Robert Jay Charlson is an American atmospheric scientist, climate scientist, pioneer in the fields of climate forcing and climate change, and coauthor of the CLAW hypothesis. He is professor of Atmospheric Sciences, Chemistry, and Geophysics at the University of Washington in Seattle, Washington. Charlson earned his Ph.D. from the University of Washington. He is a world expert in atmospheric chemistry, aerosol physics, aerosol/cloud/climate interaction, aerosol and cloud instrumentation.