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Good morning to my fellow friends and my respectful teachers. Today I am here to talk about

global warming.Global warming refers to the rising average temperature ofEarth's atmosphere

and oceans, which started to increase in the late 19th century and is projected to keep going up.

Since the early 20th century, Earth's average surface temperature has increased by about 0.8

C (1.4 F), with about two thirds of the increase occurring since 1980.[2]

Warming of

the climate system is unequivocal, and scientists are more than 90% certain that most of it iscaused by increasing concentrations ofgreenhouse gasesproduced by human activities such

as deforestation and burning fossil fuels.[3][4][5][6]

These findings are recognized by the national

science academies of all the major industrialized nations.[7][A]

Climate modelprojections are summarized in the 2007 Fourth Assessment Report (AR4) by

the Intergovernmental Panel on Climate Change(IPCC). They indicate that during the 21st

century the global surface temperature is likely to rise a further 1.1 to 2.9 C (2 to 5.2 F) for

their lowest emissions scenario and 2.4 to 6.4 C (4.3 to 11.5 F) for their highest.[8]

The ranges

of these estimates arise from the use of models with differing sensitivity to greenhouse gas

concentrations.[9][10]

An increase in global temperature will cause sea levels to rise and will change the amount and

pattern ofprecipitation, and a probable expansion ofsubtropical deserts.[11]

Warming is expected

to be strongest in the Arctic and would be associated with continuing retreat of

glaciers, permafrost and sea ice. Other likely effects of the warming include more frequent

occurrence ofextreme-weatherevents includingheat waves, droughts and heavy rainfall, species

extinctions due to shifting temperature regimes, and changes in crop yields. Warming and related

changes will vary from region to region around the globe, with projections being more robust in

some areas than others.[12]

If global mean temperature increases to 4 C (7.2 F) above

preindustrial levels, the limits for human adaptation are likely to be exceeded in many parts of

the world, while the limits for adaptation for natural systems would largely be exceeded

throughout the world. Hence, the ecosystem services upon which human livelihoods dependwould not be preserved.[13]

Most countries are parties to the United Nations Framework Convention on Climate

Change (UNFCCC),[14]

whose ultimate objective is toprevent "dangerous" anthropogenic (i.e.,

human-induced) climate change.[15]

Parties to the UNFCCC have adopted a range of policies

designed to reduce greenhouse gas emissions[16]:10[17][18][19]:9

and to assist in adaptation to global

warming.[16]:13[19]:10[20][21]

Parties to the UNFCCC have agreed that deep cuts in emissions are

required,[22]

and that future global warming should be limited to below 2.0 C (3.6 F)relative to

the pre-industrial level.[22][B]

A 2011 report of analyses by the United Nations Environment

Programme[23]

and International Energy Agency[24]

suggest that efforts as of the early 21st

century to reduce emissions may be inadequately stringent to meet the UNFCCC's 2 Ctarget. As

a conclusion, we must save our earth global warming by reducing the pollution.

