Earth system modeling

ARBAMINCH UNIVERSITYSCHOOL OF GRADUATE

S STUDENT

FACULTY OF NATURAL SCIENCEDEPARTMENT OF HYDROLOGY AND METEOROLOGYEARTH SYSTEM MODELING

SUBMITED BY MEKONNEN DABAMAY 20, 2011

DEFORESTATION: ETHIOPIA AND ITS IMPACTSINTRODUCTION

1. 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 attimes for religious reasons.

Deforestation is the process of removing the forest ecosystem by cutting thetrees and changing the shape of the land to suit different uses.

Among developing countries, especially in Africa, Ethiopia is exceptionally richin history, as well as cultural and biological diversity.

DEFORESTATION.

Landdegradation

desertification

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 twoglobally important biodiversity hotspots. However, this rich culturaland natural heritage is threatened, especially in the form ofdeforestation.

Ethiopia has the second largest population in Africa and has been hitby famine many times due to rain shortages and a depletion of naturalresources. Deforestation may have further lowered the already meagerrainfall. As the population continues to grow, the needs of the peopleincrease. The country has lost 98% of its forested regions in the last 50years due deforastation and impact on land degradation.

Cont’d…One of the major challenges facing Ethiopia in striving for

development is environmental degradation, manifested in thedegradation of land and water resources as well as loss of biodiversity.

Land degradation is expressed in terms of soil erosion and loss of soilfertility. Deforestation/devegetation is one of the major factorscontributing to land degradation by exposing the soil to various agentsof erosion. With high-intensity rainstorms and extensive steep slopes,Ethiopia is highly susceptible to soil erosion, especially in thehighlands. The organic content of soils is often low due to thewidespread use of dung and crop residues for energy.

Cont’d… Land degradation in turn greatly affects agricultural productivity and

production. In 1990 alone, for instance, reduced soil depth caused byerosion resulted in a grain production loss of 57,000 (at 3.5 mm soilloss) to 128,000 tons (at 8 mm soil depth). It has been estimated thatthe grain production lost due to land degradation in 1990 would havebeen sufficient to feed more than four million people.

The availability of land suitable for agriculture is shrinking, while atthe same time the amount of land required to feed the growingpopulation is steadily increasing.

With agricultural productivity increases lagging behind populationgrowth rates, the gap between availability and demand for agriculturalland continues to grow, resulting in severe land-use conflicts betweencrop farming, animal grazing, and forestry.

Cont’d…Forestry can play a role in reducing land pressure and land

degradation, but forestry alone cannot solve the problem. Evenif the management of existing forest resources is improved andnew trees and forests are established, this may well prove futile ifhigh population growth rates continue to increase the need forcrop and grazing land.

Using the land for forestry to improve soil fertility or torehabilitate and conserve the environment will be viewed assecondary to using the land for cropping and grazing to meetimmediate survival needs.

Attempts to alleviate land degradation are therefore criticallydependent on efforts to deal with the three main underlyingcauses of land degradation, namely population growth, lowagricultural productivity, and high dependence on fuel wood,dung, and crop residue as sources of household energy.

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 arepresented, and any future initiatives to overcome the escalating landdegradation problem in Ethiopia should first address these constraintsrealistically.

There are no universal formulae or solutions that can work across theboard; rather, solutions should be locality-specific and closely tied tothe socioeconomic setup of the communities.

Cont’d… In this regard, forestry can play a significant role in either preventing

or arresting land degradation by avoiding or reducing soil erosionthrough reduced surface runoff and maintenance of organic matter andsoil fertility. It can help not only in addressing off-farm and on-farmdimensions of soil erosion but also in maintaining the fertility of thesoil, thereby alleviating land degradation and the destruction ofnatural resources.

Favorable climatic and ecological conditions, sufficient rainfall,moderate temperatures, and well developed soils in the Ethiopianhighlands may have been the basis for early development ofagricultural systems and high human population in this agro-climaticzone.

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 depthis so reduced that the land is no longer able to support any vegetativecover.

The Hararghae highlands in Eastern Ethiopia, Tigrai, Wollo, andSemen Shoa highlands in the North and the Gamo-Gofa highlands andthe Bila-te River basin, which starts in Eastern slopes of Guragehighlands and stretches through Eastern Hadiya and Kembattahighlands, are some of the seriously eroded land surfaces in Ethiopia.

