TEMPERATE ECOSYSTEM

An Assessment
of
TEMPERATE ECOSYSTEM
DEPARTMENT OF GEOGRAPHY
KIRORI MAL COLLEGE
University of Delhi

CONTENTS
GEOLOGICAL EVOLUTION OF TEMPERATE REGION, ITS LOCATION AND
EXTENT 1
KAMLESH KUMAR
ATMOSPHERIC CHANGES 6
ABHISHEK MALIK
HYDROLOGICAL CHANGES 11
DINESH KUMAR
LAND DEGRADATION 15
AKANSHA CHADHA
LOSS OF BIODIVERSITY: HABITAT DESTRUCTION AND EXTINCTIONS 20
APOORVA TYAGI
CHALLENGES TO HUMAN COMMUNITY: TOXICITY, FOOD INSECURITY,
HEALTH IMPACTS 24
PRITY KHOKHER
BIBLIOGRAPHY 28

1
GEOLOGICAL EVOLUTION OF TEMPERATE REGION, ITS
LOCATION AND EXTENT
KAMLESH KUMAR
Temperate refers to a region or climate with mild or moderate temperature. Basically, the
region between the two extremes ie. The Tropical and the Polar Regions. Temperate region
includes the parts of the Earth’s surface lying between the Arctic circle and the tropic of Cancer
in the Northern hemisphere and between the Antarctic circle and the tropic of Capricorn in the
south. The region occupies 1/4th
of the earth’s surface. Approximately 55% of the North
Temperate Zone (NTZ) is land, and 98% percent of the south temperate zone (STZ) is ocean.
Temperate region includes large parts of United states and Canada, Argentina and Chile in
South America; Whole of Europe; Morocco, Algeria, Libya and Egypt of the N. Africa and
South Africa; Large parts of Asia; Lower half of Australia and the New Zealand.
Average annual temperature: Land surface- Coldest months 6° to -50° in NTZ and 2° to 8°C
in STZ; Warmest months: 10° to 28°C in NTZ and 8° to 20°C in STZ.
Average annual precipitation: 50-80 cm.
Total annual radiation: 70-160 kcal per cm2
.
Soil formation is generally marked by leaching and the intensive mineralization of organic m
atter; Sod formation and salinization are pre-dominant. Podzolic, brown, and gray forests oils
cover large areas in the temperate zones; The most wide spread types of vegetation are forests:
taiga, mixed coniferous and broad-leaved, and summer green broad-leaved. Winters are cold
and, snowy in the north; summers are relatively warm in the north and hot in the south.
Major climatic classification:
➢ Sub-tropical climate (23.5°-35° NS): Found in southern Asia, the south-eastern United
States, parts of eastern Australia, and in eastern coastal South America.
➢ Mediterranean Climate (30°-42° NS): Regions around the Mediterranean Sea, Western
Australia, California, and the southernmost areas of South Africa characterized by long
hot summers and short mild winters;
➢ Continental Climate (35°-55° NS): Found in northern temperate Asia, the northern
United States, southern Canada, and parts of northeastern Europe featuring warm
summers and cold winters, with a large inter-seasonal temperature variation.
➢ Oceanic climate (45°-60° NS): Found in Western Europe, northwestern North America,
and parts of New Zealand cool summers and relatively warm winters. Annual rainfall
is spread throughout the entire year.
Geological History Of The Earth
The most recent supercontinent, and the only one most people are familiar with, is Pangaea,
which dominated Earth from about 300 to 150 million years ago. Pangaea gets remembered
because it's the most recent supercontinent.

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The Earth is a little over 4.5 billion years old, its oldest materials being 4.3 billion-year-old
zircon crystals. Its earliest times were geologically violent, and it suffered constant
bombardment from meteorites. When this ended, the Earth cooled and its surface solidified to
a crust - the first solid rocks. There were no continents as yet, just a global ocean with small
islands. Erosion, sedimentation and volcanic activity - possibly assisted by more meteor
impacts - eventually created small proto-continents which grew until they reached roughly their
current size 2.5 billion years ago. The continents have since repeatedly collided and been torn
apart.
The history of life on Earth began about 3.8 billion years ago, initially with single-celled
prokaryotic cells. Multicellular life evolved over a billion years later and it's only in the last
570 million years that the kind of life forms we are familiar with began to evolve, starting with
arthropods, followed by fish 530 million years ago (Ma), land plants 475Ma and forests 385Ma.
Mammals didn't evolve until 200Ma and our own species, Homo sapiens, only 200,000 years
ago. So, humans have been around for a mere 0.004% of the Earth's history.
The earth didn't always look the way it does today, but yes, there have always been continents
on Earth. The familiar configuration of the seven official continents spread out over Earth today
has undergone many permutations during the planet's geological history.
Plate tectonics has continually shifted the position of landmasses; while some were rifted apart,
creating new landmasses, others collided to create tall mountain ranges, such as the Himalayas,
and combine landmasses. At a few points in Earth's history, all the landmasses were stuck
together to form a supercontinent.
The most recent of these supercontinents was called Pangaea, which means "all lands." It began
to break up about 200 million years ago, first forming the two supercontinents Gondwana (in
the Southern Hemisphere) and Laurasia (in the Northern Hemisphere). Eventually these two
supercontinents also fragmented, forming the continents as we know them today.
Geologists call this continual breaking apart and coming together of the continents the
supercontinent cycle. The cycle of supercontinent formation, breakup, dispersal and
reformation by plate tectonics. These supercontinent cycles, which take around 300 to 500
million years to complete, date back approximately 3 billion years – basically from the very
beginnings of plate tectonics. Various versions of the Earth:
• Black Earth: Volcanism causing dense black basalt, 4.5 billion years ago.
• Blue Earth: Predominance of oceans, 4.4 billion years ago.
• Gray Earth: 3 billion years ago, when gray continents of granite first
appeared.
• Red Earth: Due to the Great Oxidation Event, 2.2 billion years ago.
• White Earth: Ice age
• Green Earth: The green of photosynthetic life is the most visible sign of the
living world.

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Geological Time Scale
Pre-Cambrian Eon (From the beginning to 650 Ma)
o Most of the important events took place during this time. The Earth formed, formation
of ocean in Hadean Epoch, Evolution of eukaryotic cells around 1.8 Ga in the
Proterozoic era.
o The first tectonic plates began to move, the atmosphere became enriched in oxygen and
just before the end of this period, complex multicellular organisms, including the first
animals evolved.
o Formation of the first ‘Craton’ supercontinent and followed by many others like:
• Vaalbara (3.6-2.5 Ga)
• Ur (3 Ga): Remains of Ur can be found in the parts of India, Africa, Madagascar,
and Australia.
• Kenorland (2.7-2.45 Ga): It likely existed around the equator and comprised most
of the later Laurentia, modern US and Canada, Greenland, the Scandinavian
countries, western Australia, and what is now the Kalahari Desert. Fragmentation
caused rainfall decreasing the toxic greenhouse gases, increasing oxygen level to
1% and creating the first ever snowball earth ie. Huronian glaciation which
persisted for 60 million years.
• Columbia (1.8-1.5 Ga in palaeo-proterozoic era): It consisted of the proto-cratons
that made Laurentia, Baltica, the Ukranian and North China, Kalaharia, Amazonian
Shields, Australia and possibly Siberia and is estimated to be 12,900 km in length
and 4,800 km wide. The east coast of India was attached to western North America,
with southern Australia against western Canada. Most of South America rotated so
that the western edge of modern-day Brazil lined up with eastern North America,
forming a continental margin that extended into the southern edge of Scandinavia.
• Rodinia (1.1Ga-750 Ma): The name derived from Russian "rodina", meaning
"motherland". It was probably located almost entirely south of the equator,
Rodinia's core was formed by the North American craton, surrounded in the
southeast with the East European craton, the Amazonian craton and the West
African craton; in the south with the Rio de la Plata and São Francisco cratons; in
the southwest with the Congo and Kalahari cratons; and in the northeast with
Australia, India and eastern Antarctica, surrounded by the super ocean Mirovia. It
began to break apart roughly 750 million years ago. The fragmentation created
‘snowball Earth’, which opened up new oceans causing sea beds to rise and paved
way for the animals and plants to evolve on land. Severe glaciation during
Cryogenian period (850-635 Ma) due to rifting of continents, seafloor spreading,
evaporation from water surface leading to increased rainfall and cooling. Leading
to rapid evolution of primitive life during Ediacaran/ Vendian period (635-545 Ma)
and Cambrian period (545-495 Ma).

