IMPACT OF DEFORESTRATION ON GLOBAL CLIMATE

By: MohSin Kawoosa Enrollment # 100222 mohsin.kawoosa@yahoo.com Department of Information Technology (CUKmr)

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TABLE OF CONTENTS INTRODUCTION.. 2 DEFORESTRATION...3 CAUSES OF DEFORESTATION...3 EFFECTS OF DEFORESTATION..5 DEFORESTATION'S EFFECT ON THE ENVIRONMENT...5

CLIMATIC ROLE OF FORESTS..6 LINKAGES BETWEEN FORESTS AND

CLIMATE................................................................................7 OTHER RELATIONSHIPS BETWEEN DEFORESTATION

AND CLIMATE CHANGE.9

LOCAL AND NATIONAL CONSEQUENCES...10 GLOBAL CONSEQUENCES.11 CONCLUSION..12 REFERENCES.12

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INTRODUCTIONThe United Nations have declared 2011 the International Year of Forests. If asked to define a forest, most of us will straightaway think of trees. While it is true that trees dominate - they are the biggest organisms present there and there are many of them - a forest is in fact a community of not just plants and animals, but of microorganisms as well. Throw into the mix the non-living, abiotic components like soil, climate and water, and take in the complex interrelationships among the organisms and the environment, and we are closer to an actual understanding of this ecosystem. Forests for people Forests have a variety of uses to humans, including wood from trees, nutrition from animals, grazing, recreation, medicinal plants and so on. Forests purify our air, preserve watersheds and improve water quality and quantity, stabilize soil and prevent erosion, provide us with natural resources such as timber products and medicinal plants, and are home to many of the worlds most endangered wildlife species. In addition, an estimated 1.6 billion people worldwide rely on forests for their livelihoods, with 60 million indigenous people depending on forests for their subsistence. Another critically important function of forests increasingly and widely acknowledged now is that they help to protect the planet from climate change by absorbing carbon dioxide (CO2), a major greenhouse gas. Forests as carbon storehouses It is now widely recognized that rising concentrations of so-called greenhouse gases (GHGs) are driving changes in the Earths climate patterns, resulting in catastrophic weather events, such as hurricanes, heat waves, droughts and floods, and threatening plant and animal life. Forests play a critical role in protecting the Earth from climate change and regulating climate patterns, as the trees trunks, branches and roots and even soil absorb and store CO2, providing a natural reservoir for this GHG. In fact, the Earths vegetation and soils currently contain the equivalent of approximately 7500 Gigatonnes (Gt) of CO2 that is more carbon than is contained in all the remaining oil stocks on the planet and more than double the total amount of carbon currently in the atmosphere. However, when forests are destroyed or degraded by activities such as logging and conversion of forests to agricultural land, they release large quantities of CO2 and other GHGs, and become a significant (and, for some developing countries, a primary) source of GHG emissions and contributor to climate change.2

DEFORESTRATIONDeforestation is the process whereby natural forests are cleared through logging and/or burning, either to use the timber or to replace the area for alternative uses. Examples of deforestation include conversion of forestland to farms, ranches, or urban use. Forests still cover about 30 percent of the worlds land area, but swaths the size of Panama is lost each and every year. Deforestation is a problem that is caused largely by greed and want for property, money and possibly status. In many parts of the world the forest is taken for granted as a replenishable resource, which it is. The problem is that the trees cannot be regrown and replanted at the rate at which they are being cut down. For this reason the forests are declining at an incredible rate and there is no forseeable future for places like the Amazon which remained untouched for 20 000 years and now could be destroyed in less than a human's life time. Deforestation is a problem with far reaching consequences ranging from a barren landscape to a higher Carbon Dioxide levels in the air. The underlying point is that we have to pull together to stop the destruction of the world's woodlands and forests.

