climate change.pptx

8/10/2019 CLIMATE CHANGE.pptx

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Climate change

Climate change is a signi ficant an d lasting change in thestatistical distribution of weather patterns over periodsranging from decades to millions of years. It may be a change in average weather conditions, or in the

distribution of weather around the average conditions (i.e.,more or fewer extreme weather events).Climate change is c aused by factors th at inclu de oceanicprocesses (s uch as oceanic circulation ), biotic proces ses,variation s in solar radiation rece ived by Earth, plate

tectonics and volcanic eruptions , and human-inducedalterations of the natural wo rld; these huma n-inducedeffects are currently causing global warming , and "climatechange" is often used to describe human-specific impacts.
http://en.wikipedia.org/wiki/Weatherhttp://en.wikipedia.org/wiki/Weatherhttp://en.wikipedia.org/wiki/Thermohaline_circulationhttp://en.wikipedia.org/wiki/Biotichttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Thermohaline_circulationhttp://en.wikipedia.org/wiki/Biotichttp://en.wikipedia.org/wiki/Plate_tectonicshttp://en.wikipedia.org/wiki/Plate_tectonicshttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Volcanic_eruptionshttp://en.wikipedia.org/wiki/Volcanic_eruptionshttp://en.wikipedia.org/wiki/Plate_tectonicshttp://en.wikipedia.org/wiki/Plate_tectonicshttp://en.wikipedia.org/wiki/Volcanic_eruptionshttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Volcanic_eruptionshttp://en.wikipedia.org/wiki/Plate_tectonicshttp://en.wikipedia.org/wiki/Plate_tectonicshttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Biotichttp://en.wikipedia.org/wiki/Thermohaline_circulationhttp://en.wikipedia.org/wiki/Weather


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Terminology

The most general definition of climate change is a change in thestatistical properties of the climate system when considered overlong periods of time, regardless of cause. [1]

Accordi ngly, fl uctuations over periods shorter than a few decades,such as El Nio , do not represent climate change.

The term sometimes is used to refer specifically to climate changecaused by human activity, as opposed to changes in climate thatmay have resulted as part of Earth's natural processes. [2

In this sense, especially in the context of environme ntal policy , the term climate ch ange has become synonymous with anthropogenic global warming . Within scientific journals, global warming refers to surfacetemperature increases while climate change includes globalwarming a nd everything else that increasing greenhouse gas levelswill affect. [3]
http://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/El_Ni%C3%B1ohttp://en.wikipedia.org/wiki/El_Ni%C3%B1ohttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Environmental_policyhttp://en.wikipedia.org/wiki/Human_impact_on_the_environmenthttp://en.wikipedia.org/wiki/Human_impact_on_the_environmenthttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Human_impact_on_the_environmenthttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Human_impact_on_the_environmenthttp://en.wikipedia.org/wiki/Environmental_policyhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/El_Ni%C3%B1ohttp://en.wikipedia.org/wiki/Climate_change


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Causes

On the broadest scale, the rate at which energy is received from thesun and the rate at which it is lost to space determine theequilibrium temperature and climate of Earth.This energy is distributed around the globe by winds, oceancurrents, and other mechanisms to affect the climates of different

regions.Factors that can shape climate are called climate forcings or "forcingmechanisms". [4] These include processes such as variations in solar radiation,variations in the Earth's orbit, mountain-building and continentaldrift and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can eitheramplify or diminish the initial forcing. Some parts of the climatesystem, such as the oceans and ice caps, respond slowly in reactionto climate forcings, while others respond more quickly.
http://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_change


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Internal forcing mechanisms

Natural changes in the components of Earth'sclimate system and their interactions are thecause of internal climate variability, or"internal forcings." Scientists generally definethe five components of earth's climate systemto include atmosphere , hydrosphere ,

cryosphere , lithosphere (restricted to thesurface soils, rocks, and sediments), andbiosphere .[5]
http://en.wikipedia.org/wiki/Earth's_Atmospherehttp://en.wikipedia.org/wiki/Hydrospherehttp://en.wikipedia.org/wiki/Cryospherehttp://en.wikipedia.org/wiki/Lithospherehttp://en.wikipedia.org/wiki/Biospherehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Biospherehttp://en.wikipedia.org/wiki/Lithospherehttp://en.wikipedia.org/wiki/Cryospherehttp://en.wikipedia.org/wiki/Hydrospherehttp://en.wikipedia.org/wiki/Earth's_Atmosphere


