He was also a contributing author of the third (TAR) and fourth (AR4) Intergovernmental Panel on Climate Change (IPCC) assessment reports. According to the Principles Governing IPCC Work, the function of contributing authors is to "prepare technical information in the form of text, graphs or data for assimilation by the Lead Authors into the draft section." They are part of the author team that bears a collectively "required to critically assess information they would like to include from any source" and this applies both to IPCC Reports and to "papers undergoing the publication process in peer-reviewed journals." Along with Bill Gutowski and Gene Takle, Arritt was one of three Iowa State faculty who contributed to AR4, which led to the IPCC sharing the 2007 Nobel Peace Prize with Al Gore. After the winners of this prize were announced, Arritt told the "Des Moines Register", "It's kind of neat: I have, like, .002 percent of a Nobel prize now – shared with about 2,000 other people". The IPCC has noted that the Nobel Prize was awarded to the organization itself rather than to any individual associated with it or its reports.