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CLIMATE PROFILE FOR
THE HIGHLANDS AT DOVE MOUNTAIN
HEAT, WATER & ENERGY IN THE SOUTHWEST
Climate Profile for
The Highlands at Dove Mountain
Climate Assessment for the Southwest (CLIMAS)
University of Arizona
May 8, 2019
Alison M. Meadow
CLIMAS and Institute of the Environment
Sarah LeRoy
CLIMAS and Institute of the Environment
Jeremy Weiss
CLIMAS and School of Natural Resources and the Environment
Ladd Keith
CLIMAS and College of Architecture, Planning, and Landscape Architecture
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Table of Contents
Executive Summary ................................................................................................................ 4
Current Climate and Near-Term Trends ................................................................................... 6
Annual Average Temperature .......................................................................................................... 6
Annual Average Precipitation .......................................................................................................... 7
Future Temperature and Precipitation Projections for Pima County ................................................. 8
Projected Changes to Annual Average Temperature ........................................................................................ 11
Projected Changes to Annual Average Precipitation ........................................................................................ 11
Projected Changes in Extremes of Temperature and Precipitation ................................................. 12
Temperature ..................................................................................................................................................... 12
Changes in Monsoon Events ............................................................................................................................. 14
Impacts ................................................................................................................................. 16
Human Health ................................................................................................................................ 16
Heat ................................................................................................................................................................... 16
Air quality .......................................................................................................................................................... 16
Flooding ............................................................................................................................................................ 18
Vector-borne diseases ...................................................................................................................................... 18
Mental health ................................................................................................................................................... 19
Food security/prices ......................................................................................................................................... 19
Ecosystem Changes ........................................................................................................................ 19
Infrastructure ................................................................................................................................ 20
Water availability .......................................................................................................................... 21
Wildfire ......................................................................................................................................... 22
Post-fire flooding .............................................................................................................................................. 23
Energy ........................................................................................................................................... 23
Real Estate/Demographics ............................................................................................................. 24
Climate Change Adaptation Planning ................................................................................... 25
Adaptation Strategies ........................................................................................................... 27
Golf Course Sustainability .............................................................................................................. 27
Emergency Preparedness ............................................................................................................... 28
Fire Protection .................................................................................................................................................. 28
Buffelgrass Reduction ....................................................................................................................................... 28
Flood Insurance ................................................................................................................................................. 29
Landscaping ................................................................................................................................... 29
Energy ........................................................................................................................................... 30
Social Resilience ............................................................................................................................. 31
References Cited ................................................................................................................... 32
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Executive Summary
The earth’s climate is changing. Global average temperatures have risen 1.8° F since 1901
(Wuebbles et al., 2017). Warming temperatures are driving other environmental changes such as
melting glaciers, rising sea levels, changes in precipitation patterns, and increased drought and
wildfires.
The magnitude of future changes will depend on the amount of greenhouse gases (GHGs)
emitted into our atmosphere. Without significant reductions in GHGs, global average
temperatures could rise as much as 9° F over pre-industrial temperatures by the end of this
century.
Pima County is also experiencing climatic changes that will impact our temperatures,
precipitation patterns, ecosystems, and human health and well-being. Changes for Pima County
include:
Temperature
Average temperature
•The long-term average temperature for Pima County is 66.8° F. However, almost every
year since 1985 has had average annual temperatures above the long-term average.
•These trends are projected to continue into the future. Average temperatures could be 2°
F above the current average by 2030 and more than 10° F higher by the year 2100.
Extreme temperatures
•Since 1950, Pima County has averaged 15 days per year where the high temperatures
reached above 105° F. The county could experience as many as 25 days above 105° F per
year by 2030 and as many as 100 days per year by the end of this century.
•Minimum temperatures are also expected to rise. Since 1950, the county has averaged 3
days per year where the minimum temperature stayed above 80° F. By 2030 the county
could see as many as 15 days per year where the minimum temperature is 80° F and by
2100 this number could be as high as 70 days per year.
Precipitation
Average precipitation
•Precipitation in this region is naturally variable from year-to-year. There is no clear trend
toward changes in average precipitation amounts in Pima County. We expect this natural
variability to continue in the future.
•However, even with no change in average precipitation, rising temperatures will increase
evaporation and transpiration rates, which will lead to drier soils and contribute to more
frequent and severe drought.
Extreme precipitation
•Over the past 30 years, the Southwest U.S. has experienced more extreme precipitation
associated with monsoon thunderstorms. However, the frequency of such events has
fallen, as has the average amount of monsoon precipitation.
•These trends of less frequent storms, decreased average precipitation, but more intense
storms are likely to continue in the future.
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•In severe storms, maximum wind gusts have become higher. Higher winds during severe
storms are also projected to continue in the future, especially for areas across Southwest
Arizona.
Impacts
Human Health
•Extreme heat can affect human health, especially in vulnerable populations (e.g., older
adults, children, and those with chronic illnesses), and can strain energy grids as residents
increase their use of air conditioning to stay cool.
•Higher temperatures, smoke from wildfires, and dust storms all lead to poor air quality
and can create serious health problems, especially in vulnerable populations.
•Climate change may affect certain vector-borne diseases, such as West Nile Virus,
because warmer temperatures will create a more welcoming environment for the
mosquitos that carry West Nile Virus.
Water Availability
•Colorado River streamflow will likely be reduced in the future, due to higher
temperatures, potential changes in precipitation, and reduced snowpack. Water levels in
Lake Mead have been dropping since 2000, but reductions in water supply will not
impact municipal deliveries for some time.
Wildfire
•Wildfire can pose a direct threat to people and structures as well as cause negative health
impacts due to poor air quality. Future fire frequency could increase 25% in the
Southwest, and the frequency of very large fires (over 12,000 acres) could triple.
•The Highlands at Dove Mountain is one of the moderate-risk communities in the
wildland-urban interface of Pima County. The main wildfire threat comes from
buffelgrass, an invasive species that outcompetes native desert plants.
Energy
•In the Southwest U.S., delivery of electricity may become more vulnerable to disruption
due to increased demand for cooling and risks to transmission infrastructure from
wildfires, among other reasons.
Real Estate/Demographics
•There is growing evidence that climate change will affect human migration patterns as
some regions become less livable and people move to more viable regions, however there
is not enough research about migration patterns specific to Arizona to be certain of trends
and impacts at this time.
Climate Change Adaptation
Climate change adaptation planning is the process of planning to adjust to new or changing
environments in ways that reduce negative effects and take advantage of beneficial opportunities.
Climate change adaptation strategies can be integrated into existing community plans, such as
landscape or infrastructure management plans or can be stand-alone plans. Adaptation planning
is a community-driven process in which community members and leaders should identify and
discuss community values, goals, and capacities. In this report we present a number of
suggestions for possible adaptation strategies for The Highlands at Dove Mountain. We hope
these stimulate both discussion and action by members of The Highlands community.
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Current Climate and Near-Term Trends
Annual Average Temperature
The long-term annual average temperature for Pima County (between 1895 and 2018) was 66.8°
F. The hottest year was 2017 with an average temperature of 70.4° F and the coldest year was
1964 at 64.5° F. However, almost every year since 1985 has had an average temperature
above that long-term average. In Figure 1, blue bars represent years with below-average
temperatures and orange bars represent years with above-average temperatures.
Figure 1: Annual average temperature for Pima County 1895 – 2018.
Disaggregating temperatures as average daily maximum, average daily minimum, as well as
overall average allows us to identify patterns in the ways in which warming is impacting a region
(Figure 2). Maximum annual average temperature tells us the average of all the warmest
(typically afternoon) daily temperature readings in an area. Minimum annual average temperature
tells us the average of the lowest temperature readings, which typically occur in the early
morning. Overall average is the average of both maximum and minimum temperatures for an
area over a given time. Figure 2 demonstrates that both maximum and minimum temperatures
are rising in Pima County, meaning our high temperatures are getting hotter and our cool
temperatures are not getting as cool as in the past.
