I study past climate and environment, mainly from polar (Antarctic and Greenland) ice cores. Ice in the polar regions preserves a unique chronological archive of information about the past. This extends so far 800,000 years in Antarctica and 128,000 years in Greenland. In collaboration with the British Antarctic Survey (also in Cambridge) and colleagues overseas, I collect ice cores, analyse them, and draw conclusions about the mechanisms of climate change.
The ice builds up year by year and stores information in three main ways: the isotopic content of the water molecules themselves tell us about past temperature; soluble and insoluble impurities trapped on the snow surface and in snowflakes record information about aspects such as past volcanic eruptions, sea ice extent, and biomass burning; finally air bubbles trapped in the ice record atmospheric composition including past greenhouse gas concentrations.
The longest (in time) record we have came from the European Project for Ice Coring in Antarctica (EPICA) ice core at Dome C, Antarctica. This has shown how climate, CO2, and many other properties co-varied through a series of glacial-interglacial cycles. My research concentrates on a number of topics:
The dynamics of glacial cycles and millennial scale climate change
The climate of interglacials (warm periods such as the present one); this includes work within the EU Past4Future project and the UK iGLASS project
Proxies for sea ice in ice cores and other media: this includes work within the UK BLOWSEA project and co-chairing the PAGES Sea Ice proxy working group
Polar atmospheric chemistry, especially as it relates to understanding the ice core record the search for oldest ice. We hope to find a site to drill an ice core reaching back 1.5 million years