Earth system modeling


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Earth system modeling

  2. 2. DEFORESTATION: ETHIOPIA AND ITS IMPACTSINTRODUCTION1. Deforestation and land degradation and their climatic impacts Deforestation refers to the conversion of forested land into non-forested lands such as agricultural, cattle pastures, residential areas, lakes and deserts. Deforestation in Ethiopia is due to locals clearing forests for their personal needs, such as for fuel, hunting, agriculture, housing development, and at times for religious reasons. Deforestation is the process of removing the forest ecosystem by cutting the trees and changing the shape of the land to suit different uses. Among developing countries, especially in Africa, Ethiopia is exceptionally rich in history, as well as cultural and biological diversity.
  3. 3. DEFORESTATION. desertification Land degradation
  4. 4. Cont’d… It is home to one of the earliest ancestors of the human species, around 80 languages are spoken by various ethnic groups, and it is home to two globally important biodiversity hotspots. However, this rich cultural and natural heritage is threatened, especially in the form of deforestation. Ethiopia has the second largest population in Africa and has been hit by famine many times due to rain shortages and a depletion of natural resources. Deforestation may have further lowered the already meager rainfall. As the population continues to grow, the needs of the people increase. The country has lost 98% of its forested regions in the last 50 years due deforastation and impact on land degradation.
  5. 5. Cont’d… One of the major challenges facing Ethiopia in striving for development is environmental degradation, manifested in the degradation of land and water resources as well as loss of biodiversity. Land degradation is expressed in terms of soil erosion and loss of soil fertility. Deforestation/devegetation is one of the major factors contributing to land degradation by exposing the soil to various agents of erosion. With high-intensity rainstorms and extensive steep slopes, Ethiopia is highly susceptible to soil erosion, especially in the highlands. The organic content of soils is often low due to the widespread use of dung and crop residues for energy.
  6. 6. Cont’d… Land degradation in turn greatly affects agricultural productivity and production. In 1990 alone, for instance, reduced soil depth caused by erosion resulted in a grain production loss of 57,000 (at 3.5 mm soil loss) to 128,000 tons (at 8 mm soil depth). It has been estimated that the grain production lost due to land degradation in 1990 would have been sufficient to feed more than four million people. The availability of land suitable for agriculture is shrinking, while at the same time the amount of land required to feed the growing population is steadily increasing. With agricultural productivity increases lagging behind population growth rates, the gap between availability and demand for agricultural land continues to grow, resulting in severe land-use conflicts between crop farming, animal grazing, and forestry.
  7. 7. Cont’d… Forestry can play a role in reducing land pressure and land degradation, but forestry alone cannot solve the problem. Even if the management of existing forest resources is improved and new trees and forests are established, this may well prove futile if high population growth rates continue to increase the need for crop and grazing land. Using the land for forestry to improve soil fertility or to rehabilitate and conserve the environment will be viewed as secondary to using the land for cropping and grazing to meet immediate survival needs. Attempts to alleviate land degradation are therefore critically dependent on efforts to deal with the three main underlying causes of land degradation, namely population growth, low agricultural productivity, and high dependence on fuel wood, dung, and crop residue as sources of household energy.
  8. 8. Cont’d… Considering the magnitude of the land degradation problem, conservation programs implemented so far are inadequate. The policy, institutional, planning, and technical constraints responsible for the inadequacy of past conservation efforts are presented, and any future initiatives to overcome the escalating land degradation problem in Ethiopia should first address these constraints realistically. There are no universal formulae or solutions that can work across the board; rather, solutions should be locality-specific and closely tied to the socioeconomic setup of the communities.
  9. 9. Cont’d… In this regard, forestry can play a significant role in either preventing or arresting land degradation by avoiding or reducing soil erosion through reduced surface runoff and maintenance of organic matter and soil fertility. It can help not only in addressing off-farm and on-farm dimensions of soil erosion but also in maintaining the fertility of the soil, thereby alleviating land degradation and the destruction of natural resources. Favorable climatic and ecological conditions, sufficient rainfall, moderate temperatures, and well developed soils in the Ethiopian highlands may have been the basis for early development of agricultural systems and high human population in this agro-climatic zone.