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Figure 2: Annual average maximum (red), minimum (tan), and overall average (orange) temperatures for Pima County from
1895 – 2018.
Annual Average Precipitation
The long-term average annual precipitation amount for Pima County is 12.1 inches. Precipitation
in the Sonoran Desert is naturally variable from year-to-year, as Figure 3 shows. In Figure 3 blue
bars represent years with above-average precipitation and brown bars represent years with
below-average precipitation. The driest year was 1956 with 6.1 inches and the wettest year was
1982 with 24.2 inches – twice the average amount of precipitation. Arizona has been in a
drought since 1999, with almost every year since then experiencing below-average
precipitation.
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Figure 3: Annual total precipitation for Pima County 1895 – 2018.
Future Temperature and Precipitation Projections for Pima County
The Intergovernmental Panel on Climate Change (IPCC), which is the international body
convened to assess climate changes and impacts across the globe, has developed a set of four
scenarios to project possible future climates for the world as a whole. Different levels of
greenhouse gases (GHGs) released into the atmosphere will have different impacts on warming
temperatures. In order to show this range of possible outcomes, climate scientists use
Representative Concentration Pathways (RCPs), which are based on the current rates of GHG
emissions and estimated emissions up to 2100, based on assumptions about global levels of
economic activity, energy sources, population growth and other socio-economic factors. These
scenarios are then used in Global Climate Models (GCMs) to estimate future global average
temperatures.
GCMs cannot firmly predict future climate patterns, but they are useful tools that point us toward
likely futures, based on the best currently available science. There are two main sources of
uncertainty regarding climate projections that should be kept in mind when considering future
climate scenarios. First, there is a range of possible ways humans will choose to manage our
emissions of GHGs in the future. The four different RCPs are one way to explore these different
possible emissions scenarios and generate climate projections for each one. A second source of
uncertainty is the ability of the GCMs to capture the complex global climate system. No single
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climate model can perfectly imitate such a complex system. For example, climate scientists tend
to trust models to project the direction of change (such as temperatures rising), but they have less
confidence in the ability of models to project the magnitude of change (exactly how much
temperatures will rise). The approach to reducing this source of uncertainty is to use the average
projections from many different models rather than rely on any single model.
The following summaries of projections – both for the globe and for Pima County – use RCP 4.5
and 8.5 (defined in Table 1 with the other RCPs) and an average of multiple climate models to
reduce uncertainty and provide reasonable estimates of possible future climates for both scales of
analysis. We chose to use RCP 4.5 because it is a reasonable, but low estimate of future
emissions. RCP 8.5 is the scenario closest to our current emissions use. Table 1 summarizes the
assumptions and projections for all four RCPs, which are represented in Figure 4.
Figure 4 shows the projected global temperature increases using the four RCPs. The green line
that runs from 1900 (far left of the timeline) through 2014 represents the observed global average
temperature for that period of time. The shading around each solid line represents the range of
results from the multiple GCMs that are used to generate the average projections (solid lines).
RCPs 2.6 and 8.5 are shown as lines on the graph and bars to the right, whereas RCPs 4.5 and
6.0 are only shown as bars on the right. Although there is a range of possible temperatures for
each scenario, they are all projecting rising temperatures.
Table 1. Assumptions and Projections for each Representative Concentration Pathway, represented in Figure 4.
Scenario
Assumptions
Projected Temperature
Increase
RCP 2.6
blue line and
shading
“Best Case Scenario” - assumes that through
policy intervention, GHG emissions are reduced
by 2020 and decline to around zero by 2080,
leading to a slight reduction in today’s GHG
levels by 2100.
Global average
temperature increase of
2.5° F (1° C) by the year
2100.
RCP 4.5
aqua bar
shown only to
the right of the
chart
Assumes that GHG emissions will peak at
around 50% higher than year 2000 levels in
about 2040 and then fall.
Global average
temperatures increase
of 4° F (1.8° C) by 2100.
RCP 6.0
yellow bar
shown only to
the right of the
chart
Assumes that emissions will double by 2060,
then fall but still remain above current levels
through 2100.
Global average
temperature increase of
5° F (2.2° C) by 2100.
RCP 8.5
red line and
shading
“Worst Case Scenario” - Assumes GHG
emissions continue to grow at current rate
through 2100.
Global average
temperature increase of
more than 8° F (3.7° C)
by 2100.
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Figure 4: Projected global temperature increases using the four Representative Concentration Pathways (RCP) scenarios.
Source: https://nca2014.globalchange.gov/report/our-changing-climate/future-climate-change.
GCMs that were built to cover the whole globe can be focused on smaller regions through a
process of downscaling. We used statistically downscaled climate models to compile climate
projection data for Pima County, which is a small enough area to capture the trends expected to
affect the county, but big enough that we have confidence in the accuracy of the projections. In
this study, we analyzed downscaled climate projection data from one model run of 30 different
global climate models using two of the scenarios described in Figure 4 – RCP 4.5 and RCP 8.5.
At present, RCP 4.5 represents an optimistic, lower-emissions scenario, while RCP 8.5 is closer
to our current, higher emissions trajectory.
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Projected Changes to Annual Average Temperature
An average of climate model projections for Pima County indicate that annual average
temperatures may rise 2
°
F by 2030, compared to about what temperatures were in the
year 2000, with continued increases (as much as 10
°
F above the long-term average) by
2100. Such changes could make the annual average temperature approximately 69° F by 2030
and possibly 77° F by 2100. In Figure 5 the red line represents a high greenhouse gas emissions
scenario (RCP 8.5). The orange line represents a moderate scenario (RCP 4.5).
Figure 5: Projected changes in average temperature for Pima County. RCP 8.5 is a high emissions scenario, and RCP 4.5 is a
moderate scenario (see Table 1). The gray line and shaded area represent historical temperatures, as simulated by the climate
models.
Projected Changes to Annual Average Precipitation
It is very difficult to project future precipitation changes in this region because it has been
challenging to accurately model the behavior of the North American monsoon (NAM). The
NAM accounts for approximately half of our annual precipitation, meaning that the inability to
capture its dynamics in climate models leads to high uncertainty about model projections.
However, the best available projections show some possible decreases in precipitation by the end
of the century, with a likely continuation of our natural year-to-year variability. In Figure 6 the
dark blue line represents RCP 8.5 (worst-case scenario) and the light blue line represents RCP
4.5, the moderate scenario. Given the uncertainty of these projections, many climate scientists
in this region recommend assuming that annual average precipitation will remain
relatively consistent, with year-to-year variation as we see now.
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Although the annual average precipitation in this region may change very little, the higher
temperatures will accelerate evaporation and transpiration from plants, resulting in less
surface water and drier soils.
Figure 6: Projected changes in total precipitation for Pima County.
Projected Changes in Extremes of Temperature and Precipitation
Temperature
Since 1950 Pima County has had an average of 15 days each year where temperatures reached
over 105° F. In Figure 7, dark gray bars show observed annual average temperatures from 1950-
2013. The horizontal line from which bars extend represents the overall average from 1961-1990
(a 30-year period of record is the standard unit for making climatological comparisons). Bars that
extend above the line show years with an above average number of days warmer than 105° F.
Bars that extend below the line were below average. Since the early 1990s, almost every year
has had more days above 105
°
F than the 1961-1990 average. This trend is also expected to
continue, based on climate model projections for the region. By 2030, the county could see as
many as 25 days per year above 105
°
F. By 2100, between 50 (RCP 4.5) and 100 (RCP 8.5)
days per year may hit high temperatures above 105° F, depending on the greenhouse gas
emissions scenario.
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Figure 7: Days per year with maximum temperatures above 105
°
F. RCP 4.5 is shown as the blue line and shaded area, and
RCP 8.5 is shown as the red line and shading.
