The author attempts to quantify the amount of water released (by various means) by the world's glaciers, and to determine the variations in these figures provoked by the warming trend which was observed for the first half of this century, and the cooling trend observed in the 1960s and 1970s. Unfortunately Antarctica has generally had to be excluded from these calculations since data on a number of components of the water balance of the Antarctic Ice Sheet are simply not available. Perhaps most significant are the author's predictions that the anticipated future rise in air temperatures will provoke increased precipitation and hence increased accumulation on the major ice sheets. Even despite increased melting in coastal areas of Greenland and Antarctica the net effect will be a positive mass balance and ultimately a lowering of sea level.