Refeered Papers: Nomenclature, Radiative Forcing and Temperature Projections in IPCC Climate Change 2007: The Physical Science Basis (AR4).

By not following standard scientific nomenclature for parts per million by volume (ppmv) and parts per million by mass (ppm), the authors of Climate Change 2007: The Physical Science Basis (AR4), introduced confusion between these units. This confusion in AR4 has spread to the scientific community and has potential to create problems. Carbon dioxide contributed approximately 11% of the change in atmospheric warming during the period from the ice ages to the pre-industrial level of 275 ppmv. This is consistent with the current proportion of warming by carbon dioxide, and casts doubt on carbon dioxide being almost 100% of the cause of atmospheric warming from 275 to 378 ppmv. The climate sensitivity parameter calculated for the projected temperature change range of 2.9°C to 6.4°C is physically impossible to achieve. The lower temperature range is unreliable. The Intergovernmental Panel on Climate Change has an important obligation to make these problems known to policymakers and the public. [ABSTRACT FROM AUTHOR]