The number of days per year where the minimum temperature stays above 80° F has also been
increasing. Almost every year since the mid-1990s has had more days per year with
minimum temperatures above 80
°
F than average. This trend is projected to continue, and by
2030 the county could see as many as 15 days per year where the minimum temperature
does not drop below 80
°
F. By 2100, this number could be as high as 70 days per year.
Figure 8: Days per year with minimum temperatures above 80
°
F. RCP 4.5 is shown as the blue line and shaded area, and RCP
8.5 is shown as the red line and shading.
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Similarly, the number of days each year with minimum temperatures below 32° F are declining.
Between 1961 and 1990, temperatures in Pima County dipped below freezing an average of 24
days per year. However, since the late 1970s, most years have not reached that average. We
expect this trend to continue, with as few as 20 days per year with minimum temperatures
below 32
°
F by 2020 and as few as 5 days per year by 2100.
Figure 9: Days per year with minimum temperatures below 32
°
F. RCP 4.5 is shown as the blue line and shaded area, and RCP
8.5 is shown as the red line and shading.
Changes in Monsoon Events
The monsoon storms that bring Pima County half its precipitation each year are also changing in
ways that are likely to affect drought conditions, flood regimes, and storm-related hazards. Over
the past 30 years, the Southwest U.S. has experienced more extreme precipitation associated with
monsoon thunderstorms. Rising summer temperatures are intensifying rainfall because
warmer air can hold more moisture and create conditions that favor heavy precipitation from
convective storms (Luong et al., 2017). In severe storms, maximum wind gusts have become
higher. Higher winds during severe storms are also projected to continue in the future, especially
for areas across Southwest Arizona (Luong et al. 2017; Castro 2017).
However, the frequency of such events has fallen, as has the average total amount of
monsoon precipitation (Castro, 2017). The change in frequency is due to changes in the
regional weather pattern at this time of year. The monsoon ridge – an area of high pressure over
the Southwest – has expanded and intensified (higher pressure) over recent decades due to the
regional warming trend. This has made it more difficult for thunderstorms that form over high
elevation, mountainous areas to move into the low-elevation deserts (Lahmers et al., 2016). With
a larger and stronger monsoon ridge, southern Arizona – including The Highlands at Dove
Mountain – is no longer on the edge of the ridge where inverted troughs—the main atmospheric
feature that allows convective storms to cluster—typically tracked (Figure 10). Inverted troughs
now are more commonly moving from east to west farther to the south. These trends—less
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frequent storms, decreased average precipitation, but more intense storms—are likely to continue
in the future.
Figure 10: The stronger monsoon ridge, which has been occurring in recent years, has reduced the frequency of storms in
Pima County. However, when storms occur they are now more intense than in the past.
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Impacts
Human Health
Heat
Extreme heat events (EHEs) are a concern in Pima County. Since 2012, there have been 63
injuries and 8 deaths attributed to heat events in Pima County. For example, June 2017 was the
hottest June on record for Tucson, with an average monthly temperature of 89.7° F. During the
month there was a 3-day heat wave, with temperatures at Catalina State Park reaching 114-115°
F on all 3 days, all of which set the record high for the day. EHEs can impact public safety in
two ways. First, there are direct impacts on human health. Extreme heat places greater stress on
the body, especially when combined with humidity (Brown et al., 2013). Older adults, children,
those who work outside, those with chronic illnesses, and those who are socially isolated tend to
be at greater risk. Nighttime temperatures are particularly important, since the human body needs
the relief of the cooler nights to reduce the stress from daytime heat. Nighttime temperatures
have been increasing faster than daytime temperatures, so it will become increasingly important
in the future to find ways to cool off at night during the heat of the summer. Second, high heat
events can strain energy grids as residents increase their use of air conditioning to stay cool. If
residents lose power, there will be an increase in human health impacts.
In addition to the human health effects of heat, there can be additional burdens placed on our
natural resources. An example of the links between heat and water use comes from a study of the
effects of the urban heat island (UHI) in Phoenix. A UHI is an urban or metropolitan area that is
significantly warmer than its surrounding rural areas due to human activities. The study found
that the more an area was affected by the UHI—specifically if the low temperature in the
neighborhood was higher than other areas of Phoenix—the more water was used by households
in that neighborhood. A 1° F increase in a neighborhood’s low temperature increased water use
per household by 290 gallons per month (Guhathakurta and Gober, 2007).
Air quality
Climatic changes are also affecting air quality, with implications for human health. Ground-level
ozone pollution, fine particulate matter 2.5 (PM2.5; particulate matter smaller than 2.5 microns),
and particulate matter 10 (PM10; particulate matter between 2.5 and 10 microns) are several of
the air pollutants likely to be affected by climatic changes. The overall rise in air pollutants
associated with climate change is expected to contribute to rising rates of asthma and other
allergic diseases (Crimmins et al., 2016).
Increased temperatures will increase ground-level ozone pollution in many areas of the United
States. Ground-level ozone is produced when nitrogen oxides and hydrocarbons from automobile
exhaust, power plant and industrial emissions, gasoline vapors, chemical solvents, and some
natural sources react in heat and sunlight. Exposure to ground-level ozone is linked to reduced
lung function and respiratory problems such as pain with deep breathing, coughing, and airway
inflammation (Brown et al. 2013). Ozone exceedance days have fallen in Pima County since the
early 2000s (Figure 11). However, ozone tends to peak in the hotter summer months – May
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through August (Figure 12). As temperatures rise and heatwaves become more common, it is
possible that ozone exceedance days may also rise.
Figure 11: Number of days ozone levels have exceeded
0.07 parts per million (ppm), which is unhealthy for
sensitive groups; 0.086 ppm, which is unhealthy for all;
and 0.106, which is very unhealthy for all, in Pima County
since 2000.
Figure 12: Average number of days from 2000 to 2018 in
which ozone exceeded 0.070 ppm in each month. May –
August, the warmest months, also had the highest number
of high ozone days.
PM 2.5 is often generated by vehicle exhaust and power plant emissions (Environmental
Protection Agency, 2013). Another source of PM 2.5 is wildfires, which are expected to become
larger and more frequent as climate conditions become hotter and drier. The smoke from
wildfires can travel and affect air quality thousands of miles away, such as smoke from the
Wallow Fire in 2011, which spread into Texas and Oklahoma from Arizona. High levels of PM
2.5 are associated with mortality related to cardiovascular problems, particularly among the
elderly, and reduced lung function and growth, increased respiratory stress, and asthma in
children (Brown et al. 2013).
In Pima County, PM10 pollution often comes in the form of dust storms. Dust storms tend to
peak during the spring months in the Southwest, due to stronger winds from changes to the jet
stream as the temperatures warm in the spring. Dust storms have been occurring more frequently
and over a longer season in recent years in Arizona due to drought conditions (Figure 13) (Tong
et al., 2017). The decade of the 2000s saw significantly more dust storms than the 1990s (Tong et
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al. 2017). Dust from unpaved roads, construction sites, fires, and abandoned fields combined
with smog, soot, smoke and ash can enter the nose and lungs and create serious health problems.
Figure 13: Monthly distribution of dust events across the Western United States in the 1990s and 2000s.
Flooding
Although overall precipitation in Pima County may remain steady or decline slightly, individual
precipitation events may become more extreme due to the ability of a warmer atmosphere to hold
more water (Gershunov et al., 2013) and changes to the NAM (discussed above). Areas in and
around the community that are already flood-prone may experience larger floods. Areas that do
not regularly flood now could become flood-prone with larger storm events. More intense
flooding means that residents need to be even more diligent about not crossing flooded washes,
and the community should consider adaptation options to combat flooding impacts (see
Adaptation Strategies section below).