  10. 10. Cont’d… 50% of the remaining highlands are highly susceptible to erosion. FAO (1984) reported that on two million ha of cultivated land, the soil depth is so reduced that the land is no longer able to support any vegetative cover. The Hararghae highlands in Eastern Ethiopia, Tigrai, Wollo, and Semen Shoa highlands in the North and the Gamo-Gofa highlands and the Bila-te River basin, which starts in Eastern slopes of Gurage highlands and stretches through Eastern Hadiya and Kembatta highlands, are some of the seriously eroded land surfaces in Ethiopia. The highland areas in Ethiopia are defined and delineated to represent the land areas above 1500 m a.s.l. and the lowlands are defined as areas below 1500 m a.s.l. in altitude. More than 90% of Ethiopia’s population live in the highlands including about 93% of the cultivated land, around 75% of the country’s livestock and accounts for over 90% of the country’s economic activity.
  11. 11. Deforestation in highland of Ethiopia. Wollo Tigrai Hararg hae Gamo- Gofa
  12. 12. Cont’d… Land degradation is seriously threatening the economic and social development of the country as a whole. Due to degradation, increasing number of Ethiopians have become vulnerable to the effects of drought. The severity of the devastating droughts and the resulting famines in 1972/73 and 1984/85 can be attributed to an accelerating process of degradation combined with widespread general poverty of the population. Measurements of land degradation usually focuses on the severity of soil erosion mainly caused by high-intensity rain storms on rugged geomorphic features, steep slopes, and barren land surfaces highly susceptible to soil erosion.
  13. 13. Deforestation and Climate Change Global climate change is a widespread and growing concern that has led to extensive congressional and international discussions and negotiations. Climate change mitigation strategies have focused on reducing emissions of greenhouse gases (GHGs), especially carbon dioxide (CO2). One significant source of CO2 emissions is deforestation. Reducing deforestation to lower CO2 emissions is seen as one of the least costly methods of mitigating climate change. Forests are carbon sinks in their natural state (i.e., they store more carbon than they release).
  14. 14. ..
  15. 15. Cont’d… Trees absorb CO2 and convert carbon into leaves, stems, and roots, while releasing oxygen. Forests account for more than a quarter of the land area of the earth, and store more than three quarters of the carbon in terrestrial plants and nearly 40% of soil carbon. When forests are cleared, some of their carbon is released to the atmosphere—slowly through decay or quickly through burning. One estimate shows that land use change, primarily deforestation, releases about 5.9 Gt CO2 (giga tons or billion metric tons of CO2) annually, about 17% of all annual anthropogenic GHG emissions. This contribution to GHG emissions makes efforts to reduce deforestation significant in international strategies to mitigate climate change.
  16. 16. Deforastation and climate change. Soil erosion due to deforastation
  17. 17. Linkages between Forests and Climate Deforestation 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. 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.
  18. 18. Cont’d…. However, logging can also lead to carbon emissions if the surrounding trees and vegetation are damaged, and if not all woody biomass is processed into products. Other activities that alter the carbon cycle in forests and affect climate.
  19. 19. Deforestation in EthiopiaI. Natural Forest cover Ethiopia‘s flora and fauna have a large number of species with a considerable rate of endemism. Forests and woodlands provide various benefits in the country including as sources of wood and construction materials, land for farming and grazing, non wood forest products and services and various ecological functions some of which have global values. However, with a growing human population of about 75 million largely dependent on low-productivity and rain-fed agriculture and over 70 million livestock population competing for land and forest resources, deforestation and forest degradation are important problems in Ethiopia.
  20. 20. Cont’d… The forest cover in Ethiopia is estimated at less than 4% compared, for example, with an average of 20% for sub-Saharan Africa (Earth Trends, 2007; WBISPP, 2004). The rate of deforestation is estimated to be as high as 5% per year (EFAP, 1994a; Reusing, 1998; WBISPP, 2004b). Reduction in forest cover has a number of consequences including soil erosion and reduced capacity for watershed protection with possible flooding, reduced capacity for carbon sequestration, reduced biodiversity and instability of ecosystems and reduced availability of various wood and non-wood forest products and services.
