CFC Destruction of Ozone - Major Cause of Recent Global Warming! 

 Robert A. Ashworth

pdf. format for printing

The animation illustrates how one chlorine atom in the stratosphere 

can destroy up to 100,000 ozone molecules.  Graphic credit goes to

University of Alaska

Abstract

There has been a lot of discussion about global warming.  Some say anthropogenic carbon dioxide (CO₂) emissions caused the earth to warm.  Others say there is no abnormality at all, that it is just natural warming.  As you will see from the data presented and analyzed, a greater than normal warming did occur in recent times but no measurements confirm an increase in CO₂, whether anthropogenic or natural, had any effect on global temperatures.  There is however, strong evidence that anthropogenic emissions of chlorofluorocarbons (CFCs) were the major cause of the recent abnormal warming.   

CFCs have created both unnatural atmospheric cooling and warming based on these facts:

• CFCs have destroyed ozone in the lower stratosphere/upper troposphere causing these zones in the atmosphere to cool 1.37 ^oC from 1966 to 1998, a time span selected to eliminate the effect of the natural solar irradiance (cooling-warming) cycle effect on the earth's temperature. 

• The loss of ozone allowed more UV light to pass through the stratosphere at a sufficient rate to warm the lower troposphere plus 8-3/4" of the earth by 0.48 ^oC (1966 to 1998).

• Mass and energy balances show that the energy that was absorbed in the lower stratosphere /upper troposphere hit the lower troposphere/earth at a sustainable level of 1.69 x 10¹⁸ Btu more in 1998 than it did in 1966. 

• Greater ozone depletion in the Polar Regions has caused these areas to warm some two and one-half (2 ½) times that of the average earth temperature (1.2 ^oC vs. 0.48 ^oC).  This has caused permafrost to melt, which is releasing copious quantities of methane, estimated at 100 times that of manmade CO₂ release, to the atmosphere.  Methane in the atmosphere slowly converts to CO₂ and water vapor and its release has created higher CO₂ concentrations in the atmosphere.

• There is a temperature anomaly in Antarctica.  The Signey Island landmass further north warmed like the rest of the Polar Regions; but south at Vostok, there has been a cooling effect.  Although the cooling at Vostok needs to be analyzed in more detail, because of the large ozone hole there, black body radiation from Vostok (some 11,400 feet above sea level) to outer space is most likely the cause.  Especially, since this phenomenon occurred over the same period that stratospheric ozone destruction took place.

Greenhouse Gases

Many scientists do not agree with the CO₂ global warming models developed by the Intergovernmental Panel on Climate Change (IPCC).  For instance, T.M.L. Wigley ¹, a senior scientist at the U.S. National Center for Atmospheric Research, calculated the "saved" warming that would accrue if every nation met its Kyoto Protocol obligations (U.S. reduction of 43%).  By 2050, the earth’s temperature would reduce by 0.07 ^oC - a change so small it could not be reliably measured.  In contrast to Wigley's projections, the IPCC has developed models ² that predict the average surface temperature of the earth relative to 1980-1990, will increase by 2 to 11.5°F (1.1 to 6.4°C) by the end of the 21st century due to increased CO₂ concentrations in the atmosphere.  They project temperature change as functions of growth rates in atmospheric carbon dioxide.  Those projections are shown in Figure 1. 

Figure 1.  IPCC projections of global warming.

Actual measurements are more in line with the analysis made by Wigley than the IPCC projections.  What is so disturbing is that the measured data plots in Figure 2 show absolutely no correlation of CO₂ concentration with the earth's temperature even with the relatively significant increase ³ that occurred from 1650 to 2006 (~160 ppmv increase).  The actual temperature in 2006 was almost 0.6 ^oC lower than the IPCC temperature shown for the zero point in 1998.  The temperature is jumping around and not following CO₂ concentrations at all.  The IPCC models are clearly flawed.  One must wonder whether the IPCC used any actual temperature measurements over time or any historic CO₂ concentrations relative to global temperature, when it developed its models. 

Figure 2.  CO₂ concentration and temperature change with time from 800 to 2006 AD.