The highland areas in Ethiopia are defined and delineated to representthe land areas above 1500 m a.s.l. and the lowlands are defined as areasbelow 1500 m a.s.l. in altitude. More than 90% of Ethiopia’s populationlive in the highlands including about 93% of the cultivated land,around 75% of the country’s livestock and accounts for over 90% of thecountry’s economic activity.

Deforestation in highland of Ethiopia

. TigraiWollo

Hararghae

Gamo-Gofa

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 ofdegradation combined with widespread general poverty of thepopulation.

Measurements of land degradation usually focuses on the severity ofsoil erosion mainly caused by high-intensity rain storms on ruggedgeomorphic features, steep slopes, and barren land surfaces highlysusceptible to soil erosion.

Deforestation and Climate Change Global climate change is a widespread and growing concern that has

led to extensive congressional and international discussions andnegotiations. Climate change mitigation strategies have focused onreducing emissions of greenhouse gases (GHGs), especially carbondioxide (CO2). One significant source of CO2 emissions isdeforestation. Reducing deforestation to lower CO2 emissions is seenas one of the least costly methods of mitigating climate change.

Forests are carbon sinks in their natural state (i.e., they store morecarbon than they release).

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 plantsand nearly 40% of soil carbon.

When forests are cleared, some of their carbon is released to theatmosphere—slowly through decay or quickly through burning. Oneestimate shows that land use change, primarily deforestation, releasesabout 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 reducedeforestation significant in international strategies to mitigate climatechange.

Deforastation and climate change.

Soil erosion due todeforastation

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 definitionby including the conversion of natural forests to artificial forests suchas plantations.

Deforestation activities affect carbon fluxes in the soil, vegetation, andatmosphere.

The effects of these activities can vary, depending on the type ofactivity. For example, logging can lead to carbon storage if trees areconverted to wood products (e.g., lumber) and deforested areas arerestored.

Cont’d…. However, logging can also lead to carbon emissions if the

surrounding trees and vegetation are damaged, and if not all woodybiomass is processed into products. Other activities that alter thecarbon cycle in forests and affect climate.

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 forfarming and grazing, non wood forest products and services andvarious ecological functions some of which have global values.

However, with a growing human population of about 75 million largelydependent on low-productivity and rain-fed agriculture and over 70million livestock population competing for land and forest resources,deforestation and forest degradation are important problems inEthiopia.

Cont’d…The forest cover in Ethiopia is estimated at less than 4%

compared, for example, with an average of 20% for sub-SaharanAfrica (Earth Trends, 2007; WBISPP, 2004). The rate ofdeforestation is estimated to be as high as 5% per year (EFAP,1994a; Reusing, 1998; WBISPP, 2004b).

Reduction in forest cover has a number of consequencesincluding soil erosion and reduced capacity for watershedprotection with possible flooding, reduced capacity for carbonsequestration, reduced biodiversity and instability of ecosystemsand reduced availability of various wood and non-wood forestproducts and services.

Cont’d…Forests in Ethiopia play a big role in protecting erosion, as tree

roots protect against washouts. Trees also help to keep water inthe soil and reduce global warming by uptake of carbon dioxide.

Because there are not enough trees, the Blue Nile is carrying allthe soil and nutrients in the water to the neighboring countriesof Sudan and Egypt.

At the beginning of the twentieth century around 420,000square kilometers (35% of Ethiopia’s land) was covered by treesbut recent research indicates that forest cover is now less than14.2% due to population growth.

Despite the growing need for forested lands, lack of educationamong locals has led to a continuing decline of forested areas.

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 habitatconversion (defined as change in forest area plus change in woodlandarea minus net plantation expansion) for the 1990-2005 intervals,Ethiopia lost 3.6% of its forest and woodland habitat.

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 demandfor crop and grazing land, livestock production, wood for fuel drierareas and construction.

Lack of viable land use policy and corresponding law also aggravatedthe rate of deforestation.

New settlements in forests are increasing from time to time and henceresulted in the conversion of forested land into agricultural and otherland use systems.