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• Pannotia (600-550 Ma in Ediacaran or Final Pre-cambrian period): It split into
Laurasia and Gondwanaland, which moved to the northern and southern extremes
of the planet, respectively.
• Starting at about 514 Ma, Laurasia drifted southward until it crashed into
Gondwanaland about 425 Ma forming Pangaea, surrounded by a vast ocean called
Panthalassa ("All Ocean"), formed approximately 356 Ma.
Ordovician period (495-443 Ma): Prominence of diverse marine invertebrates along with red-
green algae, primitive fish, corals etc. Gondwana finally reached south pole forming massive
glaciers, dropping of sea level. The 500,000-year long glaciation caused mass extinction of
60% marine invertebrate genera and 25% of all families.
Silurian period (443-417 Ma): Marked the stabilization of climate, evolution of fishes, coral
reefs, evidence of life on land, riverine and wetland ecosystem.
Devonian period (417-354 Ma): Marked by evolution of seed plants, vertebrates. North
America and Europe located near the Equator while South America, Africa, Antarctica, India,
and Australia dominated the southern hemisphere. Also known as ‘the age of fish.
Carboniferous Period (354-290 Ma): The amniote egg let the ancestors of birds, mammals,
and reptiles to reproduce on land by protecting the embryo in fluid, preventing it from drying
out. Famed for the evolution of first reptiles, highest atmospheric oxygen in the history.
Glaciation and reduced sea level led to mass extinction, this time for shallow marine
invertebrates. Originally called ‘the Coal Measures’ after its proliferation of coal-bearing
rocks. Laurussia smashed into Godwanaland producing the Appalachian mountain belt.
• Pangaea (300 Ma) Formation of the most famous, the most recent supercontinent in the
early Permian period marked by dominance of reptiles, phytoplanktons, mosses etc.
Permian period (290-248 Ma) started with an ice age and ended with the most devastating
mass extinction the Earth has ever experienced wiping out more than 90 percent of all marine
species and 70 percent of land animals. In fact, at least two mass extinctions occurred during
this time. It's also when all the continents of the world finally coalesced into one supercontinent,
named Pangaea (meaning 'the entire Earth'). As the globe warmed up and the ice retreated,
many areas of Pangaea became very arid. The oxygen level plummeted too, from 35% of the
total atmosphere to around 15%.
Triassic Period (248-205 Ma): Characterised by heat, vast deserts and warm seas leading to
the evolution of dinosaurs and the first mammals in the late Triassic (around 230 million years
ago). Pangaea started fragmenting during mid-Triassic period creating Gondwanaland and
Laurasia. Gondwanaland contained most of the landmasses in today's Southern Hemisphere,
including Antarctica, South America, Africa, Madagascar and Australia, as well as the Arabian
Peninsula and the Indian subcontinent, which have now moved entirely into the Northern

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Hemisphere. Laurasia, to the north, contained North America, Europe, and Asia (but not India).
Laurasia is thought to have fragmented into the present continents of North America, Europe,
and Asia some 66 million to 30 million years ago.
Jurassic age (205-142 Ma) marked the dominance of the dinosaurs. Continental break up led
to formation of Atlantic Ocean.
Cretaceaous Period (142-65 Ma): Modern mammals, flowering plants, amphibians. Extinction
of dinosaurs. Widening of the atlantic and the formation of Indian Ocean and beginning of the
journey of India towards Asia.
By about 65 Ma, all the present continents and oceans had been formed for the most part, and
India was drifting north, eventually smashing into southern Asia to shape the world's tallest
mountains, the Himalayas, the Karakoram Range, and the Hindu Kush. In later periods
mammals evolved, temperature rose, mountain building activities occurred, grassland
expanded in Oligocene period (34-24 Ma), forests appeared and expanded in Miocene period
(24-5 Ma), first upright ape came upland bridges/isthamus appeared and diversification of
mammals occurred. Permanent glaciation of the North pole in Pliocene period (5.3-2.6 Ma),
Series of ice ages occurred in Pleistocene epoch (2.6 Ma-11,700 years) finally leading to the
Holocene epoch.
Continents are still on the move, and they'll almost certainly continue to move until the Sun
vaporizes our planet in next five billion years. Right now, we're probably a little past halfway
through the current supercontinent cycle, with the last supercontinent Pangaea having formed
about 300 million years ago and the next supercontinent due in roughly 250 million years. In
all likelihood, the continents will merge again to form a new supercontinent.
CONCLUSION
The story of Earth is an epic filled with crises, catastrophes, and remarkable, repeated change.
Earth traces its origin to simple atoms that were created in the big bang, transformed into heavy
elements in stellar explosions, and then forged into a planet inside the nebula that gave birth to
the solar system. Like many other planets, Earth went through phases of melting, volcanism,
and bombardment by asteroids. But only on Earth did the events lead to a flourishing biosphere
life. And once life was established, it drove the evolution of our planet in startling new
directions.
We presented the journey of the Earth from nothing to everything, we observed how important
our environment is focusing on the Temperate region along with the various interlinked aspects
affecting the temperate ecosystem and how our activities have degraded it. And of course, we
did notice how the nature is paying us back through its negative feedback mechanism. We do
have to wake up to take the necessary steps towards the conservation and replenishment of the
resources for our well-being for a promising future or else soon we’ll be history.

6
ATMOSPHERIC CHANGES
ABHISHEK MALIK
Introduction: Climate has an important environmental influence on ecosystems. Changing
climate affects ecosystems in a variety of ways. For instance, warming may force species to
migrate to higher latitudes or higher elevations where temperatures are more conducive to their
survival. Climate change not only affects ecosystems and species directly, it also interacts with
other human stressors such as development.
Table 1 LEVEL OF DEVELOPMENT- TEMPERATE REGION
S.NO MAJOR
REGION
COUNTRIES H.D.I RANK LEVEL OF H.D.I
1 NORTH
AMERICA
USA 0.915 7th
VERY HIGH
CANADA 0913 8th VERY HIGH
2. EUROPE U.K. 0.907 14th
VERY HIGH
ITALY 0.876 27th
VERY HIGH
UKRAINE 0.747 81th HIGH
3. AFRICA EGYPT 0.690 108th
MEDIUM
ALGERIA 0.736 83th HIGH
MOROCCO 0.628 126th
MEDIUM
4. ASIA CHINA 0.910 11th
VERY HIGH
JAPAN 0.891 20th
VERY HIGH
KAZAKHISTHAN 0.788 56th
HIGH
5. OCEANIA AUSTRALIA 0.935 2nd
VERY HIGH
NEW ZEALAND 0.913 9th
VERY HIGH
So, we can see from the above table that most of the countries in above table are having very
high human development. But apart from high HDI countries we also have some medium level
HDI countries in this region (Temperate region). So, from there HDI we also get some idea
about their industrial development.
Industrial development:
The Industrial Revolution led to the development of factories for large-scale production, with
consequent changes in society. Originally the factories were steam-powered, but later
transitioned to electricity once an electrical grid was developed. The mechanized assembly
line was introduced to assemble parts in a repeatable fashion, with individual workers
performing specific steps during the process. This led to significant increases in efficiency,
lowering the cost of the end process. Later automation was increasingly used to replace
human operators. This process has accelerated with the development of the computer and the
robot.
Industries In Very High Human Development Countries:
18th century: In the early 1800s there were largely agricultural with more than 80 per cent of
the population in farming in USA mostly. Most of the manufacturing centred on the first stages
of transformation of raw materials with lumber and saw mills, textiles and boots and shoes
leading the way in EUROPEAN countries. The rich resource endowments contributed to the
rapid economic expansion during the nineteenth century. Ample land availability allowed the