Vector-borne diseases
Climate change seems likely to affect certain vector-borne diseases like West Nile Virus (WNV)
because warmer temperatures will create a more welcoming environment for the mosquitos that
carry WNV.
The mosquito that carries WNV are the Culex tarsalis and Culex quinquefasciatus. Warming
temperatures across the U.S. are expected to lead to a spread of WNV. However, certain areas
may experience an increase, while others may experience a decrease (Roach et al., 2017).
Climate change is likely to 1) lengthen the season during which mosquitos can survive and
breed, and 2) in some areas, extreme temperatures in mid-summer (over 104° F) may be high
enough to substantially reduce mosquito populations during the hottest months. In other words,
the mosquito season may expand, but there may be a reduction in the number of mosquitos
during the hottest months of the year in the future. However, mosquito populations may rebound
once temperatures cool in the late summer and early fall – so the reduction may be temporary.
Predicting changes in Valley fever (VF) prevalence due to climate change is harder because there
are many factors involved. We tend to see the highest incidence (cases/population) in more
populated counties. Age seems to be a risk factor as is working outdoors. VF tends to occur
when conditions are first moist, then hot, dry, and windy, which allows the fungus to grow and
then become aerosolized. It seems that the timing of these events is critical as well as the
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direction of the wind: from places where the fungus grows to places where the population is at
risk. However, because the exact location of the fungus in the soils is unknown, it is difficult to
predict if and when it might affect specific communities now or in the future (Roach et al. 2017).
Mental health
Many people exposed to climate-related disasters, such as flooding, heat, and wildfire,
experience serious mental health consequences, such as post-traumatic stress disorder,
depression, and general anxiety, which often occur simultaneously. This is especially true of
events that involve “loss of life, resources, or social support and social networks or events that
involve extensive relocation and life disruption.” Populations at particular risk of mental health
consequences include: children, the elderly, pregnant and post-partum women, people with
preexisting mental illness, the economically disadvantaged, the homeless, and first responders.
Additionally, clinical depression has been observed in patients infected with WNV. Some studies
have shown a connection between higher temperatures and suicide rates.
Food security/prices
Climate change has the potential to disrupt food availability if supply routes and processing
facilities are disrupted (Brown et al., 2015); crop yields change due to changes in temperature or
drought conditions (Hatfield et al. 2014); climatic changes shift or change the land area available
for agriculture (Takle et al. 2013); hotter nighttime temperatures increase the heat stress on
livestock (Hatfield et al., 2014; Mader, 2012); or changing moisture and temperature impact
disease distribution and proliferation among livestock (Gaughan et al., 2009).
The U.S. food system is connected to the worldwide food system. The U.S. imports about one-
fifth of its food from international markets, making our food supply susceptible to climatic
changes in other parts of the world (Hatfield et al., 2014). Southern Arizona imports the bulk of
its agricultural crops from California and Mexico. The bulk of staple crops (corn, rice, wheat,
and soy) as well as beef and dairy products are grown in the Midwest (Hatfield et al., 2014;
Takle et al., 2013).
Current research into U.S. agriculture production shows that climate change is unlikely to affect
food security until at least 2050 (Takle et al., 2013). The complexity and international reach of
the food system in the U.S. supports many intervention points to help reduce the impacts on
people and communities (Brown et al., 2015).
Ecosystem Changes
Increased minimum temperatures, combined with a decrease in freezing temperatures and a
lengthened frost-free season, will likely lead to an expansion of the boundaries of Southwestern
deserts to the north and the east, migration of plant communities to higher elevations,
susceptibility to insect infestations and pathogens, and establishment of invasive annual grasses
(Archer and Predick, 2008; Sonoran Desert Network Inventory and Monitoring Program, 2010).
As these plant communities move further upslope, species that currently live on “Sky Island”
mountain tops would have no higher habitats in which to migrate (Archer and Predick 2008;
Sonoran Desert Network Inventory and Monitoring Program 2010). Plants and animals in arid
regions already live near their physiological limits, and small changes in temperature and
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precipitation will change the distribution, composition, and abundance of species (Archer and
Predick 2008).
For example, warmer temperatures will decrease populations of velvet mesquite (Prosopis
velutina) and increase some cactus species (Munson et al., 2012). The range and abundance of
saguaros, however, will potentially decline due to drought and reduced native perennial grass
and shrub cover (Archer and Predick, 2008). Saguaros are tolerant to high, but not extreme,
temperatures. Past studies of saguaro only looked at freeze thresholds, but climate change and
global warming have prompted more research on heat thresholds. Long-term periods of drought
may affect saguaros. Drezner (2014) found that soil and higher temperatures have more influence
over saguaro mobility and mortality than does moisture. Research also found that wildfires are
the biggest threat to saguaros.
Wildfire can cause saguaro mortality up to 10 years after the fire (Narog and Wilson, 2013).
Springer et al. (2015) found that saguaro exposed to fire tried to re-establish in higher elevations,
away from the areas where fires had occurred. Fire destroys habitat required for saguaro to
reproduce and mature (Drezner, 2014). Fire also affects saguaro reproduction because they grow
slowly and are not prolific seeders. Seedlings are damaged or destroyed by fire and are out-
competed by non-native seedlings for light, moisture, and soil nutrients (Rogers, 1985).
Fire is also a threat to other cacti. Cacti have thin, exposed epidermal layers where
photosynthesis and respiratory functions take place. This exposed layer makes cacti easily
damaged, exposing the cacti to insect attack, disease infestation, and death (Thomas, 1991). Fire
also burns the spines of cacti, leaving the cacti unprotected from herbivory.
Dry desert shrubs and non-native grasses can start wildfires. Creosote bush, which offers
protection to infant saguaros, becomes extremely flammable during dry years. Invasive grasses,
including buffelgrass, are highly flammable.
Infrastructure
The intense rainfall and associated flooding and extreme heat we expect to occur due to climate
change puts our transportation infrastructure at risk (Jacobs et al., 2018). High temperatures can
stress bridge integrity, increase wear on roads, and hinder air transportation when temperatures
are too hot for safe take-off. Climate change is projected to increase the costs of maintaining,
repairing, and replacing infrastructure, with regional differences proportional to the magnitude
and severity of impacts. Nationally, the total annual damages from temperature- and
precipitation-related damages to paved roads are estimated at up to $20 billion under RCP8.5 in
2090 (in 2015 dollars) (Jacobs et al., 2018).
Roadways are one example of infrastructure impacts. With extreme temperatures, paved roads
can become rutted, cracked, and buckled (Jacobs et al., 2018). Engineering protocols in the U.S.
are based on stationary climate assumptions and are currently pegged to climate data from 1964
– 1995 (Underwood et al., 2017), meaning that roadways may not be made of materials sufficient
to withstand the climate-related stresses expected in the coming decades. In fact, Underwood et
al. (2017) found that asphalt grades are already being improperly determined in many parts of the
United States. In order to understand the impacts to any one community, it is necessary to
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identify what grade of asphalt is currently used, whether that grade can withstand expected
temperature increases, the linear miles of roadway affected, and the cost to upgrade road surfaces
using higher grade materials.
Water availability
Although water resources in the western U.S. are being affected by rising temperatures, earlier
snowmelt, more rain and less snow, and changes in storm tracks, total annual precipitation has
not changed significantly (Udall, 2013). Studies of the Colorado River indicate that for every 1°
F of warming there is a decrease in streamflow at Lees Ferry (where Colorado River flows are
measured) of 2.8-5.5 percent (Udall 2013). The same study also indicates that even if
temperatures do not change, changes in precipitation are magnified in the Colorado River system
in such a way that a one percent change in precipitation (either up or down) changes runoff by
one to two percent (Udall 2013). An additional stressor on Colorado River water is the effect of
dust on snowpack in the region, which can reduce runoff from snowpack by up to five percent
(Udall 2013).
