Unlocking a record of past climate change

Glacial landforms in Te Tiritiri-o-te-moana Southern Alps provide some of the most important records of past climate change in the Southern Hemisphere. Because Aotearoa New Zealand's glaciers are closely linked to conditions in the Southern Ocean, they offer valuable insights into the processes that influence global greenhouse gas exchange and climate.

Research at the University of Canterbury (UC) led by Professor Jamie Shulmeister of the School of Earth and Environment and Dr Leighton Watson of the School of Mathematics and Statistics is investigating why glaciers were much more extensive during earlier glacial periods, particularly before 50,000 years ago. The work seeks to determine whether these larger glaciers reflect colder and wetter climates in the past, or whether changes in the landscape itself have altered how glaciers respond to climate over time.

Researchers are reconstructing the history of glacier advances in the Matau Clutha and Rakaia valleys using cosmogenic nuclide dating, which measures exposure to cosmic radiation over hundreds of thousands of years.

Working with collaborators in Australia and the United States, the project is developing detailed chronologies of glacial cycles using beryllium-10 and aluminium-26 exposure dating. These timelines will help establish when glaciers advanced and retreated and how they responded to changing environmental conditions.

A second strand of the research focuses on the geological history of the glacial valleys themselves.

Using sedimentary stratigraphy, advanced luminescence dating techniques, and four-dimensional computer modelling, researchers are investigating how erosion and tectonic uplift have shaped Te Tiritiri-o-te-moana Southern Alps over time. The work will help determine whether changes in valley geometry have influenced glacier extent and contributed to differences between ancient and more recent glaciations.

By combining geological evidence with numerical modelling, the research aims to build a clearer picture of how climate, mountain building, and landscape evolution interact over long timescales.

Understanding how glaciers responded to past climate change provides an important foundation for predicting future climate and environmental change.

The research is undertaken within UC's geomorphology and Quaternary science programme, part of the largest geomorphology research group in Aotearoa New Zealand. Bringing together expertise in glacial geology, geochronology, landscape evolution, tectonics and climate science, the team combines field observations, advanced dating techniques, and numerical modelling to investigate how landscapes respond to environmental change over thousands of years.

By reconstructing ancient climates and landscapes, UC researchers are helping improve our understanding of Southern Hemisphere climate systems, glacier behaviour, and the global processes that influence atmospheric greenhouse gases.

Talk to Professor Jamie Shulmeister about glacial geology, climate change, Glaciers of Te Tiritiri-o-te-moana Southern Alps, landscape evolution, geochronology, and past environmental change. Talk to Dr Leighton Watson about 3-D finite element modelling, geophysical sensing, and mathematical modelling for natural hazards.