Atmospheric dust plays a key role in Earth’s climate system. Although it can have a negative impact on the environment, such fertilizing, soilssoil, dust can also have a negative impact on our planet’s ecosystems, affecting everything from the weather to global warming.
For example, in the Four Corners region—which includes portions of Arizona, Colorado, Utah and New Mexico—millions of people rely on water that comes from snow in the San Juan Mountains that melts and eventually flows downstream into the Colorado River. The snow is darkened by dust from the atmosphere, which causes it to melt faster. The snow melts faster and evaporates faster, which can impact water supplies in areas already suffering from extreme drought.
Associate professor Nick McKay and his team of paleoclimatologists in NAU’s School of Earth and SustainabilityThey have been studying dust in this high-elevation area for many years. This region is especially vulnerable to climate change. Funded through a private donation from Bob and Judi Braudy in 2016, they have collaborated with scientists at Cornell University to study the effects of dust and drought during Phase I of “The Drought-Dust Nexus in the Four Corners Region and Impacts on Society.” Now, with additional funding from the same donors, the collaborators will continue their research for five more years.
“It’s hard to overstate the impact of the Braudys’ gift,” McKay said. “It gave us the freedom to pursue some high-risk, cutting-edge science that would have been difficult to support with traditional mechanisms, while supporting three graduate students and several more undergraduate students. It helped NAU launch a new breed of scientists. Toby and I were delighted that the Braudys were interested in funding more research in a new and exciting direction.”
Associate professor and climate scientist, the Cornell team is headed by Toby Ault Includes research associate Carlos Carrillo. McKay is the principal investigator (PI), but McKay’s team also includes an assistant research professor Cody Routson, Stephanie Arcusa—who led NAU’s effort on Phase I of the project, completed her Ph.D. in December 2020 and is now a postdoctoral research fellow at Arizona State University—and Ph.D. student Frank Telles, who joined McKay’s team for Phase II. Telles is an Indigenous student from the Chiricahua Apache Nation of New Mexico. Telles’ passion for climate science is complemented by his commitment to research that will ultimately aid Indigenous peoples in the area, including the Navajo Hopi Ute and Zuni.
The Phase I collaborations saw some significant breakthroughs. They discovered new dimensions of dust and drought, land use, climate change, and more. Ault, Carrillo and Cornell developed new methods to simulate the large-scale effects on drought and dust in the region.
McKay & Arcusa, both from NAU, created new paleoclimate records using lake sediment for dust deposition over the past 15,000 year. They then compared them with records of drought derived from tree rings and other natural archives.
“The big surprise from Steph’s work in Phase I is that the natural relationship between dust and drought is much more subtle than we had assumed,” McKay said.
“From the lake records we see the Southwest is dustier today than in the past 11,000 years with peak dustiness in the mid-1800s, but this is uncorrelated with the drought records,” Arcusa said.
The NAU team published their early findings in the peer reviewed journal The Holocene, where they noted, “our results demonstrate that although the Colorado Plateau is naturally prone to dustiness, drought is a secondary driver of dust accumulation in the mountains. This suggests that land-use management decisions aimed at reducing land disturbance can mitigate future dust accumulation, despite projected increases in regional aridity.”
Scientists found that dust emissions are more sensitive to droughts than previously thought.
The team used the unanswered questions of the first phase to create research goals for the second phase. During this phase, uncrewed aircraft designed at Cornell will be deployed to chase dust storms over northeastern Arizona. They will also collect dust samples and data to aid in research. They will also use weather balloons with low-cost sensors to track dust flow from the ground into the atmosphere.
McKay, his team, and all of his associates. Paleoclimate Dynamics LaboratoryTo understand climate dynamics, they use natural records of past climate variability. They study natural climate variability in locations ranging anywhere from the tropics up to the Arctic. Their timescales range from years to millennia. The spatial scales vary from meters to meters.
“A lot of my research is at very large spatial scales, so I love getting to work locally and to address issues that affect northern Arizona directly,” McKay said. “Dust has many impacts on society, impacting human health and safety, snowpack and water resources, agriculture and the tourism industry, yet we still have a lot to learn about how climate affects dust, how dust moves through the atmosphere and how to predict when and where dust storms will occur.”
Kerry Bennett | University Marketing