A new report about climate change in the Southwestern United States says the area is one of the most climate challenged places on the continent.

The report says forest fires are one indication of climate change, but combined drought, population increases and aging water infrastructure could further stress the area.

There are 56 million people living in the Southwest, and that number is expected to grow to 75 million by 2030, said Brad Udall, director of the Getches-Wilkinson Center for Natural Resources, Energy and Environment at the University of Colorado Law School.

Growth will affect the already-stressed Southwestern water systems, particularly the Colorado River and the Sacramento-San Juaquin River Bay Delta, which is vulnerable to levy collapse or earthquakes, he said.

“The Colorado River is both overallocated and overused, and its reservoirs, the largest in the United States, are only at about 56 percent full after 12 years of drought,” Udall said.

Larger water entities in the West are adapting to climate change but progress has been "modest," according to Udall.

“I would suggest that we are facing a collision of 19th century water law, 20th century infrastructure and 21st century population growth and climate change," he said.

The climate extremes are going to be larger in the 21st century, he said, and water managers will have to make changes to handle the extremes.