Endangered Mexican wolves will continue to be kept south of Interstate 40, after a federal judge in Tucson upheld the current ...

In its main case, which the Census Bureau considers the most likely scenario, the U.S. population is projected to increase slowly from its current level of about 338 million to 369 million by 2080 ...

The weekend will start off feeling more like late May or early June from the Plains to the East Coast before a wide-reaching storm and potent cold front develop in the central US and race east.

New data from the Congressional Budget Office suggests that without immigration, the U.S. birth rate will not be sufficient to maintain the population ... to decline from current levels.

Population growth places the United States ... or fuels derived from plant materials—enough to displace 30 percent of the current national demand for petroleum fuels. That amount could be ...