African vegetation controlled by tropical sea surface temperatures in the mid-Pleistocene period

The dominant forcing factors for past large-scale changes in vegetation are widely debated. Changes in the distribution of C-4 plants-adapted to warm, dry conditions and low atmospheric CO2 concentrations(1)-have been attributed to marked changes in environmental conditions, but the relative impacts of changes in aridity, temperature(2,3) and CO2 concentration(4,5) are not well understood. Here, we present a record of African C-4 plant abundance between 1.2 and 0.45 million years ago, derived from compound-specific carbon isotope analyses of wind-transported terrigenous plant waxes. We find that large-scale changes in African vegetation are linked closely to sea surface temperatures in the tropical Atlantic Ocean. We conclude that, in the mid-Pleistocene, changes in atmospheric moisture content-driven by tropical sea surface temperature changes and the strength of the African monsoon-controlled aridity on the African continent, and hence large-scale vegetation changes.