  21. 21. Cont’d… Forests in Ethiopia play a big role in protecting erosion, as tree roots protect against washouts. Trees also help to keep water in the soil and reduce global warming by uptake of carbon dioxide. Because there are not enough trees, the Blue Nile is carrying all the soil and nutrients in the water to the neighboring countries of Sudan and Egypt. At the beginning of the twentieth century around 420,000 square kilometers (35% of Ethiopia’s land) was covered by trees but recent research indicates that forest cover is now less than 14.2% due to population growth. Despite the growing need for forested lands, lack of education among locals has led to a continuing decline of forested areas.
  22. 22. Cont’d… Change in Forest Cover: Between 1990 and 2000, Ethiopia lost an average of 140,900 hectares of forest per year. The amounts to an average annual deforestation rate of 0.93%. Between 2000 and 2005, the rate of forest change increased by 10.4% to 1.03% per annum. In total, between 1990 and 2005, Ethiopia lost 14.0% of its forest cover, or around 2,114,000 hectares. Measuring the total rate of habitat conversion (defined as change in forest area plus change in woodland area minus net plantation expansion) for the 1990-2005 intervals, Ethiopia lost 3.6% of its forest and woodland habitat.
  23. 23. II. Causes of deforestation The major cause of deforestation in Ethiopia is the rapid population growth, which leads shifting agriculture, to an increase in the demand for crop and grazing land, livestock production, wood for fuel drier areas and construction. Lack of viable land use policy and corresponding law also aggravated the rate of deforestation. New settlements in forests are increasing from time to time and hence resulted in the conversion of forested land into agricultural and other land use systems. At present, the few remaining high forests are threatened by pressure from investors who are converting the moist evergreen montane forests into other land use systems such as coffee and tea plantations.
  24. 24. ..
  25. 25. Cont’d… Developing nations are faced with a two-edged sword in the field of energy. On the one hand the rising price of oil has reduced the potential for fossil fuel energy and eroded foreign exchange reserves in oil- importing countries. At the same time deforestation may be causing increased prices or shortages of fuels such as fuel wood and charcoal
  26. 26. ..
  27. 27. III. Annual trend of naturalforest cover and deforestationEthiopia Forest Information and Data About 12,296,000 ha or 11.2% of Ethiopia is forested, according to FAO. Of this 4.2% (511,000 ha) is classified as primary forest, the most biodiversity and carbon-dense form of forest. Ethiopia had 511,000 ha of planted forest. Change in Forest Cover: Between 1990 and 2010, Ethiopia lost an average of 140,900 ha or 0.93% per year. In total, between 1990 and 2010, Ethiopia lost 18.6% of its forest cover or around 2,818,000 ha. Ethiopias forests contain 219 million metric tons of carbon in living forest biomass.
  28. 28. Cont’d… Biodiversity and Protected Areas: Ethiopia has some 1408 known species of amphibians, birds, mammals and reptiles according to figures from the World Conservation Monitoring Centre. Of these, 7.0% are endemic, meaning they exist in no other country, and 4.6% are threatened. Ethiopia is home to at least 6603 species of vascular plants, of which 15.1% are endemic. 4.9% of Ethiopia is protected under IUCN categories I-V.