http://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Global_warming#cite_note-AmericasClimateChoices-2011-FullReport-1http://en.wikipedia.org/wiki/Global_warming#cite_note-AmericasClimateChoices-2011-FullReport-1http://en.wikipedia.org/wiki/Global_warming#cite_note-AmericasClimateChoices-2011-FullReport-1http://en.wikipedia.org/wiki/Climatehttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Global_warming#cite_note-2http://en.wikipedia.org/wiki/Global_warming#cite_note-2http://en.wikipedia.org/wiki/Global_warming#cite_note-4http://en.wikipedia.org/wiki/Global_warming#cite_note-4http://en.wikipedia.org/wiki/Global_warming#cite_note-6http://en.wikipedia.org/wiki/Global_warming#cite_note-6http://en.wikipedia.org/wiki/Global_warming#cite_note-6http://en.wikipedia.org/wiki/Climate_modelhttp://en.wikipedia.org/wiki/IPCC_Fourth_Assessment_Reporthttp://en.wikipedia.org/wiki/Intergovernmental_Panel_on_Climate_Changehttp://en.wikipedia.org/wiki/Special_Report_on_Emissions_Scenarioshttp://en.wikipedia.org/wiki/Global_warming#cite_note-7http://en.wikipedia.org/wiki/Global_warming#cite_note-7http://en.wikipedia.org/wiki/Global_warming#cite_note-7http://en.wikipedia.org/wiki/Climate_sensitivityhttp://en.wikipedia.org/wiki/Climate_sensitivityhttp://en.wikipedia.org/wiki/Global_warming#cite_note-8http://en.wikipedia.org/wiki/Global_warming#cite_note-8http://en.wikipedia.org/wiki/Global_warming#cite_note-8http://en.wikipedia.org/wiki/Current_sea_level_risehttp://en.wikipedia.org/wiki/Precipitation_(meteorology)http://en.wikipedia.org/wiki/Subtropicshttp://en.wikipedia.org/wiki/Deserthttp://en.wikipedia.org/wiki/Global_warming#cite_note-10http://en.wikipedia.org/wiki/Global_warming#cite_note-10http://en.wikipedia.org/wiki/Global_warming#cite_note-10http://en.wikipedia.org/wiki/Arctic_shrinkagehttp://en.wikipedia.org/wiki/Retreat_of_glaciers_since_1850http://en.wikipedia.org/wiki/Retreat_of_glaciers_since_1850http://en.wikipedia.org/wiki/Permafrosthttp://en.wikipedia.org/wiki/Sea_icehttp://en.wikipedia.org/wiki/Extreme-weatherhttp://en.wikipedia.org/wiki/Heat_wavehttp://en.wikipedia.org/wiki/Extinction_risk_from_climate_changehttp://en.wikipedia.org/wiki/Extinction_risk_from_climate_changehttp://en.wikipedia.org/wiki/Crop_yieldhttp://en.wikipedia.org/wiki/Global_warming#cite_note-11http://en.wikipedia.org/wiki/Global_warming#cite_note-11http://en.wikipedia.org/wiki/Global_warming#cite_note-11http://en.wikipedia.org/wiki/Ecosystem_serviceshttp://en.wikipedia.org/wiki/Global_warming#cite_note-Warren2011-12http://en.wikipedia.org/wiki/Global_warming#cite_note-Warren2011-12http://en.wikipedia.org/wiki/Global_warming#cite_note-Warren2011-12http://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/Global_warming#cite_note-13http://en.wikipedia.org/wiki/Global_warming#cite_note-13http://en.wikipedia.org/wiki/Global_warming#cite_note-13http://en.wikipedia.org/wiki/Avoiding_dangerous_climate_changehttp://en.wikipedia.org/wiki/Avoiding_dangerous_climate_changehttp://en.wikipedia.org/wiki/Global_warming#cite_note-14http://en.wikipedia.org/wiki/Global_warming#cite_note-14http://en.wikipedia.org/wiki/Global_warming#cite_note-14http://en.wikipedia.org/wiki/Global_warming#cite_note-2005_unfccc_synthesis_of_non-annex_I_statements-15http://en.wikipedia.org/wiki/Global_warming#cite_note-2005_unfccc_synthesis_of_non-annex_I_statements-15http://en.wikipedia.org/wiki/Global_warming#cite_note-16http://en.wikipedia.org/wiki/Global_warming#cite_note-2011_unfccc_synthesis_of_annex_I_communications-18http://en.wikipedia.org/wiki/Adaptation_to_global_warminghttp://en.wikipedia.org/wiki/Adaptation_to_global_warminghttp://en.wikipedia.org/wiki/Global_warming#cite_note-2005_unfccc_synthesis_of_non-annex_I_statements-15http://en.wikipedia.org/wiki/Global_warming#cite_note-2005_unfccc_synthesis_of_non-annex_I_statements-15http://en.wikipedia.org/wiki/Global_warming#cite_note-2011_unfccc_synthesis_of_annex_I_communications-18http://en.wikipedia.org/wiki/Global_warming#cite_note-19http://en.wikipedia.org/wiki/Global_warming#cite_note-19http://en.wikipedia.org/wiki/Global_warming#cite_note-unfccc_2_degrees_celsius_target-21http://en.wikipedia.org/wiki/Global_warming#cite_note-unfccc_2_degrees_celsius_target-21http://en.wikipedia.org/wiki/Global_warming#cite_note-unfccc_2_degrees_celsius_target-21http://en.wikipedia.org/wiki/Global_warming#cite_note-unfccc_2_degrees_celsius_target-21http://en.wikipedia.org/wiki/Global_warming#cite_note-unfccc_2_degrees_celsius_target-21http://en.wikipedia.org/wiki/Global_warming#cite_note-unfccc_2_degrees_celsius_target-21http://en.wikipedia.org/wiki/United_Nations_Environment_Programmehttp://en.wikipedia.org/wiki/United_Nations_Environment_Programmehttp://en.wikipedia.org/wiki/Global_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