Deforestation in the Amazon:Effects on

Climate Change

GG 612 – Global Climate ChangeOctober 31, 1999 – Prof. Myneni

Ashley L. Vandegrift

2

Forests are most often defined as ecosystems with a minimum of 10% crown cover of

trees and/or bamboo, generally associated with wild flora, fauna and natural soil conditions and

not subject to agricultural practices.1 The changing area of the world’s forests, including natural

forests and forest plantations, was estimated to be 3,454 million hectares in 1995, or about one-

fourth of the land area of the Earth. (see Chart 1) About 55% of these are located in developing

countries.2 (see Chart 2) While tropical forests occupy less than 7% of the earth’s terrestrial

surface, they are home to as many as 30 million species of plants and animals, or more than half

of all life forms on our planet. 3 Their importance is thus undeniable. For example, of the

roughly 3,000 plants identified as having cancer-fighting properties, 70% grow in the rainforest.

In addition, a single acre of tropical rainforest supports between 60 and 80 tree species. 4 Of these

forests, the Brazilian Amazon is the largest contiguous region of tropical forest in the world,

making it an extremely important global resource, which is sensitive to land-use changes and

destruction. The rate and future course of these land-use changes, or forest clearing, in the

Brazilian Amazon is closely linked to human-use systems that replace the vegetation.

Deforestation often refers to a change in land-use with the depletion of tree crown cover to less

than 10%.5 More specifically, deforestation is the complete destruction of forest cover through

clearing for agriculture, cattle ranching, small holder agriculture, large-scale commodity crop

production and logging. Further, forest degradation through less-than-destructive logging, forest

land farming and fuelwood gathering is estimated to amount to more than the area of

deforestation, working to lower forests’ overall productive capacity. As global deforestation rates

have continued to soar, causing rapid and potentially severe impacts, so have concerns of how

this process effects other natural cycles. Forests are the single most important repository of

terrestrial biological diversity, as well as home to many animals and indigenous peoples.

Deforestation causes a loss of this biodiversity and habitat, as well as disrupts the natural carbon

cycle. Most importantly, it is the release of CO2 into the atmosphere due to deforestation, which

has in turn, led to an increase in climate change in regions distant from the perturbed area.

Amazonian deforestation rates are now used to determine human effects on the global carbon

cycle. Thus, climate change is becoming one of the most serious effects of large-scale

deforestation in the Amazon.

The global carbon cycle is made up of many carbon flows and stocks, proving that the

interactions between land surface and the atmosphere are significant and complex. Natural stocks

include oceans, fossil fuel deposits, the atmosphere, and the Earth itself when the element is

present in rocks and sediments, swamps, wetlands, forests and soils. Hundreds of billions of tons

of carbon as CO2 is absorbed from, or emitted to, the atmosphere through natural processes.

3

These flows include plant photosynthesis, respiration and decay, as well as oceanic absorption

and release of CO2. Currently, the atmosphere contains about 750 billion tons of carbon. (see

Chart 3) This amount is the result of an increase by about 25% in the past 100 years, or an

increase of about 1.5 ppm per year. 6 Further, the whole Amazonian hylaea retains about

115 * 109 tons of carbon. This is of the order of nearly 20% of the carbon of the entire

atmosphere’s CO2. If the entire Amazon forest was replaced by a much less voluminous, man-

made vegetation, there would be a net increase of about 8% in global atmospheric CO2 levels.7

CO2, an important greenhouse gas, forms when the carbon in biomass oxidizes as it burns or

decays. This is mostly due to human activities that alter land-uses and fossil fuel combustion.

Land-use changes include slash-and-burn agriculture; clearing land for permanent pasture,

cropland or human settlements; the development of infrastructure, such as roads and dams;

intentional and accidental forest burning; and unsustainable logging and fuelwood collection.

Land-use changes thus cause both carbon sinks and sources. A stock that is taking up carbon is a

sink. For example, forests accumulate carbon over decades and centuries. About two-thirds of

the globe’s terrestrial carbon, exclusive of that sequestered in rocks and sediments, is sequestered

in the standing forests, forest plants, leaf and forest debris, and in forest soils.8 A stock that is

releasing carbon is a source of emissions, and if enough carbon is released, the forest will

eventually become a net source. The release of CO2 will occur if the original ecosystem stored

more carbon than the modified ecosystem, thus, causing deforestation to act as a source of CO2.

