April 2023
Window on Our Future
CLIMAS Report Projects Local Consequences of Climate Change

Have you ever wondered about what climate change will mean for central Arizona? Sure, there are projections of the polar ice sheets and glaciers melting, and the images of polar bears without ice and sea-level rise in coastal cities are disturbing. But what is a changing climate likely to mean for our region?

All over the world, governments are using projections from climate models to understand the risks that climate change poses; at least 35 of the 50 largest US cities have prepared detailed “climate-profile” reports. Now the Quad Cities have done one as well.

Early in 2021 a group of local citizens initiated a campaign to commission a study to help us to understand and prepare for the likely climate-change challenges for our own region. Last spring the Prescott City Council followed through by accepting a gracious offer from Climate Assessment for the Southwest, an organization based at the University of Arizona, to prepare the report at no cost. Using climate projections from the most recent report by the International Panel on Climate Change and the US National Climate Assessment, the CLIMAS report (now available at yavapaiclimatecoalition.org/climate-actionhub) reviews climate projections and their likely consequences with the Prescott Active Management Area as its geographic focus.

The report briefly reviews the basics of the world’s climate system and the historical climate record for our region, follows with projections for our area, and then provides an overview of some of the likely impacts for human health, water resources, and natural and agricultural ecosystems. Finally it outlines some concepts of climate adaptation planning that have proven useful in other places, and provides some strategies tailored to our area.

The report is richly documented with supporting references and resources, many in the form of active hyperlinks, and highly accessible to the non-specialist.

One of the key findings is the projection that our average annual temperature will increase 4-5°F by 2050 relative to the 1961-1990 reference period, and by up to 11° by the end of the century. That would put the Prescott area just 3°F below the current annual average for Tucson. Even if we globally succeed in limiting emissions to peak at about 50% higher than 2000 levels by mid-century, projected average temperatures will be about 6°F above the 1961-1990 average by 2100.

The average number of days above 95°F in our area was about eight per year for the reference period, but recently it has averaged about 20. And if we continue carbon emissions on their current trajectory, the projections are for about 95 of those days per year by the end of the century. The risk of heat stress for people, livestock and pets is an obvious concern under these projections, but when combined with the projections for precipitation, they’re of great concern for our local ecosystems as well.

Though we don’t usually worry much about winter temperatures, the projected changes for our area are even more profound:  from 133 days per year reaching 32°F or lower between 1961 and 1990, to about 120 days recently, to as few as 55 days by 2100. Fewer days with freezing temperatures might seem like a good thing, but given that the timing of emergence and breeding for many, many plants and animals are in part regulated by temperature, these changes are likely to cause timing mismatches between plants and their pollinators, between birds and their insect prey, etc.

Total precipitation for our area is not projected to change markedly, though it’s likely to be concentrated in fewer, heavier storms. But combined with higher temperatures, even the same total precipitation will result in greater evaporation and transpiration by plants, making soils drier and water stress even greater for both plants and animals. We can expect forest cover to decrease over time, especially near the boundaries between Ponderosa pine forest and piñon pine-juniper communities, as well as between piñon pine-juniper and inland chaparral communities. Moreover, greater evaporation and transpiration will likely decrease the rate of aquifer recharge, with more direct consequences for the region.

It will come as no surprise that hotter, drier conditions will result in more frequent, more intense wildfires, reduced agricultural productivity, and a host of other effects that will be exacerbated by an increasing human population dependent on ever more limited water supplies. Concern about the impacts of climate change on human populations and the natural systems on which they depend has prompted communities the world over to prepare climate-profile studies, and the one now available for our region is as informative as it is alarming.

Combined with its recommendations for policies that can make us more resilient, it also inspires us to innovate now with confidence in our shared future.

What Can We Do About It?

Climate Steps We Can Take Locally

The climate adaptation/mitigation options report, released in February, accompanies the Quad Cities Climate Profile to help members of the community translate the CLIMAS report’s findings and suggestions into action at the local level. You can access this report and periodic updates on the Quad Cities Climate Action Hub (yavapaiclimatecoalition.org/climate-action-hub).