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number of farmers to keep growing, but activity in manufacturing, services, transportation and
other sectors grew at a much faster pace. Thus, by 1860 the share of the farm population in the
US had fallen from over 80 per cent to roughly 50 per cent.
20th century: At the beginning of the century new innovations and improvements in existing
innovations opened the door for improvements in the standard of living among American
consumers. Many firms grew large by taking advantage of economies of scale and better
communication to run nationwide operations. Concentration in these industries raised fears of
monopoly that would drive prices higher and output lower, but many of these firms were
cutting costs so fast that trends were towards lower price and more output in these industries.
Lots of workers shared the success of these large firms, which typically offered the highest
wages in the world.
Industries in Other Temperate Region Countries
Agriculture, banking, consumer goods, infrastructure, mining, oil and gas, and
telecommunications industries present in AFRICAN countries.
• Manufacturing-based industries (automotive, electronics, textile, etc.): East Asia is one of
the world’s leading manufacturing regions. The Asian industry in this region is vast in both
expanse and variety. Across China, Japan, South Korea and Taiwan, goods as cheap as toys
to as high value as cars are manufactured. Industry giants such as Samsung, Toshiba, Toyota,
and Honda are based here. Also, many corporations from the US and Europe have a major
part of their operations in Asia due to the abundant availability of labor at lower costs. The
textile industry provides employment to a considerable proportion of the population.
• Services-based industries (finance, IT, BPO, etc.): Six of the world’s most important
financial centers are located in Asia.
Pollution and Climate Change:
The pollutants released into the atmosphere cause local air pollution. However, they also cause
regional air pollution, as with huge plumes of smoke covering a large area, and acid rain.
Beyond that, we are emitting such a high level of pollutants that they are causing serious global
environmental problems: climate change and ozone depletion. The human race has become
capable of affecting the atmosphere that encircles the Earth, and the very planet itself.
Air pollution is currently the leading environmental cause of premature death. According to
the World Health Organization (WHO), approximately 7 million premature deaths annually
are due to the effects of air pollution.
Cause of Climate Change:
The recent role of the greenhouse effect
Since the Industrial Revolution began around 1750, human activities have contributed
substantially to climate change by adding CO2 and other heat-trapping gases to the
atmosphere. These greenhouse gas emissions have increased the greenhouse effect and
caused Earth’s surface temperature to rise. The primary human activity affecting the amount
and rate of climate change is greenhouse gas emissions from the burning of fossil fuels.
Carbon dioxide (CO₂) emissions from human activities are now higher than at any point in
our history. In fact, recent data reveals that global CO₂ emissions were 150 times higher in
2011 than they were in 1850.

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Fig. 1 Global Carbon Emission from fossil fuels (1900-2011)
1850-1960: Industrializing Countries Dominate Emissions
Between 1850 and 1960, the world generally experienced a constant growth of emissions,
due largely to industrialization and population growth, particularly in the United States. This
development only saw some interruptions by historic events, like the Great Depression in the
1930s and the end of World War II in 1945. By the 1950s, however, China and Russia started
seeing their emissions climb as their economies grew.
1960-2011: New Top Emitters Emerge
We saw some new developments after 1960. While the United States kept its place as the top
CO2 emitter until 2005, Asian countries also started to emerge, led by China. The graph
above shows the development of the current top five CO₂-emitting countries since 1960, with
the United Kingdom presented for comparison. The UK, once the world’s highest emitter,
stabilized its total CO₂ emissions. Russia experienced a significant reduction in emissions
with the dissolution of the Soviet Union. But the most obvious development was the rise of
China’s emissions in the first part of the 21st century and its overtaking of the United States
as the world’s largest emitter after 2005.
1960-2011: Per Capita Emissions in the West—Stable, but High
By looking at these emissions trends on a per person basis, we can observe that, while global
emissions were still rising overall, most of the industrialized countries stabilized their per
capita emissions during the second half of the 20th century. However, annual per capita
emissions in industrialized regions like North America and Europe were still far greater than
per capita emissions in Latin America and the Caribbean, Africa, and Asia - despite
consistent emissions growth in these regions. In 2011, per capita emissions varied greatly
even within the top 10 CO₂ emitters. For example, Saudi Arabia and the United States
emitted more than 17 metric tons per person as compared to China and India, which added
6.7 and 1.5 metric tons per person per year, respectively.

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1990s-2011: The Rise of Asia
In 1994, Asia’s gross domestic product became the largest in the world. Interestingly, though,
Asia became the largest emitter of CO₂ one year before—in 1993—largely due to rapid
economic growth in China. The chart above outlines this significant shift. In the past, the
largest share of global emissions came from Europe and Northern America. But by the end of
2011, Asia dominated, contributing more than half of global CO₂ emissions. As shown in the
earlier graph, Asia’s per capita emissions still remain on a much lower level than in western
regions.
Regional Impacts of climate change
Impacts on Africa
Africa may be the most vulnerable continent to climate variability and change because of
multiple existing stresses and low adaptive capacity. Existing stresses include poverty, food
insecurity, political conflicts, and ecosystem degradation.
Toward the end of the 21st century, projected sea level rise will likely affect low-lying
coastal areas with large populations, including Senegal, Liberia, and Mozambique.
Impacts on Asia
Glaciers in Asia are retreating at faster rates than ever documented in historical records.
Some glaciers currently cover 20% of the land that they covered a century ago. Melting
glaciers increase the risks of flooding and rock avalanches from destabilized slopes.
Climate change is projected to decrease freshwater availability, especially in central and
southeast Asia, particularly in large river basins. With population growth and increasing
demand from higher standards of living, this decrease could adversely affect more than a
billion people by 2050.
Impacts on Australia and New Zealand
Water security problems are projected to intensify with a 1°C global average warming in
southwestern and southeastern Australia, and in the northern and some eastern parts of New
Zealand.
Sea level rise and more severe storms and coastal flooding will continue to affect coastal
areas. Coastal development and population growth in areas such as Cairns and Southeast
Queensland (Australia) and Northland to Bay of Plenty (New Zealand), would place more
people and infrastructure at risk.
Impacts on Europe
In southern Europe, higher temperatures and drought may reduce water availability,
hydropower potential, summer tourism, and crop productivity, hampering economic activity
more than other European regions.
In central and eastern Europe, summer precipitation is projected to decrease, causing higher
water stress. Forest productivity is projected to decline. The frequency of peatland fires is
projected to increase.

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In northern Europe, climate change is initially projected to bring mixed effects, including
some benefits such as reduced demand for heating, increased crop yields, and increased forest
growth. However, as climate change continues, negative impacts are likely to outweigh
benefits. These include more frequent winter floods, endangered ecosystems, and increasing
ground instability from thawing permafrost.
Impacts on North America
Warming in western mountains will decrease snowpack, increase winter flooding, and reduce
summer flows, exacerbating competition for over-allocated water resources.
Moderate climate change in the early decades of the century is projected to increase
aggregate yields of rain-fed agriculture in northern areas, but temperature increases will
reduce corn, soy, and cotton yields in the Midwest and South by 2020. Climate change will
likely increasingly stress coastal communities and habitats, worsening the existing stresses of
population, development, and pollution on infrastructure, human health, and the ecosystem.
Difference Between Atmospheric Condition Of Temperate And Tropical Region:
Tropical climates
Much of the equatorial belt experiences hot and humid weather. There is abundant rainfall
due to the active convection of air that takes place there, and during certain periods,
thunderstorms can occur every day. Nevertheless, this belt still receives considerable
sunshine, and with the excessive precipitation, provides ideal growing conditions for
luxuriant vegetation. The principal regions with an equatorial climate are the Amazon Basin
in Brazil, the Congo Basin in West Africa and Indonesia.
Temperate climates
Temperate climates are those without extremes of temperature and precipitation. The changes
between summer and winter are invigorating without being frustratingly extreme. There are
two types of temperate climate: maritime and continental.
The maritime climate is strongly influenced by the oceans, which maintain fairly steady
temperatures across the seasons. Since the prevailing winds are westerly in the temperate
zones, the western edge of continents in these areas experience most commonly the maritime
climate. Such regions include western Europe, in particular the UK, and western North
America at latitudes between 40 and 60 north.
Effect of temperate ecosystem on tropical ecosystem:
As we know from above that most of the industrialized countries have contributed a very
high amount of co2 in atmosphere and co2 emission is the basic reason for greenhouse effect
and greenhouse effect is directly causing climate change (increase in temperature) most of
these industrialized countries are located in the temperate region . So, we can get a clear
image from this that the temperate region is directly affecting not only tropical region but
also polar region. There is rise in temperature as well as in level of sea in tropical region.
Countries like Bangladesh is having 15% of their area submerged into waters.

