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Dust-climate couplings over the past 800,000 years from the EPICA Dome C ice core

2008; Nature Portfolio; Volume: 452; Issue: 7187 Linguagem: Inglês

10.1038/nature06763

1476-4687

Fabrice Lambert, Barbara Delmonte, J. R. Petit, Matthias Bigler, P. Kaufmann, M. A. Hutterli, Thomas F. Stocker, Urs Ruth, J. P. Steffensen, Valter Maggi,

Aeolian processes and effects

The EPICA ice core, drilled at Dome C in East Antarctica, provides an undisturbed record of the past eight climatic cycles. Dust particles in the atmosphere can affect temperature by absorbing or reflecting solar radiation, and previous work suggested that production, transport and deposition of dust is influenced by climatic changes on glacial-interglacial timescales. A new analysis of the record of dust deposits in the EPICA core shows that the flux in atmospheric dust content increasingly correlates with Antarctic temperature during glacial periods as the climate gets colder, indicative of a progressive coupling of the climates of Antarctica and lower latitudes. An observed 25-fold increase in glacial dust flux over all eight glacial periods may reflect a strengthening of South American dust sources, and longer dust-particle lifetimes in the upper troposphere due to a reduced hydrological cycle during ice ages. It has been suggested that production, transport, and deposition of dust is influenced by climatic changes on glacial-interglacial timescales. This paper presents a high-resolution record of aeolian dust from the EPICA Dome C ice core in East Antarctica, which suggests that dust is increasingly correlated with Antarctic temperature as the climate becomes colder, indicative of a progressive coupling of the climates of Antarctica and lower latitudes. Dust can affect the radiative balance of the atmosphere by absorbing or reflecting incoming solar radiation1; it can also be a source of micronutrients, such as iron, to the ocean2. It has been suggested that production, transport and deposition of dust is influenced by climatic changes on glacial-interglacial timescales3,4,5,6. Here we present a high-resolution record of aeolian dust from the EPICA Dome C ice core in East Antarctica, which provides an undisturbed climate sequence over the past eight climatic cycles7,8. We find that there is a significant correlation between dust flux and temperature records during glacial periods that is absent during interglacial periods. Our data suggest that dust flux is increasingly correlated with Antarctic temperature as the climate becomes colder. We interpret this as progressive coupling of the climates of Antarctic and lower latitudes. Limited changes in glacial-interglacial atmospheric transport time4,9,10 suggest that the sources and lifetime of dust are the main factors controlling the high glacial dust input. We propose that the observed ∼25-fold increase in glacial dust flux over all eight glacial periods can be attributed to a strengthening of South American dust sources, together with a longer lifetime for atmospheric dust particles in the upper troposphere resulting from a reduced hydrological cycle during the ice ages.