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Ocean variability

Short-term fluctuations (years to a few decades)such as the El Nio-South ern O scillation , thePacific decadal oscillation , the North Atlanticoscillation , and the Arctic oscillation , representclimate variability rather than climate change. On longer time scales, alterations to oceanprocesses such as thermohaline circulation play akey role in redistributing heat by carrying out avery slow and extremely deep movement ofwater and the long-term redistribution of heat inthe world's oceans.
http://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillationhttp://en.wikipedia.org/wiki/Pacific_decadal_oscillationhttp://en.wikipedia.org/wiki/Pacific_decadal_oscillationhttp://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillationhttp://en.wikipedia.org/wiki/North_Atlantic_oscillationhttp://en.wikipedia.org/wiki/North_Atlantic_oscillationhttp://en.wikipedia.org/wiki/Pacific_decadal_oscillationhttp://en.wikipedia.org/wiki/North_Atlantic_oscillationhttp://en.wikipedia.org/wiki/North_Atlantic_oscillationhttp://en.wikipedia.org/wiki/Arctic_oscillationhttp://en.wikipedia.org/wiki/Arctic_oscillationhttp://en.wikipedia.org/wiki/North_Atlantic_oscillationhttp://en.wikipedia.org/wiki/North_Atlantic_oscillationhttp://en.wikipedia.org/wiki/Pacific_decadal_oscillationhttp://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillationhttp://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillationhttp://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillation


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External forcing mechanisms

Slight variations in Earth's orbit lead to changes inthe seasonal distribution of sunlight reaching theEarth's surface and how it is distributed across

the globe. There is very little change to the area-averaged annually averaged sunshine; but therecan be strong changes in the geographical andseasonal distribution. The three types of orbital

variations are variations in Earth's eccentricity ,changes in the tilt angle of Earth's axis ofrotation , and precession of Earth's axis.
http://en.wikipedia.org/wiki/Orbital_eccentricityhttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Precessionhttp://en.wikipedia.org/wiki/Precessionhttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Orbital_eccentricity


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Solar output

The Sun is the predominant source for energy input tothe Earth. Both long- and short-term variations in solarintensity are known to affect global climate.Oxygenation Event oxygenation of the atmospherearound 2.4 billion years ago was the most notablealteration. Over the next five billion years the sun'sultimate death as it becomes a red giant and then awhite dwarf will have large effects on climate, with thered giant phase possibly ending any life on Earth thatsurvives until that time.
http://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Great_Oxygenation_Eventhttp://en.wikipedia.org/wiki/Red_gianthttp://en.wikipedia.org/wiki/White_dwarfhttp://en.wikipedia.org/wiki/White_dwarfhttp://en.wikipedia.org/wiki/Red_gianthttp://en.wikipedia.org/wiki/Great_Oxygenation_Eventhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Sun


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Volcanism Volcanic eruptions release gases and particulates into the

atmosphere. Eruptions large enough to affect climate occur on average several

times per century, and cause cooling (by partially blocking thetransmission of solar radiation to the Earth's surface) for a period of

a few years. The eruption of Mount Pinatubo in 1991, the second largest

terrestrial eruption of the 20th century [40] (after the 1912 eruptionof Novarupta [41] ) affected the climate substantially. Globaltemperatures decreased by about 0.5 C (0.9 F).

The eru ption of Mount Tambora in 1815 caused the Year Without aSummer .[42]

Much larger eruptions, known as large igneous provinces , occuronly a few tim es every hundre d m illion years, but may cause globalwarming and mass extinctions .[43]
http://en.wikipedia.org/wiki/Atmospheric_particulate_matterhttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Mount_Pinatubohttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Novaruptahttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Year_Without_a_Summerhttp://en.wikipedia.org/wiki/Mount_Tamborahttp://en.wikipedia.org/wiki/Year_Without_a_Summerhttp://en.wikipedia.org/wiki/Year_Without_a_Summerhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Large_igneous_provincehttp://en.wikipedia.org/wiki/Mass_extinctionhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Mass_extinctionhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Mass_extinctionhttp://en.wikipedia.org/wiki/Large_igneous_provincehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Year_Without_a_Summerhttp://en.wikipedia.org/wiki/Year_Without_a_Summerhttp://en.wikipedia.org/wiki/Mount_Tamborahttp://en.wikipedia.org/wiki/Mount_Tamborahttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Novaruptahttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Mount_Pinatubohttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Atmospheric_particulate_matter