Further, the amount of carbon released is a result of deforestation at different rates according to

the method of clearance and subsequent land-use. (see Chart 4) Throughout the 1980’s, it is

believed that deforestation accounted for 1.6 billion tons of carbon emissions. 9 If forests are

simply cut and allowed to decay, then most of the carbon is released into the atmosphere within

ten to twenty years. This release is the forest’s most important contribution to climate change,

even though human activities in tropical forests also produce other greenhouse gases, such as

methane, carbon monoxide, nitrous oxide and ozone, which can act as sources as well. One of

the main differences between CO2 and these other gases is that newly added CO2 will remain in

the atmosphere from decades to thousands of years, while the others will breakdown much faster.

It is now widely believed that the accumulation of CO2 in the atmosphere, partly due to

deforestation, is responsible for the observed global warming of around 0.5°C in the past 100

years.10

Global warming is now attributed to the steady increase of atmospheric trace gases

produced largely by human activities. These gases are referred to as “greenhouse gases” because

they cause radiative forcing, by letting in most of the incoming solar radiation that heats the

4

Earth’s surface, yet also prevent the outgoing thermal radiation from escaping to space, thus

trapping some of the surface heat energy. Aerosols also contribute to climate change. Most

aerosols reflect solar radiation back to space, working to cool the earth’s surface. Although

aerosols are injected into the atmosphere from natural sources, their concentration can also be

increased by human activities such as deforestation and over-grazing, which emit dust from the

top soil into the air. The concentration of greenhouse gases, especially CO2, has fluctuated

naturally over geological time scales. The temperature of the Earth has responded to these

fluctuations by switching between ice age and interglacial conditions. In addition to these slow

natural variations, atmospheric concentrations of greenhouse gases can be altered by the burning

of fossil fuels, clearing of forests, and many other industrial activities. Human activities can

produce a change in atmospheric composition, thus leading to radiative forcing of the climate

system and an eventual change in climate. While much of the existing climate change may be

due to these natural variations, it is now widely believed that the current trends are actually due to

these anthropogenic causes. For example, for the first time ever, the Intergovernmental Panel on

Climate Change has concluded that the observed increase in global average temperature over the

last century “is unlikely to be entirely natural in origin” and that “the balance of evidence

suggests that there is a discernible human influence on global climate.”11 It has been measured

that the globally averaged temperature of the air at the Earth’s surface has warmed between 0.3°

and 0.6°C since the late 19th century.12 (see Chart 5) Further, all 10 of the warmest years on

record have occurred in the last 15 years, while the 1990s have already been warmer than the

1980s by almost 0.1°C. 13 The warming has been greatest at night, over land, in the mid-to-high

latitudes of the northern hemisphere, while the warming during the northern winter and spring has

been stronger than during other seasons. Other evidence of global warming since the 19th century

include the observed rise in sea level, the shrinkage of mountain glaciers, a reduction of northern

hemisphere snow cover, and increasing sub-surface ground temperatures. Much support for this

evidence rests on measurements from tree rings, ice cores, and corals. It is expected that mean

surface temperature of the earth will most likely rise by 1° to 2°C over the next 50 to 100 years, if

current CO2 trends continue. 14 Because CO2 changes can drive climate change, it is important to

examine those activities which effect CO2 levels. Due to the fluctuations in carbon resulting from

land-use changes, deforestation has become a major cause of present and future climate change.

In turn, these climate changes could also effect sea level; damage human health; increase the

frequency of extreme events such as hurricanes and El Nino; alter the productivity of plants and

agriculture; put severe stress on forests, wetlands and other natural habitats; cause the expansion

of the earth’s deserts; and melt polar ice caps.

5

Forest resources assessments provide information on forest extent and location, types,

condition, wood volume and biomass. They are carried out on a sub-national, national, regional

and global level. Increasingly, satellite data has been used to measure the affects of deforestation

and thus it’s influences on the carbon cycle and climate change. The use of this tool is very

important, as it documents the most extreme form of land-use, over large areas, and at low cost.

