Environment

Utah's Great Salt Lake Is Shrinking

Years of drought and over-irrigation have caused Utah's Great Salt Lake to shrink at an alarming rate, recent satellite photos show.

After the Great Lakes, Utah's Great Salt Lake is the largest body of water (by area) in the United States. Back in the middle of the 19th century, when pioneers first arrived in the area, the lake spread across roughly 1,600 square miles (4,100 square kilometers). Now, the lake covers an area of only about 1,050 square miles (2,700 square km), new satellite photos from NASA reveal. In October, the Great Salt Lake reached its lowest level in recorded history, at 4,191 feet (1,277 meters) deep.

These dramatic declines in water levels come from years of human activity — namely, diverting river water, which would normally fill the lake, for agriculture and industry, according to NASA. The agency estimates that about 40 percent of the river's water is diverted from the lake. These activities, along with the ongoing drought in the West, have drained the historic lake.

The Technosphere

Scientists have measured the Earth’s technosphere, an expanding accumulation of everything humankind needs to live, including buildings, electronics and landfill.

University of Leicester geologists estimate the current weight of the technosphere is 30 trillion tons, or about 10 pounds per square foot of Earth’s surface.

The technosphere concept is an offshoot of the Anthropocene — a proposed epoch in which the Earth is shaped by human activities.

“Many of these (manmade items), if entombed in strata, can be preserved into the distant geological future as ‘technofossils’ that will help characterize and date the Anthropocene,” said