Mann's dissertation was awarded the Phillip M. Orville Prize in 1997 as an "outstanding dissertation in the earth sciences" at Yale University. His co-authorship of a scientific paper published by "Nature" won him an award from the Institute for Scientific Information (ISI) in 2002, and another co-authored paper published in the same year won the National Oceanic and Atmospheric Administration's outstanding scientific publication award. In 2002 he was named by "Scientific American" as one of fifty "leading visionaries in science and technology”. The Association of American Geographers awarded him the John Russell Mather Paper of the Year award in 2005 for a co-authored paper published in the "Journal of Climate". The American Geophysical Union awarded him its Editors' Citation for Excellence in Refereeing in 2006 to recognize his contributions in reviewing manuscripts for its "Geophysical Research Letters" journal.