Nearly 2 billion people already live in water-stressed regions, where subtle shifts in average annual temperatures could mean inadequate water supplies for people and the environment, according to the Intergovernmental Panel on Climate Change.

When water is scarce in sub-Saharan Africa, people spend hours searching for and collecting drinking water. When drought hits Nevada, people have to change the way they wash their cars and tend to their yards.

In urban areas of arid Texas, about 25 percent of treated water goes toward landscaping, according to experts at the Texas A&M Department of Horticultural Sciences.

Even small steps can make a difference, so when planting this spring and summer, consider using native species already adapted to the environment you live in. They will