Unbeknownst to some, Mount Kilimanjaro and Mount Kenya house some of the world's centuries-old glaciers. Unfortunately, a large percentage of the ice mass has been significantly reduced due to warming temperatures. Now, however, new research is suggesting that the effects of future warming may even be greater than initially predicted.
A team of researchers from Brown University has presented a 25,000-year reconstruction from Mount Kenya in East Africa, which shows that from the last ice age, the high elevation of the tropical mountain elicited a more rapid increase in mean annual temperatures as compared to temperature changes in areas at sea-level.
To Validate the Data or To Validate an Error
Thirty years ago, CLIMAP stated that that tropical sea surface cooled by a mere -1 degree during the peak of the last ice age between 19 to 26 million years ago. However, this statement could not be reconciled by some scientists with the climate modelling data gathered on tropical mountains at a much greater 5 to 10 degrees Celsius. This literature is where the current research builds on to either validate the data or validate an error.
To validate the current data, Russel and his colleagues studied the sediment cores from the bottom of three lakes in Mount Kenya: Lake Rutundu, Lake Tanganyika and Lake Malawi. The purpose of collecting sediments from the volcanic lakes was to study organisms called GDGTs, which are temperature sensitive and could display an altered chemical composition when exposed to temperature change.
The data they gathered concurred with the hypothesis built on the data thirty years ago, as the numbers suggest that Lake Rutundu, at 10,000 feet elevation, had a mean annual temperature increase of 5.5 degrees, while the two lakes at sea level, Lake Tanganyika and Lake Malawi had mean annual temperature increase of 3.3 degrees and 2 degrees respectively.
Future Climate Models
The results of the current study suggest a discrepancy in the accuracy of current, state-of-the-art climate models. This could mean that many of the current climate models may need to be adjusted to integrate the new data. Further, the data deficiency in high-altitude tropical mountains could mean that the current data has completely underestimated the future changes that could occur in these mountains.
"These are very fragile ecosystems that house extraordinary biodiversity and unique environments such as tropical glaciers. Our results suggest future warming in these environments could be more extreme than we predict," said Russell.
