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The Amazon: The World's Largest Rainforest
The Amazon River Basin is home to the largest rainforest on Earth. The basin -- roughly the size of the forty-eight contiguous United States -- covers some 40% of the South American continent and includes parts of eight South American countries: Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana, and Suriname, as well as French Guiana, a department of France.
Reflecting environmental conditions as well as past human influence, the Amazon is made up of a mosaic of ecosystems and vegetation types including rainforests, seasonal forests, deciduous forests, flooded forests, and savannas. The basin is drained by the Amazon River, the world's largest river in terms of discharge, and the second longest river in the world after the Nile. The river is made up of over 1,100 tributaries, 17 of which are longer than 1000 miles, and two of which (the Negro and the Madeira) are larger, in terms of volume, than the Congo (formerly the Zaire) river. The river system is the lifeline of the forest and its history plays an important part in the development of its rainforests.
HISTORY
At one time Amazon River flowed westward, perhaps as part of a proto-Congo (Zaire) river system from the interior of present day Africa when the continents were joined as part of Gondwana. Fifteen million years ago, the Andes were formed by the collision of the South American plate with the Nazca plate. The rise of the Andes and the linkage of the Brazilian and Guyana bedrock shields, blocked the river and caused the Amazon to become a vast inland sea. Gradually this inland sea became a massive swampy, freshwater lake and the marine inhabitants adapted to life in freshwater. For example, over 20 species of stingray, most closely related to those found in the Pacific Ocean, can be found today in the freshwaters of the Amazon.
The World's Largest Rainforests
1. Amazon Basin, South America
2. Congo Basin, Africa
3. Indonesian Archipelago, Southeast Asia
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About ten million years ago, waters worked through the sandstone to the west and the Amazon began to flow eastward. At this time the Amazon rainforest was born. During the Ice Age, sea levels dropped and the great Amazon lake rapidly drained and became a river. Three million years later, the ocean level receded enough to expose the Central American isthmus and allow mass migration of mammal species between the Americas.
The Ice Ages caused tropical rainforest around the world to retreat. Although debated, it is believed that much of the Amazon reverted to savanna and montane forest (see chapter 3-Ice Ages and Glaciation). Savanna divided patches of rainforest into "islands" and separated existing species for periods long enough to allow genetic differentiation (a similar rainforest retreat took place in Africa. Delta core samples suggest that even the mighty Congo watershed was void of rainforest at this time). When the ice ages ended, the forest was again joined and the species that were once one had diverged significantly enough to be constitute designation as separate species, adding to the tremendous diversity of the region. About 6000 years ago, sea levels rose about 130 meters, once again causing the river to be inundated like a long, giant freshwater lake.
THE AMAZON RIVER TODAY
Today the Amazon River is the most voluminous river on Earth, eleven times the volume of the Mississippi, and drains an area equivalent in size to the United States. During the high water season, the river's mouth may be 300 miles wide and every day up to 500 billion cubic feet of water (5,787,037 cubic feet/sec) flow into the Atlantic. For reference, the Amazon's daily freshwater discharge into the Atlantic is enough to supply New York City's freshwater needs for nine years. The force of the current -- from sheer water volume alone -- causes Amazon River water to continue flowing 125 miles out to sea before mixing with Atlantic salt water. Early sailors could drink freshwater out of the ocean before sighting the South American continent.
How large is the Amazon rainforest?
In Brazil, the Amazon covers surface area of 4,100,000 square kilometers (1,583,000 square miles), of which around 3.4 million sq km (1.3 million sq mi) are presently forested. Accounting for parts of the Amazon outside of Brazil, the total extent of the Amazon is estimated at 8,235,430 sq km (3,179,715 sq mi). or comparison, the land area of the United States (including Alaska and Hawaii) is 9,629,091 square kilometers (3,717,811).
In total, the Amazon River drains about 6,915,000 square kilometers (2,722,000 square miles), or roughly 40 percent of South America.
The river current carries tons of suspended sediment all the way from the Andes and gives the river a characteristic muddy whitewater appearance. It is calculated that 106 million cubic feet of suspended sediment are swept into the ocean each day. The result from the silt deposited at the mouth of the Amazon is Majaro island, a river island about the size of Switzerland.
(NEXT Amazon rainforest ecology)
Recent news on the Amazon
Brazil allocates first funds under plan to save the Amazon
(12/10/2009) Brazil's development bank BNDES has announced the first five recipients of grants under the South American country's ambitious Amazon Fund, which aims to reduce deforestation by 70 percent over the next decade.
