Research reveals ancient sea level rise causes globally

Scientists have made new discoveries about a major sea level rise that happened around 14,500 years ago, near the end of the last ice age. This event, known as Meltwater Pulse 1a, led to sea levels rising by up to 65 feet over a very short time. Researchers at Brown University have used a new model to better understand which ice sheets contributed to this dramatic rise. The study found that melting ice in North America triggered further melting in other regions, including Europe, Asia, and Antarctica. This means that the melting of ice sheets is linked across different parts of the world. The researchers believe this understanding can help predict how current ice melting will affect sea levels globally. To study past sea level changes, scientists use records found in old shorelines and ocean sediments. These sediments contain evidence like fossil coral that shows how sea levels have changed over time. By analyzing the rise and fall of sea levels, they can trace back to the ice sheets that contributed to the meltwater, using a method called sea level fingerprinting. One key finding is how gravity affects sea level changes. When an ice sheet melts, its gravitational pull weakens, which can cause nearby waters to actually drop even as they rise elsewhere. Additionally, the Earth's crust reacts to the melting ice—when heavy ice sheets disappear, the land beneath them can rise up, affecting sea level distributions globally. In their research, the team improved upon past models by including a more detailed understanding of how the Earth’s mantle responds to melting ice. They found that this response could be significant in a much shorter timescale than previously thought. Their new scenario suggests that the Meltwater Pulse 1a began with North America's Laurentide ice sheet, which contributed about 10 feet to rising sea levels, followed by larger contributions from other regions. The findings indicate that today's melting Greenland Ice Sheet could impact the larger Antarctic Ice Sheet, despite being far apart. This study highlights the importance of understanding these complex connections in predicting future sea level rises. Further research is needed to fully explore how different ice sheets interact with each other.