Development of satellite image-mapping projects are becoming more widespread as the critical

effects of deforestation are becoming more well-known. Forest conversion to agriculture is often

monitored from space using imagery from the Landsat Thematic Mapper satellites.

Unfortunately, this approach fails to include those forest alterations that reduce tree cover, but do

not eliminate it. One such satellite project used satellite imagery covering the forested portion of

the Amazon Basin to measure deforestation and the resulting forest fragmentation and edge

effects. This project used both satellite data and GIS (Geographic Information Systems) to

stratify the Amazon on the basis of cover types. GIS provides a data management tool for

combining large amounts of spatial data and merging the information to create one large map of

the area. This particular study included the “Legal Amazon”, made up of many states in the

Amazon basin: Acre, Amapa, Amazonas, Para, Rondonia, Roraima, Mato Grosso, Maranhao, and

Tocantins. The data included 210 black and white photographic images of the Brazilian Amazon,

which were used to create a map of the deforestation and influence on forest fragmentation and

habitat degradation. Using a scale of 1:500,000, visual deforestation and standard vector GIS

techniques were used to create this single map. The digitized scenes were projected into equal-

area geographic coordinates, edge matched and merged to form a single, seamless data set of the

entire Amazon. These images include mining operations, airfields, visible roads, power lines, and

other similar human-made features, which were digitized into GIS and treated as deforestation. It

is projects such as this which have provided much of the current information on deforestation. As

with all scientific studies, there is great uncertainty in the results, specifically, with the extent and

rate of deforestation. One such uncertainty includes the fact that there are highly variable

differences between the data from this study and others previously made. These differences are a

result of three major factors: different stratification of forest, cerrado and water; slightly different

estimates of secondary forest growth; and a difference in positional accuracy, interpretation and

boundary generalizations. As far as satellite data is concerned, remote sensing techniques also

offer conflicting estimates depending on resolution and sampling coverage. Further, the rates of

deforestation have not been directly measured over time as part of agriculture or land-use

censuses, thus causing a lack of historical data. In the South American tropics, instrumental

records of climate do not extend very far into the past, adding to the uncertainty. In terms of

6

global warming, the range of estimated warming of 1° to 2°C in the next 50 to 100 years, for

example, arises from uncertainties about the response of climate to the buildup of greenhouse

gases and particles, as well as the total amount of future emissions of these gases. Factors such as

estimates of human population growth, land use changes, life styles, and energy choices yield a

range of plausible greenhouse gas emissions. Unfortunately, this prevents the comparison of

different deforestation and climate change studies.

Deforestation occurs when forestland is cleared and reforestation does not take place.

There are two fundamental forces giving rise to deforestation. First, competition between

humans and non-humans for the remaining ecological niches on land and in coastal regions. In

turn, this competition reflects the rapidly expanded population growth of developing countries.

Second, the “failures” in the workings of the international and national economic systems.

“Failures” mean the failure of economic systems to reflect the true value of environmental

systems in the workings of the economy. For example, many functions of tropical forests are not

marketed. Further, decisions to convert tropical forests are encouraged by fiscal and other

incentives for various reasons. One of the major direct causes of deforestation is the clearing of

land for other uses such as agriculture, while the greatest loss of carbon in forest ecosystems

involves the change of land-use from primary closed forest to permanent agriculture. Human uses

of tropical forests vary greatly in their ecological impacts. Other major causes of deforestation in

the Amazon are logging; rubber tapping; cattle ranching; forest conversion to cash-crop

plantations, such as oil palm and rubber; forest destruction for roads, mining, and other activities;

slash-and-burn farmers; development programs involving resettlement and infrastructure; and

wildfires and other natural phenomenon such as drought. Of these causes, logging, fires and

drought are among the greatest. It is believed that current estimates of deforestation, which often

fail to include these phenomenon, capture less than half of the forest area that is impoverished

each year, and even less during severe droughts. Loggers do not clear-cut and burn as with

agriculture, but fragment forests by harvesting or damaging the trees. Rubber tapping only uses

the forest at very low intensity through the harvest of animals, fruits, latex and other non-timber

products, but has a serious impact. The climatic and ecological consequences of deforestation in

the Brazilian Amazon are among today’s leading environmental concerns, due to the contribution

of CO2 emissions into the atmosphere and the decreases in biodiversity and soil productivity.

