Past atmospheric composition and chemistry from ice cores – progress and prospects

Eric W. Wolff; Manuel A. Hutterli; Anna E. Jones

doi:10.1071/EN07031

RESEARCH FRONT

Previous Next Contents Vol 4(4)

Past atmospheric composition and chemistry from ice cores – progress and prospects

Eric W. Wolff ^A ^B , Manuel A. Hutterli ^A and Anna E. Jones ^A

+ Author Affiliations

- Author Affiliations

^A British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.

^B Corresponding author. Email: ewwo@bas.ac.uk

Environmental Chemistry 4(4) 211-216 https://doi.org/10.1071/EN07031
Submitted: 5 April 2007 Accepted: 4 June 2007 Published: 16 August 2007

Environmental context. Investigating the past is often the only way we have of determining whether we have included all processes correctly into models, and then of verifying their behaviour. Ice cores provide an excellent way of finding out about the past. Air bubbles trapped in the ice allow us to directly access the concentration of stable trace gases, including important greenhouse gases. However, there are also tantalising possibilities to learn about aerosols and shorter-lived gases. This article describes some of the information we have already learnt from ice cores, but also describes the challenges that require understanding of atmospheric chemistry in the polar regions today in order to extract the full value of the records of the past trapped in the ice sheet.

Abstract. Ice cores provide the most direct evidence available about the past atmosphere. For long-lived trace gases, ice cores have provided clear evidence that in the last two centuries, concentrations of several greenhouse gases have risen well outside the natural range observed in the previous 650 000 years. Major natural changes are also observed between cold and warm periods. Aerosol components have to be interpreted in terms of changing sources, transport and deposition. When this is done, they can also supply evidence about crucial aspects of the past environment, including sea ice extent, trace element deposition to the ocean, and about the aerosols available for cloud nucleation, for example. It is much more difficult to extract information about shorter-lived chemical species. Information may be available in components such as nitrate and formaldehyde, but to extract that information, detailed modern atmospheric studies about air to snow transfer, preservation in the ice, and the link between the polar region boundary layer and other parts of the atmosphere are urgently required.

Additional keywords: Antarctic, Arctic, ice cores, paleoclimate.

References