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A Matter of Scale

Astronaut photography awoke many people—including scientists—to large-scale Earth events and planetary rhythms that few knew were going on. One of those events was the destruction of tropical rainforests by fire and blade.

Astronaut photograph of smoke from slash and burn agriculture across the Amazon Basin.

(NASA photograph STS41D-40-22.)

The top image, taken August 31, 1984, from the shuttle Discovery, gives an oblique view of smoke billowing from multiple fires in the Amazon rainforest in Rondonia, Brazil. Farmers and ranchers opened up lands by setting fires in the dry season to make room for cattle and crops. Near the horizon, the Andes Mountains of Bolivia provide a natural barrier so that smoke does not reach the altiplano of southern Peru and Bolivia.

The continent-size scale of slash-and-burn forest clearing was largely revealed to ecologists by astronaut photography. Kam Lulla recalls more than one astronaut marveling at the vast extent of seasonal fires and smoke across the Amazon and many other tropical regions.

Astronaut photograph of herringbone-patterned deforestation in the Amazon.

(NASA photograph STS046-88-23.)

The lower image, taken from shuttle Discovery on August 2, 1992, looks straight down on the forest to reveal the fishbone pattern of forest destruction. The first clearings in the forest are arrayed along the edges of roads. Over time, legal and illegal roads penetrate a remote part of the forest, and farmers migrate to the area to claim land along the road and clear some of it for crops.

Before astronauts rode into space, scientists and everyday citizens had hints that their world was changing. From space, the scale and the connectedness of the changes become clearer.