afforestation and conservation - geocities · lack of water resources food crisis ... lumbering and...

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Afforestation and conservation for mitigating global

environmental problems

Arid Land Research CenterDivision of Afforestrationand Land Conservation

M. INOUE

Lack of water resources

Food crisis

Environmental problems Global environmental problems

Local environmental problems

World population growth

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Afforestration and conservation for mitigating global environmental problems

What do you think are the serious problems in the world in 21st century?

We live on the earth, so we have to live harmoniously with the other creatures and environment on the earth.And we all have responsibility to protect and conserve the environment for our children. Towards this end, we should figure out the global problems we are facing.

Topics

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What are global environmental problems in the world?

Global warming

DeforestationAcid rain

Desertification

Marine pollution

Yellow dust Radioactive contamination

Wild species extinction

Industrial pollution

Ozone depletion

Urban heat-island

Local environmental problems

Global environmental problems

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0.4 0.3 0.2 0.1 million years ago

400

350

300(ppmv)

Rapid increase of Carbon dioxide gas

1200 1400 1600 1800 2000 yr

400

350

300

250

200 Glacial age

Glacial age

Glacial age

Cycle of glacial age

400

350

300

250

200Glacial age

conc

entra

tion

of c

arbo

n di

oxid

e ga

s (p

pmV

)

TemperatureConcentration of CO2Concentration of CH4

Diff

eren

ce o

f tem

pera

ture

com

pare

d w

ith p

rese

nt (℃

)

Glacial ages

Glacial ages

Glacial ages

Glacial ages

0.4 M yr ago 0.3 M yr ago 0.2 M yr ago 0.1 M yr ago

Cro-Magnon manNeanderthal man

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Global warmingFour glacial ages in the past 0.4 million years.

In each glacial age, Earth's air temperature went down 6 degrees Celsius lower than the highest in that age.

In the upper graph, we are now in the age of highest temperature fluctuation cycle. However, the temperature has become much higher than it was supposed to be over the past 100 years.The concentration of carbon dioxide gas has also gone up as shown in the graph below.

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As you see in these graphs, the atmospheric concentration of carbon dioxide and methanebefore the industrial revolution in the mid-1700s was 280ppmv and 700ppbv. They have increased to become 1.3 times and 2.4 times respectively since then.

concentrations of carbon dioxide

conc

entr

atio

ns o

f CO

2(p

pmv)

Year

concentrations of methane

Year

conc

entr

atio

ns o

f D

H4

(ppb

v)

Global warming

Change in the concentrations of carbon dioxide and methane for 300 years

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Change in the concentrations of carbon dioxide for 1000 years

Global warming

Global warming is an increase in global temperature due to greenhouse effect caused by increase in the atmospheric concentration of greenhouse gases such as carbon dioxide and methane.

greenhouse effect

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Global temperature has increased 1 degree Celsius in the past 100 years, as shown in the figure. Global warming is expected to cause: glacier retreat, sea level to rise, significant changes in hydrological circulation including the amount and pattern of precipitation and evaporation, aridification and desertification, intensification of extreme weather events, flooding and drought, spread of tropical diseases, species extinctions, and reduction in agricultural yields due to the increase in disease vectors, etc.

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The ozone layer is a layer in Earth’s atmosphere which contains relatively high concentrations of ozone. Ozone depletion denotes the decrease in both the total amount of ozone in Earth’s stratosphere, and stratospheric ozone over Earth’s polar regions since the late 1970s.The former is slow and steady, and the latter is rapid but seasonal (during spring and early summer).The latter phenomenon leads to the development of ozone hole.

Ozone depletion

This satellite picture taken in 1990 shows the ozone hole over the Antarctic. Simply speaking, when chlorofluorocarbon commonly called Freon, is transported into the stratosphere, the gas is dissociated by strong ultraviolet light , and releases chlorine atoms, which then destroy ozone layer by bonding with ozone.It is suspected that skin cancer, and eye diseases such as cataract may result from the increased harmful ultraviolet light due to ozone depletion.

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Acid rain is caused by the reaction of air pollutants (primarily sulfur oxides and nitrogen oxides) with water in the air. The main sources of these pollutants are vehicles and industrial plants. Affected areas are found all over Japan. Acid rain has been shown to have adverse effects on forests, freshwaters and soils, killing insects and aquatic lives as well as causing damage to cultural heritage and human health. Acid rain depletes minerals from soil and acidifies it, leading to reduced growth of plants. In lakes and streams, at pH below 3, most fish eggs will not hatch and adult fish and shellfish will die. As waters become more acidic, marine biodiversity shrinks.