As shown in Figure 2, over the time from 850 until 1650, the CO₂ concentration was relatively the same (~215 ppmv) but the earth's temperature varied from +0.6 to -0.2 ^o C.  The CO₂ concentration was 375 ppmv in 2006 and there was still no correlation of temperature and CO₂.  In addition, the earth's temperature from January 2007 to January 2008 dropped by almost 0.6 ^o C

Some say historically, that increased CO₂ levels in the atmosphere have created periods of global warming.  They cite the Vostok, Antarctica ice core data ⁴, as proof of this.  However, whoever came up with this analysis got the cause and effect reversed.  The data show that global warming always comes first (see Figure 2).  After a temperature spike from by the sun, the oceans start to warm and liberate more CO₂ because of the reduced solubility of CO₂ in seawater at higher temperatures.  Further, there is a lag of some 800+ years until CO₂ concentration in the atmosphere starts to increase, refer back to Figure 1.

Data that is more recent, confirms that atmospheric CO₂ concentrations have no effect on global temperature, see Figure 3.  While CO₂ levels increased some 20 ppmv over the past 10 years, global temperatures did not increase they fell.  The temperatures shown in the graph are from the National Aeronautics and Space Administration's (NASA) Microwave Sounding Unit (MSU) and the United Kingdom's (UK) Hadley Climate Research Unit.  The Mauna Loa Observatory in Hawaii measured concentrations of CO₂ in the atmosphere over this same period.  Meteorologist Joseph D'Aleo ⁵ plotted the temperature and CO₂ measurements.  Here again, actual data completely refutes IPCC modeling predictions? Even further, human emissions account for only some three percent (3%) of the total CO₂ in atmosphere ⁶.  Therefore, if anthropogenic emissions of CO₂ were banished completely, the CO₂ in the atmosphere would drop only 12 ppmv, a miniscule amount, about ½ of the increase from 1998 to 2008.  Although one would prefer not to refute another's work, the more you study CO₂ as the cause of global warming, the more ludicrous it becomes.

Figure 3. Earth temperature and CO₂ concentration 1998-2008.

Ozone Loss Effect

In 1994, ozone in the lower stratosphere in Antarctica had dropped to less than one-third of its normal level.  Although not as severe, ozone concentration north of the Arctic Circle sank to 45% of normal in the winter of 1996. 

The legendary hypotheses ⁷ of Paul Crutzen, Sherwood Rowland, and Mario Molina led to CFCs being banned because they were destroying stratospheric ozone.  Although it unleashed a storm of criticism and controversy at the time they did their work, they were vindicated by receipt of the 1995 Nobel Prize in Chemistry.  In 1978, the USA banned the use of CFCs in hair sprays and other aerosols.  In 1987, the governments of the world through the United Nations Environment Programme (UNEP), agreed to limit the production and release of a variety of CFCs.  The protocol to accomplish this was put forward at a meeting in Montreal, Canada and has since become known as the Montreal Protocol.  Since the original protocol, its provisions were amended in mid-1998; the amendments were then ratified or accepted by 120 and 78 countries, respectively. 

CFCs will be produced in China and other developing countries until 2010.  However, in July 2007, China shut down five of its six remaining CFC production plants ahead of schedule and now is only producing 550 metric tons per year.

It is well known that warming of the stratosphere is caused by ozone absorbing ultraviolet radiation.  Since ozone keeps the stratosphere warm, using straightforward logic, loss of ozone would cause the stratosphere to cool.  When ozone is lost, more UV light passes through the stratosphere to hit earth.  The effect is clearly shown (Figure 4) by temperature versus ozone concentration in Dobson Units (DU).  NASA ⁸ generated the graph below. 

Figure 4.  Ozone concentration versus stratospheric temperature.

Except for the periods of two large volcanic eruptions, temperature and ozone concentration rise and fall together.  From 1997 to 2001, the temperature of the stratosphere averaged a 1 ^oC change for every 6.45 DU increase or decrease in stratospheric ozone concentration.  Over the Polar Regions, the primal cause for colder than normal temperatures is loss of ozone.  During winter, the air temperature drops and clouds of ice crystals, with mixtures of hydrochloric, sulfuric and nitric acids, form in the stratosphere.  These ice crystals provide a surface for chemical reactions that change chlorine compounds that do not react with ozone (e.g. hydrogen chloride) into more active forms that destroy ozone, such as:

HCl + ClONO₂ -> Cl₂ + HNO₃ and CL₂ + UV -> 2 Cl ^-

In addition, the very cold air creates vortices of fast-moving air.  These vortices effectively insulate the Polar Regions from the rest of the atmosphere.  They sit there, are very stable, and keep the outside higher-ozone air from coming in.  Most stratospheric ozone is created in the tropics because of the greater intensity of solar radiation that creates ozone.  Stratospheric air currents, from the tropics, then transport ozone to the Arctic and Antarctica.  However, the strong and stable vortices hinder the migration of ozone to the poles and more UV light passes through to hit earth.  That is why the Polar Regions have warmed more that the rest of the earth.

