20th-Century doubling in dust archived in an Antarctic Peninsula ice core parallels climate change and desertification in South America

doi:10.1073/pnas.0607657104

20th-Century doubling in dust archived in an Antarctic Peninsula ice core parallels climate change and desertification in South America

^†Desert Research Institute, Nevada System of Higher Education, Reno, NV 89512;
^§Laboratorio de Estratigrafía Glaciar y Geoquímica del Agua y de la Nieve, Instituto Antártico Argentino, Centro Regional de Investigaciones Cientifícas y Teconológicas, 5500 Mendoza, Argentina; and
^¶Núcleo de Pesquisas Antárctica e Climáticas, Universidade Federal do Rio Grande do Sul, CEP 90040-060 Porto Alegre, Brazil

Edited by Inez Y. Fung, University of California, Berkeley, and approved February 9, 2007 (received for review September 1, 2006)

Abstract

Crustal dust in the atmosphere impacts Earth's radiative forcing directly by modifying the radiation budget and affecting cloud nucleation and optical properties, and indirectly through ocean fertilization, which alters carbon sequestration. Increased dust in the atmosphere has been linked to decreased global air temperature in past ice core studies of glacial to interglacial transitions. We present a continuous ice core record of aluminum deposition during recent centuries in the northern Antarctic Peninsula, the most rapidly warming region of the Southern Hemisphere; such a record has not been reported previously. This record shows that aluminosilicate dust deposition more than doubled during the 20th century, coincident with the ≈1°C Southern Hemisphere warming: a pattern in parallel with increasing air temperatures, decreasing relative humidity, and widespread desertification in Patagonia and northern Argentina. These results have far-reaching implications for understanding the forces driving dust generation and impacts of changing dust levels on climate both in the recent past and future.

Footnotes

^‡To whom correspondence should be addressed. E-mail: joe.mcconnell{at}dri.edu
Author contributions: J.R.M., A.J.A., and J.C.S. designed research; J.R.M., A.J.A., J.R.B., P.R.E., and J.C.S. performed research; J.R.M. and P.R.E. contributed new reagents/analytic tools; J.R.M. and A.J.A. analyzed data; and J.R.M. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Abbreviations:

nssCA,

non-sea-salt component of soluble calcium;

nssMg,

non-sea-salt component of soluble magnesium;

ppb,

parts per billion;

masl,

meters above sea level;

HR-ICP-MS,

high-resolution, inductively coupled plasma mass spectrometer;

ICP-PES,

inductively coupled plasma optical emission spectrometer.