1. School of Geography; Earth and Environmental Sciences; Plymouth University; Plymouth PL4 8AA UK
2. Palaeoenvironmental Laboratory; Geography and Environment; University of Southampton; Highfield Southampton SO17 1BJ UK
3. Department of Geography; College of Science; Swansea University; Singleton Park Swansea SA2 8PP UK
4. Climate and Environmental Physics; Physics Institute, and Oeschger Centre for Climate Change Research; University of Bern; CH-3012 Bern Switzerland