AMAZON/DROUGHTHow green is the Amazon?

Not as green as it used to be, as shown in an analysis of satellite images made during last year’s record-breaking drought.

Because greenness is an indication of health in the Amazon, a decline in this measurement means this vast area is getting less healthy — bad news for biodiversity and some native peoples in the region.

What does a drop in the greenness index look like? It looks gold, orange and red in a graphic accompanying an article to be published in the journal Geophysical Research Letters:

Gray areas are the norm, based on a decade of satellite observations that cover every acre (actually every square kilometer) on the planet. Dots that are gold, orange or deep red show areas with a decrease in greenness. Scientists call this the Normalized Difference Vegetation Index (NDVI on this chart) or the greenness index.530983main_NDVI_JAS_2010_full_1

The chart shows what happened during July, August and September of 2010, the height of the dry season — a deep loss of greenness. The researchers found that the 2010 drought reduced the greenness of approximately 965,000 square miles (2.5 million square kilometers) of vegetation in the Amazon, ¬†more than four times the area affected by the last severe drought in 2005.