Trouble in “Earth’s lungs”
South America’s Amazon Rainforest consists of 2.3 million square miles. That’s quite a bit of territory, roughly equivalent to the combined square miles of the 17 largest US states (AK, TX, CA, MT, NM, AZ, NV, CO, WY, OR, UT, MN, ID, KS, NE, SD, ND).
This vast area, comprising more than half of all the world’s rainforests, covers 40% of South America and encompasses parts of nine countries—Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela—though Brazil accounts for up to 60% of the rainforest.
Frequently called “the Earth’s lungs,” the Amazon rainforest absorbs large amounts of the planet’s carbon dioxide and, in turn, sends large amounts of oxygen back into the atmosphere. This amazing feat is due to the trees, upwards of 390 billion of them from some 16,000 species. The trees are essential to making the rainforest a “gigantic hydrological pump that brings humidity of the Atlantic Ocean into the continent and guarantees the irrigation of the region.”
Teeming with life, in the Brazilian portion of the rainforest alone there are an estimated 25 million insect species, 40,000 plant species, and numerous vertebrate species: fish – 3,000, birds – 1,294, reptiles—378, amphibians – 427 and mammals—427. But now the Amazon rainforest is exhibiting alarming signs of drying up, with major negative consequences not just for the region but for the entire planet itself. How and why is this happening and what can be done to reverse it?
Symptoms of decline
Since 2000, rainfall has declined by “up to 25% across a vast swath of the southeastern Amazon,” affecting 69% of the rainforest. Declining rainfall has a dramatic impact on the rainforest’s carbon storage as demonstrated during the major drought of 2005 when “the Amazon lost an estimated 1.6 gigatonnes of carbon, slightly less than Russia’s annual carbon dioxide emissions.”
Decreased rainfall has a direct impact on the tropical savannas, as well, affecting 80% of those areas.
There’s a natural occurrence poetically dubbed, “flying rivers,” which results when clouds of vapor rise from the rainforest, gather together and begin rushing toward central and southern Brazil bringing much rain. The rainforest’s flying rivers are larger than any river on the surface of the earth. This year’s flying rivers did not materialize in January and February, as they should have, due in large part to the overall drying the drought is bringing to the rainforest.
Brazil’s Sao Paulo, home to 20 million people, is particularly hard-hit by the drought and the absence of this year’s Flying Rivers. Sao Paulo’s Cantareira reservoir system is almost tapped out, with water intake pipes pulling water up from the very bottom of the reservoirs. Over 75% of Brazil’s electricity is generated by hydropower reservoirs which are “running critically low in the country’s Southeast region and could prompt emergency rationing next year.” There is also considerable uncertainty about the impact of the drought on this year’s Brazilian soybean crop, the second largest in the world.
Scientists are now able to capture the impact of the drying phenomenon in the Amazon rainforest and its savannas by studying greenness from satellites. Since 2000, 69% of the rainforest itself and 80% of the savannas experienced decreased rainfall, resulting in a noticeable change in plant greenness.
According to the scientists, “if this drying continues, and several studies predict this, it could lead to substantial carbon loss of the Amazon basin.”
There go the planet’s lungs.
Why is the Amazon drying up?
Trees are key to life in the Amazon rainforest and to the weather cycles of the region. The canopy created by the trees doesn’t just protect and sustain the floral and fauna beneath them, but results in “20 billion tonnes of vapour” evaporating daily with moisture spreading to nearby areas.
In contrast to those 20 billion tons of vapor, the Amazon River discharges “17 million tonnes of water . . . each day into the Atlantic.” The great ecological system of the Amazon rainforest is threatened by the disappearance of the canopy as trees are felled, and at an alarming rate.
Deforestation of the rainforest has taken a severe toll already, with over 289,000 square miles of rainforest disappeared since 1978. Sixty-five to 70% of the deforestation has occurred to create large open ranges for cattle. An additional 10% was cleared for large-scale crops, particularly soybeans. Each step in the deforestation process also led to the creation of more roads, pushing ever deeper into the rainforest, an open invitation to legal and illegal loggers and miners, speculators and poor farmers—all threatening the Amazon’s environment and its indigenous communities. Build a road, and the trucks will come.
