this melts away. Year forty (Fig. 15) has snowfall occurring during all four seasons in the Arctic and Antarctic. This is a result of sea ice covering the Arctic Ocean, as seen in Fig. 5, and below freezing air temperatures (Fig. 7). Comparing snowfall and precipitation rates (Fig. 12), it appears snowfall is more intense. However, this is due to the color scale for snowfall maxing out at 3 mm/day. The pocket of high winter precipitation to the east of Greenland corresponds to the presence of open water. Sea ice extends towards the lower latitudes by year 160 and the snowfall pattern matches this advance (Fig. 16). By the end of the simulation (Fig. 17) snowfall occurs year-round as far south as the Mediterranean and to the southern tips of South America and Africa. The simulation also tracks the accumulative effect of snowfall. No accumulation occurs during the first decade of the model. By year twenty, inland parts of Greenland can accumulate several meters of Figure 10. Precipitation for the four seasons during year 1. snow. Fig. 18 shows the state of the snowfield at year forty. Most of Greenland is covered with up to four meters of snow. At year 160 (Fig. 19) the depth of Greenland’s snow is relatively unchanged. However, Antarctica has caught up with Greenland. By the end of the simulation, snow depth as illustrated in Fig. 19 has not changed appreciably in the subsequent 230 years. Snow depth is only part of the picture. Fig. 20 shows the total earth ice at year forty. Since the scale is in kg/m2, ice thickness in millimeters is approximated by dividing the given number by 0.90. Most of the ice accumulation is in Alaska and Northern Siberia. By year 160 (Fig. 21) the extent of significant ice cover has spread across Northern Europe and Canada. Fig. 22 corresponds to year 390 and has one meter of ice around the Great Lakes. Curiously, Greenland and Antarctica are not accumulating any significant ice, although the snow depth from Fig. 19 is greater than that over Canada. There does Figure 11. Precipitation for the four seasons during year 10. GOLLMER Rapid ice age 2023 ICC 274
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