 I'm working on a new method for trying to understand changes to the Earth's climate system using oxygen isotopes in ice, called 17OXS. When snow falls on Antarctica, it doesn't melt because the temperatures really go above zero degrees. As more snow falls on top, the underlying snow becomes compacted and turns into ice. We can drill into this old ice and measure changes in the water isotopic composition of the ice to understand changes in the Earth's climate system. The 17OXS method looks at variations in the three isotopes of oxygen, 16, 17 and 18. When temperatures in the Southern Ocean are a little bit cooler than usual and relative humidity is a little bit higher than usual, we get a little bit less 17 oxygen compared to 18 oxygen. On the other hand, when temperatures in the Southern Ocean are a little bit warmer than usual and humidity is a little bit lower than usual, we get a little bit more 17 oxygen compared to 18 oxygen. By measuring the changes in the amount of 17 oxygen compared to 18 oxygen in our ice core records, we're able to reconstruct these changes in temperature and humidity in the Southern Ocean. However, scientists are still trying to fully understand the information that the isotopes are giving us. To do this, we need to better understand how the isotopes respond to changes in temperature and humidity. We can collect snow surface samples from all over the Antarctic continent and compare them with measurements from satellites or from stations all around Antarctica to understand how the ratios change as temperature and humidity changes. We're also able to use computer-based models to understand how the water isotopes change as they move from the ocean to the continent of Antarctica. Understanding how Earth's climate has changed in the past is really important for trying to understand our future climate, especially as we move into an uncertain climate future. By creating new methods for understanding Earth's past climate, we hope to be able to paint a better picture of what climate was like in the past so that we might be able to better predict what it will look like in the future.