Climate Forcing during the Holocene

The role of several important factors that have played a role in Holocene climate change is examined. These forcing factors operate on different time-scales: lower frequency (millennial-scale) climate changes associated with orbital forcing, century-scale variability associated with solar forcing, and annualto decadal-scale variability associated with volcanic forcing. Feedbacks within the climate system may involve non-linear responses to forcing, especially if critical thresholds are exceeded. In addition, there may be distinct regional climate anomaly patterns that result from certain types of forcing. Other anomalies that appear in Holocene paleoclimatic records may be unrelated to external forcing factors, but reflect conditions entirely within the climate system. General circulation model simulations play an important role in helping to understand how these various factors interact to produce the observed changes in Holocene climate.