What was done
The authors developed a Holocene climate record based on the relative abundance of the planktonic foraminifer Globigerinoides sacculifer found in two piston cores taken from the Gulf of Mexico (GOM) at 23.00°N, 95.53°W and 26.22°N, 91.92°W.

What was learned
The authors report they detected "century-scale variability throughout most of the Holocene," noting that "the GOM record is consistent with records from other areas," including the Cariaco Basin, the Yucatan Peninsula and the subpolar North Atlantic Ocean.  In addition, they say "the similarity in cycles found in many proxy climate records and proxy records for solar variability indicates that some of the high-frequency (century-scale) climate variability of the current interglacial is due to external (solar) forcing."

What it means
Earth's climate is always changing, primarily in cyclical fashion and on a variety of different timescales; and nearly all of these oscillations are solar-induced, in one way or another.  Consequently, external solar forcing should be one of the first things one considers in attempting to understand the reasons for current climate change; and when this is done, solar effects pop up in a host of different real-world contexts (see the thirteen sub-headings under Solar Effects in our Subject Index).  The authors of this study, for example, conclude that "some of the high-frequency (century-scale) climate variability of the current interglacial is due to external (solar) forcing."  Could it be that the see-saw warming of the 20th century falls into this category?  We believe that it does.