The tropics cover less than one-third of the Earth’s surface, but are home to more than half of all known species. Forests, savannas, grasslands, deserts: a vast array of environments stretches along the planet’s equatorial belt. This diversity, however, is not static. It is the result of millions of years of changes that have reshaped the tropical landscape time and again.Our team at the Remote Sensing Center at the Federal University of Minas Gerais (UFMG) in Brazil reconstructed the distribution of tropical vegetation over the past 3.3 million years and projected how it may experience further changes due to climate change by 2050. The study was published in the Journal of Biogeography.
The research combined satellite data, paleoclimate records and machine learning algorithms to map how forests, savannas, and deserts have redistributed themselves across the tropics over eleven large time periods, from the end of the Pliocene to the present. It showed that current climate change could, within a few decades, cause impacts on tropical vegetation similar to those of 3 million years of the planet’s history.
The results reveal profound transformations. About 3.2 million years ago, when Earth was nearly four degrees Celsius warmer than today, tropical forests reached their smallest extent throughout the entire period analyzed. The Amazon Forest covered less than half the area we know today. The Atlantic Forest was reduced to less than five percent of its potential extent. Savannas dominated landscapes that are now covered by dense forests.
