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Investigations of the time-dependent behavior of marine ice sheets and their sensitivity to basal conditions require numerical models because existing theoretical analyses focus only on steady-state configurations primarily with a power-law basal shear stress. Numerical results indicate that the choice of the sliding law strongly affects ice-sheet dynamic behavior. Although observed or simulated grounding-line retreat is typically interpreted as an indication of marine ice sheet instability introduced by Weertman (1974), this (in)stability is a characteristic of the ice sheet's steady states – not time-variant behavior. To bridge the gap between theoretical and numerical results, we develop a framework to investigate grounding line dynamics with generalized basal and lateral stresses (i.e. the functional dependencies are not specified). Motivated by observations of internal variability of the Southern Ocean conditions we explore the grounding-line response to stochastic variability. We find that adding stochastic variability to submarine melt rates that produced stable steady-state configurations leads to intermittently advancing and retreating grounding lines. They can also retreat in an unstoppable manner on time-scales significantly longer than the stochastic correlation time-scales. These results suggest that at any given time of their evolution, the transient behavior of marine ice sheets cannot be described in terms of 'stable' or 'unstable'. [ABSTRACT FROM AUTHOR]

Course requirements for undergraduate degree programs are of wide interest because they signal the subjects and disciplines that departments value, and because they indicate to prospective employers the knowledge and skills that students are trained in. Many geoscience departments are reassessing course requirements for their undergraduate majors in the face of declining enrollments and budgetary pressures. Comparing course requirements among institutions is useful during such reassessments because it enables departments to identify gaps in their curricula and to evaluate their course requirements relative to those at other institutions. To date, however, no easily accessible compilation of course requirements for geoscience majors has been developed. This presents an obstacle for quantitative, data-based assessments of geoscience course requirements. To fill this gap, we constructed a novel data compilation of course and credit requirements for undergraduate geoscience majors in 50 Geoscience departments in the United States in March-April 2024 (n = 966 courses in total). To facilitate comparisons among programs, we restricted this compilation to departments at R1 universities. For each program, we collected data on the required geoscience courses and credits inside the home department and the required cognate courses and credits outside the home department (e.g., Math, Physics, Chemistry). In addition to reporting the course and credit requirements for each major, this data compilation also reports normalized course and credit loads to help compare requirements among semester-term and quarter-term institutions, which have different term lengths and systematically different course and credit degree requirements. The dataset consists of two files: one data compilation file in spreadsheet format that contains data on geoscience undergraduate major course requirements, and one document in pdf format that contains figures displaying graphical representations of the same data. The data compilation is organized as a series of four tables, each in its own worksheet. These tables contain: 1) a list of the institutions, departments, and majors included in this compilation; 2) a matrix of course requirements in the compiled major at each institution, both in the home geoscience department and in cognate fields outside the home department; 3) a matrix of the credits associated with each course requirement; and 4) the percentage of the compiled programs that require a list of common geoscience subjects. These data can be reused by other researchers to identify subject-matter gaps in departmental curricula and to quantify the mean and variability in course requirements across institutions. This in turn can be used to inform departments' decisions about how to adapt their course requirements to best serve their students. These data can be used to investigate trends in course and credit requirements among institutions, and they can serve as a quantitative foundation for comparisons of course and credit requirements in the geosciences to those in other non-geoscience fields. Lastly, these data can be used by students comparing their course requirements to those at other institutions, which can help them choose which courses to take to strengthen their education and career prospects., (© 2024 The Authors.)