Don Blankenship: Hi, it's lovely to be here. I'm here today with a colleague with mine, David Morris. We've been working in Antarctica for about ten years together, and we are currently working on Ice Stream D, which is a major ice stream in West Antarctica. As everybody probably knows, West Antarctica is part of the Antarctic Ice Sheet in the Western Hemisphere, and what's unique about West Antarctica is that the bottom of the ice sheet is more than a mile below sea level. That means that if the ice sheet were to disintegrate, it would be replaced by open ocean, and all of the ice in the ice sheet would melt and cause sea level to rise. The sea level would rise about six meters and drown many of the world's coastal areas. The ice streams in West Antarctica are huge rivers of ice that drain the center part of the ice sheet. They are different than the main ice sheet because they slide along their bed, and it's these ice streams that we think control the stability of the West Antarctic Ice Sheet. That's why they are so important to study.

Don Blankenship: I've worked in East Antarctica, in an area called Dome C, where we were studying the geology of the East Antarctic continent beneath over two miles of ice. The area where we are studying is the location of many sub-glacial lakes, so it is very important to understand how the ice sheet interacts with the geology below to create these lakes. I'll let Dave describe what he's done for a little bit.
Dave Morris: In addition to the work on the ice stream, I have been involved in ice coring programs in both Antarctica and Greenland. With these programs, we are interested in measuring a record of the earth's climate with an ice core, drilled to the bedrock. By measuring properties of the ice, you can understand factors of the earth's climate going back hundreds of thousands of years.

Don Blankenship: As I mentioned before, the ice streams, unlike the main part of the ice sheet, slide upon their bed. For them to slide, they need to be lubricated by something. During the 1980s we discovered that they were lubricated by a mixture of sediment and water, some very slimy mud. The ice streams are warm at the bottom, because the earth is warm, and the ice makes an effective blanket. How much the earth is warm is indicated by the existence of volcanoes, as a warm crust has more volcanoes. So, we have a program with an airplane that flies around looking for volcanic rocks which happen to be very magnetic. Whenever we find these magnetic rocks, we relate their location to the condition of the ice stream. We were actually able to discover volcanoes that seem to be currently active, and by currently active, we mean that the heat coming out of the rocks is many hundreds of times what it is in a typical continental area. With this extra heat, we get extra melting at the bottom of the ice, and that water provides a component of the lubrication needed for the ice stream to move.

Don Blankenship: A geophysicist needs to know a little bit of everything. First and foremost, you need to know about the earth, or at least be interested in it. But because we work on things that you can't see that are underneath the surface, you need to understand how waves propagate, and how all the different physical laws help us understand how the earth works. So the courses that you need to take are physics, chemistry, and lots of mathematics. But it is also important to take some geology or climatology or oceanography, so you can appreciate how the earth works as a system. When you get to college, you can actually take courses in glaciology, which will teach you all about ice sheets and glaciers.

Don Blankenship: Yes, sometimes we do. Most often, geophysicists use seismic techniques that need an artificial source, like an explosion or a big shaking truck. These generate sound waves that penetrate the earth, bounce off of the interior structures, and come back to the surface, where we can observe them. Believe it or not, it's just like a sonogram of a baby, except the earth is the mother. Instead of using an artificial source, the movement of earth in an earthquake causes sound waves itself. These waves can be measured, and you can also find things out about the earth between where you measured them and where the earthquake occurred, if you measure in enough places. We've used ice quakes on the ice sheet to study both properties of the ice sheet itself, just like we would with earthquakes and the earth. We also learn about the ice quakes themselves; in other words, how the ice breaks and where it breaks, which can tell us important things about how ice streams move.

Don Blankenship: Well, we'll let Dave take that question; he's the one who studies the interactions between climates and ice sheets. Dave Morris: That is what we describe as a coupled question--you can't just talk about the ice sheet and then its effect on the earth; the rest of the earth also affects the ice sheet. It would take a large change in the earth's climate to cause the ice sheet to disintegrate, and the changing of the ice sheets would contribute to how the earth's climate is changing. One thing for certain is that sea level would change in response to the distribution of water moving from the ice sheet to the ocean. Another thing that may happen if there is less ice on the planet is that less of the planet will be covered with white stuff. Once the planet becomes darker, it absorbs more solar radiation, which causes things to become warmer still. This whole process is what we call climate feedback, which is why the earth's climate is such a difficult thing to talk about or give a single answer. Everything is related to everything else. One thing changes because something else has changed.

Don Blankenship: That's a really good question! It was difficult for me to imagine significant changes for the Antarctic animal till recently. As you know, all of the Antarctic animals-penguins and seals--are concentrated on the coast. There's also incredible marine life very very near to the coast, and all around Antarctica. You would think that the penguins would be immune to climate change, but just recently something important has happened. The ice shelves (where the ice streams go into the ocean, actually go afloat, and form vast, Texas-size pieces of floating ice) lose their ice by calving icebergs. A very large iceberg calved off of the biggest ice shelf, the Ross Ice Shelf, and drifted to the coast. As this iceberg got to the coast, the sea ice that usually goes away in the Antarctic summer wasn't able to melt. The penguin rookeries along that piece of coast didn't have access to the open ocean, and the penguin parents couldn't feed. As you can imagine, this had a devastating impact on the penguin colonies. So, as the climate warms and the ice shelves break up, unexpected changes are likely to happen, and the life around the edge of Antarctica is likely to change. I don't know how evolution will respond to this. I don't know enough about the subject to be able to predict.

