Jim White and Trevor Popp are among a team of researchers reporting in Science that the last two warmings at the onset of the current interglacial were much more abrupt than previously suspected.
Data from the North Greenland Ice Core Project shows that precipitation switched mode within one to three years, and Greenland air temperature shifted over the course of approximately fifty years. The research points up the possibility of changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next. Read "High-resolution Greenland Ice Core data show abrupt climate change happens in few years," Science, vol. 321 (1 Aug. 2008), p. 680-684. doi: 10.1126/science.1157707
See also Jacqueline Flueckiger's accompanying Perspectives piece in the same issue, "Climate change: Did you say 'fast'?," Science, vol. 321 (1 Aug. 2008), p. 650-651. doi: 10.1126/science.1159821. It is useful for clearly interpreting the NGRIP results for a more general audience.