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.