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Climate Change and the West

What Is At Stake?

The mountain and desert West has an amazing diversity of climates ranging from high altitude tundra to searing desert. Each of these climates is home to animals and plants that require specific temperature ranges, precipitation amounts, and growing seasons. Even small changes in temperature or precipitation could affect the ability of many species to survive in an altered climate.

Since humans have developed systems of agriculture, water management, lifestyle, and economies based upon our understanding of the current climate, climate change poses a threat to our ability to live and prosper in the West

Models that examine the possible consequences of climate change on the West point toward drier weather patterns and increased average temperatures. These changes are already visible and their effects can be seen across the western landscape:


coloradoriverMost of the West relies on winter snowpack to feed the rivers, streams, and lakes that sustain life. Human development in the West in based upon capturing this snowmelt to provide consistent supplies of water throughout the year.

Around the West disturbing signs of change are evident. The elevation of the snowline is moving higher over time, reducing the amount of surface area that captures and retains snow. Spring runoff is occurring earlier in the year, contributing to lower late summer river flows. In some places, changing patterns of runoff have also strained the water supplies necessary for humans and terrestrial and aquatic animals. For example, farmers relying on stored water for irrigation may have to tap that water earlier in the year, with less available during the dry, late summer months of the growing season.

Flows in the Colorado River, which supplies water to more than 30 million people in the West and millions of acres of farmland, are projected to fall by 5 - 20 percent by mid-century due to climate change. This is a tremendous concern, particularly because the river is over-allocated and fully-used today.

Western Lands

Forests are also feeling the pinch as more rapid runoff means soil moisture will decrease more quickly, stressing trees and plants and possibly leading to more frequent and severe wildfires.

pika Sensitive animal species, such as the pika, are moving higher up mountains as their habitat changes, shrinking their habitat and the decreasing the availability of food. Plant species are also being stressed, leading to plants and trees that are less able to tolerate disease and pests, such as the mountain pine beetle, and even to loss of species from their traditional range. As species can no longer tolerate changes in climate, new niches open up for invasive plants that are not viable food options for animals, resulting in these animals having to vacate their traditional habitat as well.


While humans may be more adaptable than plants or animals, a changing climate will also make the West a less tolerable environment for people.

Less water will result in greater competition for this resource and may drive up its cost. Climate change compounds the challenge of meeting many western cities’ growing water demands. While water currently used to irrigate farmland is one potential new supply, water transfers - if not well-designed - can have negative impacts on rural communities.
Western quality of life will change as vegetation and wildlife change and as urban greenscapes become more stressed or discouraged due to their water consumption.

Warmer temperatures will produce more extreme heat events, stressing people who work out of doors or have limited tolerance of heat due to age or infirmity. Energy consumption will spike with increased use of air conditioning and other cooling appliances.

All these effects of a changing climate are prompting WRA's response to address this problem head-on.