Wetlands of North Africa During the Mid-Holocene Were at Least Five Times the Area Today

The Sahara was significantly wetter and greener than today during the mid-Holocene (∼6,000 years before present), and those conditions were likely maintained by feedbacks from evaporating wetlands and riparian zones. A lack of spatially continuous wetland reconstruction is the major obstacle to investigating their impacts on climate and vegetation during that epoch. Here, we estimate high-resolution gridded wetland distribution up to 15″ in the mid-Holocene North Africa obtained with three statistical and hydrological modeling approaches forced by enhanced and calibrated precipitation from climate models. These wetland models have good performance for present-day conditions and reproduce mid-Holocene hydrological elements evaluated by 297 paleo-records. Simulation results show that 18.9 ± 4.0% of land surface in North Africa was covered by wetlands during the mid-Holocene. Our results highlight the impact of natural climate change on wetland areas and provide a data set for modeling studies to include wetland feedbacks.