 I study Earth's past climate using ice core records from Antarctica. Understanding how Earth's climate has changed in the past is really important for predicting how it will change in the future and ice core records are a really neat tool for trying to understand the past changes. For my PhD I'm using water isotope record from ice cores to try and understand changes in temperature and humidity through time but I'll be talking about this in a bit more depth in the next video. Ice core records are as the name might suggest cores drilled from ice. Most of the records come from the large polar ice sheets which in the southern hemisphere means Antarctica and in the northern hemisphere most of the records are from Greenland but we do also have records from the high alpine glaciers in places like the European Alps, Patagonia or the Himalayas. The records can be anywhere from just a couple of meters long to over 3000 meters long and the oldest record that we have available is an 800,000 year long record from East Antarctica. The record that I'm working with however is a much shorter record it's a 300 meter long record from East Antarctica which covers the last 1000 years of the Earth's climate. Earth's climate has varied a lot through time. Over the last few hundred thousand years we've seen shifts from very cold glacial periods with large ice sheets covering most of the northern hemisphere to much warmer world that we live in today but there have been also been much smaller shifts in the Earth's climate system over the last thousand years or so. In the southern Indian ocean climate systems like the southern annular mode or the Indian Ocean Dipole have varied in their strength and position throughout time and we can use ice core records to try and understand how these phenomenon have changed. For example an ice core record from the tip of the Antarctic Peninsula called the James Ross Island ice core has been used to reconstruct changes in the southern annular mode over the last 1000 years or so. The southern annular mode controls the position of the westerly wind belt surrounding Antarctica as well as the strength of these winds. Understanding changes in the strength and position of the winds is really important to us here in Australia because it affects the rain patterns that we see over the continent. Decreases in the rain that we're getting in the southern parts of Australia over the past few decades have been linked to changes in the southern annular mode with the winds both getting stronger and moving closer to the Antarctic continent. Ice core records have been really important in understanding these changes in the southern annular mode and have helped us to link these changes to human impacts with the changes being driven by things like the ozone hole over Antarctica as well as increasing greenhouse gases in the atmosphere. Ice core records continue to provide scientists with really important information to try and understand Earth's climate. Scientists are currently aiming to try and drill the longest ice core ever drilled reaching back to about 1.5 million years. At the same time, scientists from all over the world are working on much shorter records to try and better understand the variability in the climate over the last 2000 years or so.