For Arizona, climate change is water change

One of the clearest signals of climate change in Arizona is water change. The state is already experiencing more frequent and intense droughts, a shrinking snowpack, and groundwater depletion, alongside persistently high agricultural demand and growing urban demand. 

All this and more is outlined in the fifth and most recent National Climate Assessment, which paints a both concerning and hopeful picture for Arizona's water resources. Dave White, lead for the Arizona Water Innovation Initiative, a $40 million, multi-year partnership with the state of Arizona led by Arizona State University’s Julie Ann Wrigley Global Futures Laboratory in collaboration with the Ira A. Fulton Schools of Engineering, was the lead author for the Southwest Chapter of the national report.

White says that increasing temperatures are leading to a cascade of water impacts across the state. “Overall, we’re diminishing the supply and increasing the demand for water. Increases in both average annual temperatures and extreme temperatures are affecting water resources in Arizona. We are seeing that global warming, which is driven by heat trapping gasses that are causing the earth to warm, is in turn leading our region to warm. These higher temperatures drive greater water demand and lower water availability.”

The areas most at risk

While climate change is affecting the entire state, the impacts are felt differently depending on where and who you are. 

For example, says White, “the diversity of our state in terms of geography, which varies from the deserts of southern and central Arizona to the high mountains of the Colorado Plateau, has been a significant buffer for us. Particularly in Central Arizona, having access to diverse water supplies from the Salt and Verde River system, the Colorado River, and groundwater, as well as recycled wastewater, has allowed us to manage the risk of climate change to water resources for quite a long period of time.”

However, White says other parts of the state face different challenges when it comes to climate change and water. 

“I’m most concerned about parts of the state that are largely reliant on a single resource like the Colorado River, which is currently experiencing a megadrought, or only groundwater. We should be paying the most attention to the strategies we need to manage risk in those areas.”

In addition, certain communities face greater challenges than others. For example, across the Navajo Nation, lack of access to potable water is common, and that access is hindered by water infrastructure costs, which can be as much as 70 times higher for a Navajo family relying on hauled water than for non-Indigenous families with piped delivery, according to the report.

The challenge of documenting impacts

Developing a consensus-based report like the National Climate Assessment is no small task. White was nominated as the lead author for the Southwest Chapter and selected by a federal advisory committee overseen by the White House Office of Science and Technology Policy. He worked with a coordinating author from the federal government to develop the rest of the team, saying, “in retrospect, that was the single most important job I had, putting together a diverse team that worked together for two and a half years to produce our chapter.” 

To ensure that the assessment is evidence-based, the authors must follow a number of rules. For example, everything included in the report must be published in the peer-reviewed literature and within a certain time window. It is also thoroughly reviewed and vetted by not only scientific and technical experts, but also members of the public. Finally, the assessment is policy neutral and non-prescriptive.

White says that this can sometimes be challenging because not everything is published in the academic literature. For example, “certain knowledge types – particularly Indigenous knowledge – are more challenging to include because they are often not published. It really leads to the question of what counts as science, and while we’re more inclusive than ever, we still have more to do.”

He also notes that much practice-based work is not well-documented. “For example, say you're a water utility and you've implemented a new policy or management practice that's made you 20 percent more efficient, that's rarely published. We have to get that stuff out there so it can be included in these types of reports.”

What comes next

The Fifth National Climate Assessment emphasizes the urgency of taking action and the need for adaptation strategies to manage southwestern water resources in a changing climate. 

“In Arizona, we have been living beyond our means when it comes to water. We need to recalibrate and luckily there are a full range of potential actions we can take, ranging from increasing supplies to managing demand to looking at the way we allocate water. In the report, we describe which actions have been documented as effective in the region as a starting point for a dialogue,” says White.

This is particularly important, White notes, because “when it comes to climate change today, we know that science only offers one piece of the puzzle. Science is particularly effective at describing the processes of change, the impacts and the risks to things that we value. But moving into the response phase is an inherently social and cultural and policy process.”

To that end, events including webinars, meetings, workshops and direct communication with different partners have been planned to engage with a wide variety of communities.

“We want to support people in using this information to think about their climate adaptation, sustainability, or climate resilience plans whether they are part of an irrigation district or a water utility or simply an Arizona community,” White says.

There is a real opportunity for action now, White emphasizes. The state of Arizona is working on a Priority Climate Action Plan, led by the Governor’s Office of Resiliency. Simultaneously, two climate plans are being developed by Maricopa and Pima counties. Cities including Phoenix, Tucson and Flagstaff are also working on plans. 

“It is fantastic that we now have this national document with a regional chapter for the Southwest that has relevance for the state of Arizona, and at the same time we’ll have these state and local plans. The really exciting thing about that is we’ll then be able to access up to $115 million for federal implementation grants from the Inflation Reduction Act. The timing really sets us up for a once in a generation opportunity,” says White.

“We very rarely see a convergence between the scientific evidence base that helps define the risks and potential successful actions alongside the planning capacity at the state, regional, and local levels, and in parallel with funding to support actions. It's really a tremendously exciting convergence of knowledge, capacity, and funding.”

Explore opportunities to learn more and provide input:

• Events | GlobalChange.gov
• Stakeholder engagement workshops are also being planned for spring and early summer across the region.

Related information:

• Come Rain or Shine podcast: Inside the Fifth National Climate Assessment, Southwest Chapter 
• US experiencing climate change now, latest National Climate Assessment shows

About the author: Faith Kearns is the Director of Research Communication with the Arizona Water Innovation Initiative in the Julie Ann Wrigley Global Futures Laboratory at ASU.