Since the late sixties-early seventies, the loss of ozone has caused the stratosphere to cool, see Figure 5.  The exceptions to cooling caused by ozone destruction occurred at the times of the major eruptions of El Chichon, and Mt. Pinatubo volcanoes.  The Agung volcanic eruption that occurred before the time interval analyzed also warmed the stratosphere.  In 1980, Mt. St. Helens erupted but it had a much smaller effect than El Chichon and Mt. Pinatubo.  In 1998, the stratosphere was 1.37 ^oC cooler than it was in 1966.  This span of time was chosen to negate the solar irradiance cycle and the volcanic eruption effects.  The data suggests that the cooling over this time span appears to be mostly due to loss of ozone. 

Figure 5.  Global lower stratospheric anomalies from 1958 to 2008 ⁹.

The temperature changes before 1966 are most likely the result of change in the rate of solar energy that hits earth and maybe some volcanic activity.  However, after CFC refrigerants and aerosols started to be produced and released to the atmosphere, the stratosphere started to cool.  As the lower stratosphere and upper troposphere cooled, the troposphere/earth from 1966 to 1998 warmed by 0.48 ^oC, see Figure 6.  The mean used for this graph to set a zero temperature is different from Figure 5 but since only temperature change is being considered, the line depicting zero is irrelevant.

In the Arctic, surface temperatures increased 2 ½ times the average global increase (1.2 ^oC vs. 0.48 ^oC) from 1966 to 1998, see Figure 7.  This appears to be caused by less ozone in the stratosphere in polar climes where ozone destruction is exacerbated.  There is a cooling anomaly in Antarctica.  Whereas, the Signey Island landmass in the northern part of Antarctica has warmed, south at Vostok, there has been a cooling effect.  Although the cooling at Vostok needs to be analyzed in more detail, because of the large ozone hole in Antarctica, it seems likely that black body radiation from Vostok (some 11,400 feet above sea level) to outer space is most likely the cause, especially since this phenomenon occurred over the same time span that stratospheric ozone destruction took place.  One would have to use reverse logic to explain the cooling effect at Vostok being caused by increased CO₂ in the atmosphere.

Figure 6. Near earth surface temperature global change with time ¹⁰.

Figure 7. Observed Arctic temperature change ¹¹.

The change in ozone depletion chemicals in the stratosphere versus time ¹² is shown in Figure 8.  CFC concentrations peaked in the late nineties and then started dropping slightly.  The contribution of methyl bromide is split into anthropogenic (A) and natural (N) components and the natural ozone-depleting substance methyl chloride is included.  The line at 2 ppb corresponds to the time when ozone depletion was first detected (1980).  It also shows when major ozone recovery is anticipated (2050 to 2060).  Although not shown, chloroform (CHCl₃), dichloromethane (CH₂Cl₂), and a range of other chlorinated solvents contribute a further 0.1 ppb to the stratospheric chlorine. 

Figure 8.  Ozone depletion chemicals in the stratosphere.

CFC's and CCl₄ are nearly inert in the troposphere and have lifetimes of 50-200+ years.  The hydrogen-containing halocarbons like HCl are more reactive, and tend to be removed in the troposphere by reactions with [OH] radicals.  However, this process is slow and some live long enough to reach the stratosphere.  Total stratospheric organic chlorine is currently over 3 ppbv.  Methyl Chloride (CH₃Cl) is the only ozone-depleting chlorocarbon from a major natural source and makes up around 0.5 ppbv of the total.  Organic bromides and iodides also destroy ozone.

