The Amazon Basin
CE 397 Transboundary Waters
Christine Lynch
Feb 7, 2012
The Amazon’s International
Importance
Global Importance to:
Water
Carbon Cycle
Climate
Biodiversity
Amazon Overview
 The Amazon Basin is the largest basin on the planet, at
over 6,100,000 km2
 Its drainage area covers over 1/3 of the South American
continent
 The Amazon discharge (~220,800 m3/s) contributes
over 20% of the total discharge of all global rivers
 The amazon transports between 600 million and 1.2
billion tons of sediments per year
 The Amazon is estimated to be between 6400 and 7100
km long from its headwaters in the Andes to its
discharge in the Atlantic (second in length only to the
Nile)
 The Amazon affects the color and salinity of the Atlantic
for nearly 200 miles from its delta
Amazon Overview
 The Amazon has over 200 tributaries, 15 of which are
over 1000 km in length, and 3 of which are over 3000
km in length
 Over 1/3 of the total discharge is contributed by the
Madiera and Negro rivers
 The Amazon Rainforest, which is not confined to the
Amazon river basin, is the most extensive and preserved
rainforest in the world
 Makes up 60% of remaining tropical rainforests
 Makes up 56% of remaining broad leaf forests
 83% of the forest is still intact
 Produces ~20% of the Earth’s oxygen
 Key component of the global carbon cycle
Division of the Amazon
 The Amazon Basin is shared between 7 countries:
 Brazil
 Peru
 Ecuador
 Bolivia
 Columbia
 Venezuela
 Guyana
 Languages include Portuguese, Spanish, and hundreds of
critically endangered native languages
 The Amazon Rainforest extends beyond the river basin
boundaries and includes Suriname and French Guiana
Division of the Amazon
Amazon Basin Countries by Area (%)
0.8
2
5.9
<0.1
10.7
11.4
Bolivia
Peru
Brazil
Ecuador
Colombia
Venezuela
Guyana
69.1
Division of the Amazon
Country Area included in the Amazon Basin
(%)
Guyana
Venezuela
Colombia
Ecuador
Brazil
Peru
Bolivia
0
10
20
30
40
50
60
70
Division of the Amazon
Amazon Subbasins by Area
1%
Madeira
13%
Tocantins
20%
2%
Negro
2%
Xingu
2%
Tapajós
Purus
2%
Marañón
3%
Ucayali
11%
4%
Caquetá-Japurá
Juruá
Putumayo-Içá
5%
Trombetas
10%
5%
Napo
Uatumã
Orinoco
5%
7%
7%
Other
Division of the Amazon
 Human density in the Amazon is low and concentrated in
urban areas
 5 cities have >1,000,000 inhabitants, 3 cities have over
300,000 inhabitants. Major population centers are generally
located along larger rivers
 Deforested cities are “heat islands,” subject to flooding and
having cloud to ground lighting occurring at rates >3 times as
often as in nearby forests
 The Brazilian Amazon, the most densely populated portion
of the Amazon, has about 3.3 inhabitants/km2, much lower
than the average of 20 inhabitants/km2 in the remainder of
Brazil.
 The low population density is a preserving factor in the basin,
but results in a failure to prioritize collection of data
 Though the population of the Amazon (~10 million) is less
dense than that of the countries it is part of, its growth
rates range from 5.2-7.2%, well above the national
averages of Amazon countries
Climate
 The Amazon Rainforest is a major climate regulator
 Absorbs incoming radiation at equator to lower
temperatures
 Annual mean temperature over entire basin varies from 24 to
26˚C
 Absorbs and stores moisture
 Recycles between 1/2 and 2/3 of regional rainfall
 Mean annual rainfall greatly varies spatially, generally oscillating
between 1000-3600 mm with more at the mouth and less in the
interior, but exceeding 8000 mm in the Andean coastal region
 75% of the energy that drives atmospheric circulation
comes from the heat released during tropical rainfall
Climate
The rainy season starts in the south in December, and gradually moves
north through May. During this time the rains swell the rivers of
Amazonia, creating extensive wetlands. (Images by Robert Simmon,
based on data from the Global Precipitation Climatology Project)
Climate
 El Niño
 Higher than normal temperatures in the Equatorial Pacific
 Significantly reduces Amazon precipitation
 Droughts
 Fish are concentrated in deeper channels, making fishing
easier and resulting in a decline in fish stock during
subsequent years
 La Niña
 Higher than normal temperatures in the Equatorial Pacific
 Opposite effect – increased rainfall
 Flooding
Climate - Deforestation
 Between 2000 and 2007, the Brazilian Amazon was
deforested at a rate of 19,368 km2/yr. During this time,
an area of forest larger than Greece was destroyed
 Brazil is the world’s 4th largest climate polluter, with 75% of
their greenhouse gas emissions attributed to deforestation
and land use change. 59% of this is from loss of forest and
burning in the Amazon.