These potential physical changes to the amount of runoff in the Colorado River system is in
addition to a pre-existing stressor: the river is over-allocated and in a structural deficit stemming
from a combination of losses from evaporation and water use (Central Arizona Project, 2014).
The water usage in the lower basin—Arizona, California, and Nevada—is 1.2 million acre feet
(AF) greater than the inflows to Lake Mead (located on the Arizona and Nevada state line) that
supply the region.
Water levels in Lake Mead have been dropping since 2000 (Central Arizona Project, 2014). To
address the deficit, in 2007 the lower basin states agreed to a set of interim guidelines intended to
run through 2026. These guidelines were designed to provide greater certainty for water users
during times of shortages in Lakes Mead and Powell by creating a series of thresholds and
related reductions to water deliveries to guide decisions about water delivery (Jerla and Prairie,
2009). The delivery reductions will take place when the water level in Lake Mead reaches three
different thresholds: 1,075 feet above mean sea level (amsl), 1,050 amsl, and 1,025 amsl. One
thousand feet amsl is considered the critical level for Lake Mead when both water and energy
availability are at risk. If Lake Mead falls to the critical 1,000 feet amsl level, the Secretary of
the Interior will consult with the basin states to discuss further measures. Each threshold will
trigger a tier reduction.
•A Tier 1 reduction requires Arizona to reduce CAP water deliveries by 320,000 AF per
year. At this level, the CAP will make cuts to the excess storage deliveries and to the
agriculture pool.
•A Tier 2 reduction requires 400,000 AF of reductions each year to the excess and
agricultural pools.
•A Tier 3 reduction will require 480,000 AF of reductions in Arizona but will not impact
Municipal and Industrial or Indian Priority deliveries.
The first shortage declaration, at the Tier 1 level, is expected in 2020. In response, the Colorado
River basin states have prepared drought contingency plans (DCP) intended to prevent the kinds
of cuts required by a Tier 2 shortage (Lake Mead reaching 1050 feet amsl). Arizona’s portion of
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the DCP relies on voluntary cuts to CAP water use by farmers, who will receive financial
support to help them switch to groundwater for irrigation; payments to the Gila River Indian
Community and Colorado River Indian Tribes in return for them leaving water in Lake Mead;
and some loosening of Arizona’s groundwater management rules. The DCP was approved in
April 2019.
The City of Tucson Water Department has a Drought Preparedness and Response Plan, that was
last updated in 2017. The Tucson Water service area is currently in a Stage 1 drought
declaration, and will likely move to Stage 2 if the Bureau of Reclamation declares a Tier 1
reduction of CAP water (City of Tucson Water Department, 2006). Table 2 outlines the response
actions that will be asked or required of reclaimed water users for each drought stage.
Table 2: Response actions that reclaimed water users will be asked or required to do to reduce water demand during drought
response Stages 1 through 4 (City of Tucson Water Department, 2006).
Stage 1
• Continue customer education on efficient-water-use especially related to
drought conditions
• Voluntary self-audits and developing water budgets to potentially gain
exemptions from mandatory reductions in advanced drought response stages
• Tucson Water staff prepares a methodology to monitor wastewater treatment
plant flows and calculate reclaimed water customer reductions for later
drought stages if approved water budgets are not implemented
Stage 2
• Continue Stage 1 measures
• Prepare customers for potential reductions if wastewater flow reductions occur
and if an approved water budget is not implemented
• Potable water will not provide backup supplies to the reclaimed water
distribution system
Stage 3
• Implement all Stage 1 and 2 measures and may include:
• Require irrigation restrictions, with potential exemptions for sites that
have conducted audits, upgraded systems to meet minimum efficiency
standards, and irrigate with budget-based irrigation schedules
• Require signage for facilities that implement budgets stating they are in
compliance with current drought restrictions
• Potable water will not provide backup supplies to the reclaimed water
distribution system
Stage 4
• Continue Stage 1, 2, and 3 measures
Wildfire
Wildfire can pose a direct threat to people and structures as well as cause negative health impacts
due to poor air quality. Climate change has driven an increase in the area burned by wildfire in
the western U.S. by increasing temperatures and drying forests, shrublands, and grasslands,
making them more susceptible to burning. Climate models indicate that future fire frequency
could increase 25% in the Southwest, and the frequency of very large fires (over 12,000 acres)
could triple (Gonzalez et al., 2018).
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Dove Mountain is one of the moderate-risk communities in the wildland-urban interface,
according to the Pima County Community Wildfire Protection Plan. The wildfire threat to Dove
Mountain comes from the desert wash/xeroriparian corridor and creosote bush-bursage desert
scrub types, with paloverde-mixed cacti desert scrub and mesquite upland associations found at
foothills of the Tortolita mountains. An additional threat comes from buffelgrass (Cenchrus
ciliaris), an invasive species that outcompetes native desert plants for space. Buffelgrass is
highly flammable, and creates a continuous layer of grass that can fuel fast-moving wildfire.
Post-fire flooding
Following severe wildland fires, high-intensity summer thunderstorms can trigger extensive
erosion and debris flows. Intense precipitation, even years after a severe fire, can also generate
debris flows and other geomorphic changes; this occurred in the Sabino Canyon Recreation Area
in Tucson, during a high-intensity precipitation episode in 2006, three years after the 84,750-acre
Aspen fire in the Santa Catalina Mountains (Griffiths et al., 2009; Magirl et al., 2007). The event
damaged structures and roads and affected infrastructure within Tucson’s urban boundary. With
the risk of fire along the foothills of the Tortolita mountains, post-fire flooding and debris flows
into Dove Mountain is a possibility in the future.
Energy
Increased use of air conditioning (AC) from both higher temperatures and improved access to
technology, will increase energy consumption. Due to the need for additional cooling, by 2080–
2099, electric consumer energy will cost an estimated $164 million more per year in the state of
Arizona, compared to 2008–2012; on a household basis, this equates to about $100 per
household per year (Huang and Gurney, 2017). However, as temperatures warm in the
wintertime, the need for energy for heating homes will likely decrease. Whether this will cancel
out the increased energy use in the summer months is hard to determine (Cayan et al., 2013).
Furthermore, several studies (for example, de Munck et al., 2013; Ohashi et al., 2007) have
shown that AC use in cities enhances the urban heat island effect (UHI), due to the release of
waste heat from the systems themselves. The effect is more profound at night when heat emitted
from AC systems can increase surface temperatures by up to 1.8° F (1° C) in the Phoenix Metro
area (Salamanca et al., 2014). This creates a feedback loop, as higher nighttime temperatures
increase AC use, heating the air even further. This is likely not an issue for The Highlands at
Dove Mountain, as the community is located outside of the Tucson UHI, but it is an issue in
other parts of the county.
The increased use of AC can also stress the electrical grid, increasing the risk for brownouts. In
the Southwest U.S., “delivery of electricity may become more vulnerable to disruption due to
climate-induced extreme heat and drought events as a result of: increased demand for home and
commercial cooling; reduced thermal power plant efficiencies due to high temperatures; reduced
transmission line, substation, and transformer capacities due to elevated temperatures; potential
loss of hydropower production; threatened thermoelectric generation due to limited water supply;
and the threat of wildfire to transmission infrastructure” (Tidwell et al., 2013). Additionally, if
the energy comes from the burning of fossil fuels, then it will release more greenhouse gases,
increasing temperatures further, which will in turn increase demand for cooling (AC), and so on.
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Real Estate/Demographics
There is growing evidence that climate change will affect human migration patterns as some
regions become less livable and people move to more viable regions (McLeman and Smit, 2006).
As in other areas of the world, climate change in Arizona will not be the sole factor influencing
migration decisions, but in combination with other stressors such as social, cultural, and
economic changes it can influence population movements and decision-making about migration.
There does not seem to be research available on how climate change might affect intra-state
migration in Arizona (or evidence of this happening already), according to researchers at
University of Arizona’s College of Architecture, Planning, and Landscape Architecture.