CAUSES OF DEFORESTATIONDeforestation can be attributed to various causes. The obvious one is logging, however the reasons extends a lot further than that. The forests are cultivated, cleared and burned every year for international ranchers and local farmers. Every year certain factors influence the amount of forest area:

fires logging farming population expansion growth of cities roads and highways politics shifting cultivators

In a lot of third world countries the population is involved in various primary activities, one of these being logging. The native peoples in an area are put under a lot of pressure to make a living to support their families, and get jobs as loggers, often illegally so. The people are often uneducated and know nothing other than logging practices. In many countries the logging trade is the biggest foreign money-earner and therefore governments try to exploit the forests for all they can take, and more.3

Another cause is fires. In Kenya and the Amazon and various other countries there are large plantations of exotic plants in the places where there used to be indigenous forests. The exotic trees often are not suited to the environment and shed a lot of leaves. This makes the area a huge fire hazard. If a fire starts the dry leaves act like fire lighters and cause huge amounts of damage to the local area. Human settlement is a big problem in many areas. People who have left the city to live in the rural areas claim pieces of land as their own and slash and burn the surroundings, using wood for fuel and also selling it on roadsides etc. Some people who have been displaced by large ranchers or plantations have to move further into the indigenous forests because they do not know how to live off the exotic plants. By doing this they remove trees from yet more of the forest. The construction of roads and highways is a bit problem in wooded areas. In the Amazon they propose to build a 960km highway called the BR-163 from Curiaba in the middle of South America to Santarem in the top right corner of Brazil. The BR-163 will allow giant grain producers in the Matto Grosso region to export their crops to Europe via Santarem far more quickly and cheaply. It is estimated that 49 000km2 of forest will be destroyed during constructon. This is not the only worry though. When the road is built there will be a wave of squatters and farmers etc. vying for land on the superhighway. This could be the single most devastating assault on the Amazon ever. The growth of the world population is also a problem because more ground has to be cleared in order to feed the ever-growing populations. As the population grows there is a need for food. People take the initiative and buy large pieces of land that they cultivate with single crops. They have to cut down trees and bush etc. When they harvest their crop they leave the ground open to erosion. Deforestation has been an issue for decades, leading to massive loss of species and biodiversity. While governments and non-governmental organizations have worked hard to control it, there has never been a real motivation, or urgency to act until now. It is widely acknowledged that deforestation is the third largest source of greenhouse gas emissions, generating between 15-20 per cent of overall carbon emissions. There is a real opportunity to get global cooperation through a new Kyoto Protocol that sets targets for reducing industrial emissions as well as emissions from deforestation and forest degradation.

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WHAT ARE THE EFFECTS OF DEFORESTATION ?

Reduced biodiversity: Deforestation and forest degradation can cause biodiversity to decline. When forest cover is removed, wildlife is deprived of habitat and becomes more vulnerable to hunting. Considering that about 80% of the world's documented species can be found in tropical rainforests, deforestation puts at risk a majority of the Earths biodiversity. Release of greenhouse gas emissions: Deforestation causes 15% of global greenhouse gas emissions. Of these, carbon dioxide emissions represent up to one-third of total carbon dioxide emissions released because of human causes. Disrupted water cycles: As a result of deforestation, trees no longer evaporate groundwater, which can cause the local climate to be much drier. Increased soil erosion: Deforestation accelerates rates of soil erosion, by increasing runoff and reducing the protection of the soil from tree litter. Disrupted livelihoods: Millions of people rely directly on forests, through small-scale agriculture, hunting and gathering, and by harvesting forest products such as rubber. Deforestation continues to pose severe social problems, sometimes leading to violent conflict.

DEFORESTATION'S EFFECT ON THE ENVIRONMENTDeforestation is by no means a restricted problem. It can play havoc with the local community and even the country it occurs in. As with erosion, deforestation is not only caused by ignorant people. Therefore it is unfair to blame the nomads, shifting cultivators and farmers for destroying the countryside. Deforestation is a contributing factor to the green house effect. The trees are large Carbon dioxide stores, and when the trees are burnt they release this gas. This leads too an increase in the Carbon dioxide levels in the air. Carbon dioxide is the major contributor in the green house effect. Trees draw water up through their roots and release it into the atmosphere (transpiration). In the Amazon, half of the water is contained in the trees. If the trees are removed, the region cannot hold as much water and will become drier. In areas where deforestation occurs the community as a whole suffers. If there are no trees, the land becomes far more unstable than before. The roots from the trees no longer exist and therefore it leaves the forest floor open to erosion and mudslides etc. The land also becomes sandy and dry as the sun can now penetrate deep into the forest, where before, the tree-cover blocked out the damaging rays. When this occurs plants living near the cut5

