Press release: 5,700 years history of Caribbean storms
No. 46 - 14.03.2025
Research team analyses demonstrate long-term increase in tropical storms and hurricane frequency
The number of tropical storms and hurricanes in the southwestern Caribbean has increased continuously over the past 5,700 years – and many times over in the past few decades. This is shown by reconstruction based on annually layered sediments, deposited in the Great Blue Hole, an underwater cave off the coast of Belize. An international research team led by the University of Frankfurt and with the participation of the University of Göttingen created the most comprehensive list of storm events in the area to date. The results were published in the journal Science Advances.
The Great Blue Hole, a 125-metre-deep underwater cave with a diameter of about 300 metres in the otherwise very shallow lagoon of Lighthouse Reef, 80 kilometres off the coast of the Central American state of Belize, provides an extraordinary archive of climate variability and storm activity. Due to the lack of oxygen in the water layer at the bottom of the cave, annually layered sediments were deposited over several millennia and remained completely undisturbed. Researchers have now analysed these sediments from a 30-metre-long drill core.
“The sediments not only serve as a repository for a variety of climate data and provide insights into issues such as water temperatures in the past,” says first author Dr Dominik Schmitt from the University of Frankfurt, “but they also help us to date extraordinary weather events, such as storms, which are recorded by the presence of coarse-grained layers. We can interpret this information in a similar way to the clues left by tree rings.” Storm waves and storm surges transport coarse particles from the eastern coral reef of Lighthouse Reef, which can only enter the Great Blue Hole during a fierce storm and then form conspicuous, coarse layers (tempestites) at the bottom. They are clearly distinguishable from the fine-grained sediments deposited under fair weather by their colour and composition.
The research team was able to identify a total of 574 storm events over the past 5,700 years and date them to within a year, providing unprecedented insights into fluctuations in climate and hurricane cycles in the southwestern Caribbean. This data set extends back many millennia, adding to the existing instrumental records, which only go back 175 years. The findings provide insights into earlier warm and cold phases, during a time when people could not yet have made an impact on the climate.
The drill core was analysed using different methods by research groups at the Universities of Frankfurt, Cologne, Göttingen, Hamburg and Bern. About 20,000 years ago, Lighthouse Reef was still an island with a limestone cave containing a natural freshwater well, into which large amounts of organic remains from the surrounding rainforest were deposited. Seven thousand two hundred years ago, rising sea levels began to flood the island. “Studies of pollen content in the sediments clearly demonstrate that the rainforest on the island was replaced by a mangrove swamp,” explains Professor Hermann Behling from Göttingen University’s Department of Palynology and Climate Dynamics. “Algae found in the core shows that the water in the cave became brackish before it became as salty as seawater,” adds Dr Lyudmila Shumilovskikh from the same department. Complete submergence of the Great Blue Hole followed by coral reef growth began 5,700 years ago. Since then, there has been a largely undisturbed deposit of fine marine sediments with annual stratification, in which tropical storms and hurricanes have left visible traces.
Since the data obtained for previous decades show a frequency of storm events that is many times higher than in the older sediments, the research team's prognosis for the future is worrying: “On this basis, there could be a significant intensification of storm frequency in the southwestern Caribbean by 2100, far exceeding the natural level of past millennia,” the scientists say. A significant factor here is the ongoing warming of the tropical Atlantic due to human activity, which creates optimal conditions for the disproportionately frequent formation and rapid intensification of storms.
Original publication: Dominik Schmitt et al. “An annually resolved 5700-year storm archive reveals drivers of Caribbean cyclone frequency”. Science Advances 2025. Doi: 10.1126/sciadv.ads5624.
Contact:
Professor Hermann Behling
University of Göttingen
Albrecht von Haller Institute for Plant Sciences
Department of Palynology and Climate Dynamics
Wilhelm-Weber-Straße 2a, 37073 Göttingen, Germany
Email: hbehlin@gwdg.de
www.uni-goettingen.de/de/75161.html
Dr Lyudmila Shumilovskikh
University of Göttingen
Albrecht von Haller Institute for Plant Sciences
Department of Palynology and Climate Dynamics
Wilhelm-Weber-Straße 2a, 37073 Göttingen, Germany
Email: lshumil@gwdg.de
www.uni-goettingen.de/de/86432.html
https://lyudmila-shumilovskikh.com/