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I'd like to call attention to an anthropogenic influence on global sea level change. Although far less interesting for geophysicists who study natural processes, the phenomenon in question has made a significant difference, and hence ought to be taken into account in the sea level budget.

Observational evidence shows that the global sea level has risen at the rate of 1.6–2 mm/yr for the last several decades [e.g., Trupin and Wahr, 1990; Douglas, 1991]. How much of [the rise] results from natural fluctuation, how much is anthropogenic, and what are the sources and mechanisms of the rise are among the key questions asked in this era of concerns about enhanced greenhouse effect and global warming. Presumably, as the global temperature rises, the sea level will rise for two reasons: thermal expansion (the steric change), and addition of water (the eustatic change). A primary candidate for the source of the latter is melting land ice in the form of polar ice sheets and mountain glaciers. Practically nothing useful is known about the present-day mass balance of the polar ice [Zwally, 1989; Douglas et al., 1990]. The best estimate for the rate of mountain glacier mass wastage, based on scanty data, amounts to a contribution of 0.46 (±.26) mm/yr of higher sea level between 19007ndash;1961 [Meier, 1984].