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HYDROLOGICAL CHANGES
DINESH KUMAR
Water can occur in three physical phases: solid, liquid, and gas and is found in nature in all
these phases in large quantities. Depending upon the environment of the place of occurrence,
water can quickly change its phase.
The Hydrologic Cycle, also known as the water cycle, is one such cycle which forms the
fundamental concept in hydrology.
Hydrologic cycle was defined by the National Research Council (NRC, 1982) the as
“the pathway of water as it moves in its various phases to the atmosphere, to the earth,
over and through the land, to the ocean and back to the atmosphere”. This cycle has no
beginning or end and water is present in all the three states (solid, liquid, and gas).
Components of Hydrologic Cycle:
The hydrologic cycle can be subdivided into three major systems: The oceans being the major
reservoir and source of water, the atmosphere functioning as the carrier and deliverer of water
and the land as the user of water.
The major components of the hydrologic cycle are precipitation (rainfall, snowfall,
hale, sleet, fog, dew, drizzle, etc.), interception, depression storage, evaporation,
transpiration, infiltration, percolation, moisture storage in the unsaturated zone, and
runoff (surface runoff, interflow, and base flow).
Evaporation of water takes place from the oceans and the land surface mainly due to solar
energy. The moisture moves in the atmosphere in the form of water vapour which precipitates
on land surface or oceans in the form of rain, snow, hail, sleet, etc. A part of this precipitation
is intercepted by vegetation or buildings. Of the amount reaching the land surface, a part
infiltrates into the soil and the remaining water runs off the land surface to join streams. These
streams finally discharge into the ocean. Some of the infiltrated water percolates deep to join
groundwater and some comes back to the streams or appears on the surface as springs.
This immense movement of water is mainly driven by solar energy: the excess of
incoming radiation over the outgoing radiation. Therefore, sun is the prime mover of the
hydrologic cycle. The energy for evaporation of water from streams, lakes, ponds and oceans
and other open water bodies comes from sun. A substantial quantity of moisture is added to the
atmosphere by transpiration of water from vegetation. Living beings also supply water vapour
to the atmosphere through perspiration. Gravity has an important role in the movement of water
on the earth’s surface and anthropogenic activities also have an increasingly important
influence on the water movement.
Influence of Human Activities and Land use Changes on Hydrologic Cycle
The quality of water is significantly deteriorating at many places due to industrial and
agricultural activities. There has been a growing need to quantify the impact of major human-
induced changes on the hydrologic cycle in order to anticipate and minimize the potential
environmental detriment and to satisfy water resources requirements of the society. Even if the
water of adequate quantity were present at a place, its use may be limited because of poor
quality.
(a) Effects of Agricultural Changes
These changes imply that a land area that was earlier forested or a barren land is now being
cultivated. As a result, the vegetal cover changes, soil crusting and infiltration characteristics
change, and artificial bunds may be placed. The effect of these changes on the hydrologic
regime is pronounced and may be multiplicative. The water may be withdrawn from the ground
water zone or canal irrigation may be applied on the land leading to noticeable changes in the

12
water table behaviour. The impacts are also noticed in evapotranspiration, overland flow,
channel flow, and infiltration. Fertilisers, pesticides, and insecticides that are applied to crops
affect the water quality of runoff from agriculture areas.
(b) Effects of Urbanisation
A land area that was being used for purposes, such as forestry, agriculture, might be
transformed into an urban area where houses, roads, parks, parking lots, sewers, etc. are
constructed. A large increase in the impervious surface takes place which considerably reduces
infiltration and the removal of storm water is accelerated. Urban development usually increases
the volume and peak of direct runoff for a given rainfall event. The time of travel of water is
reduced, resulting in a lower lag time and a lower time of concentration.
(c) Effects of Forest Activities
These activities may be directed towards planting trees as well as cutting them. When a forested
area is deforested and forest litter removed, the interception of precipitation is virtually
eliminated. Litter removal changes infiltration capacity of soil and has a pronounced effect on
raindrop impact and the resulting soil erosion. With the loss of vegetation, evapotranspiration
is generally decreased. These changes amount to increased production of direct runoff, reduced
surface roughness, and decreased recharge to ground water. The hydrograph of direct runoff
rises more quickly because of the reduced time to peak. However, when additional trees are
planted in an area, the effect is reverse though the impact takes place gradually as the trees
grow.
(d) Effects of Structural Changes
Typical structural changes include a dam, a weir, channel improvement works, etc. A dam-
reservoir is constructed for many purposes. Regardless of its intended function, it does affect
the hydrology of the stream on which it is built. In general, the peak of outflow from a reservoir
is less and the flow may be more even than the pre-project condition. The volume of flow
downstream may be considerably less in the after-project scenario if the reservoir water is
diverted elsewhere.
Decreasing channel roughness increases flow velocity and peak discharge for the same channel
size. The removal of vegetation, lining of the channel, and proper maintenance can greatly
reduce roughness. The other alterations, such as straightening the channel, maintenance of
bands, or increasing slope, significantly affect travel time and flow velocity. Depending upon
the bed material, infiltration through the bed and banks also modifies flow characteristics.
(e) Effects of Climate Change
The increase in the temperature of the atmosphere would lead to higher evapotranspiration,
changes in precipitation pattern, timing, and distribution, melting of polar ice caps and
recession of glaciers. Higher melting of polar ice and glaciers will cause rise of sea water level
and inundation of islands of low elevations as well as cities adjacent to seas.
Climate induced changes in precipitation, winter conditions, and extreme storm events have
increased base and average stream and river flows in many parts of the World; land use
practices, water withdrawals for human use, and development are also influencing hydrological
conditions of water bodies and aquifers. Intensification of the hydrologic cycle due to climate
change and extreme precipitation events can increase the delivery of nutrients and pollutants
to downstream and coastal habitats. This has important implications for food-web structure and
ecosystem function, such as making poor water quality events and the incidence of waterborne
disease more likely. Human structures that intersect with aquatic systems, such as dams,
culverts and road crossings, are potential barriers to fish and wildlife movement.

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Regional Aspects of Hydrological Changes:
Asia
Asia is a region where water distribution is uneven and large areas are under water stress. From
west China and Mongolia to west Asia, there are large areas of arid and semi-arid lands. Asia
has a very high population that is growing at a fast rate, low development levels and weak
coping capacity
Fresh water resources: Decreasing trends in annual mean rainfall were observed in Russia,
north-east and north China. Flooding could increase the habitat of brackish-water fisheries but
could also seriously affect the aquaculture industry and infrastructure, particularly in heavily
populated mega deltas. Saltwater intrusion in estuaries due to decreasing river runoff can be
pushed 10–20 km further inland by rising sea levels. Increases in water temperature and
eutrophication in the Zhujiang and Changjiang Estuaries have led to formation of a bottom
oxygen-deficient horizon and increased frequency and intensity of ‘red tides’.Increasing
frequency and intensity of droughts in the catchment area would lead to more serious and
frequent saltwater intrusion in the estuary and thus deteriorate surface water and groundwater
quality.
Energy: Changes in runoff could have a significant effect on the power output of hydropower-
generating countries such as Tajikistan.
Biodiversity: With the gradual reduction in rainfall during the growing season for grass, aridity
in central and west Asia has increased in recent years, reducing the growth of grasslands and
increasing the bareness of the ground surface (Bou-Zeid and El-Fadel, 2002). Increasing
bareness has led to increased re ection of solar radiation, such that more soil moisture
evaporates and the ground becomes increasingly drier in a feedback process, thus adding to the
acceleration of grassland degradation.
Australia and New Zealand:
water: Ongoing water security problems are very likely to increase by 2030 in southern and
eastern Australia, and parts of eastern New Zealand that are distant from major rivers. Runoff
in twenty- nine Victorian catchments is projected to decline by 0–45%. In recent years, an
intense multi-year drought has emerged in eastern and other parts of southern Australia. For
example, the total in ow to the Murray River over the years prior to 2006 was the lowest five-
year sequence on record.
Agriculture: Farming of marginal land in drier regions is likely to become unsustainable due
to water shortages, new biosecurity hazards, environmental degradation and social disruption.
For maize in New Zealand, a reduction in growth duration reduces crop water requirements,
providing closer synchronization of development with seasonal climatic conditions.
Biodiversity: Saltwater intrusion as a result of sea-level rise, decreases in river flows, and
increased drought frequency are very likely to alter species composition of freshwater habitats,
with consequent impacts on estuarine and coastal fisheries. Impacts on the structure, function
and species composition of many natural ecosystems are likely to be significant by 2020, and
are virtually certain to exacerbate existing stresses such as invasive species and habitat loss
(e.g., for migratory birds), increase the probability of species extinctions, degrade many natural
systems and cause a reduction in ecosystem services for water supply.
Europe:
Water: Flood risk is projected to increase throughout the continent. The region’s most prone
to a rise in flood frequencies are eastern Europe, then northern Europe, the Atlantic coast and

