University of Cambridge
For understanding the mechanisms governing the operation of planet Earth, observations of its past behaviour are essential. Ice cores - cylinders of ice from (mainly) the polar ice sheets - contain quantitative information over, so far, 800,000 years - including information about the factors that cause climate to change (such as greenhouse gas concentrations), and the reaction of the climate system (temperature, sea ice, atmospheric circulation, etc.). My work aims to obtain new records of climate from ice cores, to improve interpretation of existing records, and to make inferences from this that are relevant to predicting future climate.
An underpinning task is to improve the information we obtain from ice core records, by finding new “proxies” – components of the ice whose concentration we can measure, and that tell us about an important component of the environment. By collecting data from ships in the polar regions, and through modelling, we are assessing whether the amount of sea salt in ice cores can be used to tell us how sea ice extent has varied in the past. This is crucial because sea ice is such an important part of the feedbacks in the climate system.
In a second strand I am studying interglacials - periods in the past million years or so that were warm, as opposed to glacials when ice sheets were widespread. In the last interglacial for example, both polar regions were for a time warmer than today, perhaps at temperatures similar to those expected at 2100. Sea level was a few metres higher than today - my research aims to assess how those warmer climates affected the Greenland and Antarctic ice sheets.
Finally, ice cores so far extend 800,000 years into the past, through several so-called ice age cycles. However around a million years ago, there was a major change in the pace at which these cycles occurred. We are seeking a site where ice as old as 1.5 million years can be found, in order to understand the changes that led to our current climate.
Interests and expertise (Subject groups)