From the CO2Science Archive: What was done: The authors present a high-resolution 700-year record of climate variability in tropical Africa derived from profiles of biogenic silica abundance in varved sediment cores retrieved from northern Lake Malawi, Africa (near 10degS, 34degE).
Paper reviewed: Johnson, T.C., Barry, S., Chan, Y. and Wilkinson, P. 2001. Decadal record of climate variability spanning the past 700 yr in the Southern Tropics of East Africa. Geology 29: 83-86.
What was learned: Century-scale changes in biogenic silica were noted throughout the record. Low concentrations (warmer conditions) prevailed throughout most of the period between 1300 and 1520 A.D. and between the late 1800s and the present. High concentrations (colder conditions) were sustained between 1570 and 1820. This biogenic silica record correlates well with oxygen isotope records from Quelccaya, Peru and the South Pole, which also indicate the presence of the Little Ice Age.
What it means: The results of this study clearly indicate that the well-developed Little Ice Age of the Northern Hemisphere was strong enough to influence even the normally-warm Southern Hemispheric tropics. In contradiction of the claim of the climate alarmists that the Little Ice Age was purely a localized Northern Hemispheric phenomenon, the authors thus conclude that the Lake Malawi records “further support, and extend, the global expanse of the Little Ice Age.”