Changing drivers of deforestation provides new opportunities for conservation
(12/09/2009) Tropical deforestation claimed roughly 13 million hectares of forest per year during the first half of this decade, about the same rate of loss as the 1990s. But while the overall numbers have remained relatively constant, they mask a transition of great significance: a shift from poverty-driven to industry-driven deforestation and geographic consolidation of where deforestation occurs. These changes have important implications for efforts to protect the world's remaining tropical forests in that environmental lobby groups now have identifiable targets that may be more responsive to pressure on environmental concerns than tens of millions of impoverished rural farmers. In other words, activists have more leverage than ever to impact corporate behavior as it relates to deforestation.
Brazilian tribe owns carbon rights to Amazon rainforest land
(12/09/2009) A rainforest tribe fighting to save their territory from loggers owns the carbon-trading rights to their land, according to a legal opinion released today by Baker & McKenzie, one of the world’s largest law firms. The opinion, which was commissioned by Forest Trends, a Washington, D.C.-based forest conservation group, could boost the efforts of indigenous groups seeking compensation for preserving forest on their lands, effectively paving the way for large-scale indigenous-led conservation of the Amazon rainforest. Indigenous people control more than a quarter of the Brazilian Amazon.
Destruction of old-growth forests looms over climate talks
(12/08/2009) Destruction of old-growth or primary forests looms large in discussions in Copenhagen over a scheme to compensate tropical countries for reducing emissions from deforestation and degradation (REDD). Some environmental groups are pressing for conservation of old-growth forests — the most carbon-dense, and biologically-rich state of forests — to be the centerpiece of REDD, while industry and other actors are pushing for "sustainable forest management" or logging using reduced-impact techniques to be the primary focus of REDD.
Copenhagen and Brazilian Megalomania
(12/07/2009) When people think about preserving the Amazon rainforest, captivating animals may come to mind such as the jaguar, toucan or manatee. But while wildlife must be safeguarded there are now other urgent reasons to protect the jungle. The seriousness of the problem was recently brought home to me when I visited the Amazonian city of Manaus.
Brazil could halt Amazon deforestation within a decade
(12/03/2009) Funds generated under a U.S. cap-and-trade or a broader U.N.-supported scheme to reduce greenhouse gas emissions from deforestation and degradation ("REDD") could play a critical role in bringing deforestation in the Brazilian Amazon to a halt, reports a team writing in the journal Science. But the window of opportunity is short — Brazil has a two to three year window to take actions that would end Amazon deforestation within a decade.
Cheap REDD isn't the best conservation strategy for biodiversity
(12/03/2009) The lowest-cost approach to compensating reductions in emissions from deforestation and degradation under a proposed UN program (REDD) isn't necessarily the best approach for biodiversity conservation, report researchers writing in the journal Science.
Brazil to push for 10% limit on REDD carbon offsets
(12/02/2009) Brazil will propose limiting the amount of carbon an industrialized country can offset via a proposed forest conservation initiative to ten percent of their emissions, reports Bloomberg.
Ethnographic maps built using cutting-edge technology may help Amazon tribes win forest carbon payments
(11/29/2009) A new handbook lays out the methodology for cultural mapping, providing indigenous groups with a powerful tool for defending their land and culture, while enabling them to benefit from some 21st century advancements. Cultural mapping may also facilitate indigenous efforts to win recognition and compensation under a proposed scheme to mitigate climate change through forest conservation. The scheme—known as REDD for reducing emissions from deforestation and degradation—will be a central topic of discussion at next month's climate talks in Copenhagen, but concerns remain that it could fail to deliver benefits to forest dwellers.
Guyana expedition finds biodiversity trove in area slated for oil and gas development, an interview with Robert Pickles
(11/29/2009) An expedition deep into Guyana's rainforest interior to find the endangered giant river otter—and collect their scat for genetic analysis—uncovered much more than even this endangered charismatic species. "Visiting the Rewa Head felt like we were walking in the footsteps of Wallace and Bates, seeing South America with its natural density of wild animals as it would have appeared 150 years ago," expedition member Robert Pickles said to Mongabay.com.
No-shows among South American leaders at Amazon summit
(11/27/2009) A summit between South American leaders to devise a plan to save the Amazon, failed to come up with a "common stance" on deforestation, as five of the eight invited leaders failed to show up to the meeting, reports Al Jazeera.
High gold prices, army collaboration, play role in mining invasion in southern Venezuela
(11/25/2009) Illegal gold mining involving wildcat miners, the Venezuelan army, and indigenous groups is threatening one of the country's most biodiverse river basins, according to local sources.
Google – the new eye in the sky for protecting forests?