As trees are felled in the Amazon rainforest, a chain reaction begins. Decreasing the canopy decreases the amount of humidity sent into the air, thus decreasing the Flying Rivers, and ultimately affecting up to “70% of South America’s GDP [which depends on production] in areas fed by precipitation from the Amazon.”
Another danger of loss of canopy and moisture is fire, as sunlight penetrates what used to be forest, exposing the debris from felled trees and dying vegetation which becomes tinder just waiting for a spark and then winds to further the flames. Those fires are in addition to the forest fires deliberately set to clear land.
Whatever the origin, smoke from the fires “introduces too many particles into the atmosphere, dries the clouds, and they don’t rain.”
Overall, in the latter part of the 20th century, there was a shift from traditional indigenous farming in the Amazon to clearing and use of the land for large-scale enterprises, particularly cattle-ranching and soybean farming. Dams were built to channel water for those purposes and for hydroelectric projects, while native habitat was further disturbed and bulldozed by mining and logging activities.
Until very recently there were signs that the whole-scale, destructive exploitation of the Amazon rainforest might be reined in. Brazil strengthened its law enforcement in the area and employed satellite monitoring to better detect illegal activities (including logging and mining), public and private initiatives were implemented, and so forth. That concerted effort began in 2004 and resulted in reduction in forest loss in Brazil by roughly 80% to 84%. Brazil has also been cracking down on cattle production with state-run banks ensuring proper environmental compliance before low-cost loans are approved, and major slaughterhouses pledging stricter controls to ensure the cattle brought to them are not raised by slave labor, nor on deforested land. While Brazil’s efforts were not adopted sufficiently by other countries sharing the Amazon rainforest, Brazil was making progress.
And steps back
Deforestation, which was declining, stepped up again in 2013 by almost 30 – 35%, particularly in the Brazilian states of Para and Matto Grosso, resulting in approximately 2,315 square miles of forest destroyed, primarily for agriculture. Illegal logging increased in the process, particularly in areas where roads and hydroelectric dams were being developed.
If deforestation and drought continue to escalate, it’s estimated that, by 2040, 45% of “cities that rely on rivers and reservoirs for their water will be vulnerable.”
Even now, Sao Paulo and Rio de Janeiro are searching for ways to pipe in water from other rivers such as the Paralaba do Sul and Sao Lourenco, at an estimated cost of $200 million and $900 million, respectively (US dollars).
Sao Paulo is particularly hard-hit, experiencing at this moment the worst drought in 80 years. Unusually high temperatures—including in winter—are speeding water evaporation everywhere while the Cantareira system is being overwhelmed and citizens are said to be “increasingly up in arms over periodic supply cuts.”
If 2015 doesn’t bring rain, a “really serious crisis” will unfold. Destruction of the Amazon rainforest is a contributing factor.
Lessons from the past
Archaeologists were surprised, once they began poking around in the Amazon rainforest in earnest, to find black earth, or terra preta soils that were “still fertile 500 years after they were last made.”
Investigation revealed those soils contained “high concentrations of humus, powdered charcoal, and pieces of broken pottery [with] aquatic plant remains and sand . . . scooped up [from] the river muck in the dry season and spread . . . over . . . beds.”
Apparently, some indigenous peoples in the Amazon practiced what’s called swidden farming (here and here), employing controlled slash-and-burn techniques on small plots, thus enriching the soil and enjoying good harvests, then allowing certain plots to lie fallow, covered with vegetation that would, years later, be worked back into the soil. They used raised beds, extremely efficient in retaining rainfall, but also useful for ensuring root systems wouldn’t rot from sitting in excess water for prolonged periods during the rainy season.