Acid rain

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Acid precipitation, commonly known as “acid rain” , is the deposition of acidic components, with pH less than 5.6, through rain, snow, fog, and dew, or as dry particles.

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The most serious deforestation at the current time is the destruction of tropical rainforests. Tropical forests covered 1.88 billion hectares in 1981, but the area has decreased to 1.71 billion hectares in 1990. The leading causes are ‘slash-and-burn’ agricultural practice, clear-cutting, market-driven over-lumbering and forest fire. These bars show the rate of forest decrease in each continent, because of the slash-and-burn agricultural practices. Tropical rainforests are home to about two-thirds of all the living animal and plant species on the Earth. Therefore, destruction of tropical rainforests has adverse effects on biodiversity. In addition, decrease of tropical rainforests leads to global climate change and global warming.

Deforestation

USA

Africa

Asia

Rate of forest decrease of each continent result from slash-and-burn agricultural practices

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over-grazing deforestation over-exploitation

Desertification is land degradation resulting from various factors such as over-grazing, deforestation, over-exploitation, salinization and waterlogging due to over-irrigation, decrease of soil fertility due to over-cultivation, etc.

Desertification is attributed 13% to natural factors and 87% to human-induced factors. We will discuss this more in the next lecture. Land degradation decreases land productivity and agricultural yield in arid and semi-arid region, and consequently, it could cause starvation in developing countries.

Desertification

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For example, it is reported that biodiversity has been shrinking due to extinction of some wild species in Amazon rainforest. The main cause is market-driven lumbering and over-exploitation. Exploitation of natural resources ultimately threatens human existence. For example, decrease of marine species has a great impact on marine ecosystem and ultimately results in decrease of the amount of fish catches.

Climate changes and human activities such as hunting and land development have changed environment and destroyed habitat of wildlife, and consequently, considerably decreased the number ofwild animals and reduced wild species.

世界の保護動物


25% of mammals, 11% of fowls, 20% of reptiles, 25% of amphibians, 34% of fishes are suspected to be endangered species.

Protected animals in the world

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Marine pollution is the damage to the ocean caused by the entry of wastes, debris, chemicals, polluted materials, and oils, etc.

The entry of oil is often called oil spill.

Approximately 70% of the Earth’s surface is covered by ocean which supplies variety of resources.Recently, marine pollution at various sea sites has been reported.

Eutrophication such as red tide and blue tide is an example of marine pollution, which is mainly caused by discharge of toxic drainage, sewage and industrial wastes in the ocean.

Marine pollution

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Industrial pollution, once a problem of the developed countries, is becoming serious now in urban areas in less developed countries,because of industrialization and rise in urban population.

Illegal dumping of industrial waste


World annual discharge of hydrocarbon1980 1990 2000 2010 2020

(Mton)

30

25

20

15

10

5

0

air pollution

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The graph shows the amount of world annual discharge of hydrocarbons, one of the various causes of air pollution. It once decreased due to the control of exhaust gases in developed countries, but it has been increasing as automobiles increase in less developed countries. In addition to air pollution, disposal of urban and industrial waste, and land pollution are the other forms of industrial pollution. Once hazardous chemical substances dissolve in water and penetrate into the ground, ground water will be contaminated. Without fully equipped sewage treatment facility in urban areas, water would be seriously polluted at downstream region. To solve these problems, economical growth and education are needed in developing countries.

soil pollution

Yellow dust is a seasonal meteorological phenomenon which affects Japan, China, and North and South Korea, as well as parts of the Russian Far East.

Yellow dust

The dust originates in the deserts of Mongolia and northern China and Kazakhstan, such as Gobi Desert and Takla Makan Desert. High-speed surface winds and intense dust storms kick up dense clouds of fine and dry soil particles.

Takla Makan DesertGobi Desert

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These clouds are then carried eastward by westerly winds and pass over such countries.

Dust stirred up in arid region in continent

Yellow dust is carried over in the wind

Dust descends to wide areas including Japan

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High frequency of dust storm is generally observed from March to May (during spring months) in Japan.The visibility was 3 km in Tottori city on April 25, 2006, according to the Tottori local weather station. It was the worst record in the past 10 years. Yellow dust prevents sun light and adversely affects photosynthesis of crops, stains cars and washed cloths yellow, and even affects human health as the dust is known to cause a variety of health problems such as sore throat and asthma.

Yellow dust

Visibility of 3 km in Tottori city on April, 25, 2006

April 16 April 17 (am) April 17 (pm) April 18, 2006

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Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec.

