Southern Colorado Plateau has dried 17 percent since 1985

New study projects impacts for world’s drylands

Hikers enjoying the view at Colorado National Monument, near Grand Junction. Researchers say recreation economies in the world’s drier zones are likely to take a big hit from global warming in the next few decades. @bberwyn photo.

Staff Report

Global warming is bad enough on its own for the world’s drylands, but when you add in the impacts of population growth, development and the increasing demand for water, the future looks downright grim.

The end result will be conditions that are detrimental to the recreation economy, wildlife habitat, water availability and other resources in hyper-arid landscapes, according to a recent paper published in Ecosphere. Drylands are of concern because broad-scale changes in these systems have the potential to affect 36 percent of the world’s human population.

Researchers with the U.S. Geological Survey and Northern Arizona University recently tried to quantify the impacts with a regional study covering the Colorado Plateau, spanning parts of Arizona, Utah, Colorado and New Mexico. They examined the combined effects of climate change and human land use—agriculture, recreation, energy development, mining and population growth—on a range of ecosystem functions and landscape attributes.

“Our approach offers a relatively simple method for scenario development that could be applied to a wide range of change agents, ecosystem services and regions,” said lead author Stella Copeland, NAU Merriam-Powell Center post-doctoral scholar. “Tools such as these can be used to inform natural resource planning and management efforts in the United States and elsewhere.”

Results included projections for aridity that provide context for other findings. Trend data from 1985 to 2014 show the southern and central parts of the Colorado Plateau drying at a higher rate than northerly areas. When declines in precipitation are compared to the average from 1985–2014, the increase in aridity was about 17 percent for the region as a whole.

The study examined four scenarios to estimate how climate change and overlapping land uses may influence ecosystem functions and landscape attributes. Although outcomes varied by scenario and characteristic, the recreation economy had the highest impacts for all scenarios; followed by vegetation and wildlife habitat and cultural and spiritual values; water availability; soil productivity; and cropland productivity.

The findings suggest that the recreation economy is vulnerable to negative impacts associated with the high degree of spatial overlap between areas of high recreation intensity, aridification, and petroleum and renewable energy development. Though some recreation areas such as national parks are largely protected from energy development, many of them are surrounded by public and private lands with high potential for energy development and other land uses.

“These results illustrate remarkably rapid growth in both recreation and energy development on the Colorado Plateau over the past few decades. The combined influences of these changes on natural resources and related recreational activity is unclear, especially in the context of increasing aridity,” said John Bradford, a USGS research ecologist and co-author of the study. “Higher intensity land use and warming is likely to lead to increased conflict and added complexity for resource managers.”


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