Deforestation is ultimately caused by human use systems that replace the forest.

However, the indirect causes and assessments of deforestation are not as clear. Some of the roots

of these causes are as follows: population growth, urbanization, agricultural trends, land-tenure

policies, development of infrastructure, expansion of cash crops, government and land-use plans,

7

extension programs, public perceptions and lack of knowledge of forest resources, energy needs

and laws and regulations. There is no question as to the immediate results of human degradation

on forests, and now many of the long term consequences involving climate change, but the

question of why humans deplete forest resources has often been under scrutiny. In developing

countries such as Brazil, deforestation is a result of subsistence agriculture and opportunities to

advance economically by utilizing a “free” natural resource. But, why has this occurred? One of

the first answers is population growth, which itself is not a direct cause of deforestation, but is

definitely related. The Malthusian explanation for tropical deforestation is that “surplus people”

are heading for the developing world’s agricultural frontiers in “droves”.15 This domestic

demand for agricultural commodities has been rising because the number of consumers has been

constantly multiplying with high population growth rates and extensive migration. Between 1950

and 1990, the Latin American population just about tripled, from 166 million to 448 million. 16

One third of this increase was in Brazil. Thus, demographic pressures in rural areas have been

superimposed on skewed land distributions, poverty, inadequate health and educational services,

poor infrastructure and lack of access to agricultural technology. Under these conditions,

governments frequently encourage migration to frontier areas to deflect pressures in cities.

Unfortunately, the prospects for containing Brazilian frontier expansion are doubtful as current

populations are overwhelmingly young, and those living in or near tropical forests will utilize

land, fuel and shelter for as long as the forests last. As the numbers of people needing to be fed

increases, pressures on natural resources will undoubtedly mount. Further, most people in the

Brazilian Amazon respond to these opportunities for food and shelter, as well as to capture

sizable rents, through agricultural and lumber production, by “cutting and running”. Slash and

burn cultivators rarely practice a rotary form of agriculture, which imposes great pressures on

forest fringes, as they clear extensive areas before driving deeper into the forest year after year.

This further exacerbates the problem, as sustainable use of forest resources becomes a distant

reality.

Little migration to frontier areas of tropical forests take place without roads. As

population increases and primary tropical forest is destroyed, settlement and subsequent clearance

of forest is closely followed by the expansion of a road network. This then allows for even more

deforestation. It has been argued that this type of infrastructure development is the single-most

powerful element in the deforestation of frontier areas. These effects of road building have been

greatly felt in the Brazilian Amazon. The population increase in the zone of influence of the

region’s first interregional highway (completed in the mid-1960s) is estimated to have been

between 300,000 and 2,000,000 during the 1970s. For example, the number of migrants in the

8

Amazon region of Rodonia more than doubled annually after the state’s main highway was paved

in the early 1980s. 17 In both of these cases, the surge in migration following road construction

was followed by massive deforestation. It can be assumed that since this time, infrastructure

development has only increased, thus adding more pressure on the forests. In many areas,

traditional shifting cultivation has been taken over by the wholesale removal of vast tracts,

prompted by highway development and economic incentives for large agricultural projects, large

cattle ranchers, small scale farming colonization and logging. In more economic terms,

specialization has increased in the production and export of agricultural commodities in which the

Brazilian Amazon region holds a comparative advantage. Whether this be for agricultural

commodities, or fuel for timber export or charcoal production, commercial and cash crop motives

have led to serious forest degradation. Consequently, a rise in domestic or international demand

for agricultural goods has led to an outward shift in the region’s extensive margin. This high

economic value that has been placed on the Amazon’s resources have in turn resulted in vast

deforestation. At this point in time, it seems most likely that the technology that would be needed

for a sound response to the mounting demand for agricultural commodities will not be enough to

spare the Amazon’s natural habitats. Further, the relatively rare secure land titles in these tropical

forests continue to create “open access” areas, facilitating this economic expansion. The situation

has become even worse with the onslaught of foreign companies realizing the potential monetary

gains from utilizing the Brazilian Amazon’s vast forest resources.

