Antarctica-New Zealand Interglacial Climate Extremes sought to understand the likely response of the New Zealand-Antarctic region to a warmer world.

Field camp, Antarctica

ANZICE (Antarctica-New Zealand Interglacial Climate Extremes) was a scientific research programme funded by the New Zealand Foundation for Research Science and Technology operated from the Antarctic Research Centre at Victoria University. It was closely aligned with the FRST-funded Global Change Through Time programme at GNS Science and linked with the ice core, gas analysis group at NIWA.

The programme sought to understand the likely response of the New Zealand-Antarctic region to a warmer world. To achieve this aim, the project focused on environmental changes that occurred during peak warm periods in the past when the atmosphere and surface ocean were up to 3 degrees Celcius warmer than now.

Such temperature increases are in line with those indicated for the next century by the Intergovernmental Panel on Climate Change (IPCC). We believe that by deciphering detailed environmental records of the previous warm periods, we can provide a template for the future.

Vostock glacial cycles graph
A record of greenhouse gases [carbon dioxide, methane] for the past 400,000 years as preserved in the Vostok Ice Core from Antarctica. The record shows ice ages when average temperatures were 6 - 8oC cooler than now. Such periods were punctuated by warm phases such as Stage 5e (red arrow) when temperatures were around 2oC warmer than today’s average. ANZICE will focus on those warm phases as case studies for what to expect in the future.


By evaluating past warm phases (ANZICE) aimed to:

  • provide reconstructions of environment responses to rises in temperature
  • develop the reconstructions into models to help identify potential changes and consequences for a projected warmer world
  • apply model results to guide policy for New Zealand’s future.

To achieve these goals, ANZICE took a three pronged approach:

  • Antarctic drivers of ocean-climate used new and existing records from ice cores to determine how Antarctica’s climate and ocean behaved during past warm phases such as occurred around 7,000-9,000 years ago (Holocene Climatic Optimum) and 125,000 years ago (Last Interglacial Period or Stage 5e).
  • Southern Ocean-NZ responses relied on environmental data contained within sediment cores from the Southern Ocean to identify past responses of ocean waters and currents. The impact of such changes on New Zealand were gauged from glacial and lake records preserved onshore.
  • Analogue and computer models drew on the above research results to develop models that help clarify our view of the future.
An ice core being extruded from the corer
The business end - an ice core is partly extruded from the corer.
Source: Nancy Bertler

New techniques

ANZICE introduced new techniques that greatly improved the ability to analyse, interpret and apply records of previous warmer climates.

Ice cores, collected from coastal sites, contain information with annual detail similar to tree rings. The cores were expected to recover ice at least 10,000 years old, and so included the Holocene Climatic Optimum.

Contained within the ice are a host of environmental clues:

Ice core being prepared for sampling
In cold, ultra-clean conditions an ice core is prepared for sampling.
Source: Nancy Bertler
  • gases reveal the composition of the atmosphere
  • isotopes of hydrogen and oxygen fingerprint atmospheric temperatures
  • major and trace chemical elements reflect changes in the atmospheric circulation and storminess
  • dust contents permit the study of winds, and the state of lands bordering Antarctic continent
  • sulphates, fluoride and chloride identify volcanic activity
  • the compound methylsuphonate can be used to measure sea-ice concentration.
Electron microscope view of a foraminifera shell
An electron microscopic view of a foraminifera shell, the size of a sand grain, that has been drilled with a laser to make over 140 elemental analyses per hole. Source: S Eggins, ANU.

Ice cores

Ice cores and samples are stored and processed at the state of the art New Zealand Ice Core Research Laboratory at the National Isotope Centre in Lower Hutt. This laboratory is a joint venture between GNS Science and Victoria University of Wellington, with assistance from NIWA.

The ice is analysed in laboratories at GNS Science, Victoria University, NIWA, the Universities of Maine and Hawai'i (USA) and the Alfred Wegener Institute (Germany).

Sediment cores

Sediment cores from the ocean also hold a wealth of environmental information, much of which is tied up in the remains of plankton, in particular foraminifers.

Results of anaylses made by laser ablation
The analyses made by laser ablation as it drilled (L to R) through the shell wall of the foraminiferal species, Neogloboquadrina dutertrei. As the laser passed through the 20 micron thick wall measurements including magnesium (Mg), strontium (Sr), manganese (Mn), barium (Ba) and zinc (Zn) were made. Source: S Eggins, ANU.
Franz Josef Glacier
The future of New Zealand’s glaciers, such as the Franz Josef (pictured), will be evaluated in light of their importance to water resources, tourism and local climate. Using historical meteorological data, field observations and reconstructions of past environments, supplemented with computer models,

As these animals form their sand-sized shell, they incorporate chemical elements and isotopes from the ocean. For example, the ratio of magnesium to calcium (Mg/Ca) relates to ocean temperature, and the ratio of barium to aluminium (Ba/Al) gives an insight into ocean fertility that involves the production of plant and animal plankton – the foundation of the marine food chain.

To unravel these chemical fingerprints ANZICE used Victoria University's laser ablation, inductively coupled plasma, mass spectrometer. This analytical system deploys a laser beam to “drill” through minute objects, measuring liberated elements en route.

Read more about these analytical facilities.


The use of observation-based and computer-based models was another feature of ANZICE.

Information from the ice and sediment core studies was compiled to form observational models to help answer basic research questions, for example: how did the Antarctic environment appear during the Last Interglacial period, 125,000 years ago, and what was the impact on the Southern Ocean and New Zealand?

Answers to such questions helped guide and verify the computer models to give a measure of confidence in their results. Once operational, the computer models improved our ability to understand how an environment may change under various warmer world conditions.

By changing the drivers that control a model such as ocean and air temperatures, greenhouse gas concentrations, wind strength and other factors, it becomes possible to gain an insight into potential environmental responses, while checking the results with observations of the past.

As research results and computer models took shape, ANZICE turned to communicating the information to the public and governmental agencies involved with climate change. This initiative was not only to inform, but to help shape policy.

Computer-based model of Southern Alps
An example of output from a computer-based model that was under development during this project for the Southern Alps. Termed a 'regional energy balance model', it aimed to quantify changes in snow fall and snow/ice melt that have occurred in the past, and predict what changes might occur as temperatures rise in the future. In this image (arrow indicates Tasman Glacier) the blue areas signify net accumulation of snow, while red areas signify net loss of snow and ice. The snowline (where accumulation equals melt) is shown in white.
Source: B Anderson.