By changing the climate, humans have doubled the magnitude of drought’s impact on the availability of vegetation for herbivores, including livestock, to eat in the greater Four Corners region, according to a study published this summer in the journal Earth’s Future. This is because increasing air temperatures and increasing levels of evaporative demand—or more water being soaked up into the atmosphere—stresses the grasses and shrubs that livestock and many other herbivores rely upon. Emily Williams, who is now a postdoctoral scholar at the Sierra Nevada Research Institute at the University of California Merced, was the lead author of the study. At the time, she was a doctoral student at the University of California Santa Barbara. She has a personal connection to the Southwest, as her grandparents once lived in Arizona.
“As a kid, I would go to the Southwest quite a bit and really fell in love with the desert landscape,” she said.
But that wasn’t the only reason Williams chose to look into how climate change could be impacting the vegetation in the greater Four Corners region.
The Rio Grande looks significantly different today than it did just a couple of months ago, as arid conditions led to drying in the Albuquerque area. Water managers are teaming up with fish biologists in preparation for the river to dry and to work to mitigate the impacts on the endangered Rio Grande silvery minnow. Meanwhile, irrigators have been told to expect changes in water availability and delivery schedules. “Reclamation and our partners continue to coordinate closely to manage every drop of water for multiple purposes. In the last two decades, Reclamation has leased just under 500,000 acre-feet of water to supplement flows through the Middle Rio Grande for endangered and threatened species, which, at times, also increased inflow to Elephant Butte Reservoir,” the U.S. Bureau of Reclamation’s Albuquerque Area Manager Jennifer Faler said in a press release.
After a wet start of the year, drought conditions are returning to New Mexico. A seasonal outlook from the National Integrated Drought Information System indicates that the drought conditions will likely develop over most of the state and the drought conditions that currently exist in portions of the state will persist over the next three months. NIDIS released the seasonal outlook on Thursday. As of Thursday, about 37 percent of the state is not experiencing any drought or abnormally dry conditions, according to the U.S. Drought Monitor and 18 percent of the state is experiencing drought conditions.
Returning drought conditions come amid what could be a late monsoon season and above normal July temperatures. State Engineer Mike Hamman told the Interstate Stream Commission that the heat wave and late monsoon could move New Mexico “more in the direction of severe drought conditions.”
However, he said, the substantial snowpack over the winter has helped the rivers.
Throughout the western United States, communities rely on the storage of water in mountain snowpack to feed the rivers and reservoirs that provide drinking water and irrigation supplies. But climate change is changing that and the current methods of measuring how much water is stored in the mountain snow may provide an inadequate picture, according to Kathrine Hale, an author on a paper published this week in the journal Nature Communications: Earth & Science. Hale worked on the paper with a team of researchers from the University of Colorado at Boulder, but she is now a postdoctoral researcher at the University of Vermont. The team developed a metric known as the Snow Storage Index that she says takes into account factors such as when the snow falls that impact how much moisture the mountains store and for how long. This new metric could help inform water management decisions as well as monitor ecosystem stress, according to the paper.
With major western reservoirs like Lake Powell and Lake Mead declining to historic low levels, water officials in New Mexico presented on the dire Upper Colorado River Basin conditions to the Senate Conservation Committee on Thursday. Estevan Lopez, the state’s Upper Colorado River Compact Commissioner and the governor’s representative on Colorado River matters, spoke about how climate change is impacting the hydrology in the basin. “Even if we don’t know what’s going to happen to precipitation, we know that temperatures are going up and as a result of that, the precipitation that we do get in the basin…much more of that is precipitation in the form of rain as opposed to snow…When we do get snow, that provides a natural reservoir high up in the mountains where the water is released slowly over time and it spreads the water around for the whole year,” he said. He said in addition to reducing the amount of snow in favor of rain,hotter temperatures induced by climate change also mean more evaporation of snowpack and surface waters, leading to less runoff into the water system. Lopez said last year there was a good snowpack, but the higher temperatures led to less runoff than anticipated.
