Climate change is often cited as causing sea level rises of up to a metre. However, this is a global estimate. If you are a city planner, for example, on the China coast or in Miami then you need to know how the sea level will change in your region. As a geologist, my work helps me predict the future coast changes by determining how high and low sea levels have changed over the past 1,000 years.My team and I collect soil samples from beaches around the globe. If we weren't affected by pandemic-related restrictions our ability to spend two weeks in the mud in a jungle gym made up of mangroves and coastal mangroves, could be a great way to spend two weeks. The pandemic has made it difficult for us to live in our own backyard. In this photo, we are on a Hong Kong mudflat. The city of Shenzhen, on the mainland China side of the bay, can be seen across the bay. Both Shenzhen as well as Hong Kong are part the Pearl River Delta, which is where low-lying lands face rising seas.I am pictured here with Howard Yu and Kayla Murai, my graduate students. We look at long, narrow soil samples taken with the same sediment corer that was used to collect them. The layers of Earth are what make it possible to explore the past. We can trace the history of shores by identifying features in these cores that indicate they were part coastal environments, such as mangrove swamps or mudflats, and then we can determine how they have changed over time.Howard uses fossils of foraminifera to mark the coast. These single-celled creatures have spiral shells and live on or inside sea-floor sediment. First, we will determine what foraminifera are found in modern-day sediment cores. This will help us fill in a gap in our knowledge of the China coastline between 500 and 1000 years ago.This work is like being a detective. You collect evidence from the field and then unravel the story.
