We know a lot about natural climate change from studying ice cores from Greenland and Antarctica, but we’ve had much less clear evidence of climate variations from low latitude regions. That’s why the Borneo stalagmites are important.
Other turns in history show up in the cave samples. They reflect changes when the mega-volcano in Indonesia at Lake Toba erupted around 75,000 years ago. Those were dark days throughout the region and weather was affected, as shown by the stalagmite record.
The take-away lesson about the stalagmite record in the tropics is similar to what we see in the ice core records at the poles of the planet. Change is woven into the warp and weft of Earth processes, and climate is always changing, both in terms of precipitation and temperatures. In short we are riding a bucking bronco and we’ve recently added to the risks we face by perturbing the greenhouse gas concentrations in the atmosphere.
Hold onto your hats.
Dr. E. Kirsten Peters was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University.