My name is Pete Akers, and I am a paleoclimatologist from the University of Georgia. This means that it is my job to figure out how climate and associated weather patterns have changed over the past hundreds to thousands of years for a given location. This research is important so that we can better understand the weather and climate we experience today. Modern weather records only go back a century or so for most places, but the climate can vary naturally in cycles that last many hundreds of years. So in order to fully understand what can be considered ‘normal’ conditions for a region, we need to learn how the climate has changed over centuries and millennia.

To learn about the climate in the past, we need something that preserves a record of any climate changes that have happened. These records are found in wildly different locations and environments. Some people use ice cores from Greenland and Antarctica, others may use the soil and sediment that accumulates in lake bottoms, or even the rings of trees to learn about the past. I use cave formations to tell me about how the land and climate above the cave has changed.

Cave formations are an excellent recorder of climate changes because they are created party from rain water that has filtered through the ground. Rain water that happens during drier times has a different chemistry than rain water from wetter times. When it rains above a cave, this rain water soaks into the ground and eventually may drip from the cave ceiling onto the ground. This drip water will deposit a tiny bit of minerals that preserve the chemistry of the original rain water. When the climate changes (for instance, becoming drier on average), the rain water’s chemistry and thus the drip water’s chemistry will change as well. When the drip water deposits a new layer of minerals, this new mineral layer will preserve the changed rain water chemistry. Over time, these mineral layers will build up to form a stalagmite (the cave formations that grow from the ground up). This stalagmite now contains a record of all the changes in climate that happened while the stalagmite was growing.

Follow along as I share my visit to Indiana Caverns in my next blog post and how date from Indiana Caverns will help researchers like myself unravel the mystery of past climate changes.