My interest in learning about past climate began during my Geography degree when I spent four months studying geology on Svalbard, a remote island in the Arctic at 78⁰N. We spent a couple of weeks doing remote fieldwork and spent our days hiking long distances and then balancing on the edge of mountains to examine exposures of rock. The amount that could be learnt about the past environment and climate by looking at different rock types and forms was fascinating, and the glacial landscape was beautiful.
This experience made me decide to study past climate changes after my degree, by taking a masters in Quaternary Environmental Change and then doing a PhD in Physical Geography, and I started researching climate change during the more recent past – or the last 10,000 years at least!
We can find out a lot about climate during recent millennia by taking sediment cores from different environments. Sediments accumulate very slowly on the surface of peatbogs and at the bottom of lakes and the ocean, and as they do so they are influenced by the climate and environmental conditions at the time, which leave an imprint on the sediment. By taking sediment cores from these settings and analysing each layer of sediment, we can learn a lot about past climate including temperature, storminess, rainfall or changes in local plants, to name a few!
During the last ten years I have been able find out about past variability in storminess by looking at sand layers preserved within coastal peatbogs. By analysing microscopic algae (known as diatoms) preserved within ocean sediments, I have shown past temperature variability in the Southern Ocean and North Atlantic. Finally, lake sediments have revealed past changes in catchment runoff. Palaeoclimate research can tell us how different aspects of the climate system vary naturally and how they have responded to warmer or cooler conditions in the past. This can help us to understand how the climate may vary and change in future.
Dr Lisa Orme is a palaeoclimatologist working in ICARUS (Irish Climate Research and Analysis Unit) and as a lecturer in the Department of Geography Maynooth University.Read more about Lisa here.