A new study published in the journal Science suggests that humans might have played a significant part in the sudden deforestation of rainforests from Central Africa. This work contradicts the prevailing view that the expansion of farming practices was the root cause as well as the increased incidence of long, severe dry spells.Germain Bayon, a geochemist at the French Research Institute for Exploration of the Sea in Plouzané, and his colleagues examined the weathering of sediment samples that were drawn from the mouth of the Congo River. Deforestation intensifies weathering; therefore the clay samples would provide a continuous record of...