Global Warming and Ozone Depletion

8/4/2019 Global Warming and Ozone Depletion

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Global Warming and Ozone Depletion

Global warming is the increase in the average temperature of Earths near-surface air and

oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth

Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface

temperature increased 0.74 0.18 C (1.33 0.32 F) during the 20th century. Most of the

observed temperature increase since the middle of the 20th century was caused by increasing

concentrations of greenhouse gases, which results from human activity such as the burning

of fossil fuel and deforestation. Global dimming, a result of increasing concentrations of

atmospheric aerosols that block sunlight from reaching the surface, has partially countered the

effects of greenhouse gas induced warming.

Climate model projections summarized in the latest IPCC report indicate that the global surface

temperature is likely to rise a further 1.1 to 6.4 C(2.0 to 11.5 F) during the 21st century. The

uncertainty in this estimate arises from the use of models with differing sensitivity to


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greenhouse gas concentrations and the use of differing estimates of future greenhouse gas

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

amount and pattern of precipitation, probably including expansion

of subtropical deserts. 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

include changes in the frequency and intensity of extreme weather events, species extinctions,

and changes in agricultural yields. Warming and related changes will vary from region to region

around the globe, though the nature of these regional variations is uncertain.

Temperature changes

Evidence for warming of the climate system includes observed increases in global average air

and ocean temperatures, widespread melting of snow and ice, and rising global average sealevel. The most common measure of global warming is the trend in globally averaged

temperature near the Earth's surface. Expressed as a linear trend, this temperature rose by

0.74 0.18 C over the period 19062005. The rate of warming over the last half of that period

was almost double that for the period as a whole (0.13 0.03 C per decade, versus 0.07 C

0.02 C per decade). The urban heat island effect is estimated to account for about 0.002 C of

warming per decade since 1900. Temperatures in the lower troposphere have increased

between 0.13 and 0.22 C (0.22 and 0.4 F) per decade since 1979, according to satellite

temperature measurements. Temperature is believed to have been relatively stable over

the one or two thousand years before 1850, with regionally varying fluctuations such as

the Medieval Warm Period and the Little Ice Age.

Estimates by NASAs Goddard Institute for Space Studies (GISS) and the National Climatic Data

Center show that 2005 was the warmest year since reliable, widespread instrumental

measurements became available in the late 1800s, exceeding the previous record set in 1998

by a few hundredths of a degree.

Estimates prepared by the World Meteorological

Organization and the Climatic Research Unit show 2005 as the second warmest year, behind

1998. Temperatures in 1998 were unusually warm because the strongest El Nio in the past

century occurred during that year. Global temperature is subject to short-term fluctuations that

overlay long term trends and can temporarily mask them. The relative stability in temperature

from 2002 to 2009 is consistent with such an episode.

Temperature changes vary over the globe. Since 1979, land temperatures have increased about

twice as fast as ocean temperatures (0.25 C per decade against 0.13 C per decade).Ocean


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temperatures increase more slowly than land temperatures because of the larger effective heat

capacity of the oceans and because the ocean loses more heat by evaporation. The Northern

Hemisphere warms faster than the Southern Hemisphere because it has more land and because it has

extensive areas of seasonal snow and sea-ice cover subject to ice-albedo feedback. Although

more greenhouse gases are emitted in the Northern than Southern Hemisphere this does not

contribute to the difference in warming because the major greenhouse gases persist long

enough to mix between hemispheres.

The thermal inertia of the oceans and slow responses of other indirect effects mean that

climate can take centuries or longer to adjust to changes in forcing. Climate

commitment studies indicate that even if greenhouse gases were stabilized at 2000 levels, a

further warming of about 0.5 C (0.9 F) would still occur.

External forcings

External forcing refers to processes external to the climate system (though not necessarily

external to Earth) that influence climate. Climate responds to several types of external forcing,

such asradiative forcing due to changes in atmospheric composition (mainly greenhouse

gas concentrations), changes in solar luminosity, volcanic eruptions, and variations in Earth's

orbit around the Sun.Attribution of recent climate change focuses on the first three types of

forcing. Orbital cycles vary slowly over tens of thousands of years and thus are too gradual to

have caused the temperature changes observed in the past century.

