Background
The hockeystick temperature histories of Mann et al. (1999) and Mann and Jones (2003) give little indication of the existence of the Little Ice Age, because they and others claim that this distinctive multi-century cold spell was restricted to lands surrounding the North Atlantic Ocean, and that it therefore had little impact on the global temperature trend of the past millennium.  Hence, we always keep our eyes peeled for studies that demonstrate the existence of the Little Ice Age in far-flung parts of the globe.

What was done
The authors conducted, in their words, "the first systematic and high-resolution pollen analysis of a tropical ice core."  Specifically, they worked with two long cores to bedrock extracted from the summit of the Sajama Ice Cap (18°06'S, 68°53'W), which sits atop Bolivia's highest peak on the western side of the Bolivian Altiplano.

What was learned
Liu et al. report that "the pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age consisted of two distinct phases - a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880."

What it means
According to Liu et al., "the striking similarity between the Sajama and Quelccaya proxy records suggests that climatic changes during the Little Ice Age occurred synchronously across the Altiplano," and that the Little Ice Age "was a significant and widespread climatic event across the central Andes."  We additionally note that the Little Ice Age in this part of South America was also synchronous with the Little Ice Age of the North Atlantic region, and that it was synchronous with the Little Ice Age of most of the rest of the world as well (see Little Ice Age in our Subject Index for the host of places where it has been documented to have occurred).

References
Mann, M.E., Bradley, R.S. and Hughes, M.K.  1999.  Northern Hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations.  Geophysical Research Letters 26: 759-762.

Mann, M.E. and Jones, P.D.  2003.  Global surface temperatures over the past two millennia.  Geophysical Research Letters 30: 10.1029/2003GL017814.