Don Blankenship: Lots of things, LOL! Geophysicists make hypotheses; in other words, we take a guess about how the earth works, whether it is an ice sheet or a volcano or even an oil field, and we design an experiment to see if our hypothesis is correct. These experiments will either use sound waves, like the seismic experiments, or radio waves, like our radar sounding experiments for ice sheets. and we'll perform these experiments wherever we need to be, whether that is Antarctica or the desert in Saudi Arabia or the bottom of the ocean. When we get the data back from these experiments, we reduce it, which means we take the measurements of the sound waves or the electromagnetic fields, and boil them down to get important information, or sometimes, pretty pictures. Then we evaluate this information to see if it's consistent with our hypothesis. And if it is, we write a paper that we submit to a journal, and we get on an airplane and fly around the world to tell people about it at meetings with other geophysicists. And if we are successful geophysicists, we write proposals to the government or to companies to get money to test a new hypothesis, and start all over again. So as you can see, we do a little bit of everything--from surfing the web, to fixing the trucks that we use for our experiments, to sitting around, pondering earth's secrets.

Don Blankenship: Well, when I moved to Texas, I took a look at what would happen if sea level rose twenty feet, and discovered that most of the oil refineries around Houston would be underwater. Some of the people in Houston might think this was a benefit, but not the people who own the refineries, or the people who have to clean up the mess. It's difficult to say what a benefit would be, because it would have to be weighed against the negative effects.

Dave Morris: We go essentially every year, through various projects. A project will typically involve one to say, three or four years of field trips to Antarctica. And it tends to work out that one project ends as another project is beginning. So some of us may only go a year or two, and then take a year or two off. Others have gone every year for more than ten years. But as a group, people are there every year, doing different kinds of work. As you can imagine, that lifestyle becomes tiring, and many of us try to go for as short a time as possible. Typically a field project will last two to three months. Since it is in the southern hemisphere, we like to do it when they have summer, which is November, December, January; a time which makes it difficult for those of us who have families who miss being with us at that time of year.

Dave Morris: I think you have to consider your point of view. Over the course of recorded human history, these have been very happy times for us. This has been a warm time, what we call an inter-glacial time--a short time between glacial periods. If you take a step back in your perspective and consider geological time, over the past few hundred thousand years, the earth has been in an ice age. This ice age involves something like a hundred thousand years of cold time, and ten thousand years of warm time, periodically going from warm to cold to warm, but mostly it's cold. This is why we call it an ice age. There is some dispute whether the ice age has ended or has not ended. Since the jury is still out on our current inter-glacial, what we do know is that from an even longer perspective of millions of years, the past three, four, five hundred years has been both an ice age, and a time of dramatic climate variability. The climate has been changing rapidly and dramatically from warm to cold, warm to cold. It is unclear exactly how much of the past will be repeated, but it is simplest to assume that the pattern will continue, and that the climate will continue to change from warm to cold, warm to cold. Don Blankenship: The only thing I have to add is that we know that the inter-glacial periods now repeat about every hundred and twenty thousand years. This gives us the opportunity to look at previous warm periods to see how the climate changed as a model for how the climate will change in the current warm period. Since all of the ice sheets from this last ice age that had bottoms below sea level had disappeared in our current warm period(with the exception of West Antarctica), the question we are interested in is whether West Antarctica disappeared in previous inter-glacials. If so, that means we could expect it to disappear this time. Remember that sea level will go up twenty feet if it does.

Don Blankenship: Yeah, I'd love to go to Jupiter's moon, except it's a very long ride-it takes about five years to get there. Jupiter's moon Europa has been discovered to be coated in ice. We don't know how thick the ice is, but we know by measuring the gravity of that moon that there is a combination of ice and water that is about 100 kilometers thick. The best guess that people have is that the ice is a few kilometers thick, and that there may be an ocean that's many tens of kilometers deep beneath that ice. As you can imagine, people are very excited about the possibility for life in that ocean. First thing we have to do to study that ocean is to find out how thick the ice is, and to map the ice/ocean boundary. We planned a mission to Europa that included an ice penetrating radar that would allow us to map that ice thickness like we do in Antarctica.

