Globalwarming Report

7/31/2019 Globalwarming Report

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GLOBAL WARMING AND ITS EFFECTS

SCHOOL OF PLANNING AND ARCHITECTURE

1GLOBAL WARMING AND ITSGLOBAL WARMING AND ITSGLOBAL WARMING AND ITSGLOBAL WARMING AND ITS

EFFECTSEFFECTSEFFECTSEFFECTS

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TRYAMBAKESH KUMAR SHUKLATRYAMBAKESH KUMAR SHUKLATRYAMBAKESH KUMAR SHUKLATRYAMBAKESH KUMAR SHUKLA

BACHELOR OF PLANNING (IV SEM)BACHELOR OF PLANNING (IV SEM)BACHELOR OF PLANNING (IV SEM)BACHELOR OF PLANNING (IV SEM)

BP/463/2008BP/463/2008BP/463/2008BP/463/2008

DEPARTMENT OF PHYSICAL PLANNINGDEPARTMENT OF PHYSICAL PLANNINGDEPARTMENT OF PHYSICAL PLANNINGDEPARTMENT OF PHYSICAL PLANNING

SCHOOL OF PLANNING ANDSCHOOL OF PLANNING ANDSCHOOL OF PLANNING ANDSCHOOL OF PLANNING AND

ARCHITECTUREARCHITECTUREARCHITECTUREARCHITECTURE


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2INTRODUCTION

GLOBAL WARMING

The simplest definition of global warming is that it is an increase in the surface

temperature of the earth. The term that we are all getting used to hearing now

most often means artificial warming of the earth that is due to greenhouse gases.

Global warming is the increase in the average temperature of the earth near surface

air and oceans since the mid 20th

century and projected continuation. Global

surface temperature increased 0.74 0.18C between the start and end of 20th

century. The Intergovernmental Panel on Climate Change (IPCC) concludes that

most of the observed temperature increase since the middle of 20th century wasvery likely caused by increasing concentration of greenhouse gases resulting from

human activity such as fossil fuel burning and deforestation. The IPCC also

concludes that variations in natural phenomena such as solar radiation and volcanic

eruptions had a small cooling effect after 1950.

GREENHOUSE EFFECT

A natural system known as the "greenhouse effect" regulates temperature on Earth.

Just as glass in a greenhouse keeps heat in, our atmosphere traps the suns heatnear earths surface, primarily through heat-trapping properties of certain

greenhouse gases.

Earth is heated by sunlight. Most of the sun's energy passes through the

atmosphere, to warm the earth's surface, oceans and atmosphere. However, in order

to keep the atmosphere's energy budget in balance, the warmed earth also emits

heat energy back to space as infrared radiation.

As this energy radiates upward, most is absorbed by clouds and molecules of

greenhouse gases in the lower atmosphere. These re-radiate the energy in all

directions, some back towards the surface and some upward, where other

molecules higher up can absorb the energy again. This process of absorption andre-emission is repeated until, finally, the energy does escape from the atmosphere

to space.

However, because much of the energy has been recycled downward, surface

temperatures become much warmer then if the greenhouse gases were absent from

the atmosphere. This natural process is known as the greenhouse effect.

Without greenhouse gases, Earth's average temperature would be -19C instead of

+14C, or 33C colder.


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SCHOOL OF PLANNING AND AR

GREENHOUSE GASE

Water vapour is theimportant too. Some occu

Carbon Dioxide or CO2

activities, mostly throug

climate change.

Methane is produced wh

present. Garbage dumps,

lots of methane.

Nitrous oxide can be fou

increasing the amounts.

manure are used in agricu

Halocarbons are a famil

ozone layer), and other h

Climate model projectio

global surface temperatucentury. The uncertaint

differing sensitivity to

estimates of future green

GLOBAL WAR

HITECTURE

ost common greenhouse gas. But or naturally and some come from huma

is the most significant greenhouse gas

the burning of fossil fuels. It is the

n vegetation is burned, digested or ro

rice paddies, and grazing cows and ot

nd naturally in the environment but hu

Nitrous oxide is released when che

lture.

of chemicals that include CFCs (whi

man-made chemicals that contain chl

s summarized in the latest IPCC rep

e is likely to rise a further 1.1 to 6.in this estimate arises from the u

reenhouse gas concentration and t

ouse gas emission.

Fig: contribution to greenhouse effect

ING AND ITS EFFECTS

3

hers that are veryn activity.\

released by human

ain contributor to

ted with no oxygen

er livestock release

man activities are

ical fertilizers and

ch also damage the

rine and fluorine.

rt indicate that the

C during the 21

st

e of models with

e use of differing


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4GREEN HOUSE EFFECT AND GLOBAL WARMING

PROPERTIES OF A GREENHOUSE GAS

ABSORBS INFRARED RADIATION

When molecules interact with UV radiation the energy they absorb can break

bonds. IR radiation is less powerful as the photons contain less energy. Rather than

breaking bonds it causes them to vibrate more energetically. Advanced theory

shows that a molecule will absorb IR radiation if the vibration causes a change in

its dipole moment.


