Gov. Jon Huntsman formed a Blue Ribbon Advisory Council on Climate Change last August that has recently begun reviewing the science on climate change and evaluating potential policy options for Utah.
    We applaud Gov. Huntsman for taking a leadership role in this area and wish to summarize for the BRAC and the broader community our understanding of global warming and future climate change. This understanding is consistent with the consensus view of the scientific community and is described in greater depth in recently released reports by the Intergovernmental Panel on Climate Change (www.ipcc.ch).
    Although complete certainty about all aspects of climate change is not possible, there is much that is known and accepted by the scientific community. In the past two decades the global warming signal has emerged from the natural ups and downs of climate variability, and globally averaged surface temperatures are now one degree Fahrenheit warmer than a century ago.
    Air-temperature measurements and temperature trends inferred from ice cores, tree rings and other sources indicate that the past few decades were warmer than any comparable period in the last 400 years and possibly the last millennium. Climate record inconsistencies noted by global warming critics have largely been resolved and basic scientific understanding, together with climate simulations, show that the observed warming in the past century is driven
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primarily by human-generated increases in greenhouse gas concentrations. Natural processes play only a secondary role. We are already seeing societal and environmental effects of global warming. The Arctic is warming rapidly and the coverage of Arctic sea ice reached a record low in September 2005. In Alaska, homes and highways have been damaged by permafrost thawing. Mountain glaciers are in retreat worldwide.
    It is important to recognize, however, that the climate system takes time to respond to increasing greenhouse gas concentrations. Even if we hold greenhouse gas concentrations at their current levels, the atmosphere and oceans will continue to warm over the next century and sea level rise will accelerate. Modest cuts in greenhouse gas emissions will slow but not stop the rise in greenhouse gas concentrations and ensuing climate response.
    As a result, the longer we wait to take decisive action, the greater we are committed to additional climate change. Even the most conservative climate model projections produce the largest and most rapid shifts in global climate since the emergence of modern civilization.
    Although projections of how much and how quickly the climate will change in Utah are less robust, our scientific knowledge, climate model simulations, and recent observations of declining low-elevation snowpack in the Sierra Nevada and Cascade mountains, support the view that Utah's snowpack and water resources will eventually suffer serious consequences.
    We encourage the BRAC, state leaders and the wider community to recognize that this is not a "debate" between two equally credible viewpoints. The preponderance of evidence is overwhelming and shows with certainty that the earth is warming and that human society is the cause.
    Although the specific impacts of global warming on Utah require research, this is not cause for inaction - Utah citizens and industries are contributing to global warming now and will continue to do so in the future. The longer we wait to take action, the greater the challenge that future generations will face.
    Political decisions today will play a role in defining the climate that we, our children and all future Utahns inherit.
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    * JIM STEENBURGH is chairman of the University of Utah Department of Meteorology, whose 12 academic and research professors unanimously endorse the statements and views presented in this article.