The Quichua people in the Ecuadorian Amazon continue their ancient practice of annual crop rotation, with fields lying fallow for a time following cultivation. Those fields become overgrown with weeds and young secondary forests which are worked back into the soil before re-planting, thus ensuing continuous rich soil.
Another surprise awaited archaeologists—the “vast networks in the Bolivian Amazon [which included] causeways of earth, artificial canals for canoe traffic, raised beds for growing crops in the savannas,” even fish weirs built in zig-zag fashion across the savannas in the Baures region, complete with artificial ponds so fish could be stored until needed.
The Amazon savannas, called the Cerrado, are huge, “ten times the size of Britain,” support numerous flora (12,000 species) and fauna (1,600 species), and form a major water basin. When outsiders first arrived, they looked upon the Cerrado as virtually worthless land since nothing they wanted to plant would flourish there. Then someone applied phosphorous and lime to the soil and the Cerrado became an abundant agricultural (primarily soybeans) and cattle-raising environment.
“At present, only 20% of virgin Cerrado remains, less than 3% which is really protected.”
Not only that, but the Tocantins River has been repeatedly damned for irrigating crops and hydroelectric plants. The indigenous people, the Kraho, ancient “Guardians of the Cerrado” are witnessing their ancient homeland disappear, engulfed by those who would only exploit it, and receiving little outside support to help retain it.
A key step in the way forward. Agricultural practices traditionally used by indigenous peoples in the Amazon ensured food security from year to year and generationally and also ensured the overall health of the rainforest, which is true even today. For example, between 2000-2012, while deforestation in other parts of the Brazilian rainforest continued at a 7% rate, deforestation in indigenous sectors was only 0.6% annually—and “Indigenous lands also saw 36 percent more carbon taken up and sequestered.”
There are 240 tribes in Brazil now, totaling about 900,000 people, most of them with a tradition of fierce resistance to assimilation efforts. 690 aboriginal territories are recognized by the Brazilian government; aboriginal lands constitute about 13% of the entire country. Almost all (or 98.5%) of this land lies in the Amazon.
Among many of the tribes there is also fierce resistance to illegal miners, loggers and settlers. The Ka’apor, for instance, have had their ancestral lands invaded illegally, forests converted to “towns, rice fields and cattle pastures by landless peasants, cattle ranchers, loggers and local politicians.” In response, the Ka’apor have tied up loggers, set fire to trucks and chainsaws and burned all the illegally felled logs. Another indigenous group, the Funai, have begged the Brazilian government for help in protecting their territory and expelling those illegally exploiting their land, so that they and the rainforest can be left in peace.
As archaeologists have discovered and present-day experience confirms, the indigenous people are key to maintaining the health of the Amazon rainforest. There is no way to return to the situation in the 1950s, when Brazil was 85% rural, but efforts to halt the current run-away situation—illegal and destructive occupation of the rainforest and savannas, a climate that has become unstable and even threatening—would have a better chance of succeeding if a partnership can be secured, and guaranteed, between the indigenous people, the government, and the array of individuals and groups committed to restoration of the Amazon rainforest region. Whether that partnership can be achieved is an overarching issue.
Meanwhile, among ominous future possibilities if nothing is done, and quickly, are the following:
- Deforestation in the Brazilian Amazon “skyrocketed more than 450 percent in October  from a year earlier” with no sign it will slow;
- By 2040, 45% of cities relying on rivers and reservoirs for their water will be vulnerable”;
- A feedback loop could be created, “shifting the intertropic convergence zone (ITCA)—a band that circles the planet and drives current rainfall patterns—toward the poles, increasing drying in the region. That in turn would exacerbate die-off, spurring increased emissions and further accelerating climate change.”
Experiencing on a daily level all the destructive activity in the Amazon rainforest, the Tiriyo, a tribe living deep in Suriname’s Amazon rainforest, summed up the situation as follows: “Climate change is the result of not behaving in the right way.”
The price of altering human behavior in this situation may be steep, but what’s the alternative?
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