  Understanding multi-decadal variability is an essential goal of climate
dynamics. For example, the recent phenomenon referred to as the "global warming
hiatus" may reflect a coupling to an intrinsic, pre-industrial, multi-decadal
variability process. Here, using a multi-fractal time series method, we
demonstrate that forty-two data sets of seventy-nine proxies with global
coverage exhibit pink noise characteristics on multi-decadal time scales. To
quantify the persistence of this behavior, we examine high-resolution ice core
and speleothem data to find pink noise in both pre- and post-industrial
periods. We examine the spatial structure with Empirical Orthogonal Function
(EOF) analysis of the monthly-averaged surface temperature from 1901 to 2012.
The first mode clearly shows the distribution of ocean heat flux sinks located
in the eastern Pacific and the Southern Ocean, and has pink noise
characteristics on a multi-decadal time-scale. We hypothesize that this pink
noise multi-decadal spatial mode may resonate with externally-driven greenhouse
gas forcing, driving large-scale climate processes.