Greenhouse gases
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Recent atmospheric carbon dioxide(CO2) increases. Monthly CO2measurements display

seasonal oscillations in overall yearly uptrend; each year's maximum occurs during the

Northern Hemispheres late spring, and declines during its growing season as plants remove

some atmospheric CO2.

The greenhouse effect is the process by which absorption and emission of infrared radiation bygases in the atmosphere warm a planet's lower atmosphere and surface. It was proposed

by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in

1896. The question in terms of global warming is how the strength of the presumed

greenhouse effect changes when human activity increases the concentrations of greenhouse

gases in the atmosphere.

Naturally occurring greenhouse gases have a mean warming effect of about 33 C (59 F). The

major greenhouse gases are water vapor, which causes about 3670 percent of the greenhouse

effect; carbon dioxide (CO2), which causes 9

26 percent; methane (CH4), which causes 4

9percent; and ozone (O3), which causes 37 percent. Clouds also affect the radiation balance,

but they are composed of liquid water or ice and so have different effects on radiation from

water vapor.

Human activity since the Industrial Revolution has increased the amount of greenhouse gases in

the atmosphere, leading to increased radiative forcing from CO2,methane,

tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane have

increased by 36% and 148% respectively since 1750.These levels are much higher than at any

time during the last 650,000 years, the period for which reliable data has been extracted

from ice cores. Less direct geological evidence indicates that CO2 values higher than this were

last seen about 20 million years ago. Fossil fuel burning has produced about three-quarters of

the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-

use change, particularly deforestation.

Over the last three decades of the 20th

century, GDP per capita and population growth were the

main drivers of increases in greenhouse gas emissions. CO2emissions are continuing to rise due

to the burning of fossil fuels and land-use change. Emissions scenarios, estimates of changes in

future emission levels of greenhouse gases, have been projected that depend upon uncertain

economic, sociological, technological, and natural developments. In most scenarios, emissions

continue to rise over the century, while in a few, emissions are reduced. These emission

scenarios, combined with carbon cycle modelling, have been used to produce estimates of how

atmospheric concentrations of greenhouse gases will change in the future. Using the six

IPCC SRES"marker" scenarios, models suggest that by the year 2100, the atmospheric

concentration of CO2 could range between 541 and 970 ppm.This is an increase of 90-250%


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above the concentration in the year 1750. Fossil fuel reserves are sufficient to reach these

levels and continue emissions past 2100 if coal, tar sands or methane clathrates are extensively

exploited.

The destruction of stratospheric ozone by chlorofluorocarbons is sometimes mentioned in

relation to global warming. Although there are a few areas of linkage, the relationship between

the two is not strong. Reduction of stratospheric ozone has a cooling influence on the entire

troposphere, but a warming influence on the surface. Substantial ozone depletion did not occur

until the late 1970s. Ozone in the troposphere (the lowest part of the Earth's atmosphere) does

contribute to surface warming.

Aerosols and soot

Global dimming, a gradual reduction in the amount of global direct irradiance at the Earth'ssurface, has partially counteracted global warming from 1960 to the present. The main cause of

this dimming is aerosols produced by volcanoes and pollutants. These aerosols exert a cooling

effect by increasing the reflection of incoming sunlight. The effects of the products of fossil fuel

combustionCO2 and aerosolshave largely offset one another in recent decades, so that net

warming has been due to the increase in non-CO2 greenhouse gases such as methane. Radiative

forcing due to aerosols is temporally limited due to wet deposition which causes aerosols to

have an atmospheric lifetime of one week. Carbon dioxide has a lifetime of a century or more,

and as such, changes in aerosol concentrations will only delay climate changes due to carbon

dioxide.

In addition to their direct effect by scattering and absorbing solar radiation, aerosols have

indirect effects on the radiation budget. Sulfate aerosols act ascloud condensation nuclei and

thus lead to clouds that have more and smaller cloud droplets. These clouds reflect solar

radiation more efficiently than clouds with fewer and larger droplets.[This effect also causes

droplets to be of more uniform size, which reduces growth of raindrops and makes the cloud

more reflective to incoming sunlight.[Indirect effects are most noticeable in marine stratiform

clouds, and have very little radiative effect on convective clouds. Aerosols, particularly indirect

effects, represent the largest uncertainty in radiative forcing.[

Soot may cool or warm the surface, depending on whether it is airborne or deposited.

