Climate change is increasingly altering our world at all scales, and the Chama is no exception. Decision makers in the region must approach current and future challenges with a thorough understanding of how systems we have taken for granted and relied upon for centuries are changing, and future planning must take into account the potential variability in physical systems.
CURRENT CHALLENGES
TEMPERATURE: In New Mexico, warming is occurring even faster than in other parts of the world, with annual average temperatures rising 2.7°F since 1970 (1). From 2000- 2014, the number of days over 100°F has increased to an average of 17 per year. Before 2000 the average was around 9 days per year (2). Higher temperatures contribute to increased evaporation, make irrigation and livestock maintenance require more water, and reduce the number of frosts, which increases the vulnerability of plants to pests and diseases (1).
PRECIPITATION: Droughts occur more frequently and last longer than seen historically. In conjunction with higher temperatures, this makes the landscape more prone to flash flooding. Critically, warmer temperatures are causing more precipitation to fall as rain than snow and snowpack to melt earlier. This means that less water is flowing along the Rio Chama during the peak agricultural season: one study predicts that major snowpack runoff will arrive nearly a month earlier by 2080 (3).
EXTREME EVENTS: Droughts and floods are increasing, both in frequency and intensity. Precipitation events referred to as the "one-year event" or "five-year event" because of how often they are statistically expected to occur have been seen much more frequently (2).
FUTURE IMPACTS
PHYSICAL CHANGES: Several forecasted changes are already beginning to come true. Among the most recognizable features of the local environment,piñon trees have been pushed more than a mile back from their historical range due to drought and bark beetle infestation, two problems projected to continue getting much worse (1). Drier land also reduces channel capacity, meaning that lower flows will cause flooding. Additionally, lower flows reduce the capacity of the river to absorb and dilute pollutants, worsening water quality.
ECONOMIC CONSEQUENCES: Agricultural economic sectors are likely to bear 80-90% of direct economic losses resulting from climate changes (3). Shortages during peak agriculture season will reduce crop production and increase the price of water. The centuries-old water-sharing system in place through mayordomo governance of the acequias may be in jeopardy as water brokers fight for a share of the river (4). New Mexico is already embroiled in an expensive lawsuit with Texas over deliveries of water along the Rio Grande. New Mexico’s compact obligations to ensure that a certain quantity of water makes it to Texas and Mexico do not diminish just because the water does. Both downstream and upstream users are extremely vulnerable to legal and economic challenges as water supplies dwindle.
UNPREDICTABILITY: A final essential consideration in planning for a heat- and water-stressed future is that many of the coming changes are unknowable. New Mexicans have been resilient to a hot and dry climate for centuries, but the mounting changes are aggravating those extremes and provoking land, water, flora, and fauna to change in ways we did not expect. A high degree of flexibility as well as continued monitoring and adaptation will be essential for the continued survival of the Rio Chama community.
References: 1. Funk, J., Barnett-Loro, C., Rising, M., and Deyette, J., 2016. Confronting climate change in New Mexico. Union of Concerned Scientists. https://www.ucsusa.org/sites/default/files/attach/2016/04/Climate-Change-New-Mexico-fact-sheet.pdf 2. R. Frankson, K. Kunkel, L. Stevens, and D. Easterling, 2017: New Mexico State Climate Summary. NOAA Technical Report NESDIS 149-NM https://statesummaries.ncics.org/nm 3. Hurd, B., & Coonrod, J. (2012). Hydro-economic consequences of climate change in the upper Rio Grande. Climate Research, 53(2), 103-118. doi:10.3354/cr01092 4. Rivera, J.A. (1996). Irrigation communities of the Upper Rio Grande bioregion: sustainable resource use in the global context. Natural Resources Journal. 36:491−520