RECENT climate records from Greenland ice cores(1,2) and North Atlantic sediments(3-5) have challenged the long-held notion that Pleistocene climate fluctuates between two relatively stable states (glacials and interglacials). It has been appreciated for some time that the transitions from one state to another are not smooth(6), but the new records indicate that the glacial and interglacial periods themselves appear to be punctuated by significant climate variability-several short interstadial events punctuated the last glacial period, for example. But it has not been clear whether this climate instability is a global phenomenon or is peculiar to the North Atlantic region. Here we present climate proxy records from sediment cores from the eastern margin of the North Pacific Ocean, which indicate that climate in this region was also highly unstable during the last glaciation. Our observations suggest that glacial climate instability throughout the Northern Hemisphere might be linked to rapid changes in the size of the Laurentide ice sheet and associated changes in atmospheric circulation.