Cores of ice, drilled from Arctic and Antarctic Ice sheets, are one of the most accurate proxy records of past climate. Ice cores can give information about temperature, precipitation, dust and atmospheric gases. Watch the video about how scientists use Antarctic ice cores to learn about the Earth’s past climate and answer the questions that follow.
I'm working on melting about two-and-a-half thousand years worth of ice from West Antarctica as this part of a big national project aimed at uncovering climate history and glaciology in this region. Ice cores are a really great way to look at climate history. They're not the only way and for certain locations on the Earth you can't use ice cores. But on the poles - in Greenland and on the Antarctic Ice Sheet - ice cores are a great high-resolution record that allow us to look at hemispheric and local scale climate change. There are plenty of other really good ways look at climate history for example corals, tree rings, lake sediment cores, ocean sediment cores, and every different type of record allows you to address a question in a different way or in a different location. We are melting an Antarctic ice core for the project. And here we have the melter system. We come in here every day 10 hours a day and melt as much ice as possible. And it's a way to look at the interactions of the atmosphere, the ocean and the earth surface itself. We're measuring the water flowing by continuously so we get a dust record and a conductivity record and both of those things have an annual variation in them and so in those wiggly lines we can see an annual signal kinda like tree rings. We can't really see that in this ice, but as we look at the chemistry that comes out of the ice we can see that annual record. I'm gonna turn up the pump. So we have a clean lab where we not the ice core. The ice has melted from one end to the other on a hot plate. You can hear the sound of the core, it's pretty neat, as the ice melts. And the water's pulled through that plate allowing us to get the inside of the ice core without ever having the outer part contaminate that part of the core. For the ice that we're melting today - a single years about this much ice - and so if you imagine the stuff we're measuring on a really high resolution through that year we can see changes happening and actually figure out on what season these changes are happening. You can reconstruct the temperature of Earth or the local regional temperature (so Antarctic temperature). You can reconstruct the strength of the winds or the strength of the atmospheric circulation around Antarctica. We also see volcanic eruptions and actually today we'll be melting ice that may show evidence of an ancient volcanic eruption, which would be very exciting. So these are top up arrows so the top of the core is here and we melt from top to bottom. And that way we can connect all the segments of ice because they're in 1-meter segments and create a long record. Minus 20 Celcius - not that much colder the typical winter day in Maine but still cold enough to suit up. I am prepping the cores to melt, so I need to clean the ends of the cores - there might be some dust or particles that have just sort of stuck on the ends. So I scrape those of and get the ice into its core tray. These are ceramic blades so they should not contaminate the chemistry of the core and we clean them every day. Everything in the ice core world is very sensitive because these are pristine records of ancient atmospheric chemistry, and we have to treat them that way. I mean I'm and helping track volcanic eruptions in an Antarctic ice core that spanned back to twenty-two hundred years. I mean where else am I going to get an experience like that? Two-and-half centimeters per minute. We actually had a really interesting conversation out in West Antarctica. The fact that we're taking about two miles of ice and slowly drilling it over the course of three years and then melting it all and analyzing it all. It's such a huge project that you can't really see it all at once. It's like you have to walk the distance have two miles understand how much ice there is. It's just astonishing to think about what was happening in the world at that time and the fact that this ice records the snow that fell at that time in Antarctica.