North Pacific sea surface temperatures: Past variations inferred from tree rings

March–August sea surface temperatures (SST) are reconstructed for the Gulf of Alaska (GOA) from 1750–1983 based on tree-ring data from coastal and south-central Alaska and the Pacific Northwest. Some of the trends resemble those documented in other northern instrumental and proxy records, including cooler SSTs in the early and middle 1800s, during the Little Ice Age. There is overall warming in this century, including a positive trend from the mid-1970s to 1980s, following cooler 1960s–1970s. The twentieth century warming exceeds maxima in the reconstructed SSTs back to AD 1750 and is consistent with other evidence for unusual Northern Hemisphere warming. Changes over the period of recorded North Pacific SST have been linked to a pattern of variability known as the Pacific Decadal Oscillation (PDO). Maps comparing the reconstruction to the North Pacific SST field and other analyses suggest that it may reflect variations related to the PDO over several centuries.