  29. 29. Ethiopia: Forest Cover, 2010Total Land Area (1000 square 109631kilometers)Total Forest Area (1000 ha) 12296Percent Forest Cover 11Primary Forest Cover (1000 ha) 0Primary Forest, % total forest 0Other wooded land (1000 ha) 44650Percent other wooded land 41
  30. 30. Ethiopia: Breakdown of forest types, 2010Primary forest (1000 ha | 0 0% of forest area)Other naturally regeneratedforest (1000 ha | % of forest 11785 96area)Planted Forest (1000 ha | % 511 4of forest area)
  31. 31. Ethiopia: Trends in Total (Net) Forest Cover, 1990-2010 TOTAL FOREST COVER (1000 ha) 1990 2000 2005 2010 15114 13705 13000 12296 ANNUAL CHANGE RATE (1000 ha) Negative number represents deforestation 1990-2000 2000-2005 2005-2010 -141 -141 -141
  32. 32. Cont’d…ANNUAL CHANGE RATE (percent)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 -0.97 -1.05 -1.11
  33. 33. Ethiopia: Trends in Natural ForestCover (Deforestation), 1990-2010FOREST COVER (excluding planted forests) (1000 ha) 1990 2000 2005 2010 14623.00 13214.00 12509.00 11785.00ANNUAL CHANGE RATE (1000 ha)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 -141 -141.00 -143.00ANNUAL CHANGE RATE (percent)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 -1.0 -0.96 -1.08
  34. 34. Ethiopia: Trends in Primary or Old GrowthForest Cover, 1990-2010PRIMARY FOREST COVER (1000ha) 1990 2000 2005 2010 0 0 0 0ANNUAL CHANGE RATE (1000 ha)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 0 0 0ANNUAL CHANGE RATE (percent)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 - - -
  35. 35. Ethiopia: Trends in Planted Forest Cover,1990-2010PLANTED FOREST COVER (1000 ha) 1990 2000 2005 2010 491 491 491 511ANNUAL CHANGE RATE (1000 ha)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 0 0 4ANNUAL CHANGE RATE (percent)Negative number represents deforestation 1990-2000 2000-2005 2005-2010 0 0 0.80
  36. 36. Ethiopia: Trends in carbon stock in livingforest biomass 1990-2010CARBON STOCK IN LIVING FOREST BIOMASS (million metric tons) 1990 2000 2005 2010ANNUAL CHANGE (1 000 t/yr) 254 289 236 219 0 1990 -4 2000 -4 2005 -3 2010 1222 9000 9001 0050 nnn ... sss ...
  37. 37. Impact of deforestation in Ethiopia Deforestation is a major concern in Ethiopia as studies suggest loss of forest contributes to soil erosion, loss of nutrients in the soil, loss of animal habitats and reduction in biodiversity, averting of water quality, and climate change. The vegetation resources and ecology of Ethiopia, including forests, woodlands and bush lands, conservation of soil, have been studied by several scholars who have employed different methods and have studied different localities to come up with conclusions.(deferu,2010).
  38. 38. Cont’d… One of the major impacts of deforestation is through its effect in reducing the level of agricultural production and productivity, making the nation unable to feed its people. This situation has often necessitated increased volume of food imports, in the form of commercial imports and also as food aid. In addition, the high level of deforestation has resulted in worsening the household energy consumption problems in Ethiopia, as fuel wood, dung and crop residue are the major sources of household energy consumption.
  39. 39. ..Drought and no grass No place for wild animal
  40. 40. Cont’d… During the next few decades, global ecological changes are expected to have major impacts on ecological, social, economic, and political aspects of human society (Dale, 1997). The ecological impacts include changes to biodiversity, productivity, migration, safety, and sustainability. Climate and land use changes are two major global ecological changes predicted for the future. Therefore causes and consequences of human-induced climate change and land use activities have largely been examined independently (Turner et al., 1993). However, climate change and land use affect each other
  41. 41. Cont’d… Land use activity contributes to climate change and soil erosion, and changes in land cover patterns are one way in which the effects of climate change is expressed. Land use is the human modification of natural environment or wilderness to build fields, pastures, and settlements. The major effect of land use on land cover has been deforestation of temperate regions (IPCC, 2007). More recent significant effects of land use include urban spread out, soil erosion, soil degradation, salinization, and desertification. Land use and land management practices have a major impact on natural resources including water, soil, nutrients, plants, and animals.