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5ABSORBS ENERGY IN THE WAVELENGTH RANGE 5-100M

The Earth does not emit much radiation outside the 5-100 m range and so any

gases which absorb other wavelengths will not contribute significantly to the

greenhouse effect.

ENHANCED GREENHOUSE EFFECT

The two most significant greenhouse gases in the atmosphere are carbon dioxide

and water vapour. Water makes the bigger contribution (about 60%) to the natural

greenhouse effect. Between the absorptions caused by carbon dioxide and water

there is a window where the majority of the infrared radiation can escape with

relatively little absorption (except for a narrow band where ozone absorbs.) About

70% of Earths radiation escapes into space through this window.


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6

Gases produced by human activities can increase the natural greenhouse effect of

the atmosphere. This is often known as the enhanced greenhouse effect. There are

two types of these gases:

Gases already present in the atmosphere but an increased amount is added by

human activities. This includes carbon dioxide and methane. Carbon dioxide

contributes the most to the enhanced greenhouse effect.

Gases which are not naturally present. These can sometimes absorb in the

window through which radiation would normally escape into space. This can

cause them to have a very large greenhouse effect. CFCs (chlorofluorocarbons) arean example.

The concentration of carbon dioxide is currently about 380 ppm (parts per million)

in the atmosphere and is rising by about 0.45% per year. Modellers use a scenario

of doubled CO2 concentration to assess the sensitivity of the Earths climate

system to changes in greenhouse gas concentration. They predict rises of about

1.5-4.5C. This is not just due to the direct effect of carbon dioxide there are a

large number of feedback processes which amplify the effect of the carbon dioxide.


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7Carbon dioxide is about 0.03% of the Earths atmosphere; water is more variable,

but at the surface is usually about 1-4% of the atmosphere.

EFFECTS OF GLOBAL WARMING

ENVIRONMENTAL

It is usually impossible to connect specific weather events to global warming.

Instead, global warming is expected to cause changes in the overall distribution

and intensity of events, such as changes to the frequency and intensity of heavy

precipitation. Broader effects are expected to include glacial retreat, Arctic

shrinkage including long-term shrinkage of the Greenland ice sheet, andworldwide sea level rise. Some effects on both the natural environment and human

life are, at least in part, already being attributed to global warming. A 2001 report

by the IPCC suggests that glacier retreat, ice shelf disruption such as that of

the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased

intensity and frequency of extreme weather events are attributable in part to global

warming. Other expected effects include water scarcity in some regions and

increased precipitation in others, changes in mountain snowpack, and some

adverse health effects from warmer temperatures.

CLIMATE CHANGE

Climate change is a long-term shift in the climate of a specific location, region or

planet. The shift is measured by changes in features associated with average

weather, such as temperature, wind patterns and precipitation. What most people

dont know is that a change in the variability of climate is also considered climate

change, even if average weather conditions remain the same.

Climate change occurs when the climate of a specific area or planet is altered

between two different periods of time. This usually occurs when something

changes the total amount of the sun's energy absorbed by the earth's atmosphereand surface. It also happens when something changes the amount of heat energy

from the earth's surface and atmosphere that escapes to space over an extended

period of time.

Such changes can involve both changes in average weather conditions and changes

in how much the weather varies around these averages. The changes can be caused

by natural processes like volcanic eruptions, variations in the sun's intensity, or

very slow changes in ocean circulation or land surfaces which occur on time scales

of decades, centuries or longer.


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But humans also cause

aerosols into the atmosph

stratospheric ozone layer.change are called climat

to new values.

CAUSE OF CLIMATE

Earths climate changes

earth cause cycles of wa

Earth's climatic history.

interglacial swings durin

scales and can have largearth has been in the wa

are much shorter, with th

Other natural causes of c

can alter the distribution

(which can sporadicall

blocking out more sunlig

Still, for thousands of

Temperature and the bala

right for humans, animalkeeping this balance.

Because we burn fossil

and manufacture all sorts

atmosphere. By increasin

capability of the natural g

GLOBAL WAR

HITECTURE

climates to change by releasing green

ere, by changing land surfaces, and by

Both natural and human factors that ce forcings', since they push, or force'

CHANGE

aturally. Changes in the intensity of s

ming and cooling that have been a re

Some of these solar cycles - lik

g the past 400,000 years - extend o

amplitudes of 5 to 6C. For the pasrm interglacial phase of such a cycle.

shortest being the 11 year sunspot cy

imate change include variations in oc

f heat and precipitation) and large eru

increase the concentration of at

t).

years, the Earths atmosphere has c

nce of heat-trapping greenhouse gases

and plants to survive. But today we

uels to heat our homes, run our cars,

of products, were adding more gree

the amount of these gases, weve en

reenhouse effect.

ING AND ITS EFFECTS

8ouse gases and

depleting the

an cause climatethe climate to shift

nlight reaching the

gular feature of the

the four glacial-

er very long time

t 10,000 years, theOther solar cycles

le.

an currents (which

ptions of volcanoes

ospheric particles,

hanged very little.

have remained just

re having problems

produce electricity,

house gases to the

anced the warming


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9EFFECTS OF CLIMATE CHANGE

LANDUSE

There is distinct interconnectivity between changing land use, global warming and

future land use. The different components of the environment are influenced in

distinct and characterized ways.

