Slow (interdecadal) component of changes in DJF mean surface temperatures since 1850. Upper panel: slow component of temperature changes relative to the period 1850–1900. Lower panel: time series of area-mean (22.5°S to 67.5°N) temperature changes (black) and the area-mean temperature change accounted for by the slow component in the main panel (red). Gray areas in the upper panel are areas with insufficient data coverage for this analysis.
Reference: Schneider, T., and I. M. Held, 2001: Discriminants of twentieth-century changes in Earth surface temperatures. Journal of Climate, 14, 249–254.
Analysis updated May 19, 2015.