  42. 42. Cont’d… According to a report by the United Nation Food and Agriculture Organization (FAO, 1995), land degradation has been exacerbated where there has been no effective land use planning, or of its orderly execution, or the existence of financial or legal incentives that have led to the wrong land use decisions, or one-sided central planning leading to overutilization of the land resources - for instance for immediate production at all costs. As a consequence, the result has often been misery for large segments of the local population and destruction of valuable ecosystems. Such narrow approaches should be replaced by a technique for the planning and management of land resources that is integrated and holistic and where land users are central.
  43. 43. Cont’d… This will ensure the long term quality of the land for human use, the prevention or resolution of social conflicts related to land use, the conservation of ecosystems of high biodiversity value, and mitigation of the rate of climate change. Land use effects on climate change and soil erosion include both implications of land use change on atmospheric flux of carbon dioxide (CO2) and its subsequent impact on climate and soil, and the alteration of climate change impacts through land management. An effect of climate change on land use refers to both how land use might be altered by climate change and what land management strategies would mitigate the negative effects of climate change.
  44. 44. Cont’d… The direct ecological effects of land use and climate change are dominated by the land use change effects, at least over a period of a few decades (Dale, 1997). Because climate change effects are largely determined by land cover patterns, land use practices set the stage on which climate alterations can act. Determining the effects of climate change on land use involves resolving direct biophysical effects as well as management responses to climate impacts. The population density on given land use system links deforestation with soil erosion and facilitates their effects on climate change through land use of human activity. There are two aspects to considering impacts of land use: effects of land use on climate change and soil erosion; and the effects of human induced climate change on land use.
  45. 45. 4. Mechanism (ways) to stopdeforestationControlling deforestationFarming New methods are being developed to farm more intensively, such as high-yield hybridcrops, greenhouse, autonomous building gardens, and hydroponics. These methods are often dependent on chemical inputs to maintain necessary yields. In cyclic agriculture, cattle are grazed on farm land that is resting and rejuvenating. Cyclic agriculture actually increases the fertility of the soil. Intensive farming can also decrease soil nutrients by consuming at an accelerated rate the trace minerals needed for crop growth.
  46. 46. Forest management Efforts to stop or slow deforestation have been attempted for many centuries because it has long been known that deforestation can cause environmental damage sufficient in some cases to cause societies to collapse.
  47. 47. Reforestation In Ethiopia deforestation is a major problem and many peasants have switched from fuel wood to dung for cooking and heating purposes, thereby damaging the agricultural productivity of cropland. The Ethiopian government has embarked on a two-pronged policy in an effort to stem deforestation and the degradation of agricultural lands: (i) tree planting or afforestation; (ii) dissemination of more efficient stove technologies. The motivation in here is, therefore, to examine the potential of the strategy of disseminating improved stoves in the rehabilitation of agricultural and forests lands.
  48. 48. Forest plantations To meet the worlds demand for wood it has been suggested by forestry that high-yielding forest plantations are suitable. It has been calculated that plantations yielding 10 cubic meters per hectare annually could supply all the timber required for international trade on 5 percent of the worlds existing forestland. By contrast natural forests produce about 1-2 cubic meters per hectare, therefore 5 to 10 times more forest land would be required to meet demand. Forester Chad Oliver has suggested a forest mosaic with high- yield forest lands interspersed with conservation land.
  49. 49. ..
  50. 50. Cont’d… Carrying out afforestation programme and improved management of forest resources alone, however successful, will not be able to solve our problems as far as our need for crop and grazing land continues to grow due to high population growth rates. This is because of the fact that using the land for forestry to improve soil fertility or to rehabilitate and conserve the environment will be viewed as secondary to using the land for cropping and grazing to meet immediate needs of survival.
  51. 51. Cont’d… Hence, any attempt by the government, the public and NGOs to address the problem of deforestation in particular and land degradation in general critically depends upon our efforts and capacity to deal with the three major issues of population growth, low agricultural productivity and high dependence on fuel wood, dung and crop residue as sources of household energy. Finally, the government should devise and implement strategies and policies relating to afforestation only as an integral part of the overall rural development programme.
  52. 52. . forest Do you see the d/ce? Bare land