As the CLIMAS report makes clear, climate change is already presenting important challenges for our region. Our economy, public health, and infrastructure are interdependent with one another and the natural systems of our environment. The suggestions below are offered within a framework of sustainability, i.e., solutions that simultaneously maintain environmental integrity and economic vitality.

Water resources

All aspects of life depend on water, and in our region, with declining aquifers, water is an increasingly limited resource. Our water supply is squeezed between growth and drought.

One unique action response is termed “green infrastructure,” referring to various options to proactively improve our stormwater management system. By doing so, com munitiescan become more resilient and achieve environmental, social and economic benefits.

The report also recommends incorporating principles of ‘water-neutral development’ practices, encouraging the use of water-efficient codes and individual water-efficient practices, while developing a regional water-conservation plan.

Wildfire protection, healthy forests and grasslands

Our region is prone to wildfire, and the report projects that its frequency and intensity of wildfire will increase as a result of climate change. Wildfire threatens public safety, the regional economy, and property values across the region.

Continuing to increase the capacity of current Yavapai Firewise programs is a proven strategy. Simultaneously, we should apply the Fire Adapted Communities framework to incorporate a community-wide approach to wildfire resilience, as recommended by the Prescott Fire Department.

We should manage our forests proactively for expected ecosystem transitions, including potential threats to regional juniper forests, which are significant to our ecotourism industry. More research should focus on incorporating wildfire evacuation routes into regional transportation planning, as well as on vulnerable populations that are disproportionately affected by increased wildfire risk and higher temperatures.


Climate change aggravates the propensity for more extreme flooding events, including post-fire floods. These effects not only create hazardous conditions for homes, roads and other infrastructure, but also result in damaged ecosystems. Again, ‘green infrastructure’ options should be assessed across the county; updates to local hazard-mitigation plans should include the climate profile as a reference guide; and our attention must focus on flood-prone areas to enhance groundwater infiltration, reduce evaporation and accelerate aquifer recharge.

Energy use

Wider use of renewable energy will reduce our contribution to climate change while providing resiliency and cost savings.

Applying energy-efficient design features in new residential and commercial developments is vital. Code changes will be needed. Municipal energy audits are a good tool for assessing how our local communities can reduce energy usage with no reduction in the quality of service. Prescott Valley is currently considering various audit recommendations.

In March of 2023 community partners launched the Quad Cities Solar Co-op initiative. Led by Solar United Neighbors, with a proven track record across Arizona, homeowners and others can receive unbiased support, save money, and begin the transition to renewable energy!

Yet another proven strategy is the transition to electric vehicles by individuals, school districts and local municipalities. It’s important to reduce our emissions, thereby enhancing air quality. Electric vehicles are less expensive to operate, require less maintenance, and are fun to drive! Increased public access to charging stations will be a good start.

Agriculture and land use

Farming and ranching are important to the character and heritage of our communities and the livelihoods of residents. Conversion of all rangelands to residential and commercial developments will only exacerbate the region’s water shortage. The innovative preservation of ranch lands, which use less water and require less infrastructure than residential developments, can keep ranching viable.

Ranch land can significantly contribute to the conservation of high-quality, natural open space to preserve ecosystem health and resilience. Several local towns, along with county and state governments, are already pursuing ambitious park projects to achieve this regional goal.

Community and organizational capacity-building

As the Climate Profile indicates, successful climate adaptation requires a strategic focus on collaborative implementation.

The Working Group (described in the Preface) can be leveraged as a community-based resource for evaluating and implementing proposed climate-adaptation strategies in the region. Increasing citizen engagement and civic resources through the establishment of local or regional bodies, such as a commission, advisory council or multi-stakeholder group, will enhance the region’s strategic goal of climate resiliency while also focusing on community-wide sustainability.

The Local Climate Action report is a springboard for meaningful conversation and action on climate solutions in our region.

Patrick Grady is Chair of the Yavapai Climate Change Coalition.

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