In a matter of decades, human activity has had a greater impact on the Amazon’s ecosystems than millions of years of natural evolution. That is the conclusion reached in a study recently published in the review Science. The 19 scientists who contributed to the article, including Juan D. Carrillo of the University of Fribourg, are sounding the alarm.
Often described as our planet’s green lung, the Amazon rainforest has a fundamental impact on the Earth’s climate. Alone it accounts for up to 16% of terrestrial photosynthesis, thus regulating carbon and water cycles. This vast ecosystem is also home to nearly one tenth of the planet’s plant and animal species. Threatened by human activity, the Amazon rainforest has lost nearly one fifth of the surface it covered prior to the beginning of European colonization. A study conducted by researchers from seven countries which has just been published in the journal Science draws an alarming picture. Changes to the Amazon’s ecosystems caused by humans are several hundred or even several thousand times more rapid than those occasioned by climatic and geological processes playing out over a period going back millions of years!
A comprehensive study
The scientists compared the pace of anthropogenic environmental changes (that is, originating in humans) to those that are due to natural factors in the Amazon and on the South American Continent, as well as on a planetary scale. They drew on the data compiled in the Science Panel for the Amazon (SPA) Assessment Report. The report’s data document the transformations to the Amazonian ecosystem over extremely long periods in terms of both cultural and biodiversity. Deforestation, wild fires, soil erosion, damming of waterways, and desertification due to global climate change are the main factors driving the destruction and degradation of the Amazonian ecosystem. The University of Fribourg paleobiologist Juan Carrillo contributed to the report by studying fossils from the region. He was able to show the extreme acceleration in the rate of the change caused by human activity. As he points out, “That means that the ecosystems, along with the animal and plant species and human societies living there, cannot adapt.”
Consequences for our planet
The extremely rapid pace at which the Amazon region is being cleared is transforming this dense forest into a landscape that is without a forest cover. “A 10,000 m2 of Amazon rainforest shelter more plant species than all of the European Continent,” Carrillo explains. “If the forest disappears, we are going to lose innumerable species before we have even studied them.” Moreover, a change on that scale has immense consequences for the Earth’s climate. From a carbon pool the Amazon rainforest is likely to become a net source of CO2. These upheavals will affect not only the peoples living in the Amazon basin, but also populations on the other Continents as well.
Scientists are sounding the alarm
Although worried, scientists have not lost all hope and are counting on political leaders to take the necessary steps to protect our planet’s green lung. “There exist stretches of rainforest in the Amazon that we can and must preserve,” Carrillo stresses. “It is also possible to restore zones that have been damaged and to take inspiration from indigenous communities that have lived there in a sustainable way for thousands of years.”