Atmospheric soot aerosols directly absorb solar radiation, which heats the atmosphere and

cools the surface. In isolated areas with high soot production, such as rural India, as much as

50% of surface warming due to greenhouse gases may be masked by atmospheric brown

clouds.]Atmospheric soot always contributes additional warming to the climate system. When


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deposited, especially on glaciers or on ice in arctic regions, the lower surface albedo can also

directly heat the surface. The influences of aerosols, including black carbon, are most

pronounced in the tropics and sub-tropics, particularly in Asia, while the effects of greenhouse

gases are dominant in the extratropics and southern hemisphere.

Solar variation

Variations in solar output have been the cause of past climate changes. The consensus among

climate scientists is that changes in solar forcing probably had a slight cooling effect in recent

decades. This result is less certain than some others, with a few papers suggesting a warming

effect.

Greenhouse gases and solar forcing affect temperatures in different ways. While both increased

solar activity and increased greenhouse gases are expected to warm the troposphere, anincrease in solar activity should warm the stratosphere while an increase in greenhouse gases

should cool the stratosphere.]Observations show that temperatures in the stratosphere have

been cooling since 1979, when satellite measurements became available Radiosonde. (weather

balloon) data from the pre-satellite era show cooling since 1958, though there is greater

uncertainty in the early radiosonde record.

A related hypothesis, proposed by Henrik Svensmark, is that magnetic activity of the sun

deflects cosmic rays that may influence the generation of cloud condensation nuclei and

thereby affect the climate. Other research has found no relation between warming in recentdecades and cosmic rays The influence of cosmic rays on cloud cover is about a factor of 100

lower than needed to explain the observed changes in clouds or to be a significant contributor

to present-day climate change.

Attributed and Expected Effects

Global warming may be detected in natural ecological or social systems as a change having statistical

significance.Attribution of these changes e.g., to natural or human activities, is the next step following

detection
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Natural systemsRising sea levels and observed decreases in snow and ice extent are consistent with warming.

Most of the increase in global average temperature since the mid-20th

century is, with high

probability,is atttributable to human-induced changes in greenhouse gas concentrations.

Changes in regional climate are expected to include greater warming over land, with most

warming at high northern latitudes, and least warming over theSouthern Ocean and parts of

the North Atlantic Ocean.

Even with current policies to reduce emissions, global emissions are still expected to continue

to grow over the coming decades.[82]

Over the course of the 21st

century, increases in emissions

at or above their current rate would very likely induce changes in the climate system larger

than those observed in the 20th

century.

In the IPCC Fourth Assessment Report, across a range of future emission scenarios, model-based estimates of sea level rise for the end of the 21

stcentury (the year 2090-2099, relative to

1980-1999) range from 0.18 to 0.59 m. These estimates, however, were not given a likelihood

due to a lack of scientific understanding, nor was an upper bound given for sea level rise. Over

the course of centuries to millennia, the melting of ice sheets could result in sea level rise of 4

6 m or more

Snow cover area and sea ice extent are expected to decrease. The frequency of hot extremes,

heat waves, and heavy precipitation will very likely increase.

Ecological systems

In terrestrial ecosystems, the earlier timing of spring events, and poleward and upward shifts in

plant and animal ranges, have been linked with high confidence to recent warming. Future

climate change is expected to particularly affect certain ecosystems

including tundra, mangroves, and coral reefs. It is expected that most ecosystems will be

affected by higher atmospheric CO2 levels, combined with higher global temperatures. Overall,

it is expected that climate change will result in the extinction of many species and reduced

diversity of ecosystems.

Social systems

There is some evidence of regional climate change affecting systems related to human

activities, including agricultural and forestry management activities at higher latitudes in the
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Northern Hemisphere. Future climate change is expected to particularly affect some sectors

and systems related to human activities. Water resources may be stressed in some dry regions

at mid-latitudes, the dry tropics, and areas that depend on snow and ice melt. Reduced water

availability may affect agriculture in low latitudes. Low-lying coastal systems are vulnerable to

sea level rise and storm surge. Human health in populations with limited capacity to adapt to

climate change. It is expected that some regions will be particularly affected by climate change,

including the Arctic, Africa, small islands, and Asian and African megadeltas. Some people, such

as the poor, young children, and the elderly, are particularly at risk, even in high-income areas.

