Correlations among charcoal records of fires from the past 16,000 years inIndonesia, Papua New Guinea, and Central and South America

Microscopic charcoal preserved in lake and swamp sediments from 10 sites in Indonesia and Papua New Guinea and from 5 sites in Central and South Ameri ca have been used to reconstruct longterm fire histories for these two regi ons. Comparison of these records demonstrates that fire is promoted during periods of rapid climate change and high climate variability, regardless of the presence or absence of humans. Broad synchrony of changes in corrected charcoal values in each region supports an atmospheric transmission of the climate signal via the dominant large-scale atmospheric circulation system s (Walker Circulation) that appears to have persisted since 16,000 cal yr B .P. Altered climate boundary conditions under the influence of changing El Nino-related variability, insolation, sea level, and sea surface temperatur e all influenced the strength of this connection. Correlation of biomass bu rning records between the regions tends to increase in the Holocene. The ma in period of inverse correlation occurs during the Younger Dryas Stade, whe n extratropical climate mast affected the tropics. The strongest correlatio n between the two regions postdates 5000 cal yr B.P., when El Nino-related variability intensified. Fluctuations in tropical biomass burning are at le ast partly controlled by orbital forcing (precession), although extratropic al climate influences and human activity are also important. (C) 2001 Unive rsity of Washington.