When I think of the tropics, I usually think of brightly-colored fish and palm trees. More recently, I also think about glaciers, which are not only in the polar regions, but also sometimes in the tropics as well. But as a warning, I wouldn’t plan my family vacation there – glaciers are on very high and remote mountains! Today, when I think of the tropics, I try to imagine what will happen to these glaciers in the future, and to help me, I use computer models to try to understand how these glaciers grow and shrink with climate change.
Glaciers grow and shrink depending on whether the long-term weather is colder versus warmer, or snowy versus less snowy. Imagine a see-saw at a playground. On one side are things that make glaciers grow, such as colder temperatures and snowy weather. On the other side are things that make glaciers shrink, such as warmer temperatures and less snowy weather. I use my computer models to figure out how changes in temperature and snowfall will affect each side of that see-saw, and whether the changes in tropical glaciers will be the same as or different from the changes in glaciers in higher latitudes, such as in the Rocky Mountains, Canada, and Europe.
Thanks to my research, when I think of the tropics, instead of just thinking about tropical fishes, I now think about a tropical ice cap that looks like an upside down frog from space. This is the Quelccaya Ice Cap in the Peruvian Andes, which is the world’s largest tropical ice mass. Since tropical glaciers are so hard to get to, scientists haven’t been able to study them until recently. But a few hundred years ago, the ice cap was larger than it is today, and in my research, I try to figure out how much colder and snowier it was during those times when the ice cap was larger. I have found that the ice cap can become significantly larger only with a slight cooling of temperatures, and that it can become significantly smaller with only a mild warming of temperatures. So next time you think about Miami, I hope you think about beautiful sandy beaches and ocean filled with stunning, colorful fish, but I hope you also think about a frog-shaped tropical ice cap, and wonder how it and other tropical glaciers are changing with global warming.
– Andy, University of Chicago, USA
