Earth Climate: the lesson learnt from the past

Prof. Carlo Barbante
Institute for the Dynamics of Environmental Processes - CNR
Università di venezia

ABSTRACT:

Ice cores have emerged in the last three decades as a cornerstone of palaeoclimate research for the most recent glacial-interglacial cycles. They complement the information about climate on land held in terrestrial archives, and about ocean circulation, chemistry and climate held in marine sediments. Together, these archives offer a wide range of constraints for climate models. Ice cores are able uniquely to supply direct information about greenhouse gas concentrations in the past, and play a strong role by combining data about a wide range of forcings (including greenhouse gases, solar and volcanic activity) with information about a wide range of responses.

Among the specific objectives tackled with the ice core records themselves were:

• Reconstruction of climate variability in Antarctica (temperature, accumulation, moisture source) on multi-decadal to orbital time scales.
• Quantification of variations in greenhouse gas concentrations (CO₂, CH₄ and N₂O), their causes as well as their influence on and feedbacks with climatic changes.
• Determination of variations in atmospheric aerosol concentrations, their interpretation in terms of atmospheric circulation and environmental conditions in aerosol source regions.
• Reconstruction of the history of solar irradiance (by cosmogenic isotopes) and the influence of variations of the irradiance and orbital parameters on climate.