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Climate Change Adaptation Planning
Climate change adaptation planning is the process of planning to adjust to new or changing
environments in ways that take advantage of beneficial opportunities and lessen negative effects
(Melillo et al., 2014).
The process of climate change adaptation planning can be similar to other resource management
planning processes and generally includes the following steps:
• Identifying risks and vulnerabilities
• Assessing and selecting options
• Implementing strategies
• Monitoring and evaluating the outcomes of each strategy
• Revising strategies and the plan as a whole in response to evaluation outcomes
Figure 14: The Adaptation Process. Source http://nca2014.globalchange.gov/report/response-strategies/adaptation
Key questions to ask community members, resource managers, decision makers, and elected
officials when considering climate adaptation are:
• What are the community’s goals and objectives in the future?
• What resources or assets need to be protected from climate change impacts?
• How will the resources be protected?
• What actions are necessary to achieve the community’s goals?
Adaptation strategies can range from short-term coping actions to longer-term, deeper
transformations. They can meet more than just climate change goals alone and should be
sensitive to the community or region; there are no one-size-fits-all answers (Moser and
Eckstrom, 2010).
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The process of planning for climate change adaptation has already begun in many places. The
federal government has required each federal agency to develop an adaptation policy (Executive
Office of the President, 2013). Fifteen states and 176 cities have climate change adaptation plans.
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Adaptation Strategies
In this section, we present a number of suggestions for possible adaptation strategies for The
Highlands at Dove Mountain. As discussed above, decisions about which strategies will be most
beneficial to and effective for any community should be made by the community. We present
these strategies as options The Highlands can consider as part of its community planning
processes.
Climate change adaptation strategies can be integrated into existing community plans, such as
landscape or infrastructure management plans or can be stand-alone plans. In either case,
revisiting the best-available data and evaluating the effectiveness of strategies on a regular basis
is necessary to ensure the overall effectiveness of the plans. There are no specific guidelines for
updating adaptation plans, but a good frame of reference is that FEMA requires counties and
states to update their hazard mitigation plans every five years to ensure that data on hazards and
vulnerabilities are kept up-to-date.
Golf Course Sustainability
The Highlands at Dove Mountain is already working to minimize use of water on its golf course,
while also maintaining a high-quality golf course. The course managers use many of the best
practices in sustainable golf course maintenance, such as:
• Ensuring the golf course drip irrigation system is modern and functioning properly to reduce
leaks and save energy usage.
• Watering different zones of the golf courses separately and as needed, utilizing soil moisture
monitoring instead of blanket timers for the entire courses.
• Keeping turf areas to a minimum.
• Evaluating the salt content of the reclaimed water used on the course to minimize damage to
the turf.
• Evaluating the potential to use native or drought-resistant turf varieties where possible.
Some additional areas to consider:
• Regularly post information about water use and costs in the clubhouse to keep residents up-
to-date about the links between water use, current water conservation efforts, and budget
information.
• Promote the course as a premier desert landscaped course, as noted by Golf Arizona -
http://www.golfarizona.com/courses/tucson/heritage-highlands.htm
• Replace any existing lakes with bunkers and native desert to reduce water use. Another
option is to reduce the size of the lakes and turn them into more natural water features.
• Utilize compost from clubhouse and reuse grass trimmings for golf course turf.
• Capture rainfall and store it for later use (stormwater harvesting). This can be difficult to
retrofit an existing course, but may be worth the long-term cost of buying less water. Here
are two examples of courses doing this:
o https://www.usga.org/articles/2016/10/alternative-water-supplies-a-win-for-golf-
courses.html
o http://www.g-a-l.info/golf-study.htm
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Several golf courses in Arizona have utilized these strategies to increase their sustainability:
• Overview of current trends in golf course sustainability:
https://urbanland.uli.org/sustainability/lack-water-hazard/
• Paradise Valley Country Club, Paradise, AZ:
http://www.usga.org/articles/2015/07/sustainability-case-study--paradise-valley.html
• Ambient Golf Course, Scottsdale, AZ: http://www.usga.org/content/usga/home-page/course-
care/water-resource-center/bmp-case-studies/2017/native-grasses-yield-water-savings.html
Emergency Preparedness
Fire Protection
The Firewise USA program teaches communities how to adapt to living with wildfire and
encourages neighbors to work together and take action now to prevent losses. The Highlands is
in the process of completing its application to become a Firewise community.
The Pima County Community Wildfire Protection Plan outlines fuel modification and treatment
plans for different types of lands, but the overarching treatment is fuel reduction, including
removing dead or dying debris, trimming down ladder fuels and fuels near power lines, and
removing invasive species. It is recommended that larger modification projects be contracted
through the fire department. Other recommendations, besides fuel modification, are listed on
pages 107-111 of the plan, and include recommendations such as: meeting with representatives
from TEP to identify locations of needed vegetative treatments, replacing and maintaining
fencing adjacent to high-use and illegal off-road-vehicle use areas, acquiring a green-waste
disposal site within a reasonable proximity to citizens and encourage its use for vegetative
material removal on private lands.
Buffelgrass Reduction
A Pima County Ordinance requires the removal of buffelgrass. According to Tucson Clean and
Beautiful, there are two ways to effectively kill buffelgrass: manually remove it or treat it with
an herbicide – and monitor the area for at least 2-3 years to remove any regrowth.
• Manual Removal: Digging up buffelgrass clumps is a highly effective (though time
consuming) way of killing buffelgrass. On larger clumps this is best done as a team, with one
person digging around the roots and the other pulling the top of the grass (and perhaps a third
person to bag or dispose of the grass!).
• After removal, buffelgrass should be placed in a plastic garbage bag and disposed of in the
landfill. The bagging process is necessary to limit seed dispersal and to reduce potential fire
hazard in urban areas.
• Herbicide control: When done correctly, using an herbicide with glyphosate as the active
ingredient in accordance with label directions is an effective way to kill buffelgrass plants.
However, the buffelgrass must be at least 50% green and actively growing for the herbicide
to work effectively (spraying herbicide on dry grass or on barren ground is ineffective). Care
must be taken to avoid spraying native or other desirable plants. There are drawbacks to this
29
method: the chemicals are expensive and the dead clump of buffelgrass will still present a
fire hazard. Other chemicals may be available, but are typically more toxic and require
further special handling. While homeowners can apply herbicide at their own home, applying
herbicide on public lands requires trained/certified herbicide applicators and permission from
the public land manager.
• Mowing: NOT RECOMMENDED – Use of weed-eaters and mowers is discouraged where
buffelgrass is present, due to the risk of spreading seeds and ineffectiveness at actually
addressing the roots of the plant. Mowing will only be effective at reducing the volume of
material, and is only recommended if it will be followed by future manual removal or
herbicide application as regrowth occurs.
• Other considered methods of removal (including by burning, animal grazing, salting, or with
vinegar solutions) have not proven to be effective for controlling buffelgrass regrowth. Only
methods that will remove the entire plant, or kill the green plant to its roots, combined with
follow-up monitoring and light removal, have proven to be effective.
• All mitigation methods: Ongoing monitoring required! Regardless of the removal
methodology used, buffelgrass plants will typically re-sprout from seed in the area where
they were previously removed. For treatment to be effective, ongoing monitoring and
additional small-scale removal will continue to be needed over a 2 to 5-year period, or
longer, depending on site conditions and nearby seed sources.
Flood Insurance
The National Flood Insurance Program allows property owners in participating communities to
buy insurance to protect against flood losses. Participating communities are required to establish
management regulations in order to reduce future flood damages. This insurance is intended to
furnish as an insurance alternative to disaster assistance and reduces the rising costs of repairing
damage to buildings and their contents caused by flood.