Between 1980 and 1995, the extent of the world’s forests decreased by about 180 million

hectares. There was a net increase of 20 million hectares in developed countries, but a net loss of

200 million hectares in developing nations. (see Chart 6) Between 1990 and 1995, developing

countries lost 65.1 million hectares of forest.18 (see Chart 7) In the past twenty years alone, 50%

of the original Amazon forests have been lost due to agricultural expansion.19 The destruction of

the Brazilian Amazon reached an all-time high in 1995, when over 11,000 square miles, an area

larger than New Jersey, were destroyed. 20 Further, the FAO estimated that the change in forest

cover caused a loss of some 2.7 billion metric tons of biomass between 1980 and 1990.21

Although the global loss of forests was still very high during this period, the overall figures

suggest that the rate of deforestation may be slowing. For example, it is expected that forest loss

in tropical Latin America will drop from 918.1 million ha in 1980 to 119 million ha in 2020.22

(see Chart 8) The current situation is still bleak. It is estimated that 10,000 to 15,000 km2 of

undisturbed forest were logged per year in 1996 and 1997, affecting an area that was 50% to 90%

the size of the area that was completely deforested in 1996.23 More recently, by mid-1998, low

rainfall in much of the Amazon attributed to El Nino contributed to a prolonged fire season, and

9

thus, further degradation. In 1997, over 2 million hectares of rain forest in Brazil burned due to

fires set by farmers and ranchers to clear old cattle pasture and burn newly cut forest which

subsequently burned out of control. Some areas in the Brazilian Amazon are experiencing a

secondary growth recovery, but unfortunately, the forest’s stature and biomass, and thus the

ability to store carbon, in these areas is still less than in primary forests.

The role of forests in carbon sequestration is very well understood and offers one of the

greatest near-term potentials for management as a sink. Fortunately, deforestation is subject to

control and influence at many points. The use of forests by people dwelling in or adjacent to

them for productive, non-productive, and symbolic and cultural purposes is a principal factor in

determining a strategy for sustainable utilization. Most importantly, the value of conserving the

forest relative to deforestation and alternative land-uses must be enhanced. Mechanisms to

sustain forests range from protecting intellectual property rights on products developed from

materials originating in the forests, to restricting widespread access into the forests, to

maximizing the value of non timber forest products. In economic terms, these strategies will, in

turn, make forests more of a public good. On the policy end, it is important to discourage farmers

and ranchers from adopting production-enhancing measures, by strengthening land tenure or

lengthening commercial forest concessions to promote replanting. Adding to the planet’s net

carbon stores in vegetative cover or soil and preventing net loss will help to moderate global

warming by keeping atmospheric levels of CO2 lower than they would otherwise be. In terms of

the carbon cycle, carbon that could be released through deforestation can be kept out of the

atmosphere through a few land-use approaches: slowing or stopping the loss of existing forests to

preserve current carbon reservoirs, while adding to the planet’s vegetative cover through

reforestation to enlarge living terrestrial carbon reservoirs; increasing the carbon stored in non-

living carbon reservoirs such as agricultural soils; increasing the carbon stored in artificial

reservoirs, including timber products; and substituting sustainable biomass energy sources for

fossil fuel consumption, thus reducing energy-related carbon emissions. Therefore, by

sustainably managing natural forests to yield economic benefits, by making exploitative activities

such as logging more efficient, improving the productivity of agricultural land to reduce pressure

on remaining forests and making logging more efficient, climate change could ultimately be

curbed.

Amazonian deforestation is a serious problem with global consequences. Not only does

the destruction of these tropical forests disrupt biological diversity and other land uses, but it is

now believed that the removal of this vital terrain is contributing to the accumulation of CO2 in

the atmosphere. Long term results of this phenomenon are now linked to climate change and

10

global warming. In some cases, the remaining vast areas of undisturbed forest in the Amazon

lead to the mistaken conclusion that deforestation is really only a minor concern. This is not true.

The use of Landsat Mapper satellites now estimate deforestation rates more realistically, helping

to predict overall rates of forest disturbance and the resulting effects on CO2 changes.

Amazonian deforestation may begin as a local problem, disrupting native lifestyles and

biodiversity, but research has proven that deforestation has turned into both a regional and global

problem. Climate change is ultimately one of the worst environmental problems that humans are

now faced with. What makes it worse, is that many of these negative results are due to human

activities. Therefore, it is important that change now begin with the alteration of these activities.