down tree die and wither in the sun. It is believed that with every tree felled another 40 are destroyed in the process. The local animals are effected just as much as the people. Thier natural habitats are destroyed and species, possibly unknown to man become extinct, because they have nowhere to live. When the bull dozers knock the trees down,

buck monkeys, and birds

are all caught in the destruction. The animals either end up in the cities and are killed, or they starve to death in their new surroundings. Native people living in forest areas are pushed out of their homes and have to encroach on more of the forest. They cannot go anywhere else because they only know how to survive on the plants in the forest. In this way more forest is destroyed and the cycle will probably continue until all forests are destroyed.

CLIMATIC ROLE OF FORESTSAs previously discussed, tropical rainforests play a vital role in local climate regulation by their interaction with water cycles. However, rainforests also have a significant effect on global weather. Rainforests, like all forms of vegetation, affect the "surface albedo" or reflectivity of a surface by absorbing more heat than bare soil. Norman Myers (1997) explains, Much of the energy that converts surface moisture into water vapor comes from the sun's radiational heating of the land surface. The energy thus depends on surface albedo, or relevant degree of reflectant "shininess" of the land surface (Gash and Shuttleworth 1992). In turn, the albedo depends on the vegetation, which absorbs more heat than does bare soil. Over thick vegetation, vigorous thermal currents take moisture (provided by the same plant cover) up into the atmosphere, where it condenses as rain. Because of its influence on convection patterns and wind currents, and hence on rainfall regimes, the albedo effect constitutes a basic factor in controlling climate. The loss of forest vegetative cover means less heat absorption translating to less moisture being taken up into the atmosphere. Rainfall is also affected when forest-clearing fires create air pollution and release tiny particles, known as aerosols, into the atmosphere. While aerosols can both heat and cool the air, depending on their size, shape, and color, high concentrations of biomass-burning aerosols directly impact local climate by increasing cloud formation but decreasing rainfall, according to research by NASA. In areas with lots of smoke, "cloud droplets form around the aerosol particles, but may6

never grow large enough to fall as rain," say researchers with NASA's Goddard Space Flight Center who studied the effect. Thus large forest fires have the effect of further reducing rainfall, leaving burned areas more prone to dryness and future fires. In the long run, these changes explain why deforested regions may experience a decline in rainfall. Tropical deforestation can also affect weather in other parts of the world. A 2005 study by NASA found that deforestation in the Amazon region of South America influences rainfall from Mexico to Texas and in the Gulf of Mexico, while forest loss in Central Africa affects precipitation patterns in the upper and lower U.S Midwest. Similarly, deforestation in Southeast Asia was found to impact rainfall in China and the Balkan Peninsula.

LINKAGES BETWEEN FORESTS AND CLIMATEDeforestation is the loss of tree cover, usually as a result of forests being cleared for other land uses such as farming or ranching. Some limit the definition of deforestation to the permanent conversion of forests to another habitat. Others add to this definition by including the conversion of natural forests to artificial forests such as plantations. Deforestation activities affect carbon fluxes in the soil, vegetation, and atmosphere.8 The effects of these activities can vary, depending on the type of activity. For example, logging can lead to carbon storage if trees are converted to wood products (e.g., lumber) and deforested areas are restored. (The issues surrounding tree planting to offset deforestation are discussed below.) Soil Impacts The impact of deforestation on soils, and the release of soil carbon, depends on the magnitude of soil disturbance and the type of soil. Soil carbon content is related to the lifecycle of the vegetation it supports. When vegetation dies, it decomposes and releases carbon. Some carbon is deposited in the soil; some is dissolved and leaches into surface waters or groundwater; and some is released directly to the atmosphere as CO2. Deforestation exposes soils to sunlight, which increases soil temperature and the rate of soil carbon oxidation. This process increases the rate of CO2 release to the atmosphere. Soil carbon can also be released at high rates if soils are disturbed, for example, by logging operations or tillage. Peat soils are particularly important for climate because of their very high carbon content (as well as CH4 content and release). Peat soils generally occur in forests where natural decomposition rates are low, such as in periodically flooded forests or forests with a short growing (and thus decomposition) season. Peat soils may partly account for the high soil carbon levels of boreal forests, but some occur in temperate and tropical forests. Peat soils are considered major carbon sinks, and could potentially be large sources of carbon emissions, if disturbed.7

