[OANNES Foro] Tropical Pacific convection sensitive to variations in global climate

[Mario Cabrejos]

Science 8 June 2012: 
Vol. 336 no. 6086 pp. 1242-1243 
DOI: 10.1126/science.1223527 

Dancing to the Tune of the Glacial Cycles
Naoyuki Kurita
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, 237-0061, Japan.E-mail: nkurita en jamstec.go.jp

Summary
Tropical convection acts as a heat engine that drives the world's atmospheric circulation. Any perturbation of this force has a global influence through interaction with other weather phenomena, such as monsoons, the El Nino/Southern Oscillation, and the genesis of tropical cyclones. How will a possibly warmer future climate affect tropical convective activity? On page 1301 of this issue, Meckler et al. provide insight to this question through their analysis of an oxygen isotope record from a stalagmite in northern Borneo, reflecting tropical Pacific convective activity from 570,000 to 210,000 years ago. The record illustrates how sensitive tropical convection is to variations in global climate. 

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Science 8 June 2012: 
Vol. 336 no. 6086 pp. 1301-1304 
DOI: 10.1126/science.1218340 
Published Online May 3 2012

Interglacial Hydroclimate in the Tropical West Pacific Through the Late Pleistocene
A. N. Meckler1,2,*, M. O. Clarkson3, K. M. Cobb4, H. Sodemann5, J. F. Adkins1
1Geological and Planetary Science Department, California Institute of Technology, Pasadena, CA, USA. 2Geological Institute, ETH Zurich, Switzerland. 3School of Geosciences, University of Edinburgh, Edinburgh EH9 3JW, UK. 4School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA. 5Institute for Atmosphere and Climate, ETH Zurich, Switzerland. To whom correspondence should be addressed. E-mail: nele.meckler en erdw.ethz.ch

Abstract
Records of atmospheric carbon dioxide concentration (Pco2) and Antarctic temperature have revealed an intriguing change in the magnitude of interglacial warmth and Pco2 at around 430,000 years ago (430 ka), but the global climate repercussions of this change remain elusive. Here, we present a stalagmite-based reconstruction of tropical West Pacific hydroclimate from 570 to 210 ka. The results suggest similar regional precipitation amounts across the four interglacials contained in the record, implying that tropical hydroclimate was insensitive to interglacial differences in Pco2 and high-latitude temperature. In contrast, during glacial terminations, drying in the tropical West Pacific accompanied cooling events in northern high latitudes. Therefore, the tropical convective heat engine can either stabilize or amplify global climate change, depending on the nature of the climate forcing. 




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