The warming climate that has kept New Mexico in a drought for the past 20 years and is depleting water supplies will continue into the next half-century and must shape long-term planning, state officials said in a virtual hearing Wednesday.
One expert painted a grim picture of what the state will grapple with in the next 50 years — temperatures rising as much as 7 degrees, drier soils reducing runoff and the recharging of aquifers, higher evaporation and lower river flows, more intense wildfires leaving landscapes barren and more vulnerable to erosion, and warming waters becoming more prone to bacterial outbreaks.
In short, the quantity and quality of water will decrease substantially in the state unless effective measures are taken.
"The impact of climate change on New Mexico's water resources is, unfortunately, quite overwhelmingly negative," said Nelia Dunbar, director of the state Bureau of Geology and Mineral Resources.
In the webinar, Dunbar and Rolf Schmidt-Petersen, director of the Interstate Stream Commission, discussed the harsh realities of what has been called a megadrought gripping the Southwest as the world faces a reckoning for the massive greenhouse gases spewed into the atmosphere in the past 150 years.
Their presentation kicked off the third phase of a 50-year water plan Gov. Michelle Lujan Grisham has called for in response to New Mexico's climate crisis.
Previous phases involved preliminary planning and assessing how water resources will be at risk in the future. This phase will bring in scientists and other stakeholders to create strategies for countering the effects of climate change on water and making these resources more resilient or able to withstand the warming trends.
The final phase will be to make recommendations to local, state and federal leaders next year.
Aside from the rainy respite of the past few weeks, the state has been in the most severe drought in the past 20 years, Schmidt-Petersen said.
This "exceptional drought" extends west to California and Nevada and shows signs of spreading to the Northwest, he said.
The San Juan River basin, which is tied to the severely depleted Colorado River and is a key supply of New Mexico's surface water, is experiencing an extraordinary drought, Schmidt-Petersen said.
Low river flows are contributing to New Mexico's reservoirs dropping to historic lows, giving water managers no buffer to get through the summer.
But with the climate changing, any 50-year water plan that's based on current or past weather patterns will be flawed, he said.
"We also need to look forward," Schmidt-Petersen said.
A group of climatologists recently published a study indicating the Southwest was in the worst drought since the late 1500s. Part of it is due to La Niña, a Pacific Ocean-cooling event that pushes storms northward as they approach the continent, making the Southwest drier.
La Niña dissipating has led to some much-welcome rainfall in recent weeks, but the moisture is barely putting a dent in the prolonged drought conditions.
Overall, precipitation will remain about the same in the next half-century, but less of it will replenish water supplies because warmer air causes greater evaporation and holds more water than cooler air, Dunbar said.
Hotter temperatures will make the soil more arid, resulting in more rain and melting snow being absorbed in the soil's top layers and not flowing into rivers or aquifers, she said.
The more intense heat will parch soil, creating dirt devoid of nutrients, and it will dry out vegetation, turning some forests into tinderboxes. This will stoke more wildfires that, in turn, will scorch hillside terrain, leaving it denuded and more prone to erosion, she said.
She noted a recent study by the state Environment Department identified 2,300 miles of streams in New Mexico that were warmer than they should be.
Water that's too warm can breed bacteria such as E.coli, she said. It also can become uninhabitable for certain fish.
One graphic Dunbar presented vividly illustrated how temperatures will rise relative to global greenhouse emissions. The more these gases are curbed, the less warming will occur.
It demonstrates the simple fact that people can take actions to prevent the worst scenarios, she said.
Still, it's better to pursue adaptive strategies to prepare for the effects of climate change, Dunbar said.
"New Mexico's climate is warming," Dunbar said. "The question is how much rather than will it continue to climb?"