14
central Europe, while projections for southern and south-eastern Europe show significant
increases in drought frequencies.
Energy: By the 2070s, hydropower potential for the whole of Europe is expected to decline by
6%, translated into a 20–50% decrease around the Mediterranean, a 15–30% increase in
northern and eastern Europe, and a stable hydropower pattern for western and central Europe.
Biofuel production is largely determined by the supply of moisture and the length of the
growing season.
Health: Climate change is also likely to affect water quality and quantity in Europe, and hence
the risk of contamination of public and private water supplies. Both extreme rainfall and
droughts can increase the total microbial loads in freshwater and have implications for disease
outbreaks and water-quality monitoring.
Agriculture:The predicted increase in extreme weather events (e.g., spells of high temperature
and droughts) is projected to increase yield variability and to reduce average yield. In
particular, in the European Mediterranean region, increases in the frequency of extreme climate
events during specific crop development stages (e.g., heat stress during the flowering period,
rainy days during sowing dates), together with higher rainfall intensity and longer dry spells,
is likely to reduce the yield of summer crops.
Biodiversity: Many systems, such as the permafrost areas in the Arctic and ephemeral (short-
lived) aquatic ecosystems in the Mediterranean, are projected to disappear. Loss of permafrost
in the Arctic will be likely to cause a reduction in some types of wetlands in the current
permafrost zone. A consequence of warming could be a higher risk of algal blooms and
increased growth of toxic cyanobacteria in lakes. Higher precipitation and reduced frost may
enhance nutrient loss from cultivated fields and result in higher nutrient loadings leading to
intensive eutrophication of lakes and wetlands. Higher temperatures will also reduce dissolved
oxygen saturation levels and increase the risk of oxygen depletion.
Latin America:
Water: droughts related to La Niña created severe restrictions for the water supply and
irrigation demands in central western Argentina and in central Chile. Droughts related to El
Niño reduced the flow of the Cauca River in Colombia.
Energy: Hydropower is the main electrical energy source for most countries in Latin America,
and is vulnerable to large-scale and persistent rainfall anomalies due to El Niño and La Niña,
as observed in Argentina, Colombia, Brazil, Chile, Peru, Uruguay and Venezuela. A
combination of increased energy demand and droughts caused a virtual breakdown of hydro-
electricity in most of Brazil in 2001 and contributed to a reduction in GDP. Glacier retreat is
also affecting hydropower generation, as observed in the cities of La Paz and Lima.
Agriculture: As a result of high rainfall and humidity caused by El Niño, several fungal
diseases in maize, potato, wheat and bean are observed in Peru. Some positive impacts are
reported for the Argentinean Pampas region, where increases in precipitation led to increases
in crop yields close to 38% in soybean, 18% in maize, 13% in wheat, and 12% in sun flower.
In the same way, pasture productivity increased by 7% in Argentina and Uruguay.
Biodiversity: In relation to biodiversity, populations of toads and frogs in cloud forests were
found to be affected after years of low precipitation. In Central and South America, links
between higher temperatures and frog extinctions caused by a skin disease (Batrachochytrium
dendrobatidis) were found.

15
LAND DEGRADATION
AKANSHA CHADHA
‘‘Land’’ normally means a physical entity in terms of its topography and spatial nature,
including the natural resources such as soils, minerals, water, and biota that the land comprises.
But sometimes due to natural and human activities the soil deteriorates causing land
degradation. Land degradation is the reduction, or total loss, of the productivity of soils
caused by changes in their inorganic and organic constituents and the natural balance between
them. Land deteriorates in three ways: physical, chemical and biological land degradation.
TYPES OF LAND DEGRADATION
PHYSICAL: physical processes are a decline in soil structure leading to crusting, compaction,
erosion, desertification, anaerobism, environmental pollution, and unsustainable use of natural
resources. Physical degradation also includes soil erosion by water and wind.
CHEMICAL: Chemical deterioration is a type of soil degradation involving loss of nutrients
or organic matter (leaching), salinisation, acidification, soil pollution, cation retention capacity
and fertility decline.
BIOLOGICAL: Biological processes include reduction in total and biomass carbon, and
decline in land biodiversity.
Principle Causes of Land Degradation In Temperate Region
1. Natural - Precipitation (water), wind, slope steepness and Weather conditions (drought &
flood).
2. Human induced - consist of developmental activities such as agriculture, mining and
constructions. Such activities generally remove the protective vegetation cover (deforestation),
resulting in accelerated erosion by both water and wind.
Following are the major human induced factors causing land degradation in temperate
region of the world:
• Overgrazing (35%) causes degradation when the soil loses its fertility and sparse vegetation
cover.
• Overgrazed lands become more vulnerable to erosion as compaction of the soils reduces
infiltration, leading to greater runoff.
• Deforestation (30%) the trees anchor the soil with their roots. Due to loss of trees the soil
is left loose becoming prone to water and wind erosion. For eg: Overexploitation of land to
produce fuelwood (7%).
• Intensive agriculture practices (28%) have virtually mined nutrients from the soil. Due to
over application of chemicals and imbalance in the application of fertilizers and pesticides
the cultivable lands have become sick.
• Industrialisation and urbanization (1%)- sealing of land through urbanization and
industrialization, excludes all further uses of soil and land such as biomass production,
filtering, buffering, and transformation, as well as the function of soil as a gene reserve.
Unsustainable use of land functions, like tourism causes compaction & contamination.
Land Degradation In Developing Countries Of Temperate Region
Northern Africa
• Overgrazing (34% of land) as livestock rearing is an prominent economic activity,
Urbanization 1% of land in Egypt while deforestation (36%) and unsuitable agricultural
practices has degraded 28% of land in northern Africa.