 The removal of forest (done using slash and burn
techniques)
 reduces the retention of humidity in the soil’s top layer for 1
meter in depth
 Facilitates sudden evaporation of water previously retained
in forest canopy
 Increases albedo (reflectiveness) and temperature
 Reduces porosity of soil, causing faster rainfall drainage,
erosion, and silting of rivers and lakes
Climate - Deforestation
 Widespread convection has been documented in
deforested areas, forming shallow cumulous clouds
which usually do not evolve into nimbus clouds and as a
result may not produce rain
 Forests expel hygroscopic salts and organic fibers along
with water during evapotranspiration, and these act as
water vapor condensation nuclei at higher elevations.
This process results in formation of abundant clouds and
represents almost 50% of recycled rainfall.
 The Amazon is estimated to store between 80-120
billion tons of carbon. If destroyed, it will emit roughly
50 times the annual greenhouse gas emissions from the
U.S.
 Amazon rain is generally acidic. It is unknown at this
time whether this is due to naturally occurring carbonic
acids, or nitrous and sulfuric acids from fossil fuel
burning and deforestation
Climate - Deforestation
 Compared to the pasture it is generally replaced with:
 Forests absorb ~11% more solar radiation
 The average albedo of the Amazon forest is 13.4%, of
pastures, 18%
 The average temperature in the Amazon is ~ 24.1˚C, in
pastures it is 33 ˚C
 The daily temperature variation of Amazon soils at 20 cm
did not exceed 2.8 ˚C, though under pastures it was 8 ˚C
 The volumetric moisture content in the upper 1 m of
pasture soil is about 15% less than under nearby forest
 Deeper forest roots can pump more soil moisture to the
surface, producing 20-30% more air humidity and
consequently 5-20% more precipitation than pastures
 Several numeric models have suggested that large-scale
deforestation would diminish superficial drainage by 1020% and increase the surface air temperature by 0.6-2 ˚C,
resulting in huge changes in the regional water cycle
Land Use
 Land use tied to deforestation and thus inextricably
connected to climate and water cycle
 Early settlement of the Amazon occurred mainly in the
várzeas due to their river resources, including the fertile
alluvial soils which supported agriculture and cattle.
These activities were supplemented by hunting and
gathering.
 Hunting for subsistence and skins has virtually eliminated
turtles and freshwater manatees from some areas
 Prior to 1960s, economy based on extraction of natural
resources, primarily rubber, cocoa, and fish

Rubber the main export until the beginning of the 20th century, when
competition from SE Asia, a decline in rubber demand, and fungal
plague brought the decline of the Amazon’s rubber production
around 1950
Land Use
 Construction of roads and highways in the 1960s altered
social structure and settlement of the Amazon region
 Highways parallel to large rivers led to increased deforestation
along rivers
 Logging companies built roads deep into forests and away from
rivers, enabling extraction and export of timber but also of
settlement away from rivers
 Timber is collected primarily for export. Deforestation of flooded
forests for timber (and cattle) remove important feeding grounds for
several commercially valuable fish, and also negatively affects the
harvesting of Brazilian Nuts
 Road construction negatively impacted surface water by
preventing normal flow, flooding some areas while drying
others
 Connected Amazon to the rest of Brazil
 Allowed easier access to mining centers - after 60s mining of
bauxite and gold became important and people began to
migrate from the rivers to areas near these industries
Land Use
 Mining
 15% of the world’s supply of bauxite
 Some of the largest suppliers of iron and steel to world
markets
 Mining is scattered but has environmental impacts –
primarily alluvial gold
 Gold mining contributes to high mercury levels in fish and
releases geologic arsenic
 Mining of bauxite in Oriximiná, Pará, almost destroyed Batata
Lake by extensive silting, though there was no legal punishment
for the company responsible
 Agriculture
 Rice, cassava, corn, and beans are subsistence farmed,
while Soya, coffee, and cacao are produced commercially
 Fertilizers create local eutrophication
 Brazilian Nuts, rubber, and açaí, although many medicinal
and aromatic plants are harvested for pharmaceutical and
cosmetic industries
Land Use - Cattle
 Cattle ranching is responsible for the majority of Amazon
deforestation
 Brazil has the largest commercial cattle heard in the world
and has been the world’s largest beef exporter since 2003
 In 2006 cattle occupied 79.5% of land already in use in the
Brazilian Legal Amazon (this includes forest outside of the
Amazon Basin) and 3 head of cattle per inhabitant
 Around 40% of Brazil’s cattle are located within the Amazon,
and this is where the most growth or cattle ranching occurs
 Belched methane from livestock constitutes roughly 30% of
greenhouse gas emissions from agriculture, making it one of
the largest agricultural sources.
