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Ginny Catania is a glaciologist who specializes in understanding ice sheet motion using ice-penetrating radar and GPS. She is originally from Canada but enjoys living in the warmth of Texas when she’s not camping out on ice sheets. She has worked extensively in Antarctica, but recently expanded this work to Greenland. We had the opportunity to chat with Ginny last week about her work why it is so important to the planet.
Q: What is a glaciologist? What sort of work does that entail?
I am a glaciologist, which is a fancy way of saying that I study ice.
There are many flavors of glaciologists from those who study ice crystals (to better understand the physical properties of ice) to those who examine ice cores (to reconstruct past climate variability) to those who look at how big ice sheets work. I’m the latter kind.
In particular, I’m interested in how the ice sheets move. I’m also what you’d call an observational geophysicist which is a fancy way of saying that I measure how, when and why the ice moves using geophysical equipment. I specialize in using ice-penetrating radar techniques which allow me to get a picture of the internal layers and the base of the ice sheet. These pictures are very much like looking at a road cut along a highway and interpreting why the rock layers look like they do. Instead, we look at ice layers and interpret how they are deformed using ice flow models. This allows us to determine the ice flow history (how ice flowed in the past and how it flow changed is a key to understanding future changes in flow). It also helps us to understand current processes that act on the ice sheet.
For example processes such as melting, stretching, compression etc., within the ice all change the stratigraphy. Models help us to extract out which processes dominate the layer signals. To collect radar data we travel to the ice sheets and drive on snowmachines that tow the radar system for several hundreds of kilometers. I also use high-precision GPS instruments to measure ice motion.
Q: Why is study of the Arctic and Antarctic ice sheets important?
For starters, it would be a shame to lose such natural wonders. But more importantly, the ice sheets are an integral part of the Earth’s climate system. Not only would we face rapid sea-level rise and coastal flooding if the ice sheets melted but dramatic changes in weather patterns would be likely. One example is the Gulf Stream, an important ocean circulation pattern which delivers warm water (and thus air) to Northern Europe so folks in England can live comfortably at 65 degrees N. If we were to add enormous amounts of cold, fresh water in the polar regions because of ice sheet melting this would have big impacts on the pattern of this current which would likely divert southward and throw Northern Europe into a period of cooling similar to what currently occurs at similar latitudes in Canada. The impacts of ice sheets also extend to loss of habitat of animals that depend on cold climates (e.g. polar bear populations are diminishing as the sea ice extent shrinks). In addition, changing weather patterns can upset where we traditionally grow food crops and could cause economic problems.
Q: As you know, there are conflicting stories about climate change in the popular media today. Some that say we’ll all be underwater in 100 years, some that say we’ll be living in a severe unending drought, some that say we have caused it, and others that say we have played no role in it. What is the reality of the situation as you see it from your studies? What will the Earth look like in the future if current trends continue?
Unfortunately, the big problem is dealing with the uncertainty that is part of the natural world. The oceans, atmosphere, cryosphere etc., are very complicated systems which are difficult to model and difficult to understand. Predicting when and to what degree climate will be impacted in the future is a tough thing to do but many scientists are working on this problem every day. On top of this, there is an incredible amount of natural variability within each of these systems. For example, many of you will have heard of El Nino which is a coupled ocean-atmosphere climate fluctuation that comes about naturally and results in temperature fluctuations in the surface waters of the tropical Pacific Ocean (among other things). Another example is ice ages. We all know that the Earth has undergone extensive glaciations in the past and that ice sheets have waxed and waned as result of natural changes in the Earth’s movement in the solar system causing large temperature fluctuations on the Earth’s surface. These changes are natural. The problem that scientists have is trying to separate natural signals from so-called ‘forced’ signals or signals that are not due to natural fluctuations. This is very difficult, especially if the time-scale for the natural signal is similar to the time-scale for the forced signal. Models of the Earth are becoming increasingly important as tools to help us separate natural vs. forced fluctuations but the models are only as good as our understanding and our knowledge of the Earth. More research is needed to improve models so that we can be certain of changes.
However, there are some things that most scientists are certain about and that is that humans are affecting the climate system. You will be hard-pressed to find a SCIENTIST who disagrees with this. The news media is another thing. Take a look here. This image shows observed temperatures measured from ~1900 to ~1995 (black line). It also shows modeled temperatures using a global climate model and the error associated with the model is shown as grey regions around the brown line. Down below this, the author shows expected temperature changes that result from various changes in the atmosphere (these are also modeled). Some of these are human-induced such as ‘greenhouse gases’ which result from car and industry emissions etc; ‘ozone‘ which result from destruction of the ozone layer and as well as release of ozone into the low-lying atmosphere creating smog and; ’sulfates’ which are also human-induced emissions.
Others are natural changes such as ’solar’ which represents temperature changes resulting from natural fluctuations in the Earth’s motion around the Sun and; ‘volcanic’ which represent volcanic emissions that can also act as greenhouse gases. The interesting thing about this figure is that if you look at just the natural changes ’solar’ and ‘volcanic’ they cannot explain the modeled or observed temperature changes that we see in the past records. Only ‘greenhouse gases’ can explain why we’re getting such an increase in temperature since ~1960. This type of evidence for human-induced global warming is evident in many other models and many other data sets. This is why there is a scientific consensus on human-induced global warming.
Q: (Assuming people have played a role in global warming) What should we be doing everyday to mitigate or reverse global warming? Is that even possible at this point?
This is a difficult question to answer since I can only tell you how the Earth is changing and it’s up to governments and individuals to actually do something about it and enforce restrictions on industry and changes to society. We need large-scale changes to occur in order to even just slow down what we’ve already put in place. It’s not clear to me that such changes are forthcoming but I try, in how I live and how I vote, to be mindful of the environment.
Q: What made you interested in this field?
I initially got interested in glaciology because it was an excuse to travel to some very exotic places that most people either don’t want to go to or can’t get to easily. Over time, the traveling part wasn’t as exciting as the science part…and I got hooked on the science.
Q: What does your typical day of work in Antarctica entail?
A typical day in the field includes waking up and forcing myself to get out of my warm sleeping bag! We camp on the ice in tents (they are quite warm though) and so we spend a lot of time doing camp duties like making water from melted snow, digging out doorways, cooking meals, etc. We also communicate with a more established base station every day so that they know we’re safe. Usually, we look at satellite images on computers to determine where we want to go and we travel to those places with snowmachines and hand-held GPS units. We work outside all day either using GPS to measure the locations of poles in the ice (to determine ice velocity) or towing the radar system. Someone makes a big, hot meal for everyone back in camp and we look over our newly acquired data, do some minimal processing and talk about where we want to go the next day. And repeat until you’re done.