Prescott 2050

Climate Change Report

Climate Change Subcommittee Final Report and Recommendations
Victor Holm Chair
Doris Cellarius
Sarah Frost
Howard Mechanic

January 6, 2009

Table of Contents:

Executive Summary: 1
Recommendations: 2
Mitigation of Climate Change: 5
Adaptation: 6
Supplemental Information:  Scientific Basis for Climate Change: 7
Executive Summary
Within the past year whatever doubt that remained whether the earth’s climate is becoming warmer has been answered.  The main cause of this warming is the increase in greenhouse gases, primarily carbon dioxide in the atmosphere.  This increase is primarily manmade.  The main instrument of this new consensus is a comprehensive study entitled “Fourth Assessment Report, Climate Change 2007: Synthesis report” by the Intergovernmental Panel on Climate Change.  The report is over 3400 pages and was written by over 600 scientists from 40 countries.  It was then reviewed by over 620 experts and 113 governments.  It has been suggested that this report represents the most important scientific findings in the history of science.
The two most important findings were that: “Warming of the climate is unequivocal” and “Most of the observed increase in global average temperature since the mid-20th century is very likely (greater than 90% confidence) due to the observed increase in anthropogenic greenhouse gas concentrations.”
Arizona Climate:  At the current time it is not possible to use these global models to accurately predict climate change on an area the size of the Southwest let alone Prescott.  However it is possible to make some general statements about the future climate of Prescott.  Climate Assessment for the Southwest (Climas) with the University of Arizona has prepared a series of papers showing climate change in the southwest.  The average temperature of Arizona has increased sharply since 1980.  They project global warming affects on the Southwest will include higher temperatures, with more heat waves; more droughts and, less snow cover.  This could have a negative effect on water resources; and result in an earlier spring with more large wildfires.  They project that average annual temperatures in Arizona could increase by 7 deg F during this century.  This would amount to 1 deg F every fourteen years; there is evidence that since 1980 this has already occurred.
There is some evidence that this heating will cause stronger and more frequent summer storms.  These storms have the potential to cause severe local flooding.  The heating will likely cause the formation of long lasting high-pressure cells over Arizona in the winter blocking Pacific storms from entering or diverting them to the north.  Since winter storms are responsible for most of the soil moisture and groundwater recharge, the overall result will be less beneficial water for Arizona.  Another result of climate change will be that the Pinion-Juniper, Ponderosa pine transition will move from its present elevation of 5200-5600 ft to a higher elevation.  The connection between hot weather and widespread tree die-off has been established, as has the link between large wildfires and rising temperatures.
Recommendations:  Our recommendations are grouped into what Prescott can do to mitigate the projected climate change and what adaptations Prescott will need to make to live with the climate change that already happening.  Our most important recommendation is that the City Council of Prescott should form a Sustainability Advisory Committee.  Such a committee could allow Prescott to be in the forefront of the coming changes.

References:
Climate Change 2007: Synthesis Report, Intergovernmental Panel on Climate Change http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf
Global Warming in the Southwest; Melanie Lenart; Climas, 2007. http://www.climas.arizona.edu/pubs/pdfs/GWSouthwest.pdf
Recommendations
Mitigation Recommendations:
1. Form a Sustainability Advisory Committee in 2009.  The committee will review public and private development plans and suggest how they could be improved by considering various sustainability criteria.
2. The City Council of Prescott should adopt a resolution that will commit both the city government and the community to reduce the emission of greenhouse gases by 2% a year starting in 2010 and continuing until 2050.  This reduction should be based on total emissions.  If the city continues to expand in population the per capita reduction would have to be proportionately greater.
3. Adopt a new energy efficiency building code for commercial and residential construction that will require:
• Solar hot water heaters be installed
• Increased wall and attic insulation
• Specify that new air conditioners and furnaces be energy efficient
• When economic new construction should also be required to install photovoltaic panels.
4. Later require upgrading of older homes and businesses with the new code.  This could be done through a system of tax reductions and low interest loans. 
5. Begin immediately to include consider greenhouse gas reduction in any new transportation plan.
6. Require that upgrades to major arterials include lanes for bicycles.
7. Establish a community wide mass transit system covering the main arterials.  The buses should be powered to reduce greenhouse gas emissions as much as possible.  The first buses could use natural gas but subsequently they should be electric powered.
8. All new city vehicles should be natural gas powered or when available should be electric or plug-in hybrid.
9. Consider ride sharing and car sharing programs such as used in other cities. 
10. Consider supporting short-term auto rental including one-way rentals.
11. Attract a large solar power station to the area.
12. Setup community gardens to encourage more local food production.
13. Establish a program to encourage people to eat less meat.  A goal should be to reduce meat consumption by 50%.  Meat production is one of the largest sources of greenhouse gases.
14. Waste reduction:
• City should reduce waste sent to landfill by greater promotion of local
opportunities to reuse and recycle.
• City should create incentives for new businesses that utilize local waste products
to make new products.
• City should have incentives to reduce waste sent to landfill by 25% 2020, 50% by 2040; 75% by 2059.
• City should create variable garbage rates to encourage more recycling.
• City should aggressively collect and sell all recyclable wastes, especially
cardboard which has high value.
• City should provide education about home compositing of green waste and create a program to collect green waste for composting and sell the compost locally.
• City should collect and use sewage plant methane year-round to generate heat and/or energy.
• At the City’s annual big waste collection - use separate containers so as
much as possible can be recycled.

