Northern California so polluted it can be seen from space

A waterway in Northern California is so polluted it's now visibile from space. 

Earlier this month, NASA took images of Clear Lake in Lake County, just north of Napa Valley's wineries. 

Satellite images show green swirls across most of the lake's surface.

NASA says this may indicate an infestation of blue-green algae, as well as other types of phytoplankton that can be dangerous to humans.

Scientists say the lake has contained large algal populations going back thousands of years.

But recent nutrient inputs to the lake by humans has increased the number of harmful blooms.

An algal bloom clouded the waters of California’s Clear Lake in mid-May 2024. Photo: NASA