What was done
The authors "recovered a 14,000-year mineral-magnetic record from White Lake, a hardwater lake containing organic-rich sediments in northwestern New Jersey, USA," which is located at approximately 41°N, 75°W.

What was learned
Li et al. report that "comparison of the White Lake data with climate records from the North Atlantic sediments shows that low lake levels at ~1.3, 3.0, 4.4, and 6.1 ka [1000 years before present] in White Lake occurred almost concurrently with the cold events at ~1.5, 3.0, 4.5, and 6.0 ka in the North Atlantic Ocean (Bond et al., 2001)," and that "these cold events are associated with the 1500-year warm/cold cycles in the North Atlantic during the Holocene" that have "been interpreted to result from solar forcing (Bond et al., 2001)."

What it means
The four researchers conclude that "the close correlation between White Lake and the North Atlantic suggests that, in response to the decreased temperatures, the White Lake area climate [is] expressed as periods of reduced moisture abundance," and, therefore, that "the Holocene 1500-year lake level fluctuations of White Lake probably represent responses to the broad-scale climate variability in the continental North Atlantic region." Consequently, it is clear that broad-scale periods of warmth (in both space and time) have occurred over and over again throughout the Holocene - and beyond (Oppo et al., 1998; Raymo et al., 1998) - forced solely by variable solar activity, which suggests that the Current Warm Period was also instigated by this same recurring phenomenon and not the CO2 output of the Industrial Revolution.

References
Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N., Showers, W., Hoffmann, S., Lotti-Bond, R., Hajdas, I. and Bonani, G. 2001. Persistent solar influence on North Atlantic climate during the Holocene. Science 294: 2130-2136.

Oppo, D.W., McManus, J.F. and Cullen, J.L. 1998. Abrupt climate events 500,000 to 340,000 years ago: Evidence from subpolar North Atlantic sediments. Science 279: 1335-1338.

Raymo, M.E., Ganley, K., Carter, S., Oppo, D.W. and McManus, J. 1998. Millennial-scale climate instability during the early Pleistocene epoch. Nature 392: 699-702.