December 1, 2023

Evidence of Unprecedented Modern Sea-Level Rise Found in Ancient Caves

University of the Balearic Islands co-principal private investigator stands next to a big mineral deposit in the Dets Ases cavern in Mallorca, Spain. Credit: University of South Florida
The team found evidence of a previously unknown 20-centimeter sea-level rise that took place nearly 3,200 years ago when ice caps melted naturally over the course of 400 years at a rate of 0.5 millimeters annually. Otherwise, in spite of major climatic events like the Medieval Warm Period and the Little Ice Age, the sea level remained exceptionally steady until 1900.
” The results reported in our research study are disconcerting,” said lead author Bogdan P. Onac, a geology professor at USF. “The sea-level increase because the 1900s is extraordinary when compared to the natural change in ice volumes over the last 4,000 years. This suggests that if international temperature levels continue to rise, sea levels could ultimately reach higher levels than scientists previously approximated.”
To create the timeline, the team collected 13 samples from eight caverns along the coastline of the Mediterranean Sea. The deposits are uncommon– just forming near the shoreline in cavern passages that were consistently flooded by seawater, making them precise markers of sea-level modifications in time. Each deposit holds important insight into both the past and future, assisting researchers determine how rapidly the water level will increase in the coming years and centuries.
University of South Florida student Giuseppe Lucia and USF geologist Bogdan Onac. Credit: University of South Florida
The samples were required to the University of New Mexico and the University of Bern in Switzerland, where unique instruments were utilized to identify their age by a uranium-series technique. With time, uranium decomposes into other aspects such as thorium and lead, allowing scientists to create a timeline of the sea level documented in each deposit.
A complicated software application at Harvard University helped create predictions using various ice models and Earths parameters to showcase an accurate history of the sea level. These predictions are necessary since they permit researchers to approximate past global mean sea level, which is key in addressing future sea-level increase.
Phreatic overgrowth can be observed on speleothems within the Vallgornera Cave in Mallorca, Spain. Credit: University of South Florida
” If people continue to be the primary motorist and the temperature increases 1.5 degrees in the near future, there will be irreversible damage,” Onac stated. “There will be no turning back from that point on.”
Based on ice mass loss from the Antarctic and Greenland, the average sea-level rise because 2008 is 1.43 millimeters per year.
Irreversible flooding from the increasing sea level will not take place overnight, however Onac says it will be seen increasingly more throughout storm surges and cyclones. With almost 40 percent of the worlds population living within 62 miles of a coast, the increasing water level could be disastrous with substantial social and economic effects.
Professional divers were trained to look for phreatic overgrowth on speleothems underwater. Credit: University of South Florida
” Even if we stop right now, sea level will continue to rise for at least a couple of decades, if not centuries, simply due to the fact that the system is heated up.”
In June, Onac received a brand-new research study grant from the National Science Foundation to continue his research to anticipate future sea-level increase due to global warming. The grant will permit Onac to broaden the research study even more into history by 130,000 years and produce a much better understanding of sea level internationally. Starting in September, Onac and his team will start evaluating cave deposits from around the globe, including Italy, Greece, Mexico, and Cuba.
Recommendation: “Exceptionally stable preindustrial sea level presumed from the western Mediterranean Sea” by Bogdan P. Onac, Jerry X. Mitrovica, Joaquín Ginés, Yemane Asmerom, Victor J. Polyak, Paola Tuccimei, Erica L. Ashe, Joan J. Fornós, Mark J. Hoggard, Sophie Coulson, Angel Ginés, Michele Soligo and Igor M. Villa, 29 June 2022, Science Advances.DOI: 10.1126/ sciadv.abm6185.
This study was performed in collaboration with scientists from Harvard University, University of New Mexico, University of the Balearic Islands, University Rome Tre, Rutgers University, Australian National University, Los Alamos National Laboratory, and the University of Bern.

The sea level has increased 18 centimeters given that the start of the twentieth century, according to a worldwide team of experts led by the University of South Florida (USF).
This suggests that if global temperatures continue to rise, sea levels might ultimately reach greater levels than scientists previously estimated.”
To develop the timeline, the group gathered 13 samples from 8 caves along the shoreline of the Mediterranean Sea. Each deposit holds valuable insight into both the past and future, assisting researchers determine how quickly the sea level will increase in the coming centuries and years.
The grant will permit Onac to expand the research study further into history by 130,000 years and develop a much better understanding of sea level globally.

University of South Florida geologist Bogdan Onac stands beside preindustrial overgrowths in the Cala Varques cave in Mallorca, Spain. Credit: University of South Florida
A geology teacher at the University of South Florida has actually discovered the influence of the commercial boom on worldwide warming.
The early 1900s were an exhilarating moment for individuals all around the world, with tremendous advancements in the steel, electrical, and car sectors. Industrial developments likewise represent a tipping point in our climate. The sea level has actually increased 18 centimeters because the beginning of the twentieth century, according to a global group of specialists led by the University of South Florida (USF).
The research, which appeared on the cover of Science Advances on July 1, tries to determine preindustrial sea levels and examines the influence of present greenhouse warming on sea-level increase.
The group, that included graduate students from USF, headed to Mallorca, Spain, which has more than 1,000 cavern systems, some of which include deposits that go back millions of years. They focused on deposits from 4,000 years ago to the present day for their examination.