Future projections for terrestrial biomes indicate widespread warming and moisture reduction in forests up to 2100 in South America

Abstract

Terrestrial biomes are the main reservoirs of biodiversity and CO2 on the planet. In South America, they play a crucial role in climate regulation and biodiversity conservation. Despite scientific advances and recent efforts, there is still no detailed analysis of trends in surface air temperature and precipitation changes until the end of the 21st century and magnitude of change for South America’s terrestrial biomes. In this study, we used the annual mean of temperature and annual cumulative precipitation variables provided by WorldClim (version 2.1) from an ensemble of five Global Circulation Models from the most recent simulations of the CMIP6 project. We used four-time intervals between 2020 and 2100, combined at two climatic trajectories (SSP2-4.5 and SSP5-8.5), to map climate change scenarios’ trend magnitude in South America. Also, we evaluate the exposure level of the nine terrestrial biomes according to their respective vegetal cover densities. Our results indicate that in the two possible futures evaluated (SSP2-4.5 & SSP5-8.5), the terrestrial biomes of South America would be exposed to climatic conditions that are not analogous to the current ones. The results indicate a persistent and long-term annual temperature trend increase, indistinctly for all terrestrial biomes and a significant moisture reduction in forest biomes. The consolidation of such climate scenarios can make potentially modify water and carbon cycling patterns and promoting biodiversity loss, mainly at forest biomes, with probably more severe effects under the pessimistic scenario.

Keywords

• CMIP6 scenarios
• Temperature increase
• Moisture loss
• Climatic crisis