Global Change

We are certain that the Earth's climate is changing because of the trends that we see in the instrumented climate record and the changes that have been observed in physical and biological systems.  The instrumental record of climate change is der
A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity.
Paleontologists now have evidence that dinosaurs lived on all of the continents.
Not specifically. Our charge is to understand characteristics of the earth, especially the earth's surface, that affect our Nation's land, water, and biological resources. That includes quite a bit of environmental monitoring.
Definitions of often used glaciology and glacial geology terms can be found at the USGS Glacier Photoglossary Web site.
Land use change is perhaps the most observable of all environmental changes.
The link between land use and the climate is complex.  First, land cover, as shaped by land use practices, affects the global concentration of greenhouse gases.
While there is no global standard for what size a body of ice must be to be considered a glacier, USGS scientists in Glacier National Park use the commonly accepted guideline of 0.1 square kilometers (about 25 acres) as the minimum size of a glacier.
No, it does not. The term actually refers to changes in the position of the glacier’s terminus over a period of time. Like water, ice flows down its surface gradient and never goes back up valley.
In addition to qualitative methods like Repeat Photography, USGS scientists in Glacier National Park collect quantitative measurements of glacier area and mass balance to track how some o