About Evan

Hi, My name is Evan Gowan. I am a geophysicist/geologist/climate scientist (choose a label!) who is predominantly interested in ice sheets and their interaction with the Earth. I originally started in the field of ice sheets because I had an interest in the properties of the Earth at tens of kilometers below the surface. It might seem strange to look at something that happens at the surface of the Earth to probe what happens deep below, but it has a big effect! When you look at something as huge as a continent sized ice sheet (modern existing ice sheets are located on Greenland and Antarctica), their immense mass causes the Earth to slowly deform. The rocks deep within the Earth are hot and behave somewhat like a fluid on the scale of thousands of years, so the impacts of the ice sheet persist thousands of years after they disappear, as is currently the case in Canada and northern Europe. This process is known as glacial isostatic adjustment. The title of my website “Raised Beaches” refers to the fact that you can find ancient beaches well above present day sea level in areas where the land is rising due to this process (as well as rare times when sea level was higher than present)!

Ice sheets represent a very important part of the surface of the Earth. They contain vast stores of fresh water. They increase the Earth’s albedo, reflecting sunlight back into space. Icebergs that break off of them present a hazard to shipping lines (think Titanic). And of course, when ice sheets retreat, as they currently are in Greenland and Western Antarctica, they cause sea level rise. The retreat of past ice sheets also affect us, as ongoing glacial isostatic rebound affects sea level in coastal areas of northern North America and Europe, and has been implicated in unusual interplate earthquakes. These factors motivate my research. Changes in the past can tell us about what is happening in the present! My current research is focusing on improving our understanding of how ice sheets behave, and what they looked like in the past.

I am also very interested in the data that goes behind these modelling activities. You can determine how climate varied in the past by looking at what are known as proxies. For instance, you might take a sediment core from a lake, and analyze changes in pollen what kind of trees there were in the past. The type of trees can then let you know the climate, as certain trees live in cool and dry areas, versus some that need warm and wet climates to survive. One of the main proxies I am interested in is variations in the oxygen isotopes in the ocean. When ice sheets grow, light isotopes of oxygen are preferentially taken out of the ocean. The relative amount of oxygen isotopes can be determined by measuring their concentration in fossils of single celled organisms called foraminifera. Using this information, you can determine how much ice was locked on land in ice sheets, and therefore understand how climate varied in the past.

The opinions expressed of this website are the my opinions and mine alone, and do not reflect the views of my employer.