The study, co-authored by Dr Thomas Stevens, from the Department of Geography at Royal Holloway, University of London, found a previously unknown mechanism by which the joining of North and South America changed the salinity of the Pacific Ocean and caused
major ice sheet growth across the Northern Hemisphere.
The
growth and decay of continental
ice sheets represents a slow feedback operating over millennia; if one is concerned with the more rapid response of the climate to CO2,
ice sheets have to be accounted for as a
major forcing.