Homeowners can determine whether their property lies in a flood-prone area by searching using
an online tool developed by the Federal Emergency Management Agency.
https://msc.fema.gov/portal/home.
A challenge of the NFIP is that FEMA relies on historical flood data to determine 100-year flood
plains. Although recommendations have been made to the agency to begin to incorporate climate
change projections, they have not yet started the process.
Additionally, most flood infrastructure is built with the 100-year historic flood as a reference. As
storms are expected to become more intense, communities may consider reanalyzing existing
drainage systems and washes to ensure that they can handle higher flooding.
Landscaping
Landscaping is an important part of the aesthetics of The Highlands. The community Common
Areas Committee ensures that common areas are landscaped using low-water, desert-adapted
vegetation and works exclusively with landscaping companies who are committed to maintaining
these standards.
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The Architecture and Landscaping Committee (ALC) ensures that private resident landscaping
adheres to community standards. There are some opportunities through the ALC to encourage
residents to move toward landscaping that embraces their Sonoran Desert surroundings.
• The ALC could include landscaping information in the welcome packet for new residents
and make an introduction to desert landscaping part of the new resident orientation.
• The ALC could revise their approved plant list to include more desert-adapted species
and design the list to highlight “strongly recommended” species that are low-water and
desert-adapted. Resources for revising the plant list include:
o Pima County Plant List;
http://webcms.pima.gov/cms/One.aspx?portalId=169&pageId=52688
o Arizona Municipal Water Users Association; https://www.amwua.org/plants/
o Arizona-Sonora Desert Museum; https://www.desertmuseum.org/plantcare/
o Tohono Chul; https://tohonochul.org/gardens-2/gardens/
• An annual xeriscape yard competition or showcase could incentivize the practice for
residents.
• The ALC could host additional workshops or talks about desert landscaping. Some
resources for speakers include:
o UA Campus Arboretum; https://desertlandscaping.arizona.edu/
o Watershed Management Group; https://watershedmg.org/
o Pima County Master Gardeners; https://extension.arizona.edu/pima-master-
gardeners
• Additional local resources for residents interested in learning more about desert
landscaping:
o Tucson Botanical Gardens; https://tucsonbotanical.org/community-resources/
o Arizona Native Plant Society; http://www.aznps.com/nativegardening.php
Energy
Reducing household energy use is one way to both mitigate the causes of climate change (by
reducing GHG emissions) and reduce household costs for energy.
• Consider installation of solar panels on HOA managed buildings or parking lots for both
renewable energy and increasing available shade.
• Revisit the community’s covenants, conditions, and restrictions (CC&Rs) and ensure they are
in compliance with Arizona State Statute Article 3 chapter 4 section 33-439 which voids
CC&Rs restricting installation of solar energy devices
(https://www.azleg.gov/ars/33/00439.htm).
• Retrofit homes/buildings for energy efficiency
• A low-cost option is for individual homeowners to strategically plant shade trees to provide
additional cooling for their homes and reduce their energy use and costs. Tucson Electric
Power provides the following guidelines for their subsidized tree planting program:
o Trees must be planted within 15 feet of the structure’s west, east or south sides to
provide shade during the summer months.
o Trees also must be planted at least 10 feet from sewer lines, 5 feet from water lines
and 3 feet from all other utility lines. Do not plant trees under any overhead utility
31
lines and maintain a safe distance from chimneys, power lines and other potential
sources of combustion. Do not plant in a public right-of-way without a permit.
Social Resilience
The Building Resilient Neighborhoods (BRN) Work Group prepares Southern Arizona
neighborhoods for extreme heat and other weather-related emergencies via community cohesion.
BRN provides workshop education, materials, and best practices through community-led action
and preparation. BRN is part of the Physicians for Social Responsibility-Arizona (PSR-AZ)
Chapter based in Tucson. https://www.buildingresilientneighborhoods.org/
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References Cited
Archer, S.R., Predick, K.I. (2008) Climate Change and Ecosystems of the Southwestern United
States. Rangelands 30, 23-28.
Brown, H.E., Comrie, A.C., Drechsler, D.M., (2013) Human Health, in: Garfin, G., Jardine, A.,
Merideth, R., Black, M., LeRoy, S. (Eds.), Assessment of Climate Change in the Southwest
United States: A Report Prepared for the National Climate Assessment. Island Press, Washington
D.C., pp. 312-330.
Brown, M.E., Antle, J.M., Backlund, P., Carr, E.R., Easterling, W.E., Walsh, M.K., Ammann,
C., Attavanich, W., Barrett, C.B., Bellemare, M.F., Dancheck, V., Funk, C., Grace, K., Ingram,
J.S.I., Jiang, H., Maletta, H., Mata, T., Murray, A., Ngugi, M., Ojima, D., O’Neill, B., Tebaldi,
C., (2015) Climate Change, Global Food Security, and the U.S. Food System. US Department of
Agriculture.
Castro, C.L., (2017) Assessing Climate Change Impacts for Department of Defense Installations
in the Southwest United States During the Warm Season.
Cayan, D.R., Tyree, M., Kunkel, K., Castro, C., Gershunov, A., Barsugli, J., Ray, A.J.,
Overpeck, J., Anderson, M., Russell, J., Rajagopalan, B., Rangwala, I., Duffy, P., (2013) Future
Climate: Projected Average, in: Garfin, G., Jardine, A., Merideth, R., Black, M., LeRoy, S.
(Eds.), Assessment of Climate Change in the Southwest United States: A Report Prepared for the
National Climate Assessment. Island Press, Washington D.C., pp. 101-120.
Central Arizona Project, (2014) State of the Colorado River.
City of Tucson Water Department, (2006) City of Tucson Water Department Drought
Preparedness and Response Plan. 2012 Update. City of Tucson, Tucson.
Crimmins, A., Balbus, J., Gamble, J.L., Beard, C.B., Bell, J.E., Dodgen, D., Eisen, R.J., Fann,
N., Hawkins, M.D., Herring, S.C., Jantarasami, L., Mills, D.M., Saha, S., Sarofim, M.C., Trtanj,
J., Ziska, L. (2016) The Impacts of Climate Change on Human Health in the United States: A
Scientific Assessment. U.S. Global Change Research Program, Washington, DC.
de Munck, C., Pigeon, G., Masson, V., Meunier, F., Bousquet, P., Tréméac, B., Merchat, M.,
Poeuf, P., Marchadier, C. (2013) How much can air conditioning increase air temperatures for a
city like Paris, France? International Journal of Climatology 33, 210-227.
Drezner, T.D. (2014) How long does the giant saguaro live? Life, death and reproduction in the
desert. Journal of Arid Environments 104, 34-37.
Environmental Protection Agency, (2013) Particulate Matter.
Executive Office of the President, (2013) The President's Climate Action Plan, Executive Order
13514.
33
Gaughan, J., Lacetera, N., Valtorta, S., Khalifa, J., Hahn, L., Mader, T., (2009) Chapter 7:
Response of domestic animals to climate challenges, in: Ebi, K.L., Burton, I., McGregor, G.
(Eds.), Biometeorology for Adaptation to Climate Variability and Change. Springer,
Netherlands, pp. 131-170.
Gershunov, A., Rajagopalan, B., Overpeck, J., Guirguis, K., Cayan, D.R., Hughes, M., Dettinger,
M.D., Castro, C., Schwartz, R.E., Anderson, M., Ray, A.J., Barsugli, J., Cavazos, T., Alexander,
M., (2013) Future Climate: Projected Extremes, in: Garfin, G., Jardine, A., Merideth, R., Black,
M., LeRoy, S. (Eds.), Assessment of Climate Change in the Southwest United States: A Report
Prepared for the National Climate Assessment. Island Press, Washington D.C.