Days Average annual monthly occurrence days of Yellow dust (from 1971to 2000)

Radioactive contamination is typically the result of a spill or accident during the production or use of radioisotopes, an unstable nucleus which has excessive energy. Contamination may occur from radioactive gases, liquids or particles.

Nuclear fallout is the distribution of radioactive contamination by a nuclear explosion. The worst nuclear accident in history is the Chernobyl disaster in 1986. Nuclear fallout is the residual radiation hazard from a nuclear explosion, was spread over an extensive geographical area including England 2000km far away from Chernobyl.Other examples of serious accidents include the Three Mile Island accident in 1979 and Windscalefire in 1959.When air, rivers and reservoirs are contaminated by radioactivity, forests die, and animals either die or stop reproducing or be stunted because of thyroid damage. Radioactive contamination can enter the human body through ingestion, inhalation, or absorption, and can cause thyroid cancer.

Radioactive contamination

Forbidden region

Chernobyl nuclear power station

Republic of Belarus

Ukraine

Minsk

BelarusMoscow

Kiev

Gomeri

RussiaBlack sea

Ukraine

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Urban heat-island An urban heat island is an urban area where the temperature is significantly higher than surrounding rural areas.

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Rural areas

Rural farmland

ParkDowntownCommercial Urban Residential

Suburban Residential

Suburban Residential

Late

afte

rnoo

n te

mpe

ratu

res

(℃)

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Sketch of an urban heat-island profile

Green space is lower temperature

Green space is lower temperature

hotcool cool

Heat-island

Urban heat-island 18

The main cause of the urban heat island is the urban architecture with less vegetation. Materials used for urban architecture, such as concrete and asphalt, have more heat capacity than bricks or trees or soils, so they store solar heat all through the day and emit it at night. When water evaporates from plants and soils, it cools down the air. Without vegetation, evapotranspiration is low due to the lack of transpiration from plants and evaporation from soils. The other causes are waste heat generated by energy usage, and the buildings with multiple surfaces which reflect and absorb sunlight.

17.0

16.5

16.0

15.5

16.0

14.5

14.0

13.5

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Temperature in 2000 increases 3 degree more than in 1905

Tem

pera

ture

(

℃)

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Variation in average annual temperature in Tokyo

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Water on the earth is about 1.4 billion Km3, 97.4% is saline water and 2.6% is fresh water. Most of fresh water is in glaciers in the North and South Poles, and the remaining 0.8% is ground water, and water in rivers and streams. Water resources that are available for actual usage are only 0.01% of total amount of water on the Earth.

104,620 km3

Fresh water resources

Limited fresh water resources

Lack of water resources in the world

Ocean

Groundwater

GlacierLake and swamp

Soil water

Atmosphere, river, living body

Second topic

0.014%

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Hydrological circulation is a continuous movement of water on, above and below the surface of the Earth.

Hydrological circulation

Water resources

Vapor transport

40,000 km3

Rainfall 111,000 km3 Evaporation Transpiration 71,000 km3

Evaporation 425,000 km3

Rainfall 385,000 km3

Flow from land to sea 40,000 km3Groundwater flow

landOcean

Lake

Percolation

Surface runoff

River

Water can change states from solid (ice) to liquid, to gas (vapor) at various places in the hydrological circulation, such as precipitation and evaporation.

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Hydrological circulationWater resources

Vapor transport

40,000 km3

Rainfall 111,000 km3 Evaporation Transpiration 71,000 km3

Evaporation 425,000 km3

Rainfall 385,000 km3

Flow from land to sea 40,000 km3

Groundwater flowland

OceanLake

Percolation

Surface runoff

River

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For example, some 385,000 km3 of water falls down to the ocean and returns to the air by evaporation. World annual water resources amount to 45, 000 km3, which is the remainder amount of the annual precipitation on the land, after evaporating from surface of land and plants. This water is kept on the land surface in lakes and swamps, but eventually flows into ocean as a groundwater flow, or through rivers or streams.

As population grows and lifestyle changes, water demand for agriculture, industry and living use has increased to become 9 times that of 100 years ago. Agriculture accounts for 70% of water consumed worldwide. Water is a resource of life. Water accounts for about 55-65% of the human body by weight. Generally speaking, we have to consume 1.15 litter of water from food, 1 litter from drinking water and 0.35 litter from metabolic process.

