RMAG Distinguished Lecture Series, 2000

Title: A Climate of Doubt about Global Warming

Speaker: Dr. Robert C. Balling, Jr., Director, Office of Climatology, Arizona State University, Tempe, Arizona, AAPG Distinguished Lecturer

Date: March 10, 2000

Publication: The Outcrop, March 2000, p. 7

Over the past decade, global warming has become a front-page environmental issue capturing the attention of thousands of scientists and policy makers worldwide. According to numerical models of climate, the continued buildup of greenhouse gases will lead to a substantial rise in planetary temperature, melting icecaps and alpine glaciers, rising sea levels, changes in regional climate patterns, and can increase in extreme weather events.

However, many of the most fundamental global warming issues remain in a state of considerable debate in the scientific community. For example, in the most recent half decade, the atmospheric concentration of many greenhouse gases has slowed or even stabilized. Numerical models of the climate continue to have serious weaknesses, including their representation of cloud processes and the coupling of the atmosphere and ocean. Thermometer records may show global warming, but serious concerns remain about the true representativeness of their readings. The entire issue is further complicated by the fact that satellite-based and balloon-based measurements of lower atmospheric temperature show no warming whatsoever over the past few decades.

We now fully realize that the future climate will be impacted by many changes in atmospheric composition, including the buildup of greenhouse gases. Increasing levels of sulfate and mineral aerosols and the depletion of stratospheric ozone all have a known cooling effect that may completely cancel any projected warming. Finally, the evidence is overwhelming that the climate impact of a fully-implemented Kyoto Protocol will be trivial over the next fifty years.