The University of Arizona

Monthly Archive | CLIMAS

Monthly Archive

Drought and People

Monday, September 15, 2008


Water is a critical natural resource for people in the arid Southwest, as the region is highly susceptible to drought. Climate change impacts on southwest drought could thus have profound implications for society. Global climate projections indicate the future holds higher annual temperatures and less winter precipitation for the Southwest. These warmer temperatures may intensify the impact of drought on residents of the Southwest: recent research links the regional drought that peaked in intensity in summer 2002 (Figure 1) with more severe impacts on water, land, and people, than previous, drier droughts, due to warmer temperatures (read more). 

Streamflow: Natural Variability and Human-Caused Changes

Monday, September 15, 2008

Current observations suggest that climate change is altering streamflows in ways that negatively impact water supply for southwestern populations. Many climate models suggest that these changes will worsen as the climate warms, accentuating the natural variability inherent in river flows.

Since water is one of the most vital resources in the arid Southwest, the consequences of reduced streamflows and changes in the timing of peak river flows will impact water consumption, agriculture production, economic growth, recreation opportunities, and electricity generation, among other vital services. (Find out more)

Mountain Snowpack in the West and Southwest

Monday, September 15, 2008

In the West, as much as 70 percent of the region’s precipitation falls during winter. Arizona and New Mexico are critically dependant on this winter precipitation. The region’s two main water lifelines, the Colorado River and the Rio Grande, tap the winter snows in the Rocky Mountains for approximately 70 percent of their annual water flow. (Read more)

Invasive Species

Monday, September 15, 2008

An invasive species is a plant, animal, or microbe that adversely affects the native ecosystem upon introduction to a new community. Invasive species are well-adapted to encroach upon new territory, and invaders compete with native species for resources like water and soil nutrients. Many invasive species are so well-adapted to diverse conditions that they can outcompete their native counterparts, leading to environmental damage and decreased biodiversity. Regional impacts of climate change, including warmer temperatures, decreased precipitation, and increased levels of carbon dioxide will affect how and where invasive species migrate and colonize (Read more).

Human Health

Monday, September 15, 2008


Health risks are linked to climate change through direct and indirect cause-and-effect chains, and depend on factors such as a person’s age, health condition, economic status, access to quality healthcare programs, and exposure to the elements. In the Southwest, regional health risks linked to climate change include extreme heat conditions, poor air quality, and increased food-, water-, fungal- and animal-borne diseases (Read More).

Groundwater in the Arid Southwest

Monday, September 15, 2008

Groundwater provides drinking water to urban and rural communities and supports agriculture and industry, all of which have helped enable rapid population growth in Arizona and New Mexico. Population expansion, however, has not been without its consequences. It has led to increasing groundwater withdrawals that are outpacing the rate at which the vital resource is naturally replenished. As a result, the region’s groundwater resources are among the most overused in the United States (continue reading). 

Climate and Floods in the Southwest

Monday, September 15, 2008


Despite the Southwest’s arid climate, rivers in the region are not immune to overflowing their banks and flooding city streets, farms, and desert. Climate change likely will increase both flash floods and regional floods, making the region’s growing population more susceptible to losses of life and property. How climate change alters future floods remains an open-ended question. However, recent observations and research are contributing to a better understanding of flooding in the Southwest (read more).


Drought and the Environment

Sunday, September 14, 2008

Drought deeply affects the land, water, and people of the Southwest. It occurs when precipitation averages fall below the norm. A drought can persist for many years, punctuated by particularly severe dry stretches and sometimes a relatively rainy year. The cloudless skies associated with drought not only imply below-average rainfall, but also an increase in the amount of direct sunlight hitting the ground, which leads to higher evaporation rates.

(read more)


Sunday, September 14, 2008

In the Southwest, normal changes in seasonal climate make the landscape ripe for fires. Every winter, precipitation spurs plant growth, while the dry months of April, May, and June turn the vegetation into tinder. At the time in which the landscape is most primed for fire, convective monsoon storms generate lightning, providing the match. Add in fire suppression by federal agencies, population growth that increases numbers of campfires and careless people, and human-caused climate change and the relationship between fire and climate becomes complicated (read more).

Phenology: Changes in Ecological Lifecycles

Friday, September 12, 2008


Lilac flowers bloom with cues from the weather. Caribou give birth at the peak of plant abundance so that their newborns have plenty to eat. In the Southwest, as well as all other parts of the world, variations in the climate trigger life cycle events in plants and animals. Studying these events and their relation to climate is known as phenology. The information obtained is vital for understanding the impact climate change has on humans and ecosystems. Phenology includes the timing of flower blooms, agricultural crop stages, insect activity, and animal migration. All of these events are changing as a result of climate change and these changes impact humans (Learn More).