Solar activity during the last 1000 yr inferred from radionuclide records
Identification of the causes of past climate change requires detailed knowledge of one of the most important natural factors—solar forcing. Prior to the period of direct solar observations, radionuclide abundances in natural archives provide the best-known proxies for changes in solar activity. Here we present two independent reconstructions of changes in solar activity during the last 1000 yr, wh