Prescott 2050

Climate Change Interim Report

Introduction
Last year the Intergovernmental Panel on Climate Change issued a major report that concluded with a high level of confidence that climate change was occurring and that man made greenhouse gases, primarily carbon dioxide, was the cause.  Before this report there were still some scientists who felt more study was needed.  This report has removed the doubt of all but a few.  The report through the use of new computer models, for the first time predicted the future rise in temperature with confidence.  Unless the entire world reduces the emission of greenhouse gases these models predict that there will be severe consequences for the entire planet but especially for semi deserts.  The Climate Change Committee has separated its recommendations into two categories: Mitigation and Adaptation. 
Mitigation
The recommendations under Mitigation list some of the things Prescott can do to reduce climate change.  It is obvious that these measures by themselves will not reduce climate change.  For there to be meaningful reduction in greenhouse gas emissions the entire planet must adopt similar measures.  The sooner the world begins to reduce its emissions, the less the second set of recommendations on adaptation will be needed.
Adaptation
In the past several years climate models have begun to provide forecasts of what changes to the world we can expect over the next forty years.  There is still considerable uncertainty in these forecasts.  It is even more difficult to forecast climate changes for a small region such as Yavapai County.  In spite of this uncertainty it is still useful to consider what could happen.  Worldwide temperatures have risen about 1.5deg F during the past 150 years while in Prescott temperatures have raised about 7deg F.  There is good reason to believe that Arizona and Prescott will continue to warm more rapidly than the average for the earth.  The other change that has occurred in the past fifty years is Prescott is now receiving less precipitation in winter; and combined with the rise; in temperature this has resulted in significantly less snowfall.  Snowfall has traditionally been the main source of recharge to the groundwater aquifers.  Monsoon moisture in the summer has not shown the same decrease in precipitation but it has become more erratic.  In the future we can expect more droughts as well as more severe summer thunder storms.  Combined with the higher evaporation and transpiration rates due to increased temperature this will result in stress to the forest.  Over the next forty years we can expect the Ponderosa forest to retreat to higher elevations and be replaced by chaparral and Pinion-Juniper.  Prescott will have to adapt to both less water and less forest. 

VISION

Climate Change Committee
September 25, 2008

Climate change is an established fact.  The most important cause of this change is the emission of greenhouse gases, primarily CO2 from manmade sources.  Prescott is expected to experience an above average increase in temperature as well as possible reduction in precipitation and change in season.  Between now and 2050 Prescott must do its part in a worldwide effort to mitigate the change by reducing its emissions of greenhouse gases.  It will also be necessary for the city to adapt to the increasing temperature and less available water.  These changes are inevitable.  The Climate Change Committee will develop recommendations that address both the mitigation and adaptation to the problem.

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