Don Blankenship: We take the two instruments that are important for studying ice sheets, and the two instruments that are important for studying the rocks beneath the ice sheets, and put them together in one airplane. The instruments for studying ice sheets are ice penetrating radar, and a laser altimeter, which measures the surface position of the ice to within a few inches, measured from the center of the earth. The instruments for studying the rocks include a magnetometer, to look for magnetic rocks like we expect from volcanoes, and the ability to measure gravity, which is how hard the earth's pull is, based on how the mass is distributed in the earth. What I mean by that is some rocks are light and some rocks are heavy, and light rocks don't create as much gravitational pull as heavy rocks. Believe it or not, we can fly around and map to see how hard gravity is pulling, letting us tell where the light rocks, like sediments, and the heavy rocks, like granite, lie beneath the ice.

Dave Morris: We have usually been using teams of about ten people--the scientists and our assistants, who perform the measurements. Since we have so many people, we will often have other people with us to help us run the camp, to help us do our work, so we may have as many as fifteen or so people working on a project at one time. This will allow us to work around the clock if we need to, such as when the weather is nice, and when the weather is bad, we wait. Sometimes we will go with a smaller group of people, perhaps as few as six, for a short project that may take only a few weeks. But for a larger project that is two months or so long, we will have more than ten people.

Don Blankenship: Believe it or not, the most dangerous thing that happened to myself and the people I was working with was carbon monoxide poisoning. Because it is so cold, you spend lots of time in small buildings, huts, or vehicles, and these are all heated by fuel oil. If there is a leak, carbon monoxide can build up very quickly, so strangely enough, the biggest danger isn't crashing your airplane, or falling into a crevasse, but dying from carbon monoxide poisoning in your sleep. Because of carbon monoxide detectors, this has recently become a much smaller problem, but I have seen many people in the past succumb to this kind of poisoning. If you remember the stories of Admiral Byrd from the thirties, he spent an entire winter suffering from carbon monoxide poisoning, alone in a hut on the ice sheet. The other dangers are, of course, airplane crashes and falling in crevasses. We go to very great lengths to avoid both of those, so I have not been involved in either, although I have had lots of rough rides. Dave Morris: To add to the hazards that Don just mentioned, he described being in small shelters that are heated. It is a very cold and drying environment and the humidity is very low, so another hazard is fire. You are using a fuel burner as your heater in a small wood structure or tent, and you can easily start a fire which would burn your structure down quickly. So you always have to be prepared with emergency shelter, emergency clothing, and emergency food, in the event you have a fire and have to make a new camp. I think in terms of perceived hazards, I have been more frightened driving in my car going to the airport than in Antarctica. In Antarctica we are much more careful, and we plan each moment to deal with emergencies that we sometimes forget when we are back home.

Dave Morris: I think these warm cold cycles ARE global warming, but what we have learned from the fact that the climate goes through these cycles is that the climate can change very quickly and very dramatically. From what we understand of the climate record, we are in a time of unprecedented warmth that has likely been contributed to by human activity. It is difficult to predict with any certainty what these contributions might lead to.

Don Blankenship: Interesting question. We are probably not having impact on the ice sheet from the warming perspective, but humans do have an impact from the stuff they leave behind. Many experiments depend on careful measurements, the chemistry of the ice sheet, and with people moving around, it is possible for us to leave molecules behind that will mess up these measurements. The best example of that was the atmospheric nuclear tests of the fifties. Believe it or not, we rely on the radioactive particles that were deposited by those tests to establish a date for snow or firn cores. By looking at the radioactive decay of the layers of the snow, we can identify these bomb horizons, and we know how old the snow is at that depth. We can take how many years it's been since then, and the depth of those horizons, and calculate how much it has snowed each year since. But obviously we have to be very careful in the future not to leave signs of our being there behind. The Antarctic Program for the United States flies about eight airplanes over the Antarctic summer, and the impact of that much activity is still probably small, given that Antarctica is the size of the United States and Mexico put together.

Don Blankenship: I spend time with my family, because they miss me when I'm gone. And I travel to meetings, to report on our results. Dave does more interesting things--I'll let him say. Dave Morris: I spend a lot of time reducing and interpreting the data from previous fieldwork in Antarctica. We have people who work on this data year round back home, so I work with them, to help them understand the data that they have. I also spend time writing proposals to do more work for the future. And every now and again, I try and take a vacation.

Don Blankenship: Yes it is! As scientists, we can study these things, but you're right, it takes a whole society to change them. The best we can do is learn as much about these changes as we can, and vote. Because it's our legislators who can actually change things, and everybody can contribute to that solution.

Dave Morris: We are in the midst of working on Ice Stream D. This is the work we've described earlier. We will be returning to Ice Stream D next season, for more seismic work. We also have proposals that are pending that may allow us to do work in dry valleys of Antarctica, which are areas where there is very little ice cover, and rock is exposed. We also have a proposal pending for a very large survey in West Antarctica, in the Amundsen Sea Embayment, which includes the Pine Island and Thwaites Glaciers. This is the drainage of West Antarctica, where the ice is flowing mostly due northwards, and is showing the most substantial and dramatic changes over the past decade.

Don Blankenship: We just want to say thank you, I'm glad everybody showed up, I thought the questions were really good, and we enjoyed answering them. If anybody needs to know anything else, you can look us up on our website at UTIG. We will always be here--except when we are in Antarctica!