Wood Utilization/Wood Waste Deforestation can lead to carbon emissions from decomposing vegetation left on the forest floor. However, wood converted into productssuch as lumber and plywoodcould store carbon for many years, ranging from an average of 10 years for shipping pallets to 100 years or more for lumber. Paper products store carbon for a brief duration, often less than a year. The proportion of a tree converted to products varies widely, and depends on the size (diameter) and form (taper and branching) of the tree as well as the particular species. The purpose of the tree cutting also affects utilization and waste. Harvesting pulpwood for paper production, for example, can include much more of the woody biomass than harvesting veneer bolts for plywood or sawlogs for lumber. Cutting to clear a site for agriculture yields much more waste, as the woody biomass is generally burned to prepare the site for crop or pasture production. In addition, the harvest method can affect wood utilization and waste. Selective logging, where certain trees or species are harvested, can lead to large quantities of wood waste because more roads are needed and because the harvest and extraction procedures often damage the remaining trees. Clear-cutting can reduce wood waste, when the majority of the trees can be removed for wood products, but can increase biomass waste if done to clear land for agriculture. One techniquereduced impact logging (RIL)has been developed to reduce timber harvest damage to soils and residual trees. 11 Descriptions of RIL are typically either lacking in details or highly site-specific with limited general applicability, because the practices that will reduce logging damages depend on a variety of site conditions, such as soil type and water content, and tree species diversity. Nonetheless, one source reported that RIL reduces wood waste by more than 60% and soil disturbance in roads, landings, and skid trails by almost 50%. However, a major barrier to increased use of RIL is illegal logging in the tropics. Biomass not removed for products remains on the site and decomposes. Some of the carbon is deposited in the soil and some is released into the atmosphere. If the remaining biomass is burned, as is common in clearing lands for agriculture and in preparing sites for reforestation, the carbon is quickly released to the atmosphere. For unburned on-site biomass, the rate of decomposition (and hence of carbon emissions) varies due to moisture (many fungi and bacteria grow better in moist environments), temperature (higher temperatures also improve fungi and bacteria growth), and type of wood (some species contain chemicals that inhibit decomposers), among other things. BurningNatural and Anthropogenic Forest firesboth natural and anthropogeniccan kill some or all of the trees in a forest. Forested ecosystems have evolved with a variety of natural fire regimes. Some ecosystems have rare natural fires; others are fire-prone. The nature and extent of natural fires are related to the evolutionary development of the natural fire regimes, to climatic conditions such as drought, and to the amount of woody fuels in some ecosystems. Fire affects climate by releasing large quantities of CO2 to the atmosphere in short periods, and thus extensive burning can affect the global climate.16 Fires also produce large quantities of fine particulates and aerosols. These8

pollutants can be hazardous to human health, but they also absorb and reflect sunlight, which creates cooler temperatures in the forest. Anthropogenic burning is a greater concern for carbon emissions than natural fires. For example, fire is commonly used to clear land in the tropics. Studies report that anthropogenic ignitions are the predominant factor in starting wildfires in tropical forests. Man-made fires in areas not prone to natural fires can lead to a positive feedback loop, where increasing fire frequency can alter plant regrowth until forests do not regenerate and the areas are converted to brush fields. In contrast, natural fires are part of the carbon cycle, with carbon emissions balanced by plant regrowth over the long run. According to some, this balance justifies not controlling natural fires to mitigate climate change. Others contend that natural fires could exacerbate the ecological effects of anthropogenic fires on forest ecosystems, and argue that both should be regulated and controlled, depending on the location and fire history of the site.

