CLIMATE CHANGE-The Present and Future

8/3/2019 CLIMATE CHANGE-The Present and Future

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K.L.E.Societys

B. V. B. College of Engineering &

Technology, Hubli-31.

CLIMATE CHANGE

-The Present and Future

Authors

Satish M Pattanashetti Prashant V Arasanal

8th sem, Mechanical 8th sem, Mechanical

B.V.B.C.E.T, Hubli-31 B.V.B.C.E.T, Hubli-31

[email protected] [email protected]

Guide

Prof. Anand M ShivapujiDept.of Mechanical Engineering

B.V.B.C.E.T, Hubli-31


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Introduction:

Climate is usually defined as the average weather, or more rigorously, as the

statistical description of the weather in terms of the mean and variability of relevantquantities over periods of several decades. These quantities are most often surface

variables such as temperature, precipitation, and wind, but in a wider sense the

climate is the description of the state of the climate system.

The climate system consists of the following major components:

(a) The atmosphere,

(b) The oceans,

(c) The terrestrial and marine biospheres,

(d) The cryosphere (sea ice, seasonal snow cover, mountain glaciers and

continental scale ice sheets), and

(e) The land surface.

These components interact with each other, and through this collective

interaction, determine the Earths surface climate. These interactions occur through

flows of energy in various forms, through exchanges of water, through flows of various

other radiatively important trace gases, including CO2 (carbon dioxide) and CH4

(methane), and through the cycling of nutrients. The climate system is powered by the

input of solar energy, which is balanced by the emission of infrared (heat) energy back

to space. Solar energy is the ultimate driving force for the motion of the atmosphere and

ocean, the fluxes of heat and water, and of biological activity.

Figure below presents a schematic picture of the climate system, showing some

of the key interactions between the various components and the component properties

which can change. The components of the climate system influence global and regional

climate in a number of distinct ways:

(a) By influencing the composition of the Earths atmosphere, thereby modulating

the absorption and transmission of solar energy and the emission of infrared energy

back to space.

(b) Through alterations in surface properties and in the amount and nature of

cloud cover, which have both regional and global effects on climate, and


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(c) By redistributing heat horizontally and vertically from one region to another

through atmospheric motions and ocean currents.

In the natural state, the various flows between the climate system components

are usually very close to being exactly balanced when averaged over periods of one to

several decades. For example, prior to the industrial revolution, the uptake of CO2 by

photosynthesis was almost exactly balanced by its release through decay of plant and

soil matter, as evidenced by the near constancy of the atmospheric CO2 concentration

for several millennia prior to about 1800. However, from one year to the next there can

be modest imbalances which fluctuate in sign, due to the natural variability of the

climate system. Humans are affecting the operation of climate processes, and hence

the natural balance of the climate system, through persistent regional to global scale

alterations in the composition of the Earths atmosphere and in the properties of the

land surface.


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Human Perturbations to the Composition of the Atmosphere:

Humans are altering the concentration of greenhouse gases and aerosols, both

of which influence, and are influenced by, climate. The greenhouse gases reduce the

net loss of infrared heat to space, while having little impact on the absorption of solar

radiation, thereby causing the surface temperature to be warmer than it would be

otherwise and producing the so-called greenhouse effect. Aerosols, on the other hand,

are important largely because of their impact on solar radiation, and have a

predominantly cooling effect.

Some greenhouse gases occur naturally but are influenced either directly or

indirectly by human activity, whereas others are purely anthropogenic. The main

naturally-occurring greenhouse gases are water vapour (H2O), carbon dioxide (CO2),

ozone (O3), methane (CH4), and nitrous oxide (N2O). The main groups of purely

anthropogenic greenhouse gases are the CFCs, HCFCs, and HFCs collectively known

as halocarbons), and fully fluorinated species such as sulphur hexafluoride (SF6).

