title: Carbonaceous aerosol tracers in ice-cores record multi-decadal climate oscillations.
abstract: Carbonaceous aerosols influence the climate via direct and indirect effects on radiative balance. However, the factors controlling the emissions, transport and role of carbonaceous aerosols in the climate system are highly uncertain. Here we investigate organic tracers in ice cores from Greenland and Kamchatka and find that, throughout the period covered by the records (1550 to 2000 CE), the concentrations and composition of biomass burning-, soil bacterial- and plant wax- tracers correspond to Arctic and regional temperatures as well as the warm season Arctic Oscillation (AO) over multi-decadal time-scales. Specifically, order of magnitude decreases (increases) in abundances of ice-core organic tracers, likely representing significant decreases (increases) in the atmospheric loading of carbonaceous aerosols, occur during colder (warmer) phases in the high latitudinal Northern Hemisphere. This raises questions about causality and possible carbonaceous aerosol feedback mechanisms. Our work opens new avenues for ice core research. Translating concentrations of organic tracers (μg/kg-ice or TOC) from ice-cores, into estimates of the atmospheric loading of carbonaceous aerosols (μg/m(3)) combined with new model constraints on the strength and sign of climate forcing by carbonaceous aerosols should be a priority for future research.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Hokkaido, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Seki
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Hokkaido, Japan.
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Kawamura
authors.affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham, UK.
authors.forename: James A P
authors.initials: JA
authors.lastname: Bendle
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Hokkaido, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Izawa
authors.affiliation: Faculty of Science, Tokyo Metropolitan University, Tokyo, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Suzuki
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Hokkaido, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Shiraiwa
authors.affiliation: National Institute of Polar Research, Tokyo, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Fujii