global warming by simuzar rzaquliyeva

8/8/2019 Global Warming by Simuzar Rzaquliyeva

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By Simuzar Rzaquliyeva


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Global warmingGlobal warming is the increase in the averageis the increase in the averagetemperature of the Earth's neartemperature of the Earth's near--surface air andsurface air andoceans since the midoceans since the mid--20th century and its20th century and itsprojected continuation. Global surfaceprojected continuation. Global surfacetemperature increased 0.74temperature increased 0.74 0.180.18 C (1.33C (1.33 0.320.32 F) between the start and the end of theF) between the start and the end of the20th century. The Intergovernmental Panel on20th century. The Intergovernmental Panel onClimate Change (IPCC) concludes that most ofClimate Change (IPCC) concludes that most ofthe observed temperature increase since thethe observed temperature increase since themiddle of the 20th century was caused bymiddle of the 20th century was caused by

increasing concentrations of greenhouse gasesincreasing concentrations of greenhouse gasesresulting from human activity such as fossilresulting from human activity such as fossilfuel burning and deforestation.fuel burning and deforestation. The IPCC alsoThe IPCC alsoconcludes that variations in naturalconcludes that variations in naturalphenomena such as solar radiation andphenomena such as solar radiation andvolcanism produced most of the warmingvolcanism produced most of the warming

from prefrom pre--industrial times to 1950 and had aindustrial times to 1950 and had asmall cooling effect afterward. These basicsmall cooling effect afterward. These basicconclusions have been endorsed by more thanconclusions have been endorsed by more than40 scientific societies and academies of40 scientific societies and academies ofscience,science, including all of the nationalincluding all of the nationalacademies of science of the majoracademies of science of the major

industrialized countriesindustrialized countries

Global mean surface

temperature difference from the

average for 19611990


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Global Warming predictions2070-2100

y Climate model projections summarizedin the latest IPCC report indicate thatthe global surface temperature will

probably rise a further 1.1 to 6.4 C (2.0 to11.5 F) during the twenty-first century.The uncertainty in this estimate arisesfrom the use of models with differingsensitivity to greenhouse gasconcentrations and the use of differingestimates of future greenhouse gasemissions. Some other uncertaintiesinclude how warming and relatedchanges will vary from region to regionaround the globe. Most studies focus on

the period up to the year 2100. However,warming is expected to continue beyond2100 even if emissions stop, because ofthe large heat capacity of the oceans andthe long lifetime of carbon dioxide in theatmosphere.


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y An increase in global temperature will causesea levels to rise and will change the amountand pattern of precipitation, probably

including expansion of subtropical deserts.The continuing retreat of glaciers, permafrostand sea ice is expected, with warming beingstrongest in the Arctic. Other likely effectsinclude increases in the intensity of extreme

weather events, species extinctions, andchanges in agricultural yields.

y Political and public debate continuesregarding climate change, and what actions (ifany) to take in response. The available optionsare mitigation to reduce further emissions;adaptation to reduce the damage caused by

warming; and, more speculatively,geoengineering to reverse global warming.Most national governments have signed andratified the Kyoto Protocol aimed at reducing

greenhouse gas emissions.


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y The most commonly discussed measure of global

warming is the trend in globally averagedtemperature near the Earth's surface. Expressed asa linear trend, this temperature rose by 0.74C0.18C over the period 19062005. The rate ofwarming over the last half of that period wasalmost double that for the period as a whole

(0.13C 0.03C per decade, versus 0.07C 0.02Cper decade). The urban heat island effect isestimated to account for about 0.002 C ofwarming per decade since 1900. Temperatures inthe lower troposphere have increased between 0.12and 0.22 C (0.22 and 0.4 F) per decade since

1979, according to satellite temperaturemeasurements. Temperature is believed to havebeen relatively stable over the one or two thousandyears before 1850, with regionally-varyingfluctuations such as the Medieval Warm Period orthe Little Ice Age.

y


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global warming by simuzar rzaquliyeva

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