It is different in the stratosphere; the major source of CFC decomposition there is photolysis ¹³, reaction with ultraviolet (UV) light radiation.  Ultraviolet light has wavelengths in the 200-400 nm region.  UV-A light is a low energy UV light with wavelengths between 320-400 nm.  Only about 5% of the UV-A light is absorbed by ozone and most reaches the surface of the Earth.  UV-B light is of moderate energy and has wavelengths between 290-320 nm.  Ozone absorbs most of the UV-B light before it reaches the surface of the Earth.  UV-C light is a higher energy UV light with wavelengths in the range of 200-290 nm.  Both ozone and oxygen molecules absorb the UV-C light before it can reach the Earth's surface.  Therefore, where there is low stratospheric ozone, more UV (A, B & C) light from the sun passes through the atmosphere to hit earth and heat it up. 

The initial products from high energy UV-C light hitting a CFC molecule are a chlorine atom and an organic radical, considering CFC-11 (trichlorofluoromethane):

CCl₃F + UV-C light = CCl₂F + Cl

The free chlorine atom can then react with ozone to form ClO:

Cl + O₃ -> ClO + O₂

 The ClO in turn will react with nascent oxygen (O) to release a chlorine atom; thus, a continuous destruction of ozone occurs because the chlorine atoms are not sequestered into stable compounds:

ClO + O -> Cl + O₂

 The CFC chlorine can take other reaction paths, but this is believed to be the predominant ozone destruction cycle.  It has been estimated that one CFC molecule in the stratosphere will destroy 100,000 molecules of ozone over its natural lifetime there.  Though the concentration of CFCs is only 3 ppbv, they have the ozone destruction effect of a concentration of 0.03% based on one reaction per ozone molecule. 

Figure 9 shows a correlation of CFC concentration and average stratosphere and earth temperature plotted versus time. As shown by the arrows, in a logical sequence, CFC concentration started to drop first causing a reduction in stratospheric cooling and then a reduction in earth warming.

Figure 9. Stratospheric cooling, earth warming and CFC concentration.

When one sees like trends, it is a good indication that the trends are related to one another.  Contrarily, when one looks at CO₂ concentrations versus earth temperature there are no trends that show increased CO₂ concentrations create increases in global temperature.  The only observable trend between the two is that a global spike from the sun creates a higher temperature on earth and some 800 years or so later when CO₂ concentrations start to increase.

Large solar heating-cooling cycle variations occur every 80,000 to 110,000 years, but the sun's thermostat also regularly increases and decreases in shorter term cooling-warming cycles (approximately 11 years) ¹⁴, see Figure 10.  For the mass and energy balances completed, to eliminate the short-term solar irradiance warming-cooling cycle effect on global warming, the period from 1966 to 1998 was chosen.  At these two points in time, the solar irradiance hitting the earth was approximately the same (1368.8 W/m²).

According to NASA, the lower stratosphere and upper troposphere, both of which have cooled together ¹⁵, extends from 8 to 19 km above the surface of the earth with the lower troposphere being in the 0 to 8 km elevation zone.   Knowing how much the lower stratosphere-upper troposphere cooled and how much the lower troposphere-earth warmed, mass and energy balances could be made to determine how much more radiant energy hit the earth in 1998 compared to 1966 due to the destruction of ozone. 

Figure 10. Solar irradiance cycle effect on earth.

Table 1 shows the mass and energy balances completed around the lower stratosphere/upper troposphere (8-19 km above sea level) zone, 1966 versus 1998 based on measured atmospheric temperatures that showed these zones had cooled 1.37 ^oC over this time span. 

TABLE 1.  UV-B LIGHT NOT ABSORBED IN UPPER TROPOSPHERE/LOWER STRATOSPHERE

The mass and energy balance in Table 2 shows the effect of the additional energy being absorbed by the troposphere/earth (surface to 8 km above sea level) in 1998 compared to 1966.  It is similar to this.  Say you have one million pounds of water.  You measure the temperature of the water, and then you add one million Btus of energy to it and measure the temperature again to find it has raised 1 ^oF. 

TABLE 2.  HEAT ABSORBED IN LOWER TROPOSPHERE AND EARTH SURFACE

The additional UV radiation passing through the upper atmosphere is sufficient to heat the lower troposphere and the top 8-3/4 inches of the earth by 0.48 ^oC.  The temperature of the lower troposphere and 8-3/4" of earth (land and water) in 1966 had an average heat content of 9.7755 x 10 ²⁰ Btu and in 1998; it had a heat content of 9.7924 x 10 ²⁰ Btu.  The added instantaneous UV energy that hit the earth in 1998 was 1.6855 x 10¹⁸ Btu.  The added energy hitting the earth was used to first heat the troposphere and the remaining energy was then applied to heat land and water.  To make the energy balance, 8-3/4" of earth/water needed to be heated.