Water vapour is the strongest contributor to the natural greenhouse effect, but it

is the most directly linked to climate and therefore least directly controlled by human

activity. This is because evaporation is strongly dependent on surface temperature, and

because water vapour cycles through the atmosphere quite rapidly, about once every

eight days on average. Concentrations of the other greenhouse gases, in contrast, arestrongly and directly influenced by emissions associated with the combustion of fossil

fuels, by forestry and most agricultural activities, and by the production and use of

various chemicals.

With the exception of ozone, all of the greenhouse gases that are directly

influenced by human emissions are well mixed within the atmosphere, so that their

concentration is almost the same everywhere and is independent of where emissions

occur. Ozone also differs from the other greenhouse gases in that it is not directly

emitted into the atmosphere; rather, it is produced through photochemical reactions

involving other substances referred to as precursors which are directly emitted.

With regard to removal processes, all of the non-water vapour greenhouse gases

except CO2 are removed largely by either chemical or photochemical reactions within

the atmosphere. Carbon dioxide, in contrast, continuously cycles between a numbers of


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reservoirs or temporary storage depots (the atmosphere, land plants, soils and ocean

water and ocean sediments). The sources of natural greenhouse gases, and the

removal processes of all greenhouse gases, are themselves influenced by climate

Aerosols are suspensions of small particles in the air which influence climate primarily

through their role in reflecting a portion of the incoming solar energy back to space (a

direct effect) and in regulating to some extent the amount and optical properties of

clouds (an indirect effect). Aerosols also absorb infrared radiation to some extent.

Aerosols are produced both naturally and through human activity; natural aerosols

include sea salt, dust, and volcanic aerosols, while anthropogenic aerosols are

produced from burning of biomass and fossil fuels, among other sources.

Climate Sensitivity:

Definition: The term climate sensitivity refers to the steady-state increase in

the global annual mean surface air temperature associated with a given global mean

radiative forcing. It is standard practice to include only the fast feedback processes,

including changes in water vapour, in the calculation of climate sensitivity, but to

exclude possible induced changes in the concentrations of other greenhouse gases.

Climate Sensitivity: Constancy and Independence:Given the many non-linearities associated with the fast feedback processes,

which determine the climate sensitivity as defined above, one might expect that the

climate sensitivity will depend both on the magnitude of the forcing and on the vertical,

latitudinal and seasonal distribution of the forcing. However, experiments with a variety

of models indicate that, for forcings up to the magnitude that could be experienced

during the next century, the climate sensitivity is approximately constant (that is, the

global mean surface temperature response is roughly proportional to the global mean

forcing). Also, for a number of different forcings, the climate sensitivity is largely

independent of the specific combination of factors producing a given global mean

forcing. In particular, the global mean temperature response to a mixture of greenhouse

gas increases is within about 10 per cent of the response to a CO2 increase alone

having the same global mean forcing as for the mixture of gases.


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Observed Changes in Earths Surface Temperature and Precipitation:

Over the 20th century there has been a consistent, large scale warming of both

the land and ocean surface and it is likely that most the observed warming over the last

50 years has been due to the increase in green house gas concentration. The global

mean surface temperature has increased by 0.6C (0.4-0.8C) over the last 100 years,

with 1998 being warmest year and the 1990s very likely being the warmest decade.

Precipitation has very likely increased during the 20th century by 5-10% over

most mid and high latitudes of Northern hemisphere continents, but in contrast rainfall

has likely decreased by 3% on average over much of the subtropical land areas. There

has likely been 2-4% increase in the frequency of heavy precipitation events in the mid

and high latitudes of the Northern hemisphere over the latter half of the 20 th century.

These were relatively small increases over the latter half of the 20 th century in land

areas experiencing severe draught severe wetness; in many regions, these changes

are dominated by inter and multi decadal climate variability with no significant trends

evident.

The figure shows trends represented by the area of the circle, with red

representing increases and blue decreases.