Ozone Depletion

Ozone depletion describes two distinct, but related observations: a slow, steady decline of

about 4 percent per decade in the total volume ofozone in Earth'sstratosphere (the ozone

layer) since the late 1970s, and a much larger, but seasonal, decrease in stratospheric ozone

over Earth's polar regions during the same period. The latter phenomenon is commonlyreferred to as the ozone hole. In addition to this well-known stratospheric ozone depletion,

there are alsotropospheric ozone depletion events, which occur near the surface in polar

regions during spring.

The detailed mechanism by which the polar ozone holes form is different from that for the mid-

latitude thinning, but the most important process in both trends iscatalytic destruction of ozone
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by atomic chlorine and bromine.[1]

The main source of these halogen atoms in the stratosphere

is photodissociation ofchlorofluorocarbon (CFC) compounds, commonly called freons, and

ofbromofluorocarbon compounds known as halons. These compounds are transported into the

stratosphere after being emitted at the surface.[2]

Both ozone depletion mechanisms

strengthened as emissions of CFCs and halons increased.

CFCs and other contributory substances are commonly referred to as ozone-depleting

substances (ODS). Since the ozone layer prevents most harmful UVB wavelengths (270

315 nm) ofultraviolet light (UV light) from passing through the Earth's atmosphere, observed

and projected decreases in ozone have generated worldwide concern leading to adoption of

the Montreal Protocol that bans the production of CFCs and halons as well as related ozone

depleting chemicals such as carbon tetrachloride and trichloroethane. It is suspected that a

variety of biological consequences such as increases in skin cancer, cataracts,[3]

damage to

plants, and reduction ofplankton populations in the ocean's photic zone may result from theincreased UV exposure due to ozone depletion.

Ozone Hole and its Causes

The Antarctic ozone hole is an area of the Antarctic stratosphere in which the recent ozone

levels have dropped to as low as 33% of their pre-1975 values. The ozone hole occurs during

the Antarctic spring, from September to early December, as strong westerly winds start to

circulate around the continent and create an atmospheric container. Within this polar vortex,over 50% of the lower stratospheric ozone is destroyed during the Antarctic spring.

As explained above, the primary cause of ozone depletion is the presence of chlorine-

containing source gases (primarily CFCs and related halocarbons). In the presence of UV light,

these gases dissociate, releasing chlorine atoms, which then go on to catalyze ozone

destruction. The Cl-catalyzed ozone depletion can take place in the gas phase, but it is

dramatically enhanced in the presence ofpolar stratospheric clouds (PSCs).

These polar stratospheric clouds(PSC) form during winter, in the extreme cold. Polar winters are

dark, consisting of 3 months without solar radiation (sunlight). The lack of sunlight contributes

to a decrease in temperature and the polar vortex traps and chills air. Temperatures hover

around or below -80 C. These low temperatures form cloud particles. There are three types of

PSC clouds; nitric acid trihydrate clouds, slowly cooling water-ice clouds, and rapid cooling

water-ice(nacerous) clouds; that provide surfaces for chemical reactions that lead to ozone

destruction.[21]
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The photochemical processes involved are complex but well understood. The key observation is

that, ordinarily, most of the chlorine in the stratosphere resides in stable "reservoir"

compounds, primarily hydrochloric acid (HCl) and chlorine nitrate (ClONO 2). During the

Antarctic winter and spring, however, reactions on the surface of the polar stratospheric cloud

particles convert these "reservoir" compounds into reactive free radicals (Cl and ClO). The

clouds can also remove NO2 from the atmosphere by converting it to nitric acid, which prevents

the newly formed ClO from being converted back into ClONO2.

The role of sunlight in ozone depletion is the reason why the Antarctic ozone depletion is

greatest during spring. During winter, even though PSCs are at their most abundant, there is no

light over the pole to drive the chemical reactions. During the spring, however, the sun comes

out, providing energy to drive photochemical reactions, and melt the polar stratospheric

clouds, releasing the trapped compounds. Warming temperatures near the end of spring breakup the vortex around mid-December. As warm, ozone-rich air flows in from lower latitudes, the

PSCs are destroyed, the ozone depletion process shuts down, and the ozone hole closes.

