Impervious Surface Area—tarring the surface of the Whole Earth . . . (Setaria veridis)  
Introduced to North America. For me, the sight of roadside weeds breaking through asphalt
is not reason to get the Roundup spray bottle out of the garage,
but rather a sure sign of the remarkable regenerative forces alive & well
within Nature. Something we should celebrate, I think, as well as reason for
optimism:

Impervious Surface Area

A recent study published by Harvey Leifert & the
American Geophysical Union includes these most interesting
statistics:

[...] As calculated by the researchers, the total impervious surface area of the 48 states and District of Columbia is approximately 112,610 square kilometers, and, for comparison, the total area of the state of Ohio is 116,534 square kilometers. [...]

That's two and one half Switzerlands covered in asphalt,
concrete & tar.

[...} The population of the United States is increasing by three million persons annually, Elvidge writes. New impervious surface areas are rapidly covering vegetated surfaces, including one million new single family homes and 20,000 kilometers of new roads per year. [...]

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