Global environmental challenges
How 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.
Farmers are often portrayed as the villains, slashing and burning trees to clear land for crops and wrecking forests from the Amazon to Indonesia (…not to mention Europe, where people cleared most forests thousands of years ago).
But a report today by the World Agroforestry Centre indicates that farms aren’t such enemies of trees as usually thought - it says tree canopies cover at least 10 percent of almost half the world’s farmland. That is a gigantic area the size of China, or Canada. (For a story, click here).
Clashes in the Amazon between indigenous protestors and Peru’s army that killed some 60 people last week throw some old issues into sharp new relief: development versus the environment and local versus foreign control of natural resources.
Indigenous tribes, worried they will lose control over natural resources, have protested since April seeking to force Peru’s Congress to repeal new laws that encourage foreign mining and energy companies to invest billions of dollars in huge tracts of pristine rain forest.
The Amazon rainforest lost trees and plants in a 2005 drought – shedding carbon equivalent to the weight of 140,000 Eiffel Towers or almost 200 Great Pyramids of Giza.
The drought, one of the worst in the past century, revealed the forest’s unexpected vulnerability to shifting rainfall and a huge role in releasing greenhouse gases – compounding problems such as logging and land clearance to create farmland.