The key to understanding the history of Earth can be found in 500-year-old clams that most unassuming fisherman dredge up to be used in soup, a new study has suggested.

By studying growth rings inside the shells of quahog clams, which are also known as chowder clams, scientists were able to patch together 1,000 years of north Atlantic Ocean history, according to research published Tuesday in the peer-reviewed journal Nature Communications. The findings may help scientists better understand how changes in the ocean, parts of which are hundreds of millions of years old, will impact and form new weather and climate patterns.

The analysis of shell growth rings is similar to the practice of removing tree cores to determine water and temperature data over time from tree rings. Using shells from the North Icelandic shelf, scientists from Cardiff University and Bangor University in Wales were able to better understand the role of ocean activity on climate in the past and compare those conditions to recorded recent history.

“The changes that we are seeing in ocean chemistry are unprecedented relative to the last 1,000 years,” David Reynolds, lead author and researcher from Cardiff University, told USA Today.

The study shed new understanding of the relationship between the warming atmosphere and planet observed today and the historical relationship warming trends have had with the ocean.

Before the industrial age, the global climate was marked by a gradual cooling with fluctuations caused by things like solar and volcanic activity. However, in the 19th and 20th centuries, human activity and greenhouse gas emissions began to change climate patterns and processes. Those changes have in turn led to a rise in global temperatures and changes to natural processes on Earth, including the chemical makeup of oceans and their circulation patterns. While the ocean influenced the atmosphere during pre-industrial times, the atmosphere has a heavier influence now, the new study suggested.

Temperatures have been breaking records recently. The United States experienced its warmest autumn on record, the National Oceanic and Atmospheric Administration announced Wednesday, and recorded its second warmest November in recorded history.