1. Department of Geological Sciences and Bolin Centre for Climate Research; Stockholm University; Stockholm SE-10691 Sweden
2. Department of Applied Environmental Science and Bolin Centre for Climate Research; Stockholm University; Stockholm SE-10691 Sweden
3. School of Geography, Archaeology and Palaeoecology; Queen's University Belfast; Belfast BT7 1NN UK
4. School of Geography, Earth and Environmental Sciences; Plymouth University; Drake Circus Plymouth PL4 8AA UK