As the population growth and lifestyle change, water demand for agriculture, industry and living usage has increased to become 9 times that of 100 years ago

Change of water demand with time

Lack of water caused by increase of water demand is serious problem in 21 century

Water demand in the world

Water resources

1900 1920 1940 1960 1980 2000

6000

4800

3600

2400

1200

0

西暦

全世

界の

水需

要　

　km

3 /年

総量農業用水工業用水生活用水

Total amount

Agriculture water

Industrial water

Daily life water

Wat

er d

eman

d in

the

wor

ld

(km

3 /yr)

Year

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0.0

100.0

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500.0

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700.0

1960

1962

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生産量コメ

生産量コムギ

生産量コーン

消費量コメ

全消費量コムギ

全消費量コーン

This figure shows production and consumption of rice, wheat and corn in the world from 1960 to 2002. The production and consumption have gradually increased.

However, please pay attention to the rice and wheat production peaks shown in red circle. The production has been reducing since this point. As population grows, we might not be able to gain enough productions to meet demands.

Change of production

Production and consumption of rice, wheat and corn in the world.

(100 Mton)

Production (rice)

Production (wheat)

Production (corn)

Consumption (rice)

Consumption (wheat)

Consumption (corn)

Food crisisThird topic 23

Production increase has been brought by increasing cultivated lands, irrigation systems, fertilizers and improved crop variety.

This graph shows the changes in world population and population growth ratio of developed and developing countries. The bars show the changes in world population, the red are of developed countries, and the black are of developing countries. The lines show the population growth rate, as showed in legend above.


The world population in July 2008 was estimated to be just over 6.684 billion and population growth rate was 1.4%.

1 9 5 0 1 96 0 1 9 70 1 9 8 0 19 9 0 2 00 0 20 1 0 2 0 200

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

先進地域

発展途上地域

発展途上地域

世界全域

先進地域

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2

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Wor

ld p

opul

atio

n (b

illio

n) Developing country

Developed country

Developing

World

Developed

5

4

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2

1

0

Popu

latio

n gr

owth

ratio

(%)

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In developed countries, the variation trend of population growth rate is different in each country. For example, the growth rate of USA was increasing, but that of Japan decreasing in 2007. On the other hand, the growth rate was increasing in developing countries as a whole, and it was higher than that of USA. The growth rate of Africa such as Congo, Ethiopia, Tanzania and Nigeria was significantly high. As you can see, world population is increasing.

Population growth and growth rate in each country

Population in developed and developing countries

Country 1998 2050 Population Growth

(Million) (Million) (%) (%)

Developed

USA 270 349 + 79 + 29

Rossia 147 121 − 26 − 18

Japan 126 105 − 21 − 17

Germany 82 73 − 9 − 11

France 59 60 + 1 + 2

England 58 57 − 1 − 2

Italy 57 41 − 16 − 28

Developing

India 989 1529 + 540 + 55

China 1243 1478 + 235 + 19

Pakistan 142 345 + 235 +143

Nigeria 122 244 + 122 +100

Brazil 162 244 + 82 + 51

Ethiopia 58 169 + 111 +191

Congo 49 160 + 111 +227

Egypt 66 115 + 49 + 74

Tanzania 31 81 + 50 +161

Mexico 98 147 + 49 + 50

growth ratio

Population growth has a great impact on global environmental issues, food security, and water resources.

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Per capita annual consumption of wheat

Kg/

capi

ta

As I have shown before, the world wheat production has increased to 600 million ton. However, the world population has increased more rapidly. Consequently, per capita total consumption of wheat per annum reached a peak before 1990, and it has been gradually decreasing since then.

Food crisis

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0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

生産量コメ

生産量コムギ

生産量コーン

消費量コメ

全消費量コムギ

全消費量コーン

Production (rice)

Production (wheat)

Production (corn)

Consumption (rice)

Consumption (wheat)

Consumption (corn)

prod

uctio

n (m

illio

n to

n)

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Forecast of crop production in the world

per capita total crop production (kg)

World population is expected to increase further more by 2050, and become 8 billion. If so, per capita total crop cultivated area and total irrigated area would decrease under the condition of the same crop cultivated total area at 2008.

per capita total crop cultivated area (ha)

(ha)

(ha)

(kg)

(kg)

per capita totalirrigated area (ha)

per capita totalfish catches (kg)

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For example, the population in Mali has increased to become 2.5 times that of 40 years ago (1995-1955). In contrast, Millet yield (production per hectare) has decreased by 30%.

Now, look at the below graph. Per capita world total Millet consumption has decreased from 1960 to 2005, as the world population increased at the same time.

(Million) Change of population (Million)

Millet production per cultivated area (kg/ha)

Millet production in Mali and per capita world total consumption

Mali

Mali

Per capita total Millet consumption (kg/capita)

Millet

Kg/

capi

ta

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Roughly speaking, world population has doubled and gross world crop production has become 2.5 times in 40 years. Thus today, the total food supply meets the demand in the world as a whole, but food supply is not enough in some developing countries. In these countries, food hunger and starvation are the serious problems.