OTHER RELATIONSHIPS BETWEEN DEFORESTATION AND CLIMATE CHANGEFour other relationships between deforestation and climate change are discussed in the literature: Disturbances Other Than Fire. Forests are disturbed by insect infestations, disease, drought, invasive species, wind and ice storms, and landslides, among other things. Understanding of how these disturbances relate to climate change is generally incomplete. An exception is the relationship between increased pine beetle infestations in the Rocky Mountains and warmer temperatures. Warmer temperatures allow pine beetles to increase their seasonal reproductive rate and expand their range among pine stands. Some are concerned that climate change will exacerbate forest disturbances, leading to further climate change (i.e., creating a positive feedback loop). Albedo Effect. Albedo is a measure of the reflectivity of surfaces (e.g., vegetation, soils, and water)darker surfaces absorb more sunlight (e.g., fir forests), while light-colored surfaces reflect more sunlight (ice or snow). Darker surfaces heat the surrounding atmosphere more than lighter surfaces, making albedo important for climate. Climate models have shown that the reduced surface heating from the very high albedo of snow-covered boreal forest openings more than offsets the warming from the CO2 released in creating those openings. For temperate forests, where the openings are snow-covered for a briefer period, the albedo effect is relatively minor. For tropical forests, where there is no snow and where the vegetation is a broader mix of species, there is no significant difference in albedo between the forest canopy and forest openings. Carbon Dioxide Fertilization of Forests. Because CO2 is critical to vegetative growth, some have hypothesized that elevated CO2 levels will increase forest growth. Studies of temperate forests report that excess carbon in the atmosphere can increase photosynthesis and plant growth in trees for short periods, particularly for young stands. Long-term effects are unknown because9

experiments need more time to collect data. Other researchers note that sustained enhanced growth due to high CO2 levels may be limited by factors such as drought and nitrogen availability. For tropical forests, some suggest that carbon saturation by leaves of tropical trees may limit response to CO2 enrichment, and decreased productivity could result from periods of higher temperatures and drought. Hydrological Patterns. Climate change can directly alter precipitation patterns, sometimes causing drought in some areas. Researchers report that higher CO2 levels and temperatures increase water use by plants. The combination of drought and demand for greater water could stress forests and cause changes in the ecosystem. In contrast, broad-scale deforestation has been shown to reduce evapotranspiration (water loss to the atmosphere) by plants, which reduces cloud formation and downwind precipitation. The combination of changes in precipitation patterns, plant water use, and evapotranspiration could have significant synergistic effects.

LOCAL AND NATIONAL CONSEQUENCESLOSS OF LOCAL CLIMATE REGULATION The local level is where deforestation has the most immediate effect. With forest loss, the local community loses the system that performed valuable but often underappreciated services like ensuring the regular flow of clean water and protecting the community from flood and drought. The forest acts as a sort of sponge, soaking up rainfall brought by tropical storms while anchoring soils and releasing water at regular intervals. This regulating feature of tropical rainforests can help moderate destructive flood and drought cycles that can occur when forests are cleared. When forest cover is lost, runoff rapidly flows into streams, elevating river levels and subjecting downstream villages, cities, and agricultural fields to flooding, especially during the rainy season. During the dry season, such areas downstream of deforestation can be prone to monthslong droughts which interrupt river navigation, wreak havoc on crops, and disrupt industrial operations. Situated on steep slopes, montane and watershed forests are especially important in ensuring water flow and inhibiting erosion, yet during the 1980s, montane formations suffered the highest deforestation rate of tropical forests. Additionally, the forest adds to local humidity through transpiration (the process by which plants release water through their leaves), and thus adds to local rainfall. For example, 50-80 percent of the moisture in the central and western Amazon remains in the ecosystem water cycle. In the water cycle, moisture is transpired and evaporated into the atmosphere, forming rain clouds before being precipitated as rain back onto the forest. When the forests are cut down, less10

