The Younger Dryas (YD) delta-O-18 changes are most extreme in the Greenland ice core values; the result of precipitation from Atlantic surface evaporation. Ther

The Younger Dryas (YD) delta-O-18 changes are most extreme in the Greenland ice core values; the result of precipitation from Atlantic surface evaporation. There are multiple variables that influence this value like 1. Sea Surface Temperature, 2. delta-O-18 of the surface water, and 3. distance from source to destination (how monsoon data is extracted from Asian cave stalactites). The YD was initiated by massive meltwater pulses. Depending on the fluid dynamics of freshwater mixing in the Atlantic, the early YD should logically result in delta-O-18 spikes due to the influx of freshwater. The meltwater pulses are not caused by sudden temperature spikes though it is plausible that the freshwater influx disrupts the major Atlantic currents and has localized temperature impacts. YD-style spikes occur after each glacial termination in the era of 100-ky glacial cycles as seen in the LR04 data set; parallel meltwater pulse events every 100 ky. You are correct, the graphs showing sharply lower temperatures are common and these graphs are technically correct because they are plotting delta-temperature-“equivalents”, but drastic changes can be the result of freshwater changes alone at a constant temperature.