Local communities need to prepare for the impacts of climate change, New Mexico State Climatologist David DuBois said during the Four Corners Air Quality Group meeting Wednesday in Farmington. The air quality group consists of state agencies from Colorado, Utah and New Mexico as well as federal and tribal agencies working together to address air quality in the Four Corners region.
This group started more than 15 years ago. At the time, the area was on the verge of violating federal ozone standards, Michael Baca of the New Mexico Environment Department Air Quality Bureau said. He said the air quality has improved, but ozone levels remain a challenge and federal standards have become more strict.
“We have a tremendous task ahead of us to address the climate challenge,” Claudia Borchert, climate change policy coordinator for NMED, said.
Borchert highlighted the state’s efforts to address emissions including the Energy Transition Act, the natural gas waste rule and the ozone precursor rules.
DuBois provided statistics focused on the northwest corner of the state. Since 1970, the area has warmed on an average rate of 0.6 degrees Fahrenheit per decade.
At the same time, the southwest United States has been gripped by drought for more than 20 years.
While the drought isn’t as dry as past droughts, DuBois said the warmer temperatures exacerbate the conditions.
“Drought is more complex than just lack of water,” he said.
DuBois said dry soil and increased evaporation means less water is available even when it does rain.
Dead and dying piñon trees dot the slopes of northwest New Mexico, particularly in an area north of Cuba. For the past few years, the State Forestry Department has been monitoring the die off. John Formby, a forest health specialist with the State Forestry Department, said bark beetles have been infesting trees that are already weakened by drought conditions. The State Forestry Department and the U.S. Forest Service conduct aerial surveys in the summer. Last year, Formby said, they did a special aerial survey of the Cuba area.
With the changing climate, incidents like droughts and heatwaves can be interlinked.
This was the case in 2021 when the drought conditions in the southwest United States triggered record-breaking heat, according to a study published in the journal Geophysical Research Letters on June 18. Johns Hopkins University researchers Benjamin Zaitchek and Mahmoud Osman along with their colleague Nathaniel Winstead conducted the analysis. Osman and Zaitech typically study flash droughts, or droughts that come on very quickly. “We usually think about drought as being kind of more of a creeping disaster that comes over time,” Zaitech said. He said flash droughts come fast and can have really damaging effects, like destroying soy crops in the midwest.
Drought doesn’t only impact the availability of food and water for people and, as dry conditions continue to grip the state even amid the start of monsoon season, the New Mexico Department of Game and Fish has urged residents to be “bear aware.”
Bear-human encounters tend to increase in drought times as wildlife moves into suburbs or even cities in search of resources.
In a press release issued earlier this month, Rick Winslow, a bear and cougar biologist with New Mexico Department of Game and Fish, said that droughts have historically led to more conflicts with bears “not only at camping and picnic sites, but also in more populated areas.”
Nick Forman is the carnivore and small mammal program manager for the department. He spoke with NM Political Report via phone about this topic. Bears, he said, are omnivorous and rely on food sources like acorns, currant berries and juniper berries. Last fall, he said, the state had decent production of these food sources and, currently, the juniper bushes have berries on them and wildflowers can also provide bears with food. “There’s definitely available food out there,” he said.
Scientists at Los Alamos National Laboratory modeled future drought indicators to gauge how climate change could impact the Colorado River Basin. “We really think that drought is one of the greatest risks in terms of climate change to the stability of the Colorado River Basin,” said Katrina Bennett, a member of the Los Alamos team that published the results of that modeling in the journal Earth and Space Science.
Bennett said that drought is complex, but using a simplified machine learning, or artificial intelligence, process, allowed the team to assess the changing drought indicators. The team modeled indicators like soil moisture, runoff, evaporative demand, changes in temperature and precipitation.
Bennett said her team saw a large change in soil moisture as well as runoff and streamflow. She said changes in snowpack in the Upper Colorado River basin will mean that runoff from the snowmelt occurs earlier in the year. She said that is already well documented, but the modeling her team did found that even in scenarios where precipitation increases, the higher temperatures will lead to more of it evaporating rather than flowing downstream.