The 20th century was a modern time for people all over the world, with huge advances in steel, electricity and the automobile. Yet industrial development has also led to climate change. According to a study by an international team of experts from the University of South Florida (USF), sea levels have risen by 18 centimeters since the beginning of the 20th century.
The study, which appears on the cover of Science Advances, seeks to determine pre-industrial sea levels and investigate the current contribution of the greenhouse effect to sea level rise. The team, which includes USC graduate students, traveled to the Spanish island of Majorca, home to more than 1,000 cave systems, some of which contain sedimentary rocks dating back millions of years. Their investigation focused on deposits from 4,000 years ago to the present.
The team found evidence of a sea level rise of 20cm, which occurred almost 3,200 years ago, when the ice sheet was melting naturally at a rate of 0.5mm per year. Despite historical events such as the Medieval Warm Period and the Little Ice Age, sea levels remained remarkably stable until 1900.
The results of the study are startling, with sea level rise since 1900 unprecedented compared to natural changes in ice mass over the past 4,000 years. This means that if global temperatures continue to rise, sea levels could eventually reach higher levels than scientists had previously estimated.
To create the timeline, the team collected 13 samples from eight caves along the Mediterranean coast. These deposits are very rare and only form in cave passages near coasts that have been repeatedly inundated by seawater, making them an accurate indicator of changes in sea level over time.
Each repository contains valuable information about the past and the future, helping researchers determine how fast sea levels will rise over the next few decades and centuries.