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• Chemical factors such as salinization occurs mainly in irrigated plains located in the
western part of the Algeria where many surface areas are fully degraded. While salinity,
water logging, depletion of soil fertility, excessive use of pesticides, fertilizers, and
inappropriate machines of tillage has degraded 12% land of Egypt.
Water erosion threatens 12 million hectares in northern and western Algeria. While in
Egypt, it is about 55% due to inadequate maintenance of their irrigation and drainage networks,
over abstraction of groundwater, and seawater intrusion in coastal areas. Water erosion is
common in the Jabal Nefusa about 70% and in Jabal Al Akhdar about 88% in upland area of
Libya. Other countries of Northern Africa are not much affected by water erosion due to low
precipitation (less than 200 mm). Whereas, wind erosion threatens more than 7 million ha of
arid and semi-arid land of Algeria and affects 90% of the total area in Egypt. Wind erosion in
south Tunisia is most effective because of shallow and sandy soils. It is also prevalent in all
areas of Libya due to the following factors: aridity of climate, absence of adequate vegetative
cover, light texture of moist soil, intensive wind regimes. It is estimated that about 30% of
irrigated land, 47 % of rainfed cropland, and 73% of rangeland in these areas have been affected
by desertification to varying degrees.
ASIA
In temperate Asia, major causes of land degradation are overgrazing, decreasing
vegetativecover, deforestation, desertification, intensive agriculture, mining activity and
increasing urbanization highly contributing to salinization, water and wind erosion. Wind
erosion affects 60% of the land under crops and pasture in Iran and 44% in China. Water
erosion effects 47% in China.
Reducing fallow periods and introducing irrigation are used to maintain output, leading to
erosion by lowering soil fertility and promoting salinization. Salinization affects 33 Mha in
Iran and 8.3% land in China. Urbanization affects 1.9% of total land in China. About 70% of
Afghanistan and 27% of China suffers from desertification. In Iran and Afghanistan,
deforestation occurs to obtain timber, fuelwood. In 1980’s Afghan government stated that
19000 sq. km land was covered with forests and now 70% of it has been destroyed for firewood.
Altogether 140 million hectares, or 43% of the Asia's total agricultural land, suffers from
degradation. The worst country affected was Iran, with 94% of agricultural land degraded,
followed by Bangladesh (75%), Pakistan (61%), Afghanistan (33%), Nepal (26%), India (25%)
and Bhutan (10%).
SOUTH AMERICA
Major causes of land degradation in temperate South America are: intensive agriculture,
deforestation, improper irrigation, abuse of cultivation techniques and intensive grazing. Major
economic activity is agriculture and commercial grazing in temperate South America. For eg:
62% of the Chilean hillsides are subjected to intense grazing and removal of shrub vegetation,
hence, suffering from soil erosion. Hillside soils are generally used in seasonal agricultural
production and have no plant cover for part of the year. Soils in Copiapo valley in Chile has
been degraded by salinization due to excessive use of machinery in vineyards. Uruguay is an
agricultural country with cattle-ranching constituting over 85 percent of the country’s exports.
About 30% of the land is degraded, due to loss of organic matter. Uruguayan soils are
vulnerable to water erosion especially when a wheat crop is cultivated. Wheat cultivation
would lose 25 to 50cm topsoil over 20 years. In 2005, 4.3% of the total arable area was affected
by soil degradation. Wind erosion affects 60 million ha in Argentina due to this land use
change from forests and natural grasslands to urban areas.

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Land Degradation In Developed Countries Of Temperate Region
NORTH AMERICA
A major causes of land degradation in North America are agricultural activity (57%)
deforestation (11%), overgrazing (24%) and overexploitation of vegetation (7%). Unlike other
continents, North America shows declining trends of land degradation due to reduction in
tillage intensity since 1982. For eg: Between 1982 and 2007, soil erosion on U.S. cropland
decreased.
Water erosion on cropland in 2007 declined from 1.68 billion tons per year to 960 million tons
per year and wind erosion declined from 1.38 billion tons per year to 765 million tons per year.
Water erosion (2007)—54% occurred in the Corn Belt and the Northern Plains. Wind erosion
(2007)—93% occurred in the Northern Plains, Southern Plains, Mountain, and Lake States.
Mining used to affect 3% of total land area of North America but Surface mining regulations
in most of North America require topsoil and spoiled area reclamation to reverse soil
degradation. In the U.S., urban land use has increased by 400% from 6 to 24 million ha since
1945 accounting for ~3% of total land resulting in agricultural land losses at a rate of ~120 ha
for each added kilometre.
EURASIA
Major causes of land degradation in European countries are human activities such as
Industrialization and urbanization which leads to diffuse contamination and the sealing of soil
surfaces in populated countries of western and northern Europe. Another cause is agricultural
intensification, the pressure has increased on little agricultural land available for producing
food to support large population. For 12 of EU countries, the number of contaminated sites
adds up to 1,500,000. Total 1.5% of land is highly degraded due to land degradation in Europe.
Water erosion has affected 115 million ha of land and wind erosion has affected 42 million ha
of land in Europe.
For eg: Broad areas of land in southern Russia suffer from erosion due to overuse of chemical
fertilizers have contaminated agricultural areas. Forests in more accessible parts of the country
suffer from deforestation caused by extensive logging. A considerable part of reindeer pastures
continues to deteriorate, through overgrazing , fires and technogenic contamination. Built-up
lands affects Central Russia (4.8%). The lands damaged under mining work and geological
prospecting are situated in the Ural region, Western Siberia and in the Far East.
AUSTRALIA
Wind erosion, vegetative degradation, and salinity are greater problems in the arid regions of
Australia because of the combined effects of drought and overgrazing affecting more than 50
percent of the total rural land area. Water erosion affects non arid regions of Eastern Australia.
Only 10% land can support crops and improved pasture here. Heavy applications fertilizer, and
the use of herbicides and insecticides to control weeds and pests have contaminated soil and
water especially in cotton-producing areas.
Decreased rainfall over winter and spring across large parts of southern and inland eastern
Australia has increased risk of drought, 17 of the 26 El Niño events since 1900 have seen major
droughts over significant parts of Australia. About 42% of land suffers from desertification.
Declining Productivity Due to Land Degradation in The Temperate Region
Productivity is an average measure of the efficiency of production. It can be expressed as the
ratio of output to inputs used in the production process. Declining productivity refers to when
input cost is more than profits. Agricultural productivity declines due to the land degradation
which causes loss of organic matter in soil.
AFRICA: The productivity of some lands in Africa has declined by 50% as a result of soil
erosion and desertification. Yield reduction in Africa range from 2 to 40%, with a mean loss
of 8.2% for the continent. Yield reductions by 2020 may be 16.5%. Annual reduction in total

18
production for 1990 was 8.2 million tons for cereals, 9.2 million tons for roots and tubers, and
0.6 million tons for pulses.
Canada and USA: on-farm effects of land degradation were estimated to range from US$700
to US$915 million in 1984. Yield reductions of 20 to 40% have been measured for row crops
(corn and soybean) in Ohio and Midwest USA. It is estimated that the total annual cost of
erosion from agriculture is about US$44 billion per year, about US$247 per ha of cropland and
pasture.
Reductions in crop yields are 25% in maize, 20% in soybeans, and 30% in oats over a seven-
year period. On-farm losses through land compaction are at US$1.2 billion in USA and US$1.3
billion in Canada per year.
ASIA: 20% productivity losses caused by erosion in Asia, especially in India, China, Iran,
Israel, Jordan, Lebanon, Nepal, and Pakistan. In South Asia, annual loss in productivity is
estimated at 36 million tons of cereal equivalent valued at US$5,400 million by water erosion,
and US$1,800 million due to wind erosion. In Afghanistan, 9 million people are facing food
shortages and farmers of Northern Afghanistan are unable to plant crops.
AUSTRALIA: decline of 6 per cent of agricultural production or $1.5 billion each year. It is
projected to lower crop production by 0.16 per cent and animal product output by 0.03 per cent.
A 1% increase in the index of degradation due to soil structure decline is projected to lower
crop and livestock production by around 0.01 per cent.
EUROPE: Soil compaction due to adoption of mechanized agriculture. It has caused yield
reductions of 25 to 50% in some regions of Europe. About 7.9% shows a land productivity that
is stable but stressed, 5.6% shows early signs of land productivity decline, and 1.5% is in
decline. Less than 1% of EU arable land, 0.2% of pastureland and more than 11% of permanent
crops (tree crops) fall into the declining land productivity category.
Impact Of Land Degradation
On-site effect is directly created through the loss of soil nutrients. This effect is particularly
crucial on agricultural land because it involves the loss of soil quality, structure and soil
stability making it infertile.
While off-site effect involves movement of sediments and agricultural pollutants into
watercourses leading to sedimentation in rivers and disruption of ecosystems. Sedimentation
makes it difficult for light to shine through the water, harming the growth of plants and
promoting algae growth causing depletion of oxygen that animals and plants need. Animals
lose their natural habitat due to depletion of forests. This could result in extinction of species.
Soil particles in the air can affect human and animal health when they are inhaled. The particles
accumulate in the lungs and cause chronic respiratory problems. Blowing dust also increases
the risk of car accidents due to lowered visibility.
REMEDIES
1) Biological methods
a) Strip cropping - Practiced in USA
b) Crop rotation- Practiced in Europe, middle east, USA, Canada
c) Application of manure- Practiced in Europe, China, North America, India
d) Shelter belt- Practiced in China, Great plains shelterbelt project in USA, Canada
e) Vegetation cover- Used in Europe, USA.
2) Mechanical methods
a) Contouring - Practiced in USA, Mediterranean region, Western Canada, Australia.
b) Terracing - Practiced in Pakistan, Upper Mississippi River basin (USA), China,
India,
Japan, Andes of South America, Oceania hilly terrain of Asia.
c) Control of gully erosion through retention of run-off, diversion of run-off.