(11/22/2009) Google looks set to play a part in a called-for "new environmental world order" by satellite-monitoring the rates of deforestation of tropical rainforests and pinpointing illegal logging and land misuse, Google’s Northern and Central Europe head Philipp Schindler has revealed. Schindler made the announcement in London on November 19 at a meeting at St James's Palace hosted by the Prince's Rainforests Project about a new climate change reduction mechanism, REDD (Reduced Emissions from Deforestation and Degradation). An inter-governmental report produced this month by an Informal Working Group (IWG) for Interim Funding of REDD has outlined an initiative to save the CO2 equivalent of the annual emissions of the US over five years by rewarding developing countries for reducing deforestation, with payments on a performance basis.
Deforestation emissions should be shared between producer and consumer, argues study
(11/19/2009) Under the Kyoto Protocol the nation that produces carbon emission takes responsibility for them, but what about when the country is producing carbon-intensive goods for consumer demand beyond its borders? For example while China is now the world's highest carbon emitter, 50 percent of its growth over the last year was due to producing goods for wealthy countries like the EU and the United States which have, in a sense, outsourced their manufacturing emissions to China. A new study in Environmental Research Letters presents a possible model for making certain that both producer and consumer share responsibility for emissions in an area so far neglected by studies of this kind: deforestation and land-use change.
Ecological benefits of REDD boosted by inclusion of private landowners, potentially harmed by plantations
(11/17/2009) Reducing Emissions from Deforestation and Degradation [REDD] programs that include landowners will conserve more habitat and ensure greater ecosystem services function than programs that focus solely on protected areas, report researchers from the Woods Hole Research Center (WHRC), the Instituto de Pesquisa Ambiental da Amazônia (IPAM), and the Universidade Federal de Minas Gerais (UFMG).
Brazil pledges to restrain emissions growth
(11/15/2009) In a move that some observers say could provide a path forward on a future climate agreement that includes emissions cuts in developing countries, Brazilian President Luiz Inacio Lula da Silva said his country will aim to reduce emissions 14 to 19 percent below 2005 levels by 2020.
Brazil releases official Amazon deforestation figures for 2009
(11/13/2009) Deforestation in the Brazilian Amazon fell nearly 46 percent to the lowest annual loss on record in 2009, reported the Brazilian government Thursday.
Will Brazil's blackout drive a new push for more rainforest dams?
(11/12/2009) The power outage that affected nearly a third of Brazil's population Tuesday could be used by development interests to justify a renewed push for hydroelectric dams in the Amazon rainforest.
How rainforest shamans treat disease
(11/10/2009) Ethnobotanists, people who study the relationship between plants and people, have long documented the extensive use of medicinal plants by indigenous shamans in places around the world, including the Amazon. But few have reported on the actual process by which traditional healers diagnose and treat disease. A new paper, published in the Journal of Ethnobiology and Ethnomedicine, moves beyond the cataloging of plant use to examine the diseases and conditions treated in two indigenous villages deep in the rainforests of Suriname. The research, which based on data on more than 20,000 patient visits to traditional clinics over a four-year period, finds that shamans in the Trio tribe have a complex understanding of disease concepts, one that is comparable to Western medical science. Trio medicine men recognize at least 75 distinct disease conditions—ranging from common ailments like fever [këike] to specific and rare medical conditions like Bell's palsy [ehpijanejan] and distinguish between old (endemic) and new (introduced since contact with the outside world) illnesses. In an interview with mongabay.com, Lead author Christopher Herndon, currently a reproductive medicine physician at the University of California, San Francisco, says the findings are a testament to the under-appreciated healing prowess of indigenous shaman.
Disney commits $4 million to rainforest conservation in the Amazon, Congo
(11/03/2009) The Walt Disney Company will invest $7 million in forest conservation projects in the U.S., the Congo Basin, and the Amazon in an effort to reduce its greenhouse gas emissions.
Install a programmable thermostat to keep your house comfortably warm in the winter and comfortably cool in the summer.
Use compact fluorescent light bulbs with the ENERGY STAR® label.
Air dry dishes instead of using your dishwasher's drying cycle.
Turn off your computer and monitor when not in use.
Plug home electronics, such as TVs and DVD players, into power strips; turn the power strips off when the equipment is not in use (TVs and DVDs in standby mode still use several watts of power).
Lower the thermostat on your hot water heater to 120°F.
Take short showers instead of baths.
Wash only full loads of dishes and clothes.
Drive sensibly. Aggressive driving (speeding, rapid acceleration and braking) wastes gasoline.
Look for the ENERGY STAR label on home appliances and products. ENERGY STAR products meet strict efficiency guidelines set by the U.S. Department of Energy and the Environmental Protection Agency.