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Figure below indicates the trends represented by area of the circle, with green

representing increases and brown decreases

Projected Changes: The figure shows the period 2071-2100 relative to 1961-90.


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Steps Taken to mitigate Climate Change:

Kyoto Protocol:

The Kyoto Protocol is an agreement made under the United Nations Framework

Convention on Climate Change (UNFCCC). Countries that ratify this protocol commit to

reduce their emissions ofcarbon dioxide and five othergreenhouse gases, or engage in

emissions trading if they maintain or increase emissions of these gases.

The Kyoto Protocol now covers more than 160 countries globally and over 55%

of global greenhouse gas (GHG) emissions.

At its heart, the Kyoto Protocol establishes the following principles:

(a) Kyoto is underwritten by governments and is governed by global legislation

enacted under the UNs aegis.

(b) Governments are separated into two general categories: developed countries,

Annex I and developing countries, referred to as Non-Annex I countries
http://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Changehttp://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Changehttp://en.wikipedia.org/wiki/Countrieshttp://en.wikipedia.org/wiki/Ratifyhttp://en.wikipedia.org/wiki/Protocol_(treaty)http://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/Emissions_tradinghttp://en.wikipedia.org/wiki/United_Nationshttp://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Changehttp://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Changehttp://en.wikipedia.org/wiki/Countrieshttp://en.wikipedia.org/wiki/Ratifyhttp://en.wikipedia.org/wiki/Protocol_(treaty)http://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/Emissions_tradinghttp://en.wikipedia.org/wiki/United_Nations


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(c) Any Annex I country that fails to meet its Kyoto obligation will be penalized by

having to submit 1.3 emission allowances in a second commitment period for

every ton of GHG emissions they exceed their cap in the first commitment

period (i.e, 2008-2012).

(d) By 2008-2012, Annex I countries have to reduce their GHG emissions by an

average of 5% below their 1990 levels. While the average emissions reduction

is 5%, national limitations range from 8% reductions for the European Union to

a 10% emissions increase forIceland. Reduction limitations expire in 2013.

(e) Kyoto includes "flexible mechanisms" which allow Annex I economies to meet

their GHG emission limitation by purchasing GHG emission reductions from

elsewhere.

(f) Only CDM Executive Board-accredited Certified Emission Reductions (CER)

can be bought and sold in this manner.

(i) International Emissions Trading: Through International Emissions Trading (IET)

industrialized countries are allowed to meet their commitments by buying and

selling excess emissions credits among themselves. By creating a financial value

for emissions credits, it is anticipated that market forces will provide a cash

incentive for governments and industry to switch to cleaner fuels and industrial

processes, achieving emissions targets and moving towards sustainable

development

(ii) Joint Implementation: Joint Implementation (JI) permits industrialized countries to

cooperatively implement projects which will reduce greenhouse gas emissions.

The investor from one country would receive emissions credits equal to the

amount of emissions that were reduced or avoided as a result of the project. The

recipient country would receive new technology and know-how. (Article 6 of the

Kyoto Protocol).

(iii)Clean Development Mechanism (CDM): CDM is an arrangement under the Kyoto

Protocol allowing industrialised countries with a greenhouse gas reduction

commitment (so-called Annex 1 countries) to invest in emission reducing
http://en.wikipedia.org/wiki/Icelandhttp://en.wikipedia.org/wiki/Kyoto_Protocolhttp://en.wikipedia.org/wiki/Kyoto_Protocolhttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Change#Annex_I_countrieshttp://en.wikipedia.org/wiki/Icelandhttp://en.wikipedia.org/wiki/Kyoto_Protocolhttp://en.wikipedia.org/wiki/Kyoto_Protocolhttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/United_Nations_Framework_Convention_on_Climate_Change#Annex_I_countries


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projects in developing countries as an alternative to what is generally considered

more costly emission reductions in their own countries.

Indias initiatives:

India has undertaken numerous response measures that are contributing to the

objectives of the United Nations Framework Convention on Climate Change (UNFCCC).