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CONCLUSION
Land degradation is a major issue around the world that needs to be urgently dealt with. Loss
of fertile land with rapidly increasing population is threatening food security. According to the
UNFAO (2008), 1.5 million people in this world may starve due to land erosion problem. Many
nations focus on water and air degradation while keeping soil degradation as their second
priority. Since land resources are non-renewable, it is necessary to adopt a positive approach
to sustainable management of these finite resources.

20
LOSS OF BIODIVERSITY: HABITAT DESTRUCTION AND EXTINCTIONS
APOORVA TYAGI
Biodiversity is defined as “the variability among living organisms from all sources including,
inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of
which they are part; this includes diversity within species, between species and of
ecosystems.”
The term biodiversity encompasses variety of biological life at more than one scale. It is not
only the variety of species (both plant and animal) but also the variety of genes within those
species and the variety of ecosystems in which the species reside. Biodiversity forms the
foundation of the vast array of ecosystem services that critically contribute to human well-
being.
Due to the growth in the human population, in production and consumption, over the last two
centuries the natural ecosystems of our planet have been subjected to an impressive depletion
of their biodiversity, with an overall decrease, measured by the Living Planet Index, equal to
30% from 1970 to 2005.
A major report, the Millennium Ecosystem Assessment, released in March 2005 highlighted a
substantial and largely irreversible loss in the diversity of life on Earth, with some 10-30% of
the mammals, bird and amphibian species threatened with extinction, due to human actions.
The World Wide Fund for Nature (WWF) added that earth is unable to keep up in the struggle
to regenerate from demands we place on it.
According to International Union for Conservation of Nature (IUCN):
• 1 out of 8 birds;
• 1 out of 4 mammals;
• 1 out of 4 conifers;
• 1 out of 3 amphibians;
• 6 out of 7 marine turtles are at the threat of extinction in temperate region.
Due to Biodiversity loss the current scenario of the world is following:
• 75% of genetic diversity of agricultural crops has been lost.
• 75% of the world’s fisheries are fully or over exploited.
• Up to 70% of the world’s known species risk extinction if the global temperatures rise
by more than 3.5°C.
• 1/3rd
of reef-building corals around the world are threatened with extinction.
• Over 350 million people suffer from severe water scarcity.
Habitat Loss And Extinction In Temperate Region
The problem of loss of biodiversity in temperate region is severe; the natural habitats are being
destroyed. The fields, forests, and wetlands where wild plants and animals live are
disappearing. Land is cleared to plant crops or for building houses and factories. Forests are
cut for lumber and firewood. As habitats shrink, fewer creatures are surviving there. The

21
creatures that survive have fewer breeding partners, so genetic diversity declines. Most of the
developed countries are there in temperate region and these countries had seen biodiversity as
all people resource and after causing much destruction in the world these countries are
propagating the idea of conservation of biodiversity.
In the past hundred years, biodiversity around the world has decreased dramatically.
Many species have gone extinct. Extinction is a natural process; some species naturally die out
while new species evolve. But human activity has changed the natural processes of extinction
and evolution. Scientists estimate that species are dying out at hundreds of time the natural rate.
Human activities have increased the rate of natural extinction and it is estimated that the current
climate change will worsen the situation further. The problem is worse in temperate region as
most of the developed countries of the world come under this region and this region has a very
high level of industrialization and urbanization which led to exploitation of environment and
biodiversity loss.
Reasons For Loss Of Biodiversity:
Alteration and loss of the habitats: the transformation of the natural areas determines not
only the loss of the vegetable species, but also a decrease in the animal species associated to
them. Forests and grasslands are cleared for formation of industries and cities.
Introduction of exotic species and genetically modified organisms: species originating from
a particular area, introduced into new natural environments can lead to different forms of
imbalance in the ecological equilibrium. Refer to, “Introduction of exotic species and
genetically modified organisms. Brown tree snakes, for instance, were accidentally brought
into Guam, an island in the South Pacific, in the 1950s. Because brown tree snakes have no
predators on Guam, they quickly multiplied. The snakes, which hunt birds, have caused the
extinction of nine of the island’s 11 native forest-dwelling bird species.
Pollution: The pollution is very high in this region. Human activities influence the natural
environment producing negative, direct or indirect, effects that alter the flow of energy, the
chemical and physical constitution of the environment and abundance of the species.
Overfishing and overhunting: There is culture of fishing and hunting in this region. Fishing
and hunting is seen as a recreational activity in countries like USA, Britain, etc which is leading
to biodiversity loss as man is not giving time species to re-evolve.
Climate change: heating of the Earth’s surface by industries, vehicles and CFCs affects
biodiversity because it endangers all the species that adapted to the climate of that region.
Overexploitation of resources: there is over exploitation of resources in temperate region ad
this region has large number of industries.
Impacts Of Biodiversity Loss:
• There is more pollution and which is leading to health problems among the people.
• The cost to tackle the problem of biodiversity loss and the problems and other cascading
effects would be enormous as it can be assumed that industrial pollution could increase,
with less natural ecosystems to soak it up.
• Biodiversity declines will lead to subsequent declines in ecosystem functioning and
ecosystem stability.

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Table 2 Status of Species
Why Should We Conserve Biodiversity?
NARROW UTILARIAN: We derive most of our requirements from ecosystem, everything
we need comes from nature and hence we need to conserve biodiversity.
BROADLY UTILARIAN: Biodiversity is fundamental for ecosystem. We get very important
things like oxygen and other gases which are very essential from the biodiversity.
ETHICAL: Human beings are ethically connected to biodiversity. We have certain customs
and traditions in which biodiversity and ecosystem is seen very important for human beings.
Decreasing Biodiversity And Measures For Conservation:
People all over the world are working to maintain the planet’s biodiversity. In the United States,
the Endangered Species Act protects about 2,000 organisms that are in danger of becoming
extinct.
Around the globe, thousands of wilderness areas have been set up to conserve plants, animals,
and ecosystems. Local, national, and international organizations are cooperating to preserve
the biodiversity of regions threatened by development or natural disasters. UNESCO’s World
Heritage Site program recognizes areas of global importance, such as the enormous wetland

23
region of the Pantanal in South America. Many national parks, such as Glacier National Park
in the U.S. state of Montana, protect biodiversity within the park by restricting extractive
activities, such as mining and drilling.
Marine protected areas (MPAs) have been established to preserve sea life. In the marine
protected area around Australia’s Great Barrier Reef, no-fishing zones have helped fish
populations thrive. People are also working to limit pollution and restore coral reef ecosystems
in the area. As ecosystems become healthier, their biodiversity increases.
Biodiversity Hotspots -Biodiversity hotspots are a method to identify those regions of the
world where attention is needed to address biodiversity loss and to guide investments in
conservation. The idea was first developed by Norman Myers in 1988 to identify tropical forest
‘hotspots’ characterized both by exceptional levels of plant endemism and serious habitat loss,
which he then expanded to a more global scope .
Conservation International adopted Myers’
hotspots as its institutional blueprint in 1989, and in 1999, the organization undertook an
extensive global review which introduced quantitative thresholds for the designation of
biodiversity hotspots. A reworking of the hotspots analysis in 2004 resulted in the system in
place today. Currently, 35 biodiversity hotspots have been identified, most of which occur in
tropical forests. They represent just 2.3% of Earth’s land surface, but between them they
contain around 50% of the world’s endemic plant species and 42% of all terrestrial
vertebrates. Overall, Hotspots have lost around 86% of their original habitat and additionally
are considered to be significantly threatened by extinctions induced by climate change.
Mesoamerica, Caribbean island, Horn of Africa, Japan, etc are amongst the most important
biodiversity hotspots of the temperate region.