 Greenhouse gas emissions from beef are 13 kg CO2-eq per
kg. This means consuming a kg of beef represents roughly the
same greenhouse gas emissions as flying 100 km of a flight,
per passenger.
Land Use - Cattle
Land Use - Cattle
Rates of
deforestation
are affected by
international
commodity
price
fluctuations,
especially meat
and soya. When
the price of
both products
drop,
deforestation
rates decrease
the following
year.
Water Use
 Navigation
 Ports in Iquitos (Peru) and Porto Velho city (Brazil) receive
ships that travel over 3500 km along the rivers
 Estimated that over 40,000 km of waterways within the
basin are navigated by various types of craft
 Not all rivers are navigable
 Fishing
 Over 200 species of fish are exploited, but the commercial
market is based only on a few dozen
 Of these two are already considered overexploited
 Conflicts between local subsistence fishers and commercial
fishermen in the várzea and industrial fishermen in the
estuary
 Protect healthy stocks from commercial practices
 Introduction of alien species in Andean waters
Water Use - Dams
 Hydroelectric energy is complemented by fuel-burning
thermo-electric centers
 Dams create habitat fragmentation, interrupt fish
migration, and substitute river habitats with lake
habitats
 Local extinction of migratory species possible but
unrecorded
 Poor knowledge of species makes assessment of impacts
difficult
 Case study: Tucuruí Hydroelectric Dam on the Tocantins
River
Water Use - Dams
Dam Capacity (MW) by country
1%
6%
6%
Brazil - 11 dams
47%
Venezuela - 1 dam
Ecuador - 5 dams
Peru - 7 dams
Bolivia - 4 dams
40%
Water Use - Dams
Decomposition of submerged organic material creates greenhouse
gases, including methane, which is released when pressure suddenly
drops as water is released by the turbines
Water Use - Dams
 According to Brazil’s National Institute for Space
Research (INPE), the world’s 52,000 large dams
contribute to more than 4% of the total warming impact
of human activities, and dam reservoirs are the largest
single source of human-caused methane emissions.
 A molecule of methane does 34 times more damage
than a molecule of CO2
 According to one analysis, greenhouse emissions from
hydroelectric production of the Curuá-Una Dam in Para,
Brazil, were 3.5 times higher than if the electricity had
been produced by its fossil fuel burning counterparts
 Drying conditions in the Amazon may make hydropower
a less viable power source
Health
 Health is negatively impacted mostly in deforested areas
 Malaria, hepatitis, yellow fever, and dengue exhibit a
tendency to break out after habitats are modified
 Arsenic has been found in rivers due to deforestation and
mining (as well as a small amount of natural geologic
arsenic from the Andes)
 Mercury from gold mining has impacted fish
 In one village, the hair from people who ate fish contained
twice as much mercury as from those who didn’t
 This was a village that obtained most of its protein from
beef
Obligation of the Amazon Countries?
 In 1990, the Brazilian Amazon contributed 3.5% of GDP,
despite occupying over 45% of Brazil
 “…rainforest land converted to cattle operations yields
the landowner $60 per acre; if timber is harvested, the
land is worth $400 per acre. However, if medicinal
plants, fruits, nuts, rubber, chocolate, and other
renewable and sustainable resources are harvested, the
land will yield the landowner $2,400 per acre.” The
Healing Power of Rainforest Herbs (Square One
Publishers, Inc. Garden City, NY 11040, © Copyrighted
2004) By Leslie Taylor
 Do you believe it is truly possible for countries to
sustainably harvest from the Amazon in a way that is no
less profitable than alternative methods?
 If not, do you think is it the responsibility of the Amazon
countries to sacrifice their economic potential for the
good of the rainforest?
Questions?