Forest: 31% increase in the concentration of carbon dioxide in the atmosphere

since the industrial revolution. 45% of carbon dioxide increase in the

atmosphere has been attributed to the lost of forest cover.

Fig: contribution of CO2 from forest depletion

Desert Ecosystem: The potential to provide major carbon sinks in both theirsoils and vegetation. It has normally low carbon storage per unit area. Deserts

and semi desert region may be one of the most responsive to elevated levels of

carbon dioxide and the resultant changes due to the green house effect.

About 37% of the global land surface is desert. The studies predict that with

the 50% increase in carbon dioxide, plant production could be enhanced as

much as 70% in desert ecosystem. It decreases the influence of salinity on

plant growth.


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10EXAMPLES OF EFFECT OF GLOBAL WARMING

WARMING OF POLAR REGIONS

Arctic air temperatures increased by about 5C in the 20th century ten

times faster than the global-mean surface temperature while Arctic sea-

surface temperatures rose by 1C over the past 20 years.

In the Northern Hemisphere, spring and summer sea-ice cover decreased by

about 10 to 15% from the 1950s to the year 2000; sea-ice extent in the

Nordic seas has shrunk by 30% over the last 130 years.

Arctic sea-ice thickness declined by about 40% during late summer and

early autumn in the last three decades of the 20th century.

CHANGE IN THE RAINFALL PATTERN

Precipitation over many mid- to highlatitude

land areas in the Northern Hemisphere has become more and more intense.

Rainfall has generally declined in the tropics and subtropics of both

hemispheres; when rain does fall, it is frequently so heavy that it causes

erosion and flooding.

Desertification has been exacerbated by lower average annual rainfall,

runoff and soil moisture, especially in southern, northern and western Africa.

RISE IN SEA LEVEL

Vast expanses of the oceans have warmed over the past 50 years; globally,

sea-surface temperatures have risen in line with land temperatures.

The global mean sea level has risen by 10 - 20 cm during the 20th century

ten times faster than the rate for the previous three thousand years.

More water is evaporating from the sea surface; this has likely resulted in

total atmospheric water vapor increasing by several percent per decade overmany regions of the Northern Hemisphere.


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ECONOMIC EFFECT

Global Warming can hav Climate change wo

countries

A small increase in

against 1990 levels

many developing c

developed countrie

The aggregate mar

a small increase in

a few percent of w

P

The above picture shows

GLOBAL WAR

HITECTURE

the following effects on the economiuld increase income inequalities betw

global mean temperature (up to 2 C

) would result in net negative market s

ountries and net positive market sector

s

et sector impact (i.e., total impacts ac

global mean temperature would amou

rld GDP.

RTAGE GLACIER, ALASKA

the melting of glacier due to increase i

ING AND ITS EFFECTS

11

conditions:en and within

y 2100, measured

ector impacts in

impacts in many

oss all regions) of

t to plus or minus

n temperature.


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12COLORADO RIVER, ARIZONA

JUNE 2002 DEC 2003

MITIGATION TO GLOBAL WARMING

Due to increase in temperature, the sea level is rising and its causing floods and

other natural calamities. The IPCC's Working Group III is responsible for crafting

reports on mitigation of global warming and the costs and benefits of different

approaches. The 2007IPCC Fourth Assessment Report concludes that no one

technology or sector can be completely responsible for mitigating future warming.

They find there are key practices and technologies in various sectors, such

as energy supply, transportation, industry, and agriculture that should be

implemented to reduced global emissions. They estimate that stabilization

of carbon dioxide equivalent between 445 and 710 ppm by 2030 will result in

between a 0.6 percent increase and three percent decrease in global gross domesticproduct.

Mitigation of global warming is accomplished through reductions in the rate

of anthropogenic greenhouse gas release. The world's primary international

agreement on reducing greenhouse gas emissions, the Kyoto Protocol, now covers

more than 160 countries and over 55 percent of global greenhouse gas

emissions. As of February 2010, only the United States, historically the

world's largest emitter of greenhouse gases, has refused to ratify the treaty. The


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13treaty expires in 2012. International talks began in May 2007 on a future treaty to

succeed the current one. The 2009 United Nations Climate Change Conference met

in Copenhagen in December 2009 to agree on a framework for climate changemitigation. No binding agreement was made.

There has also been business action on climate change, including efforts to

improve energy efficiency and limited moves towards use of alternative fuels. In

January 2005 the European Union introduced its European Union Emission

Trading Scheme, through which companies in conjunction with government agree

to cap their emissions or to purchase credits from those below their allowances.

Australia announced its Carbon Pollution Reduction Scheme in 2008. United

States President Barack Obama has announced plans to introduce an economy-wide cap and trade scheme.


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14BIBLIOGRAPHY

INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE

KYOTO PROTOCOL

INTERNET RESOURCES

Globalwarming Report

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