moisture is evapotranspired into the atmosphere resulting in the formation of fewer rain clouds. Subsequently there is a decline in rainfall, subjecting the area to drought. If rains stop falling, within a few years the area can become arid with the strong tropical sun baking down on the scrub-land. Today Madagascar is largely a red, treeless desert from generations of forest clearing with fire. River flows decline and smaller amounts of quality water reach cities and agricultural lands. The declining rainfall in interior West African countries has in part been attributed to excessive clearing of the coastal rainforests. Similarly, new research in Australia suggests that if it were not for human influencesspecifically widespread agricultural firesthe dry outback might be a wetter, more hospitable place than it is today. The effect of vegetation change from forests that favor rainfall to grassland and bush can impact precipitation patterns. Colombia, once second in the world with freshwater reserves, has fallen to 24th due to its extensive deforestation over the past 30 years. Excessive deforestation around the Malaysian capital of Kuala Lumpur, combined with the dry conditions created by el Nio, triggered strict water rationing in 1998, and for the first time the city had to import water. There is serious concern that widespread deforestation could lead to a significant decline in rainfall and trigger a positive-feedback process of increasing dessication for neighboring forest cover; reducing its moisture stocks and its vegetation would then further the dessication effect for the region. Eventually the effect could extend outside the region, affecting important agricultural zones and other watersheds. At the 1998 global climate treaty conference in Buenos Aires, Britain, citing a disturbing study at the Institute of Ecology in Edinburgh, suggested the Amazon rainforest could be lost in 50 years due to shifts in rainfall patterns induced by global warming and land conversion. The newly dessicated forest becomes prone to devastating fires. Such fires materialized in 1997 and 1998 in conjunction with the dry conditions created by el Nio. Millions of acres burned as fires swept through Indonesia, Brazil, Colombia, Central America, Florida, and other places. The Woods Hole Research Center warned that more than 400,000 square kilometers of Brazilian Amazonia were highly vulnerable to fire in 1998.

GLOBAL CONSEQUENCESTropical rainforests play a vital role in the functioning of the planet's natural systems. The forests regulate local and global weather through their absorption and creation of rainfall and their exchange of atmospheric gases. For example, the Amazon alone creates 50-80 percent of its own rainfall through transpiration. Cutting the rainforests changes the reflectivity of the earth's surface, which affects global weather by altering wind and ocean current patterns, and changes rainfall distribution. If the forests continue to be destroyed, global weather patterns may become more unstable and extreme.

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CONCLUSIONReducing deforestration & degradation is highly cost-sffective way of reducig GHG- one that can be done immediately if drivers of deforestration are addressed strategically. If done right, it can also benefit biodiversity conservation and people. Countries need to develop national frameworks to to tacke forest based emmisions. Reduced deforestration and forest degradation must be part of the solution to the global climate problem WWFs Climate Solutions report indicates that if emmissions from deforestration and forest degradation are not curbed, the likelihood of success in preventing dangerous climate change is drastically reduced.

REFERENCES1. See D. P. Dykstra, Reduced Impact Logging: Concepts and Issues, FAO Corporate Document Repository, http://www.fao.org/docrep/005/ac805e/ac805e04.htm. 2 Tropical Forest Foundation, Reduced Impact Logging, at http://www.tropicalforestfoundation.org/get-verified/reduced-impact-logging. 3 See CRS Report RL33932, Illegal Logging: Background and Issues, by Pervaze A. Sheikh. 4 M. A. Krawchuk et al., Global Pyrogeography: The Current and Future Distribution of Wildfire, PLoS One, vol. 4,no. 4 (April 2009), pp. 1-12. 5 For more information, see CRS Report R40811, Wildfire Fuels and Fuel Reduction, by Ross W. Gorte. 6 T. M. Bonnicksen, Greenhouse Gas Emissions from Four California Wildfires: Opportunities to Prevent and Reverse Environmental and Climate Impacts, The Forest Foundation, FCEM Report No. 2, Auburn, CA, March 12, 2008, pp. 1-19. 7 V. Ramanathan et al., Warming Trends in Asia Amplified by Brown Cloud Solar Absorption, Nature, vol. 448 (2007), pp. 575-578. 8 M. A. Cochrane and C. P. Barber, Climate Change, Human Land Use and Future Fires in the Amazon, Global Change Biology, vol. 15, no. 3 (November 2008), pp. 601-612. 9. Deforestation and Climate Change, at http://wwf.panda.org/about_our_earth/about_forests/deforestation/ 10. Global Impact of DeforestationClimatic Role of Forests, at http://rainforests.mongabay.com/0906.htm 11. Local And National Consequences, at http://rainforests.mongabay.com/0906.htm 12. Environmental Issues in the 21st century Deforestation at, http://library.thinkquest.org/C0127068/deforestation.html

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