Drought is a period of significantly less precipitation than average, leading to a water shortage. Prolonged deficiency impacts water sources like soils, lakes, streams, and underground reservoirs. The American Southwest is currently experiencing extended drought, posing challenges for ecosystems and human populations.
Why the Southwest is Prone to Drought
The Southwest is naturally susceptible to drought due to its arid climate. Water supply depends on Rocky Mountain snowpack, which melts and feeds rivers like the Colorado River. Higher temperatures increase evaporation, decreasing soil moisture and exacerbating dry conditions.
Natural climate variability plays a role in drought patterns. La Niña events, characterized by cooler Pacific Ocean temperatures, often lead to drier, warmer Southwest winters. Internal atmospheric variability and La Niña contributed to extreme dry conditions from Fall 2020 to Spring 2021.
Beyond natural cycles, climate change intensifies these conditions. Average daily temperatures in the Southwest between 2000 and 2020 were almost 1.1°C higher than in 1950, amplifying drought severity. Rising temperatures have worsened the current drought’s effects by approximately 42%. This warming trend is projected to continue, leading to a thirstier atmosphere that further dries out the Southwest.
Impacts of Drought on the Region
Prolonged drought in the Southwest has consequences across multiple sectors. Water supply is heavily affected, with major reservoirs like Lake Mead and Lake Powell significantly depleted. The Colorado River, a primary water source for 40 million people and millions of acres of farmland across seven states, has seen its flow drop by 20% over the last century, with half of that reduction attributed to climate change.
Agriculture experiences strain due to reduced water availability. Crop yields are impacted, and livestock production suffers, leading to economic difficulties for farming communities.
Drought also stresses ecosystems and wildlife. Native plant species face hardship, and dry vegetation increases the risk of severe wildfires. Warmer stream temperatures threaten native fish species due to increased groundwater and air temperatures, and reduced stream flows. Ecosystems also become more susceptible to bark beetle outbreaks and widespread forest dieback.
Beyond agriculture and ecosystems, the broader economy is affected. Tourism and recreation, particularly winter skiing, are at risk due to decreased snowpack. The Colorado River system supports a $26 billion tourism economy jeopardized by declining water levels.
Addressing Water Scarcity
Strategies are being implemented to manage water resources and mitigate drought effects in the Southwest. Conservation efforts across residential, agricultural, and industrial sectors are gaining traction. Arizona has seen a decline in water usage despite population growth, partly due to strategic planning.
Water management policies are evolving, including interstate agreements and state-level actions. In May 2023, Arizona, California, and Nevada agreed to reduce their take from the Colorado River by 3 million acre-feet through 2026. This agreement aims to prevent reservoir levels from falling to low points.
Technological solutions are being explored. Improved irrigation techniques help conserve water in agriculture. Wastewater recycling, including direct potable reuse, is gaining momentum, with states like Nevada and Arizona recycling a significant portion of their treated wastewater. California has also approved rules allowing highly purified sewage water to be piped directly into drinking water supplies. Desalination of ocean water remains an option, though its high energy cost is a consideration.
Infrastructure improvements enhance water efficiency. Investments in piping, storage, and delivery systems are being made to build resilience. The Infrastructure Investment and Jobs Act allocates $105 billion towards clean drinking water, water storage in Western states, and resilience infrastructure.