while the northeastern region show a minimum rate of less than 3 cm/yr, showing significant changes as a whole. In addition, using spatial distribution and the time coefficients of the first two models obtained by EOF decomposition, ice sheet quality in the southeastern and northwestern regions of Greenland show different significant changes in different periods from 2003 to 2015, while the other regions showed relatively stable changes; (3) in terms of driving factors temperature, there is an anti-phase relationship between ice sheet mass change and land surface temperature by the mean XWT-based semblance value of −0.34 in a significant oscillation period variation of 12 months. Meanwhile, XWT-based semblance values have the largest relative change in 2005 and 2012, and the smallest relative change in 2009 and 2010, indicating that the influence of land surface temperature on ice sheet mass significantly varies in different years. [ABSTRACT FROM AUTHOR]

The article discusses forecasting of sea-level rise associated with global warming and research results regarding melting of the East Antarctica Ice Sheet (EAIS) that factor into such forecasts. The article discusses 3 studies published in "Nature" and "Nature Geoscience" since 2008 that measured ice loss from the EAIS. Totten Glacier in East Antarctica is noted to be losing up to 1.9 meters of ice thickness annually. Several researchers are cited regarding glacial melting in East Antarctica including marine geologist Maureen Raymo, glaciologist Donald Blankenship, and scientist Fausto Ferraccioli.

The article offers international news brief related to ocean environment. A new study states that sea level will rise at an average of 3.3 meters instead of 5 or 6 meters due to the collapse of the West Antarctic ice sheet. The National Conservancy research shows that shellfish reefs are now the most threatened marine habitat. The UNESCO World Heritage Committee have added two European sites in their World Heritage List, the Wadden Sea in Germany and the Netherlands, and the Italian Dolomites.

The article discusses the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment, which admitted that poorly characterized uncertainties have prevented a best estimate or upper bound on sea-level rise that has been catalyzed by accelerations in outland glaciers of the Greenland and Antarctic ice sheets. Research on the topic is presented chronologically, beginning with the discovery that surface meltwater can facilitate summer ice flow. The difficulty associated with accruing quantitative research is examined, and the ambiguity of the relationship between ice sheets and their underlying beds is highlighted.

The article offers information on the book "Understanding Sea-Level Rise and Variability," by John Church, Philip Woodworth, Thorkild Aarup, and Stan Wilson. It relates on the community adaption for sea level rise through the development of ice sheet and international ocean monitoring and modelling programs. Doctor John Church notes that by generating data, it can project global sea-level rise. He adds that populations in deltaic regions are at risk as sea-level changes the coastal fringes.