Most of the ozone that is destroyed is in the lower stratosphere, in contrast to the much

smaller ozone depletion through homogeneous gas phase reactions, which occurs primarily in

the upper stratosphere.

Consequences of Ozone layer depletionSince the ozone layer absorbs UVB ultraviolet light from the Sun, ozone layer depletion is

expected to increase surface UVB levels, which could lead to damage, including increases in skin

cancer. This was the reason for the Montreal Protocol. Although decreases in stratospheric

ozone are well-tied to CFCs and there are good theoretical reasons to believe that decreases in

ozone will lead to increases in surface UVB, there is no direct observational evidence linking

ozone depletion to higher incidence of skin cancer in human beings. This is partly due to the

fact that UVA, which has also been implicated in some forms of skin cancer, is not absorbed by

ozone, and it is nearly impossible to control statistics for lifestyle changes in the populace.

Increased UV

Ozone, while a minority constituent in the Earth's atmosphere, is responsible for most of the

absorption of UVB radiation. The amount of UVB radiation that penetrates through the ozone

layerdecreases exponentially with the slant-path thickness/density of the layer.
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Correspondingly, a decrease in atmospheric ozone is expected to give rise to significantly

increased levels of UVB near the surface.

Increases in surface UVB due to the ozone hole can be partially inferred by radiative

transfer model calculations, but cannot be calculated from direct measurements because of the

lack of reliable historical (pre-ozone-hole) surface UV data, although more recent surface UV

observation measurement programmes exists.

Because it is this same UV radiation that creates ozone in the ozone layer from O2 (regular

oxygen) in the first place, a reduction in stratospheric ozone would actually tend to increase

photochemical production of ozone at lower levels (in the troposphere), although the overall

observed trends in total column ozone still show a decrease, largely because ozone produced

lower down has a naturally shorter photochemical lifetime, so it is destroyed before the

concentrations could reach a level which would compensate for the ozone reduction higher up.

Biological effects

The main public concern regarding the ozone hole has been the effects of increased surface UV

and microwave radiation on human health. So far, ozone depletion in most locations has been

typically a few percent and, as noted above, no direct evidence of health damage is available in

most latitudes. Were the high levels of depletion seen in the ozone hole ever to be common

across the globe, the effects could be substantially more dramatic. As the ozone hole over

Antarctica has in some instances grown so large as to reach southern parts of Australia, New

Zealand, Chile, Argentina, and South Africa, environmentalists have been concerned that the

increase in surface UV could be significant.

Effects on humans

UVB (the higher energy UV radiation absorbed by ozone) is generally accepted to be a

contributory factor to skin cancer. In addition, increased surface UV leads to increased

tropospheric ozone, which is a health risk to humans.

1. Basal and Squamous Cell Carcinomas The most common forms of skin cancer inhumans, basal and squamous cell carcinomas, have been strongly linked to UVB exposure. The

mechanism by which UVB induces these cancers is well understoodabsorption of UVB

radiation causes the pyrimidine bases in the DNA molecule to form dimers, resulting in

transcription errors when the DNA replicates. These cancers are relatively mild and rarely fatal,

although the treatment of squamous cell carcinoma sometimes requires extensive
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reconstructive surgery. By combining epidemiological data with results of animal studies,

scientists have estimated that a one percent decrease in stratospheric ozone would increase

the incidence of these cancers by 2%.

2. Malignant Melanoma Another form of skin cancer, malignant melanoma, is much less

common but far more dangerous, being lethal in about 1520% of the cases diagnosed. The

relationship between malignant melanoma and ultraviolet exposure is not yet well understood,

but it appears that both UVB and UVA are involved. Experiments on fish suggest that 90 to 95%

of malignant melanomas may be due to UVA and visible radiation whereas experiments on

opossums suggest a larger role for UVB. Because of this uncertainty, it is difficult to estimate

the impact of ozone depletion on melanoma incidence. One study showed that a 10% increase

in UVB radiation was associated with a 19% increase in melanomas for men and 16% for

women. A study of people in Punta Arenas, at the southern tip ofChile, showed a 56% increase

in melanoma and a 46% increase in nonmelanoma skin cancer over a period of seven years,along with decreased ozone and increased UVB levels.

