Ancient Maya may have started influencing climate change thousands of years ago through agricultural cultivation, according to new research.
Belize’s “Birds of Paradise” is a complex agricultural wetland carved into a tropical ecosystem whose complexity rivals that of the intense architectural structures scattered throughout the region. New research published in the Proceedings of the National Academy of Sciences suggests that it may be even larger than previously believed.
"We knew Maya civilization had a large footprint, but these [findings] show many more times greater wetland agroecosystem footprint, indicating the importance of intensive farming systems as opposed to extensive systems," study author Timothy Beach told IFLScience.
In order to adapt to a growing population and environmental pressures like drought and rising sea levels, the Maya would have turned to farming and trade in order to boost their ability to support a large society. Burning events used to clear the dense forest would have added carbon dioxide (CO2) and methane into the atmosphere at a time when South America and China were also growing exponentially between 1,000 and 2,000 years ago.
"We now are beginning to understand the full human imprint of the Anthropocene in tropical forests," said Beach in a statement. “These large and complex wetland networks may have changed climate long before industrialization, and these may be the answer to the long-standing question of how a great rainforest civilization fed itself."
Researchers produced maps of the ground using 250 square kilometers (96 square miles) of airborne light detection and ranging imagery (LIDAR). Previous studies using the technique have helped to find thousands of ancient structures, a mega-city, and a once lost city hidden for centuries. In this case, the researchers found that the Maya responded to the growing population by expanding fields and canals so that their civilization would be accessible via canoe. In the fields, researchers found cultivated food like maize as well as animal bones and shells.
"Even these small changes may have warmed the planet, which provides a sobering perspective for the order of magnitude greater changes over the last century that are accelerating into the future," added study co-author Sheryl Luzzadder-Beach.
The study authors tell IFLScience that their findings show the early use of tropical forests for intensive farming, as well as how humans adapted to rises in local water tables that were driven by sea-level rise and adaptations to severe droughts.
"These fill in knowledge about the Early Anthropocene, but indigenous people had only meagre impacts on environmental degradation compare with the modern world," said Beach. "Humans adapted and survived against drought and sea-level rise, which are predicaments we face again today."
A study published earlier this year similarly found that Romans were influencing the climate thousands of years before current society. The researchers say that understanding past human climate change may help to inform how we interact with our planet in the face of modern climate change.