Besides the carbon dioxide increase in the atmosphere, atmospheric concentrations of methane have increased by 150 percent from approximately 700 (pre-industrial) to 1,745 ppbv in 1998 ¹⁶.  In 1966, the methane concentration was around 1400 ppbv.  In 2000, methane concentrations leveled off at 1755 ppbv and appear to be slowly dropping.  This is during the same time span when stratospheric CFC concentrations leveled off and started to slowly drop. 

A recent study ¹⁷ showed that permafrost melting in North Siberia is releasing methane sequestered there since the Pleistocene era (10,000 to one million years ago) from the surface of thawing lakes.  Further, methane is being emitted at a rate much greater than previously thought.  The methane being released was estimated to be some 100 times the rate of carbon dioxide released from the burning of fossil fuels. Methane (CH₄) slowly converts to CO₂ in the atmosphere.  If the researchers from Florida, Alaska and Russia are correct most of the recent CO₂ increases have come from the melting of permafrost.

Conclusion

Many factors influence the earth's temperature.  However, from a scientific analysis, carbon dioxide has little to no effect on the temperature.  This is clearly shown, by an earth temperature drop of almost 0.6 ^oC from January 2007 to January 2008.  It should be obvious to everyone who has analyzed climate change that climate-driving forces, other than CO₂, control the temperature. 

However, chlorofluorocarbon destruction of stratospheric ozone can be correlated nicely with both the cooling and warming temperature anomalies seen over the time span from 1966 to 1998.  One can account for most, if not all, of the 0.48^oC rise in earth's temperature from 1966 to 1998 with the additional UV light that hit the earth due to ozone destruction in the upper atmosphere.

Ozone destruction has also indirectly created an increase in CO₂ concentrations due to the melting of the permafrost in Siberia that has warmed two and one-half (2½) times more than the average earth temperature has risen.  The higher temperatures started melting the permafrost, and this in turn created a significant release of methane.  Methane slowly reacts with oxygen to convert to CO₂ in the atmosphere. 

Unless we remove the CFCs from the atmosphere, it appears that the whole earth will continue to be warmer than normal and higher concentrations of CO₂ (from permafrost release of methane) will exist until the CFCs in the stratosphere slowly disappear naturally over the next 50-100 years.  The exceptions that could alter this are large volcanic eruptions or weather modification techniques as proposed by physicist Freeman Dyson, wherein fine particulate, such as bauxite (Al₂O₃), is sprayed into the stratosphere to simulate a volcanic eruption, which would absorb more UV light in the stratosphere and would cool the earth.  

China and other developing countries are to phase out CFC production in 2010.  Some CFC production plants have been shutdown ahead of schedule in these developing countries, which is very beneficial.  However, it would not be that difficult to remove CFCs from the atmosphere to bring earth's temperature back to normal much quicker.  Although the atmosphere is intricate in how it acts and reacts, it appears that CFCs are the dominant cause of greater than normal earth warming from 1966 to 1998.

Einstein ⁽¹⁸⁾ once said, "The grand aim of all science is to cover the greatest number of empirical facts by logical deduction from the smallest possible number of hypotheses or axioms".  One can do that here using CFC destruction of ozone to explain the recent earth temperature anomalies seen.

The United States Congress will be considering a $1.2 trillion carbon tax this year that, if implemented, would make the recent increase in the cost of gasoline look pale in comparison to the price energy will be after such a tax is imposed.  Taxing carbon makes absolutely no sense and will dramatically hurt the economy of every country that implements it - all for no good reason!  This paper is a direct challenge to the IPCC; their models are way off base.  When one develops a model, actual data needs to be observed to confirm or refute the model that one develops.   It looks as though the IPCC did not do this.

Acknowledgements

I would like to thank Christopher Monckton for his support and suggestions.  Most of all I would like to pay tribute to three gentlemen; Paul Crutzen, Sherwood Rowland, and Mario Molina, who saved this earth through their work on the CFC effect on the environment.  If they had not worked to stop CFC production, what we are seeing now with global warming would be nothing compared to how bad it would have been without their efforts to stop its production.  Their work was not only important from the standpoint of reducing global warming, but also in reducing the occurrence in skin cancer.

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