Recommendations to help city to adapt to climate change:
1. City should work with the Forest Service to reduce open burning by finding a use for forest waste such as slash.
2. As the temperature rises the Ponderosa pine forest will migrate to higher elevations.  The city should have an active program to remove dying trees and replant with more heat resistant native species.  The city should also work with the Forest Service remove dying trees from the surrounding forest.
3. City should adopt a program to reduce per capita water consumption by 25% by 2015 and 50% by 2030.
4. City should discourage impervious paving and restore wetlands and riparian areas so that floodwaters infiltrate the aquifer rather than eroding soils and being lost.

Mitigation of Climate Change
The increase in greenhouse gases is the first environmental crisis that is affecting the entire planet.  These gases are not confined to the area or country where they are produced but affect everyone.  The solution must also be a worldwide effort.  There is nothing that Prescott can by itself do to mitigate climate change.  Over the next several years the US and Arizona will be adopting far reaching programs to help mitigate climate change.  Our committee feels that Prescott should begin planning now for these changes.  This planning can be assisted by Prescott forming a Sustainability Advisory Committee.  Many international environmental groups have agreed on a policy of an 80% reduction in greenhouse gases by 2050 in the industrial countries. We recommend that Prescott join these groups in committing to reduce greenhouse gas emissions by 2% per year.
Energy efficiency is one way to reduce greenhouse gas emissions.  A number of our recommendations address ways that Prescott can reduce its energy use.  Many of these are economically viable today; other will become viable as energy costs increase.  Retrofitting older, especially low-income housing, will require some new programs to help pay for these improvements.
Generation of electric power is the major source of greenhouse gas in the US.  Since Prescott purchases its power from APS there is not much that the city can do to change the source of this power to renewable source.  The city can however join other Arizona cities in encouraging APS to covert its generating capacity.
Transportation is another major source of greenhouse gases and here Prescott can have a critical influence.  Our recommendations strive to reduce the number of miles driven by personal vehicles. Foremost on the list is establishing a mass transit system for the city and also connecting to the surrounding communities.  Other recommendations try to make Prescott friendlier to pedestrians and bicycles.
Another way to reduce the emissions from transportation is to try to obtain more of our goods locally or regionally.  Encouraging the production of locally grown produce will result in both in less greenhouse gas emissions but also a fresher and more wholesome product. 
Waste management is another area where the city can take steps to reduce greenhouse gas emissions and at the same time conserve resources by recycling.  We recommend several simple but important steps to encourage this.

Adaptation
Regardless of what the world does to mitigate climate change it will continue to get hotter and for Arizona probably drier this century.  Prescott must start planning now how it will adapt to these changes.  Reducing greenhouse gases will probably result in increased transportation cost and energy costs.  Efficiency improvements in every aspect of life, already discussed in the section on mitigation, will also help the community to adapt to climate change.  There are three areas that we feel particular attention needs to be addressed.
Water Use:  It is likely that the Prescott area will receive less precipitation especially in winter.  This means that in order to reach safe yield of our aquifers we will have to reduce residential and commercial water use.  This is especially true of that portion of water that is not returned to the aquifer as recharge.  Even with the Big Chino water ranch, water will be in short supply.  We have looked into water use in the community compared to other water scarce cities and we find that it would be possible to reduce residential water by 25% without causing hardship.  Simple steps such as low-flow toilets and showers, recirculating hot water systems, fixing leaks and smart outdoor watering could substantially reduce water consumption.
Ponderosa Pine Die- off:  As already mentioned drier and hotter weather especially less winter snowfall will reduce soil moisture and result in the Ponderosa pine being slowly replaced by Pinion-Juniper.  This effect is already being observed and will accelerate in the future.  The city should begin planning now for the loss to much of the forest on the west side of town next 50 years.
Local Growing of Produce:  We have already recommended under mitigation that the community adopt programs to encourage the growing of local food in order to reduce transportation and mitigate climate change.  This recommendation will also assist in adaption since the more self sufficient a community becomes it will be better able to guard against increased prices and shortage of supply.  This is where water policy becomes critical.  If the community is to become more self-sufficient water will have to be diverted from residential use to farming.  If the city was to encourage this change it is critical that these farms use the best available practice to reduce water use.

