Roger A. Pielke Sr. (born October 22, 1946) is an American meteorologist with interests in climate variability and climate change, environmental vulnerability, numerical modeling, atmospheric dynamics, land/ocean – atmosphere interactions, and large eddy/turbulent boundary layer modeling.

Pielke spearheaded development of the Regional Atmospheric Modeling System (RAMS) with William R. Cotton.

Pielke has served as Chairman and Member of the American Meteorological Society Committee on Weather Forecasting and Analysis, as Chief Editor of Monthly Weather Review, was elected a Fellow of the American Meteorological Society (AMS) in 1982 and a Fellow of the American Geophysical Union (AGU) in 2004, has served as Editor-in-Chief of the U.S. National Science Report to the International Union of Geodesy and Geophysics, as Co-Chief Editor of the Journal of the Atmospheric Sciences, and as Editor of Scientific Online Letters on the Atmosphere.

[1] Although he had stated that carbon dioxide is not the predominant forcing of global warming, Pielke said in 2007 that he was not a "sceptical scientist" about climate change:[2][3] Pielke has criticized the IPCC for its conclusions regarding CO2 and global warming and accused it of selectively choosing data to support a selective view of the science.

[4] In 2010 Pielke revisited a question provided by Andrew Revkin[4] "Is most of the observed warming over the last 50 years likely to have been due to the increase in greenhouse gas concentrations", Pielke stated that "the 2010 answer ... remains NO", and that "The added greenhouse gases from human activity clearly have a role in increasing the heat content of the climate system from what it otherwise would be", but "there are other equally or even more important significant human climate forcings" and furthermore "We now know, however, that the natural variations of atmospheric and ocean circulation features within the climate system produces global average heat changes that are substantially larger than what was known in 2005.