India's development plans balance economic development and environmental concerns.

The planning process is guided by the principles of sustainable development. Reforms

in the energy and power sector have accelerated economic growth and enhance the

efficiency of energy use. These have been complemented by notable initiatives taken by

the private sector.

In the last few years several measures relating to environmental issues have

been introduced. They have targeted increasing significantly, the capacity of renewable

energy installations; improving the air quality in major cities (the world's largest fleet of

vehicles fuelled by compressed natural gas has been introduced in New Delhi); and

enhancing aforestation. Other similar measures have been implemented by committing

additional resources and realigning new investments, thus putting economic

development on a climate-friendly path.

Opposition to Kyoto:

The two major countries currently opposed to the treaty are the United States

and Australia. Some public policy experts who are skeptical of global warming see

Kyoto as a scheme to either retard the growth of the world's industrial democracies or to

transfer wealth to the third world in what they claim is a global socialism initiative.

Others argue the protocol does not go far enough to curb greenhouse emissions.

Many environmental economists have been critical of the Kyoto Protocol. Many

see the costs of the Kyoto Protocol as outweighing the benefits, some believing the

standards which Kyoto sets to be too optimistic, others seeing a highly inequitable and

inefficient agreement which would do little to curb greenhouse gas emissions. It should
http://www.recipeland.com/facts/?title=Global_warming&action=edithttp://www.recipeland.com/facts/?title=Third_world&action=edithttp://www.recipeland.com/facts/Socialismhttp://www.recipeland.com/facts/Environmental_economicshttp://www.recipeland.com/facts/?title=Global_warming&action=edithttp://www.recipeland.com/facts/?title=Third_world&action=edithttp://www.recipeland.com/facts/Socialismhttp://www.recipeland.com/facts/Environmental_economics


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be noted, however, that this opposition is not unanimous, and that the inclusion of

emissions trading has led some environmental economists to embrace the treaty.

Conclusion:

The earth's climate has changed over the last century. There is new and stronger

evidence that most of the warming observed the last 50 years is attributable to human

activities. Evolving computer models are predicting that, because of greenhouse gas

emissions, temperatures should continue to rise over the 21st century, impacting nature

and mankind both positively and negatively.

The impacts should vary among regions, but they can not yet be predicted

accurately, especially for small-scale areas. However, it is expected that,

1. the more the greenhouse gases are emitted, the higher the tendency for the

earth to warm,

2. the greater and faster the warming, the more the adverse effects will dominate,

3. And the higher the possibility, although probably remote, of large-scale and

possibly irreversible impacts.

Therefore, although an acceptable level for greenhouse gases has not yet been

determined, reducing emissions should reduce the risk of adverse effects. Many options

for emission reductions are available; their costs need to be balanced with the risks left

for future generations.

References:

Books: Environmental Control System by Fuller Moore, Mc-Graw Hill international.

Atmospheric science and Environment by S.N.Ghos, Allied Publishers Ltd.

Journals: Journal of Economic Dynamics and Control, University of California.

Journal of Environment and Development Volume 13, Sage Publication.

Websites: http://www.parliament.uk/documents/upload/POSTpn245.pdf

http://www.ipcc.ch/present/graphics.htm
http://www.greenfacts.org/studies/climate_change/toolboxes/glossary.htm#greenhouse_gashttp://www.parliament.uk/documents/upload/POSTpn245.pdfhttp://www.ipcc.ch/present/graphics.htmhttp://www.greenfacts.org/studies/climate_change/toolboxes/glossary.htm#greenhouse_gashttp://www.parliament.uk/documents/upload/POSTpn245.pdfhttp://www.ipcc.ch/present/graphics.htm


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http://search.bnet.com/search/clean+development+mechanism.html
http://search.bnet.com/search/clean+development+mechanism.htmlhttp://search.bnet.com/search/clean+development+mechanism.html

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