Climate Change and how it will affect Prescott
The climate of the earth is in constant change both in terms of years and over many millions of years.  At the beginning of the Triassic period about 240 million years ago the earth rapidly warmed and resulted in the extinction of most of the marine and land life on the planet.  The cause of this rapid warming is still uncertain but greenhouses gases are the likely cause.  Much of what was to become the western US was a vast sand desert at first nearly devoid of life but as conditions cooled and became somewhat wetter the dinosaurs developed and thrived.  The best known extinction event was at the end of the Cretaceous period 65 million year ago which destroyed the dinosaurs; it was almost certainly caused by the impact of a large comet or asteroid.  Less well known was a smaller extinction event 50 million years ago which we know was caused by increasing greenhouse gases in the atmosphere.  The source of these gases is uncertain but may have been volcanic.  This caused a rapid increase in temperature and the extinction of many early mammals.  There is no doubt that the climate of the earth can change rapidly and cause temperature increases that can result in extinction of plants and animals.
About four million years ago the earth began to cool.  There is still some uncertainty as to the cause of this cooling but the closing of the Isthmus of Panama, which caused a change in worldwide ocean currents probably was one cause.  The eventual result of this cooling was the ice ages.  Over the past two million years the ice has expanded and contracted several times.  At times of maximum glaciations, the north and south hemispheres were ice covered with ice to the 45th latitude.  That would include about a third of the continental US, all of Canada and most of Europe.  During the interglacials, such at present, the ice retreats to Greenland and Antarctica.  The cause of these cycles is uncertain but it is known that feedback both positive and negative has an important effect.  As the ice expands it reflects more sunlight causing additional cooling and greenhouse gases show a decrease early in the glacial advance and rise during the retreat causing either additional cooling or warming.  What is still uncertain is whether the greenhouse gases are a cause or an effect of the glacial cycles. There is no doubt that they act like a positive feedback process and accelerate the time it takes for a cycle to complete.
Climate also changes over shorter time scales.  Beginning about 700 AD the Northern Hemisphere began to warmer compared to the previous thousand years.  This resulted in Europe being able to support more people and the population may have doubled in one hundred years.  The Norse people colonized Iceland and Greenland.  In the Americas the Aztec, the Maya and Anastasia civilizations arose.  Starting in the late thirteenth or early fourteenth centuries the earth cooled again.  There are reports of people ice-skating on the Thames River and the Norse colonies collapsed.  After 1850 the Northern Hemisphere again began to grow warmer.  Glaciers retreated and temperatures gradually rose.  Since the nineteen seventies this rise in temperature has accelerated, the cause of this acceleration is manmade greenhouse gases.
If the earth has historically been subjected to climate change some rapid how do we know that the present warming is manmade?  The evidence is of three types.

Direct Observations of Recent Climate Change:
Warming of the climate system is unequivocal; it is evident from observations of increased average air and ocean temperatures, widespread melting of snow and ice and rising global sea level.
• Eleven of the last twelve years (1995-2006) rank among the twelve warmest years in the instrumental record of global surface temperature (since 1850).
• Observations since 1961 show that the average temperature of the global ocean has increased to depths of at least 3000m and that the ocean has been taking up over 80% of the heat being added to the climate system.
• Increases in sea level are consistent with warming. Global average sea level rose at an average rate of 1.8 mm per year over 1961 to 2003 and at an average rate of about 3.1 mm per year from 1993 to 2003.
• Observed decreases in snow and ice extent especially in the arctic are consistent with warming.
• Temperatures at the top of the permafrost layer have generally increased since the 1980s in the Arctic by up to 3°C.
• Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1300 years.
These observations now have a sufficiently long record that statistically there is no longer any scientific doubt about this increase.

