Protecting Water, Farms, and Communities:
How Policy and Planning Can Protect New Mexicans From Their Hotter, Drier Future
Is New Mexico Really in a Drought?
We frequently hear and read that NM is in a drought. But then I recently learned that an acequia board commissioner says that he doesn’t believe we’re in a drought, just a temporary lack of water. So, what is a drought and are we in one?
Defining Drought: A Temporary Water Shortage
Going to the internet we learn that drought is generally defined as a prolonged period of abnormally low rainfall or total precipitation, leading to a shortage of water for some activity, group, or environmental sector. It’s a complex phenomenon that can manifest differently depending on the region and the specific needs being affected. Droughts can last anywhere from a few weeks to several years. Certainly, NM and the SW would qualify as being in a drought as we have had a “shortage of water” for several years, at least. So, “drought” implies a temporary climatic condition that typically reverses within weeks, months, or a few years.
When Drought Becomes Aridification
But what should it be called when the water shortage period is longer, perhaps not reversible within a decade or perhaps much longer? Then, two additional terms become relevant to consider: aridification and desertification. Again, going to the Internet we learn that aridification refers to a gradual process during which a region becomes increasingly dry, moving towards an arid or desert-like climate. It’s not just about a temporary lack of rainfall (drought), but a long-term shift towards a drier state, often linked to climate change and increased temperatures.
Desertification: A Long-Term Climate Threat
In turn, we learn that desertification is the degradation of land in already dry regions, influenced by both natural factors (like climate change and droughts) and human activities. Certainly, NM and the SW would qualify as “land in already dry regions” and appear to be getting drier. Thus, both aridification and desertification are terms currently appropriate to apply to NM and the SW in general. A clear dividing line between the terms does not appear to exist.
Climate Warming as the Driving Force
Note that for both the concepts of aridification and desertification, climate change can lead to their defined conditions. Here it is important to recognize that the term “climate warming” as the actual cause now driving both concepts. It is the increasing rate that solar energy heats the atmosphere, causing the increased drying of soils as well as the alteration of historic wind, precipitation, hurricane, and other storm patterns, all of which can be collectively called “climate change.”
Scientific Evidence for Climate Change
We currently hear some politicians assert that claims of the ongoing patterns are climate change as being a hoax. They say we are not experiencing human-induced climate warming nor is climate change due to emissions of carbon dioxide, methane, and other greenhouse gases occurring.
In contrast we know the simple facts that a great diversity of scientific investigations starting in at least in 1774 have shown that inputs of the sun’s energy heats the earth and our atmosphere. Then beginning in 1856, we additionally learned that increasing the concentration of carbon dioxide in the air can produce a greater magnitude and persistence of atmospheric warming by the sun.
Today, there is abundant solid scientific evidence from modeling and monitoring, as well as from direct every-day observations that new records are being established locally and regionally for daily, seasonal, and annual high temperatures in the air around us as well as new records for the extents and durations regional floods and wildfires. These changes are being directly linked to climate warming alterations to air flow patterns, collectively disputing claims that increasing threats from climate change are a hoax.
Clearly, it is appropriate to claim that increasing aridification is occurring in NM and across the SW. What about claiming that desertification is occurring? Here we turn to scientific information produced by atmospheric modeling and monitoring. These results document how climate warming is significantly altering atmospheric circulation and causing shifts in wind patterns.
The Role of Atmospheric Circulation (Hadley Cells)
Of particular concern for us in the SW is how the atmospheric circulation patterns are changing. One of these major air circulation patterns (Hadley cells) result from hot, moist air rising from the equatorial tropics. This air then flows northward and southward, dropping rain and drying out along the way until this dried air historically has fallen at about 30 degrees north and south latitude tending to produce dry often desert conditions on the ground below.
Monitoring has revealed that the downdraft edges of the Hadley cells have expanded poleward by about one degree latitude in each hemisphere, with the magnitude of the expansion dependent on global temperature increases. The scientific literature reports that this indicates the total amount of latitudinal expansion of the Hadley cells over the period 1979–2005 was about two degrees in latitude, north and south. Over that same period the increase in global temperature was about 0.5°C. The poleward edges of the Hadley Cells appear to move about two degrees poleward in latitude for each degree Celsius of global warming. Of interest here, the internet tells us that, “Current policies are projected to lead to a 2.7°C median warming above pre-industrial levels by 2100.”
Currently, the rate of climate warming is expected to increase steadily as the United States’ past regulatory efforts to constrain or even to reverse climate change are now themselves being reversed. Based on the above temperature increase and the Hadley cells expansion rate, the northern (and southern) drying down draft of desert forming air could move its historical location of approximately 30 degrees latitude north (and south) to approximately 35.4 degrees.
What Desertification Means for New Mexico
Albuquerque is located at about 35 degrees north latitude. Therefore, due to the increasing likelihood of rapid atmospheric warming, it is clearly appropriate to describe NM as being at present risk from desertification, if it is not already impacting some, particularly southern, part of our state.
Water Resource Challenges in the Middle Rio Grande Valley
These climate warming projections point to the urgent needs for NM and other SW states to implement new, dynamic approaches for water resource management. This becomes a particular concern for those living along the Middle Rio Grande Valley who are being threatened both by prospects of desertification increasing into the future and by requirements to meet Rio Grande Compact delivery flows to Elephant Butte Reservoir. (We have previously characterized the pending crisis related to the Compact: https://nmwateradvocates.org/middle-rio-grande-compact-compliance-crisis-deepens/).
Acequia Traditions and Shortage Sharing
When periods of drought threaten acequia communities these threats are addressed through a practice called “shortage sharing.” Typically, since all acequia members know each other and work together to maintain their acequia system, they develop levels of empathy toward each other and share the water shortages to ensure that no one suffers disproportionally.
Conclusion: Preparing for a Drier Future
Current and upcoming water shortages along the MRG valley and elsewhere across NM require even a greater degree of water user empathy toward each other to implement the magnitude of shortage sharing now becoming required. Of concern, MRG water users lack the level of neighborly relationships found in acequia communities. Therefore, to develop the necessary regional-scale of water management that can produce water distribution equities similarly to those found with acequia shortage sharing clearly requires extensive regional planning efforts that we discussed elsewhere (https://nmwateradvocates.org/why-nm-water-planning-matters/).