At present, the few remaining high forests are threatened by pressurefrom investors who are converting the moist evergreen montane forestsinto other land use systems such as coffee and tea plantations.

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 orshortages of fuels such as fuel wood and charcoal

III. Annual trend of naturalforest cover and deforestationEthiopia Forest Information and DataAbout 12,296,000 ha or 11.2% of Ethiopia is forested,

according to FAO. Of this 4.2% (511,000 ha) is classified asprimary forest, the most biodiversity and carbon-denseform of forest. Ethiopia had 511,000 ha of planted forest. Change in

Forest Cover: Between 1990 and 2010, Ethiopia lost anaverage 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.Ethiopia's forests contain 219 million metric tons of carbon

in living forest biomass.

Cont’d… Biodiversity and Protected Areas: Ethiopia has some 1408 known

species of amphibians, birds, mammals and reptiles according tofigures 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 which15.1% are endemic. 4.9% of Ethiopia is protected under IUCNcategories I-V.

Ethiopia: Forest Cover, 2010Total Land Area (1000 squarekilometers)

109631

Total Forest Area (1000 ha) 12296

Percent Forest Cover 11

Primary Forest Cover (1000 ha) 0

Primary Forest, % total forest 0

Other wooded land (1000 ha) 44650

Percent other wooded land 41

Ethiopia: Breakdown of forest types, 2010

Primary forest (1000 ha |% of forest area)

0 0

Other naturally regeneratedforest (1000 ha | % of forestarea)

11785 96

Planted Forest (1000 ha | %of forest area)

511 4

Ethiopia: Trends in Total (Net) Forest Cover, 1990-2010

TOTAL FOREST COVER (1000 ha)

ANNUAL CHANGE RATE (1000 ha)

Negative number represents deforestation

1990 2000 2005 2010

15114 13705 13000 12296

1990-2000 2000-2005 2005-2010

-141 -141 -141

Cont’d…

ANNUAL CHANGE RATE (percent)

Negative number represents deforestation

1990-2000 2000-2005 2005-2010

-0.97 -1.05 -1.11

Ethiopia: Trends in Natural ForestCover (Deforestation), 1990-2010FOREST COVER (excluding planted forests) (1000 ha)

ANNUAL CHANGE RATE (1000 ha)Negative number represents deforestation

ANNUAL CHANGE RATE (percent)Negative number represents deforestation

1990 2000 2005 2010

14623.00 13214.00 12509.00 11785.00

1990-2000 2000-2005 2005-2010

-141 -141.00 -143.00

1990-2000 2000-2005 2005-2010

-1.0 -0.96 -1.08

Ethiopia: Trends in Primary or Old GrowthForest Cover, 1990-2010PRIMARY FOREST COVER (1000ha)



1990 2000 2005 2010

0 0 0 0

1990-2000 2000-2005 2005-2010

0 0 0

1990-2000 2000-2005 2005-2010

- - -

Ethiopia: Trends in Planted Forest Cover,1990-2010

PLANTED FOREST COVER (1000 ha)



1990 2000 2005 2010

491 491 491 511

1990-2000 2000-2005 2005-2010

0 0 4

1990-2000 2000-2005 2005-2010

0 0 0.80

Ethiopia: Trends in carbon stock in livingforest biomass 1990-2010CARBON STOCK IN LIVING FOREST BIOMASS (million metric tons)

ANNUAL CHANGE (1 000 t/yr)

1990 2000 2005 2010

1990 2000 2005 2010

289 254 236 219

0 -4 -4 -3

1990

2000

2005

2010

n.s.

n.s.

n.s.

Impact of deforestation in Ethiopia

Deforestation is a major concern in Ethiopia as studies suggest loss offorest contributes to soil erosion, loss of nutrients in the soil, loss ofanimal 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 byseveral scholars who have employed different methods and havestudied different localities to come up with conclusions.(deferu,2010).

Cont’d…One of the major impacts of deforestation is through its effect in

reducing the level of agricultural production and productivity, makingthe nation unable to feed its people.

This situation has often necessitated increased volume of foodimports, in the form of commercial imports and also as food aid.

In addition, the high level of deforestation has resulted in worseningthe household energy consumption problems in Ethiopia, as fuel wood,dung and crop residue are the major sources of household energyconsumption.

..