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CHALLENGES TO HUMAN COMMUNITY: TOXICITY, FOOD
INSECURITY, HEALTH IMPACTS
PRITY KHOKHER
Temperate climate has cold winter, hot summers with temperature of 10c. These forests can
feel the impact of natural forces and human activity that influence the environment in the
negative ways. As human number increases, this resulted in unsustainable exploitation of
earth’s biological diversity which worsen the climate change, ocean acidification and other
anthropogenic environmental impacts. Problems which are generally faced by humans are
climate related, health, loss of land productivity, food insecurity, toxicity, hydrological and
atmospheric changes which leads to disturbance in ecological balance between human and
nature.
Toxicity
● It's a degree to which a substance can damage an organism. Toxicity is species specific
and have effect on an animal, bacterium or plant.
● Mainly two kind of toxicity is prevalent in the form of pesticides & lead toxicity in
temperate regions.
Sources: automobiles, industries, used ammunition, fertilisers, pesticides, paint chips, lead-acid
batteries etc.
Adverse effects of insecticides & pesticides:
● Degradation of environment by killing non targeted organisms, accumulation in food
chain, direct pesticide poisoning.
● Their amount if larger than required may pollutes air and dissipate in surrounding areas.
● Discharge of effluents, runoff from farm fields, sewage and factories effluent, residual
dyes from different industries imposes great threat to aquatic systems.
US focused on pesticides applied to applied to crops & unintentional exposure of foraging bees
to them, resulted in residues in hive products, beeswax. Due to this colony of bees have
declined by 45% over 60 years.
Adverse impacts of lead toxicity
● It prevents vegetation and animals from normal biochemical process.
● It may hinder the chemical breakdown of inorganic soil fragments and lead in soil may
become more soluble thus can be taken up by the plants.
● Altered the natural distribution of lead in the aquatic environment.
● It slows down the rate of decomposition of matter.
How toxicity impacts human community?
● They are designed to kill because of no specific mode of action to one species.
● It's exposure can cause neurological health effects such as memory loss, uncontrollable
behaviour, loss of coordination, reduced visual ability, reduced speed of response to
stimuli.
● Enter through skin, lungs or digestive tracts in body and can cause asthma, allergies,

25
hypersensitivity
● Pesticides exposure also linked with cancer, hormone disruption and reproduction
problems with fatal development. Example: Kepone shakes of 1975 : 70 workers are
affected by an organochlorine insecticide in Virginia and after that this was substituted
with organophosphates.
WHO estimates 3 million cases of pesticides poisoning in each year & up to 220000 deaths
mainly in developing countries.
Food insecurity
The WHO defines it as a situation when all people at all times have physical & economic access
to sufficient & nutritious food that meets their dietary needs and food preference for an active
& healthy life.
Indicators are classified along the four dimension of food security -- availability, access,
utilization and stability.
Issues related to food security
The world is facing a potential crisis in terms of food security. The challenge is to provide the
world’s growing population with a sustainable, secure supply of safe, nutritious, and affordable
high-quality food using less land, with lower inputs, and in the context of global climate
change, other environmental changes and declining resources.
Constraints to food security
● The post-war ‘second agricultural revolution’ in developed countries, and the ‘green
revolution’ in developing nations in the mid-1960s transformed agricultural practices
and raised crop yields dramatically, but the effect is levelling off and will not meet
projected demand.
● Pestilence: Estimates vary, but around 25% of crops can be lost to pests and diseases,
such as insects, fungi and other plant pathogens.
● Pests may consume large quantities of crops once they are grown. Even after food is
grown, stored and transported, serious losses can occur, and in developing nations
where ‘plentiful’ food is wasted.
● Climate change associated with agriculture is also a global issue. Agriculture is a
significant contributor to greenhouse gases and is estimated to account for 10-12% of
total greenhouse gas (GHG) emission.
More people die each year from hunger and malnutrition than from AIDS, tuberculosis and
malaria combined, and the World Bank estimates that cereal production needs to increase by
50% and meat production by 85% between 2000 and 2030 to meet demand.
Health
Health is a state of complete physical, social & mental well-being & not merely the absence of
diseases. It can be positive and negative.
Health indicators are required to measure health status of people.
● Nutritional, social & mental health, disability indicators
● Crude death rate, life expectancy, infant & maternal mortality rate

26
● Incidence counts of low birth weight, obesity, diabetes, asthma, chronic pain,
depression, injuries & foodborne illness.
Some of the organisms that cause temperate diseases are bacteria and viruses. Some of the
major diseases are Dengue, Yellow fever, Rotavirus, AIDS, Ebola, Cholera, Tuberculosis,
Malaria, Typhoid, Hepatitis A, Diabetes.
● Major diseases which causes burden on countries wealth and human health are
Cardiovascular, Respiratory, Autism spectrum disorder, water, food borne & infectious
diseases.
The straightest impact of climate on human society can be seen in the extreme climates such
as heat waves & cold spells.
Death rate during winter are 10-25% higher than those in the summer.
Disease Female death rate Male death rate
Mental & behavioural
disorders
6% 3%
Nervous system diseases 7% 4%
Circulatory system diseases 33% 32%
Respiratory diseases 10% 9%
Digestive disease 4% 4%
Musculoskeletal system &
connective tissue
1% 1%
Genitourinary system 3% 2%
Infectious & parasitic diseases 3% 3%
Cancer 22% 25%
Endocrine, nutritional &
metabolic diseases
4% 4%
External causes 5% 10%
Others 2% 3%
Total 100% 100%

27
Health impacts
• Major impacts are caused due to air pollution, climate change, food & water
contamination.
• Increased intensity of heat
waves,reduction in cold
related deaths, increased flood
& drought, change in vector-
borne diseases & risk of
disasters & malnutrition
resulted in change in
demographic structure .
• Extremes of temperature &
rainfall affects malaria,
dengue & incidence of
diarrhoeal diseases.
• Disasters may lead to
mobilisation of dangerous
chemicals from storage which
risk river bank inhabitants as a
consequence of lead & cadmium contamination of floodplain soils.
• High-density city traffic leads to an increase in respiratory diseases due to increase in air
pollution.
• Global climate change has serious health implications which can be measured in terms of
mortality rate.

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BIBLIOGRAPHY
Environmental geography: H.M.Saxena, 1999
Education.seattlepi.com
WHO website
FAO official website
Cambridge.org
http://www.weather-climate.org.uk/13.php
https://www.epa.gov/climate-change-science/causes-climate-change
http://www.iass-potsdam.de/en/content/air-pollution-and-climate-change
www.undp.org/
http://rainforests.mongabay.com/0903.htm
https://naturvernforbundet.no/international/environmental-issues-in-russia/category930.html
http://www.pc.gov.au/research/supporting/land-degradation/landdegr.pdf
http://www.mnn.com/lifestyle/arts-culture/blogs/9-examples-terrace-farming-around-world
http://ec.europa.eu/eurostat/statistics-explained/index.php/Land_cover_statistics
https://www.britannica.com/topic/terrace-cultivation
https://www.reference.com/science/erosion-affect-environment-d583fe9b316c9938#
http://www.skyenimals.com/browse_habitat.cgi?habitat=temperate_forest
wwf.panda.org
www.globalissues.org - Loss of Biodiversity and Extinctions
Conservationists Name Nine New "Biodiversity Hotspots"
John Roach: http://news.nationalgeographic.com/news/2005/02/0202_050202_hotspots.html
National Geographic Video: A New Perspective on Biodiversity(video)
http://www.eniscuola.net/en/argomento/biodiversity1/loss-of-biodiversity/causes-of-the-loss-
of-biodiversity/
http://www.biodiversitya-z.org/content/biodiversity
http://www.nature.com/scitable/knowledge/library/causes-and-consequences-of-biodiversity-
declines-16132475

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