If not, resulting climate change will in turn disrupt even more natural cycles. A warmer earth will

speed up the water cycle, interrupting the exchange of water among the oceans, atmosphere and

land; higher temperatures could cause more evaporation, drying out soils at a faster rate;

increased amounts of water in the atmosphere could mean more rain or snow overall; global mean

sea level could continue to rise and flood many coastal areas. And these are just a few of the

consequences of continued use of fossil fuels and deforestation. The earth is an interactive being,

as one change will in turn effect many other natural processes. In the case of deforestation, this is

best exemplified by the fact that the burning of trees in the Amazon can cause changes in

temperature which will reach the other side of the earth. There are still many unknowns, but what

has been proven, should be enough to trigger efforts to halt what we know now will create a

bleaker situation in the future.

11

Endnotes

1 Katrina Brown and David W. Pearce, ed., The Causes of Tropical Deforestation. (British

Columbia, 1994), 8.2 FAO. “The State of the World’s Forests 1999.”3 David Skole and Compton Tucker. “Tropical Deforestation and Habitat Fragmentation in the

Amazon: Satellite Data from 1978 to 1988.”4 James F. Kasting. “Tropical Rainforest Facts.” Natural Resources Defense Council.5 Katrina Brown and David W. Pearce, ed., The Causes of Tropical Deforestation. (British

Columbia, 1994), 8.6 US Global Change Research Information Office. “The Carbon Cycle, Climate, And The

Long-Term Effects Of Fossil Fuel Burning.”7 Daniel C. Nepstad, et al. “Large-scale impoverishment of Amazonian forests by logging and

fire.” Nature (April 8, 1999): 505-508.8 Roger A. Sedjo, Brent Sohngen and Pamela Jagger. “Carbon Sinks in the Post-Kyoto World.”

Resources For The Future-Internet Edition-Climate Issue Brief #12, 1998.9 Katrina Brown and David W. Pearce, ed., The Causes of Tropical Deforestation. (British

Columbia, 1994), 3.10 Fung, Inez. “Oh Where Oh Where Does the CO2 Go?” NASA Goddard Institute for Space

Studies.11 Union of Concerned Scientists. “Global Warming.”12 US Global Change Research Information Office. “Has the World Warmed?”13 Union of Concerned Scientists. “Global Warming.”14 US Global Change Research Information Office. “The Carbon Cycle, Climate, And The

Long-Term Effects Of Fossil Fuel Burning.”15 Katrina Brown and David W. Pearce, ed., The Causes of Tropical Deforestation. (British

Columbia, 1994), 135.16 Katrina Brown and David W. Pearce, ed., The Causes of Tropical Deforestation. (British

Columbia, 1994), 159.17 Katrina Brown and David W. Pearce, ed., The Causes of Tropical Deforestation. (British

Columbia, 1994), 162.18 FAO. “The State of the World’s Forests 1999.”19 Daniel C. Nepstad, et al. “Large-scale impoverishment of Amazonian forests by logging and

fire.” Nature (April 8, 1999): 505-508.

12

20 James F. Kasting. “Tropical Rainforest Facts.” Natural Resources Defense Council.21 Sten Nilsson. “Do We Have Enough Forests?” International Union of Forestry Research

Organizations.22 Sten Nilsson. “Do We Have Enough Forests?” International Union of Forestry Research

Organizations.23 H. Sioli. “The Effects of Deforestation in Amazonia.” In The Human Impact Reader, ed.

Andrew Goudi, 360.

13

Bibliography

1. Brown, Katrina and David W. Pearce, ed. The Causes of Tropical Deforestation. British

Columbia: 1994.

2. Dickenson, Robert E., ed. The Geophysiology of Amazonia. New York: John Wiley & Sons,

1987.

3. FAO. “The State of the World’s Forests 1999.” http://www.fao.org.

4. Fung, Inez. “Oh Where Oh Where Does the CO2 Go?” NASA Goddard Institute for Space

Studies. http://www.giss.nasa.gov/research/intro/fung.01/.

5. Kasting, James F. “Tropical Rainforest Facts.” Natural Resources Defense Council.

http://www.nrdc.org/triv/rainf.html.