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Plate tectonicsThe position of the continents determines the geometry of the oceans andtherefore influences patterns of ocean circulation. The locations of the seas are important in controlling the transfer of heat andmoisture across the globe, and therefore, in determining global climate. A recent example of tectonic control on ocean circulation is the formation of theIsthmus of Pa nama about 5 milli on years ago, which shut off direct mixing

between the Atlantic and Pacific Oceans.This strongly affected the ocean dynamics of what is now the Gulf Stream and mayhave led to Northern Hemisphere ice cover. [48][49]

During the Carboniferous period, about 300 to 360 million years ago, platetectonics may have triggered large-scale storage of carbon and increasedglaciation .[50]

Geologic e vidence points t o a "meg amonsoonal" circulation pattern during thetime of the supercontinent Pangaea , and climate modeling suggests that theexistence o f t he supercontinent was conducive to the establishment ofmonsoons. [51]
http://en.wikipedia.org/wiki/Isthmus_of_Panamahttp://en.wikipedia.org/wiki/Isthmus_of_Panamahttp://en.wikipedia.org/wiki/Atlantichttp://en.wikipedia.org/wiki/Atlantichttp://en.wikipedia.org/wiki/Pacifichttp://en.wikipedia.org/wiki/Atlantichttp://en.wikipedia.org/wiki/Pacifichttp://en.wikipedia.org/wiki/Western_boundary_currenthttp://en.wikipedia.org/wiki/Gulf_Streamhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Carboniferoushttp://en.wiktionary.org/wiki/glaciationhttp://en.wiktionary.org/wiki/glaciationhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Supercontinenthttp://en.wikipedia.org/wiki/Pangaeahttp://en.wikipedia.org/wiki/Supercontinenthttp://en.wikipedia.org/wiki/Pangaeahttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Pangaeahttp://en.wikipedia.org/wiki/Supercontinenthttp://en.wikipedia.org/wiki/Climate_changehttp://en.wiktionary.org/wiki/glaciationhttp://en.wikipedia.org/wiki/Carboniferoushttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Gulf_Streamhttp://en.wikipedia.org/wiki/Western_boundary_currenthttp://en.wikipedia.org/wiki/Pacifichttp://en.wikipedia.org/wiki/Atlantichttp://en.wikipedia.org/wiki/Isthmus_of_Panama


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Human influences

In the context of climate variation, anthropogenic factorsare human activities which affect the climate.The scientific consensus on climate change is "that climateis changing and that these changes are in large part causedby human activities," [52] and it "is largely irreversible." [53]

Of most concern in these anthropogenic fact ors is theincrease in CO 2 levels due to emis sions from fossil fuel combustion, followed by aerosols (par ticulate matter in theatmosphere) and the CO 2 release d by cement ma nufacture.Other factors, incl uding land use , ozone depletion , animalagriculture [54] and deforestation , are also of concern in theroles they play both separately an d in conjunct ion withother factors in affecting climate, microclimate , andmeasures of climate variables.
http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Particulatehttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Particulatehttp://en.wikipedia.org/wiki/Cementhttp://en.wikipedia.org/wiki/Ozone_depletionhttp://en.wikipedia.org/wiki/Ozone_depletionhttp://en.wikipedia.org/wiki/Ozone_depletionhttp://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Ozone_depletionhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Microclimatehttp://en.wikipedia.org/wiki/Microclimatehttp://en.wikipedia.org/wiki/Microclimatehttp://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Ozone_depletionhttp://en.wikipedia.org/wiki/Cementhttp://en.wikipedia.org/wiki/Particulatehttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change


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Physical evidence for and examples ofclimatic change

Evidence for climatic change is taken from a variety ofsources that can be used to reconstruct past climates.Reasonably complete global records of surfacetemperature are available beginning from the mid-late19th century. For earlier periods, most of the evidence is indirect climatic changes are inferred from changes in proxies ,indicators that reflect climate, such as vegetation , icecores ,[55] dendrochronology , sea level change , andglacial geology .
http://en.wikipedia.org/wiki/Proxy_(climate)http://en.wikipedia.org/wiki/Vegetationhttp://en.wikipedia.org/wiki/Ice_corehttp://en.wikipedia.org/wiki/Ice_corehttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Dendrochronologyhttp://en.wikipedia.org/wiki/Sea_level_changehttp://en.wikipedia.org/wiki/Glacial_geologyhttp://en.wikipedia.org/wiki/Glacial_geologyhttp://en.wikipedia.org/wiki/Sea_level_changehttp://en.wikipedia.org/wiki/Dendrochronologyhttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Ice_corehttp://en.wikipedia.org/wiki/Ice_corehttp://en.wikipedia.org/wiki/Vegetationhttp://en.wikipedia.org/wiki/Proxy_(climate)


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climate change.pptx

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