Drought and nograss

No place forwild animal

Cont’d… During the next few decades, global ecological changes are expected to

have major impacts on ecological, social, economic, and politicalaspects 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 changespredicted for the future.

Therefore causes and consequences of human-induced climate changeand land use activities have largely been examined independently(Turner et al., 1993). However, climate change and land use affect eachother

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 ofclimate change is expressed.

Land use is the human modification of natural environment orwilderness to build fields, pastures, and settlements. The major effectof 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. Landuse and land management practices have a major impact on naturalresources including water, soil, nutrients, plants, and animals.

Cont’d… According to a report by the United Nation Food and Agriculture

Organization (FAO, 1995), land degradation has been exacerbatedwhere there has been no effective land use planning, or of its orderlyexecution, or the existence of financial or legal incentives that have ledto the wrong land use decisions, or one-sided central planning leadingto overutilization of the land resources - for instance for immediateproduction at all costs.

As a consequence, the result has often been misery for large segmentsof the local population and destruction of valuable ecosystems. Suchnarrow approaches should be replaced by a technique for the planningand management of land resources that is integrated and holistic andwhere land users are central.

Cont’d… This will ensure the long term quality of the land for human use,

the prevention or resolution of social conflicts related to landuse, 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 bothimplications of land use change on atmospheric flux of carbondioxide (CO2) and its subsequent impact on climate and soil,and the alteration of climate change impacts through landmanagement. An effect of climate change on land use refers toboth how land use might be altered by climate change and whatland management strategies would mitigate the negative effectsof climate change.

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 fewdecades (Dale, 1997).

Because climate change effects are largely determined by land coverpatterns, land use practices set the stage on which climate alterationscan act.

Determining the effects of climate change on land use involvesresolving direct biophysical effects as well as management responses toclimate impacts. The population density on given land use system linksdeforestation with soil erosion and facilitates their effects on climatechange through land use of human activity.

There are two aspects to considering impacts of land use: effects ofland use on climate change and soil erosion; and the effects of humaninduced climate change on land use.

4. Mechanism (ways) to stopdeforestationControlling deforestationFarming New methods are being developed to farm more intensively,

such as high-yield hybridcrops, greenhouse, autonomousbuilding gardens, and hydroponics.

These methods are often dependent on chemical inputs tomaintain necessary yields. In cyclic agriculture, cattle are grazedon farm land that is resting and rejuvenating.

Cyclic agriculture actually increases the fertility of the soil.Intensive farming can also decrease soil nutrients by consumingat an accelerated rate the trace minerals needed for crop growth.

Forest management

Efforts to stop or slow deforestation have been attempted for manycenturies because it has long been known that deforestation can causeenvironmental damage sufficient in some cases to cause societies tocollapse.

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 aneffort to stem deforestation and the degradation of agricultural lands:(i) tree planting or afforestation; (ii) dissemination of more efficientstove technologies.

The motivation in here is, therefore, to examine the potential of thestrategy of disseminating improved stoves in the rehabilitation ofagricultural and forests lands.

Forest plantations

To meet the worlds demand for wood it has been suggested by forestrythat high-yielding forest plantations are suitable.

It has been calculated that plantations yielding 10 cubic meters perhectare annually could supply all the timber required for internationaltrade on 5 percent of the world's 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 meetdemand. Forester Chad Oliver has suggested a forest mosaic with high-yield forest lands interspersed with conservation land.

Cont’d… Carrying out afforestation programme and improved management of

forest resources alone, however successful, will not be able to solve ourproblems as far as our need for crop and grazing land continues to growdue to high population growth rates.

This is because of the fact that using the land for forestry to improvesoil fertility or to rehabilitate and conserve the environment will beviewed as secondary to using the land for cropping and grazing to meetimmediate needs of survival.

Cont’d… Hence, any attempt by the government, the public and NGOs to

address the problem of deforestation in particular and landdegradation in general critically depends upon our efforts and capacityto deal with the three major issues of population growth, lowagricultural productivity and high dependence on fuel wood, dung andcrop residue as sources of household energy. Finally, the governmentshould devise and implement strategies and policies relating toafforestation only as an integral part of the overall rural developmentprogramme.

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Do you see the d/ce?

Bare land

forest

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