Gonzalez, P., Garfin, G.M., Breshears, D.D., Brooks, K.M., Brown, H.E., Elias, E.H.,
Gunasekara, A., Huntly, N., Maldonado, J.K., Mantua, N.J., Margolis, H.G., McAfee, S.,
Middleton, B.R., Udall, B.H., (2018) Southwest, in: Reidmiller, D.R., Avery, C.W., Easterling,
D.R., Kunkel, K.E., Lewis, K.L.M., Maycock, T.K., Stewart, B.C. (Eds.), Impacts, Risks, and
Adaptation in the United States: Fourth National Climate Assessment, Volume II. U.S. Global
Change Research Program, Washington D.C., pp. 1101 - 1184.
Griffiths, P.G., Magirl, C.S., Webb, R.H., Pytlak, E., Troch, P.A., Lyon, S.W. (2009) Spatial
distribution and frequency of precipitation during an extreme event: July 2006 mesoscale
convective complexes and floods in southeastern Arizona. Water Resources Research 45.
Guhathakurta, S., Gober, P. (2007) The Impact of the Phoenix Urban Heat Island on Residential
Water Use. Journal of the American Planning Association 73.
Hatfield, J., Takle, G., Grotjahn, R., Holden, P., Izaurralde, R., Mader, T., Marshall, E.,
Liverman, D., (2014) Ch. 6: Agriculture, in: Melillo, J., Richmond, T.C., Yohe, G.W. (Eds.),
Climate Change Impacts in the United States: The Third National Climate Assessment. U.S.
Global Change Research Program, pp. 150-174.
Huang, J., Gurney, K.R. (2017) Impact of climate change on U.S. building energy demand:
Financial implications for consumers and energy suppliers. Energy and Buildings 139, 747-754.
Jacobs, J.M., Culp, M., L. Cattaneo, Chinowsky, P., Choate, A., DesRoches, S., Douglass, S.,
Miller, R., (2018) Transportation, in: Reidmiller, D.R., Avery, C.W., Easterling, D.R., Kunkel,
K.E., Lewis, K.L.M., Maycock, T.K., Stewart, B.C. (Eds.), Impacts, Risks, and Adaptation in the
United States: Fourth National Climate Assessment, Volume II. U.S. Global Change Research
Program,, Washington D.C., pp. 479-511.
Jerla, C., Prairie, J., (2009) Colorado River Interim Guidelines for Lower Basin Shortages and
the Coordinated Operations for Lake Powell and Lake Mead & Efforts Addressing Climate
Change and Variability. , Intermountain West Climate Summary, pp. 5-7.
Lahmers, T.M., Castro, C.L., Adams, D.K., Serra, Y.L., Brost, J.J., Luong, T. (2016) Long-Term
Changes in the Climatology of Transient Inverted Troughs over the North American Monsoon
Region and Their Effects on Precipitation. Journal of Climate 29, 6037-6064.
34
Luong, T., Castro, C., Chang, H., Lahmers , T., Adams, D., Ochoa-Moya, C. (2017) The More
Extreme Nature of North American Monsoon Precipitation in the Southwestern United States as
Revealed by a Historical Climatology of Simulated Severe Weather Events. Journal of Applied
Meteorology and Climatology 56, 2509 - 2529.
Mader, T. (2012) Impact of environmental stress on feedlot cattle. American Society of Animal
Science Western Section 62, 335-339.
Magirl, C.S., Webb, R.H., Griffiths, P.G., Schaffner, M., Shoemaker, C., Pytlak, E.,
Yatheendradas, S., Lyon, S.W., Troch, P.A., Desilets, S.L. (2007) Impact of recent extreme
Arizona storms. Eos, Transactions American Geophysical Union 88, 191-193.
McLeman, R., Smit, B. (2006) Migration as an Adaptation to Climate Change. Climatic Change
76, 31-53.
Melillo, J., Richmond, T.C., Yohe, G.W., (2014) Climate change consequences in the United
States: The third national climate assessment. U.S. Global Change Research Program, p. 841.
Moser, S., Eckstrom, J.A. (2010) A framework to diagnose barriers to climate change adaptation.
PNAS 107, 22026-22031.
Munson, S.M., Webb, R.H., Belnap, J., Andrew Hubbard, J., Swann, D.E., Rutman, S. (2012)
Forecasting climate change impacts to plant community composition in the Sonoran Desert
region. Global Change Biology 18, 1083-1095.
Narog, M.G., Wilson, R.C., (2013) Burned Saguaro: Will They Live or Die?, USDA Forest
Service Proceedings.
Ohashi, Y., Genchi, Y., Kondo, H., Kikegawa, Y., Yoshikado, H., Hirano, Y. (2007) Influence of
Air-Conditioning Waste Heat on Air Temperature in Tokyo during Summer: Numerical
Experiments Using an Urban Canopy Model Coupled with a Building Energy Model. Journal of
Applied Meteorology & Climatology 46, 66-81.
Roach, M., Brown, H.E., Clark, R., Hondula, D., Lega, J., Rabby, Q., Schweers, N., Tabor, J.,
(2017) Projections of Climate Impacts on Vector-Borne Diseases and Valley Fever in Arizona. A
report prepared for the Arizona Department of Health Services and the United States Centers for
Disease Control and Prevention Climate-Ready States and Cities Initiative.
Rogers, G.F. (1985) Mortality of Burned Cereus Giganteus. Ecology 66, 630-632.
Salamanca, F., Georgescu, M., Mahalov, A., Moustaoui, M., Wang, M. (2014) Anthropogenic
heating of the urban environment due to air conditioning. Journal of Geophysical Research:
Atmospheres 119, 5949-5965.
Sonoran Desert Network Inventory and Monitoring Program, (2010) Climate Change in the
Sonoran Desert.
35
Springer, A.C., Swann, D.E., Crimmins, M.A. (2015) Climate change impacts on high elevation
saguaro range expansion. Journal of Arid Environments 116, 57-62.
Takle, E., Gustafson, D., Beachy, R., Nelson, G., Mason-D’Croz, D., Palazzo, A., (2013) U.S.
Food Security and Climate Change: Agricultural Futures, Economics Discussion Papers. Kiel
Institute for the World Economy.
Thomas, P.A. (1991) Response of Succulents to Fire: A review. International Journal of
Wildland Fire 1, 11-22.
Tidwell, V.C., Dale, L., Averyt, K., Wei, M., Kammen, D.M., Nelson, J.H., (2013) Energy:
Supply, Demand, and Impacts, in: Garfin, G., Jardine, A., Merideth, R., Black, M., LeRoy, S.
(Eds.), Assessment of Climate Change in the Southwest: A Report Prepared for the National
Climate Assessment. Island Press, Washington D.C., pp. 240-266.
Tong, D.Q., Wang, J.X.L., Gill, T.E., Lei, H., Wang, B. (2017) Intensified dust storm activity
and Valley fever infection in the southwestern United States. Geophysical Research Letters, n/a-
n/a.
Udall, B., (2013) Water: Impacts, Risks, and Adaptation, in: Garfin, G., Jardine, A., Merideth,
R., Black, M., LeRoy, S. (Eds.), Assessment of Climate Change in the Southwest United States:
A Report Prepared for the National Climate Assessment. Island Press, Washington D.C., pp.
197-217.
Underwood, B.S., Guido, Z., Gudipudi, P., Feinberg, Y. (2017) Increased costs to US pavement
infrastructure from future temperature rise. Nature Climate Change 7, 704.
Wuebbles, D.J., Fahey, D.W., Hibbard, K.A., DeAngelo, B., Doherty, S., Hayhoe, K., Horton,
R., Kossin, J.P., Taylor, P.C., Waple, A.M., Weaver, C.P., (2017) Executive summary, in:
Wuebbles, D.J., Fahey, D.W., Hibbard, K.A., Dokken, D.J., Stewart, B.C., Maycock, T.K.
(Eds.), Climate Science Special Report: Fourth National Climate Assessment, Volume I
Washington, DC, pp. 12 - 34.