9 December 2004
Climate: North and south
The climate history of the high northern latitudes is characterized by large abrupt shifts. Relationships between these shifts and climate in the tropics and Southern Hemisphere are poorly understood, partly because of the lack of precisely dated past climate records in the tropics. A new uranium-series dating study of the growth patterns of cave calcite and surface spring deposits in semi-arid northeastern Brazil provides exactly the type of record required. Abrupt shifts in rainfall in the southern tropics are found to correlate precisely with abrupt shifts in Northern Hemisphere climate. The findings underline the importance of the tropics in abrupt climate change. Climate history in this area is critical to our understanding of the evolution of Amazonian and Atlantic rainforests, as wet intervals may represent times in the past when the rainforests were connected.
Wet periods in northeastern Brazil over the
past 210 kyr linked to distant climate anomalies
XIANFENG WANG, AUGUSTO S. AULER, R. LAWRENCE EDWARDS,
HAI CHENG, PATRICIA S. CRISTALLI, PETER L. SMART, DAVID A. RICHARDS &
CHUAN-CHOU SHEN
Nature 432, 740–743 (2004); doi:10.1038/nature03067
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Climate change: Tropical flip-flop connections
JOHN C. H. CHIANG & ATHANASIOS KOUTAVAS
A long climatic record shows that episodic wet periods in northeastern
Brazil are linked to distant climate anomalies. The ocean-atmosphere system
can evidently undergo rapid and global reorganization.
Nature 432, 684–685 (2004); doi:10.1038/432684a
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