Limited understanding of the production and loss of organic aerosol (OA) to the atmosphere has resulted in poorly constrained source estimates ranging from 140 to 910 TgCyr−1 [Goldstein and Galbally, 2007]. We use satellite observations to quantitatively estimate the atmospheric burden of organic aerosol and the associated production. We find that attributing the mid-visible continental aerosol optical depth (AOD) observed by the MISR satellite entirely to OA implies a global source of 430 TgCyr−1 of sub-micron OA. We use a model (GEOS-Chem) to remove the contribution of inorganic aerosol, dust and soot from the observed AOD and derive a continental OA production of 150 TgCyr−1 (equivalent burden of 2.5 TgC), with 80% uncertainty. This result significantly reduces the uncertainty in the global OA budget and provides an upper limit for the “missing source” of OA.