Increase in Greenhouse gases:
Since the beginning of the industrial age man has had an increasing effect on the balance of greenhouse gases (GHG).  The primary greenhouse gas is Carbon Dioxide (CO2) which is produced by the burning of fossil fuels but also by the burning of existing forests and wild lands.  Other important greenhouse gases are methane (CH4) and nitrous oxide (N2O).  Carbon dioxide (CO2) is the most important anthropogenic GHG. Its annual emissions have grown between 1970 and 2004 by about 80%, from 21 to 38 gigatonnes (Gt), and represented 77% of total anthropogenic GHG emissions in 2004.

Global atmospheric concentrations of CO2, CH4 and N2O have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years.  The current concentration of these gases exceeds by far the natural range over the last 650,000 years.  Global increases in CO2 concentrations are due primarily to fossil fuel use, with land-use change providing another significant but smaller contribution.  The other gases come mainly from human agriculture.

The global atmospheric concentration of CO2 increased from a pre-industrial value of about 280 ppm to 379 ppm in 2005. The annual CO2 concentration growth rate was larger during the last 10 years (1995-2005 average: 1.9ppm per year) than it has been since the beginning of continuous direct atmospheric measurements.  The other greenhouse gases show a similar increase. 

Concentration of greenhouse gases during the last 10,000 years

Climate Models:
In order to understand why science now believes that most of the recent climate change has been caused by manmade increases in greenhouse gases it is necessary to describe climate models.  Climate models are based on well-established physical principles and have been demonstrated to reproduce observed features of recent climate and past climate changes.  There is considerable confidence that Atmosphere-Ocean General Circulation Models (AOGCMs) provide credible quantitative estimates of future climate change, particularly at continental and larger scales.  These AOGCM models have only been developed in the past ten years and represent a significant improvement over the previous Earth System Models (ESM).  They are based on well-understood physical principles that are known to affect climate.  One of the ways that these models are tested is to run them in the past. When this is done they very accurately predict the currently observed temperature rise over the past fifty years.
Changes in the atmospheric concentrations of GHGs and aerosols (smoke and dust), land cover, clouds and solar radiation all alter the energy balance of the climate system and are drivers of climate change. They affect the absorption, scattering and emission of radiation within the atmosphere and at the Earth’s surface. The resulting positive or negative changes in energy balance due to these factors are expressed as radiative forcing, which is used to compare warming or cooling influences on global climate.
There is very high confidence that the global average net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 W/m2.  The combined radiative forcing due to increases in CO2, CH4 and N2O is +2.3 W/m2, and its rate of increase during the industrial era is very likely to have been unprecedented in more than 10,000 years. The CO2 radiative forcing increased by 20% from 1995 to 2005, the largest change for any decade in at least the last 200 years. 

As the maps above show temperature observations clearly are following the model predictions.
Arizona Climate:
At the current time it is not possible to use these global models to accurately predict climate change on an area the size of the Southwest let alone Prescott.  However it is possible to make some general statements about the future climate of Prescott.  The Climas with the University of Arizona has prepared a series of papers show climate in the southwest.  The figure at right shows that the average temperature of Arizona has increased sharply since 1980.  They project global warming affects on the Southwest will include higher temperatures, with more heat waves; more droughts and, less snow cover.  This could have a negative effect on water resources; and result in an earlier spring with more large wildfires.  They project that average annual temperatures in Arizona could increase by 7 deg F during this century.  This would amount to 1 deg F every fourteen years; there is evidence that since 1980 this has already occurred.
There is some evidence that this heating will cause stronger and more frequent summer storms.  These storms have the potential to cause serve local flooding.  The heating will likely cause the formation of long lasting high-pressure cell over Arizona in the winter blocking Pacific storm from entering or diverting them to the north.  Since winter storms are responsible for most of the soil moisture and groundwater recharge, the overall result will be less beneficial water for Arizona.
Another result of climate change will be that the Pinion-Juniper, Ponderosa pine transition will move from its present elevation of 5200-5600ft to a higher elevation.  The connection between hot weather and widespread tree die-off has been established more explicitly, as has the link between large wildfires and rising temperatures. 
References:
Climate Change 2007; The Physical Science Basis:  IPCC report, 2008.  http://www.ipcc.ch/ipccreports/ar4-wg1.htm
Climate Change and Arizona; Mike Crimmins: 2008
Global Warming in the Southwest; Melanie Lenart; Climas, 2007. http://www.climas.arizona.edu/pubs/pdfs/GWSouthwest.pdf