Southern Arizona is particularly vulnerable to climate change, as temperatures rise, resources become scarce and those living in poverty are disproportionately affected, experts said Thursday during a forum at the University of Arizona.

“Our regional temperatures have already increased and they’re projected to increase quite significantly over the course of this century,” said Gregg Garfin with the university’s Institute of the Environment. “Tucson’s temperatures in 50 years will be more like Yuma’s temperatures.”

If the amount of heat-trapping gases emitted globally continues at the current pace, panelists said, climate change would bring a cascade of negative effects throughout the world.

At the local level, tourism and agriculture will falter, energy costs will skyrocket as people struggle to keep cool, depleted soil moisture will lead to more forest fires and the health of more vulnerable populations, such as the elderly, will be threatened.

“We also know that climate change is water change and with increased temperatures, future droughts will be more frequent, more severe and longer, and that will lead to a less reliable water supply,” Garfin said.

Kathy Jacobs, director of the Center for Climate Adaptation Science and Solutions, said the evidence for human-induced climate change was clear and that everyone should understand the difference between trends and variability.

“What the people in the Southeastern United States are experiencing is not identical to what is being experienced everywhere else,” Jacobs said. “But there are trends in the same direction everywhere across the United States, including the warmest decade on record in every region.”

Jacobs was also director for the third edition of the National Climate Assessment, which brought together more than 300 experts to produce a comprehensive look at climate change and its impact on the United States.

The report links the rise in sea level, the melting of glaciers and extreme weather events — including prolonged periods of heat, heavy downpours, floods and droughts — to climate change.

It also warns of the increased danger faced by at-risk populations.

“It’s easy to believe that climate change is an equal opportunity hazard, but the reality is different, with disproportionate climate impacts on low-income and minority communities,” said Margaret Wilder with the Udall Center for Studies in Public Policy.

The Southwest region has high socioeconomic vulnerability, she said, with Arizona having one of the worse poverty rates in the country. Border counties and Native American communities also have high poverty.

“The region is both a hot spot for physical climate change and for social vulnerability, with a clear climate gap between rich and poor,” Wilder said.

But it’s not all doom and gloom, experts noted, and pointed to events such as the forum, which was sponsored by the World Wildlife Fund and the university, as a way to further discussion and find solutions.

“We have opportunities to do our part here in Tucson to address the root causes of climate change, the emissions of those heat trapping gases, and also by planning to adjust to changing conditions,” Garfin said, adding that the time to act is now.

“The longer we wait, the longer we are going to be exposed to this risk and the more that it will cost us.”

Contact reporter Luis F. Carrasco at lcarrasco@tucson.com or 807-8029. On Twitter: @lfcarrasco