USA

Australia

Food surpluses StarvationFood insufficiency Food sufficiency

India

China

Botswana

Ecuador

Mauritanian

Burkina Faso

Guinea

Tanzania

EthiopiaSomali

Niger

Zaire

Mozambique

Guatemala

Benin

Bolivia

South AfricaArgentina

Food crisis

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Cambodia

Japan

Lack of water resources

Food crisis

Afforestation and conservation for mitigating global environmental problems

Environmental problems

Global environment

Global warming

Deforestation

Acid rain

Desertification

Marine pollution Yellow dust

Radioactive contamination



Ozone depletion

Urban heat-island

Local environment

World population growth problem

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2

3Landslide disaster

Topics

Afforestation and conservation

Countermeasures

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Afforestation is the process of establishing a forest on land that is not a forest, or has not been a forest for a long time, by planting trees or their seeds. Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics.

The term reforestation generally refers to the reestablishment of the forest after its removal, or planting more trees for example after a timber harvest. Since the industrial revolution many countries have experienced centuries of deforestation, and some governments and non-governmental organizations directly engage in programs of afforestation to restore forests and assist in preservation of biodiversity.

Reforestation is the restocking of existing forests and woodlands, which have been depleted, with native tree stock. The term reforestation can also refer to afforestation, the process of restoring and recreating areas of woodlands or forest that once existed but were deforested or otherwise removed or destroyed at some point in the past. The resulting forest can provide both ecosystem and resource benefits and has the potential to become a major carbon sink.

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Global environment

Global warming

Deforestation

Acid rain

Desertification

Yellow dust

Absorption of CO2 gas by forest

Forest recovery by afforestation

Wild species extinctionMitigation of aeolian sand transport and effect of storm protection by afforestation

Countermeasures to prevent and mitigate environmental problems

Bio-drainage by tree planting

Urban heat-island Cooling effect by rooftop gardening

Local environment


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Global environment

Global warming Absorption of CO2 gas by forest



CO2 gas

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100

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The most effective way to mitigate global warming is forest recovery by afforestation or reforestation, because forests absorb carbon dioxide (CO2) gas and reduce concentration of CO2 in the air.Forest has a potential to become a major carbon sink.

Global environment

Deforestation

DesertificationForest recovery by afforestation




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Obviously, forest recovery can mitigate deforestation. In addition, forest recovery by afforestation or reforestation is also effective in mitigating desertification, because the one factor of desertification is deforestation, which means removal of forests in this context. Furthermore, tropical forest recovery is effective in mitigatingwild species extinction, because it can bring a major habitat back for wildlife.

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Global environment

Desertification


Bio-drainage by tree planting

Urban heat-island

Landslide disaster


Groundwater table rising up

Over-irrigation

Infiltration

Groundwater table rising up

Evaporation

Channel

Groundwater table moving down

Salt accumulation

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Now, I would like to explain in detail about the forest recovery which is effective for mitigating desertification. Desertification with soil degradation and salt accumulation results from significant evaporation from the land surface which occurs when groundwater level rise due to over-irrigation. In order to let the water level down, bio-drainage is useful. Bio-drainage is a drainage technique which uses a tree to absorb groundwater that has risen to near the surface. This technique is exercised in lowlands for drainage and agricultural fields for water management by planting trees of high water absorption capacity. It would also protect crops from winds.

Global environment

Yellow dust



gravel mulching

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Yellow dust is caused by high-speed surface winds and intense dust storms which kick up dense clouds of fine and dry soil particles. Most effective practices to prevent yellow dust are gravel mulching and increasing vegetation rate of the region in which the dust originates、because they will prevent dust to fly as well as prevent winds to kick up dust.

Mitigation of aeolian sand transport and effect of storm protection by afforestation

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Global environment


Cooling effect by rooftop gardening


Contour cropping

Contour tillage

Contour planting

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Local environment

To prevent water erosion, afforestation with some techniques is useful.

Cooling by rooftop gardening is one of the effective practices to mitigate urban heat-island which is listed as a local environmental problem.

Urban heat-island

Afforestation technique

Exercise(1)Please list typical four global environmental problems.

1)

2)

3)

4)

(2)Please describe the role and capacity of the afforestation and conservation in mitigation of the problems which you list in question (1)

(3)Please explain the following technical word.

1) greening

2) afforestation

3) vegetation

4) reforestation

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afforestation and conservation - geocities · lack of water resources food crisis ... lumbering and...

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