3. Cortical Cataracts Studies are suggestive of an association between ocular

cortical cataracts and UV-B exposure, using crude approximations of exposure and various

cataract assessment techniques. A detailed assessment of ocular exposure to UV-B was carried

out in a study on Chesapeake Bay Watermen, where increases in average annual ocular

exposure were associated with increasing risk of cortical opacity. In this highly exposed group of

predominantly white males, the evidence linking cortical opacities to sunlight exposure was the

strongest to date. However, subsequent data from a population-based study in Beaver Dam, WIsuggested the risk may be confined to men. In the Beaver Dam study, the exposures among

women were lower than exposures among men, and no association was seen. Moreover, there

were no data linking sunlight exposure to risk of cataract in African Americans, although other

eye diseases have different prevalences among the different racial groups, and cortical opacity

appears to be higher in African Americans compared with whites.

4. Increased Tropospheric Ozone Increased surface UV leads to

increased tropospheric ozone. Ground-level ozone is generally recognized to be a health risk, as

ozone is toxic due to its strong oxidant properties. At this time, ozone at ground level is

produced mainly by the action of UV radiation on combustion gases from vehicle exhausts.
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Ozone Hole and Global Warming

There are five areas of linkage between ozone depletion and global warming:

The same CO2 radiative forcing that produces global warming is expected to cool

the stratosphere. This cooling, in turn, is expected to produce

relative increase in ozone (O3) depletion in polar area and the frequency of ozone holes.

Conversely, ozone depletion represents a radiative forcing of the climate system. There

are two opposing effects: Reduced ozone causes the stratosphere to absorb less solar

radiation, thus cooling the stratosphere while warming the troposphere; the resulting

colder stratosphere emits less long-wave radiation downward, thus cooling the

troposphere. Overall, the cooling dominates; the IPCC concludes that "observed

stratospheric O3losses over the past two decades have caused a negative forcing of the

surface-troposphere system" of about 0.15 0.10 watts per square meter (W/m). One of the strongest predictions of the greenhouse effect is that the stratosphere will

cool. Although this cooling has been observed, it is not trivial to separate the effects of

changes in the concentration ofgreenhouse gases and ozone depletion since both will

lead to cooling. However, this can be done by numerical stratospheric modeling. Results

from the National Oceanic and Atmospheric Administration's Geophysical Fluid

Dynamics Laboratory show that above 20 km (12.4 miles), the greenhouse gases

dominate the cooling.

Ozone depleting chemicals are also greenhouse gases. The increases in concentrations

of these chemicals have produced 0.34 0.03 W/m of radiative forcing, corresponding

to about 14% of the total radiative forcing from increases in the concentrations of well-

mixed greenhouse gases.

The long term modeling of the process, its measurement, study, design of theories and

testing take decades to document, gain wide acceptance, and ultimately become the

dominant paradigm. Several theories about the destruction of ozone were hypothesized

in the 1980s, published in the late 1990s, and are currently being proven. Dr Drew

Schindell, and Dr Paul Newman, NASA Goddard, proposed a theory in the late 1990s,

using a SGI Origin 2000 supercomputer, that modeled ozone destruction, accounted for78% of the ozone destroyed. Further refinement of that model accounted for 89% of the

ozone destroyed, but pushed back the estimated recovery of the ozone hole from 75

years to 150 years.
http://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Stratospherehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Tropospherehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/National_Oceanic_and_Atmospheric_Administrationhttp://en.wikipedia.org/wiki/Geophysical_Fluid_Dynamics_Laboratoryhttp://en.wikipedia.org/wiki/Geophysical_Fluid_Dynamics_Laboratoryhttp://en.wikipedia.org/wiki/SGI_Origin_2000http://en.wikipedia.org/wiki/SGI_Origin_2000http://en.wikipedia.org/wiki/Geophysical_Fluid_Dynamics_Laboratoryhttp://en.wikipedia.org/wiki/Geophysical_Fluid_Dynamics_Laboratoryhttp://en.wikipedia.org/wiki/National_Oceanic_and_Atmospheric_Administrationhttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Tropospherehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Stratospherehttp://en.wikipedia.org/wiki/Global_warming

Global Warming and Ozone Depletion

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