6. Ma, Quancheng. . “Greenhouse Gases: Refining the Role of Carbon Dioxide.” NASA

Goddard Institute for Space Studies. http://www.giss.nasa.gov/research/intro/ma.01/.

7. Nepstad, Daniel C., et al. “Large-scale impoverishment of Amazonian forests by logging and

fire.” Nature (April 8, 1999): 505-508.

8. Nilsson, Sten. “Do We Have Enough Forests?” International Union of Forestry Research

Organizations. http://iufro.boku.ac.at/iufro/publications/dowehave.htm#sensetivitlanduse.

9. Sedjo, Roger A., Brent Sohngen and Pamela Jagger. “Carbon Sinks in the Post-Kyoto

World.” Resources For The Future-Internet Edition-Climate Issue Brief #12, 1998.

10. Sedjo, Roger A. “Harvesting the Benefits of Carbon ‘Sinks’.” Resources (Fall 1998): 10-13.

11. Sioli, H. “The Effects of Deforestation in Amazonia.” In The Human Impact Reader, ed.

Andrew Goudi, 356-363.

12. Skole, David and Compton Tucker. “Tropical Deforestation and Habitat Fragmentation in the

Amazon: Satellite Data from 1978 to 1988.”

http://www.bsrsi.msu.edu/overview/papers/science1/.

13. Union of Concerned Scientists. “Global Warming.”

http://www.ucsusa.org/warming/warm-home.html.

14. US Global Change Research Information Office. “Has the World Warmed?”

http://www.gcrio.org/ipcc/qa/02.html#fig1.

15. US Global Change Research Information Office. “The Carbon Cycle, Climate, And The

Long-Term Effects Of Fossil Fuel Burning.”

http://www.gcrio.org/CONSEQUENCES/vol4no1/carbcycle.html.

16. World Resources Institute. “Mitigating climate change through forest management.”

http://www.wri.org/climate/mitigate.html.

CHART 1Total Forest 1990 & 1995 (1000 ha)

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

Brazil Tropical South America World

1990 1995

Source: FAO "State of the World's Forests 1997"

CHART 2Forest areas by main regions in 1995

North America13.2%

Latin America, Caribbean

27.5%

Africa15.1%

Asia/Oceania - Developed

3.0%

Asia/Oceania - Developing

14.2%

Europe27.0%

Source: FAO "State of the World's Forests 1999"

CHART 3The World's Carbon Reserves (GtC)

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Atmosphere Forests Soils SurfaceOcean

Coal Oil Natural Gas

Source: www.gcrio.org, "The Carbon Cycle, Climate, And The Long-Term Effects of Fossil Fuel Burning"

Original Shifting Permanent PastureCarbon Agriculture Agriculture

Closed primary 283 -204 -220 -220Closed secondary 194 -106 -152 -122Open forest 115 -36 -52 -52

Source: Brown & Pearce, 1994

Changes in carbon with land-use conversion

CHART 4

CH

AR

T 5

Global T

emperature A

nomalies (0.01 C

)

-60

-40

-20 0 20 40 60 80

1866

1872

1878

1884

1890

1896

1902

1908

1914

1920

1926

1932

1938

1944

1950

1956

1962

1968

1974

1980

1986

1992

1998

Source: G

HC

N 1701-08/1999

CHART 6Forest Area in 1995 as Compared with 1980

(% of 1980 forest area)

-12

-10

-8

-6

-4

-2

0

2

4

6E

urop

e

Nor

th A

mer

ica

Aus

tral

ia,

Japa

n, N

ewZ

eala

nd

Dev

elop

edW

orld

Dev

elop

ing

Asi

a/O

cean

ia

Afr

ica

Latin

Am

eric

a,C

arib

bean

Dev

elop

ing

Wor

ld

Source: FAO "State of the World's Forests 1999"

CHART 7Total Forest Change 1990 to 1995 (1000 ha)

-60,000 -50,000 -40,000 -30,000 -20,000 -10,000 0

Brazil

Tropical South America

World

Source: FAO "State of the World's Forests 1999"

CHART 8Accumulated Losses in Tropical Forests from 1990 to 2050

(million ha)

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

Tropical Africa Tropical Asia Tropical LatinAmerica

Total

1990 2020 2025

Source: International Union of Forestry Research Organizations