Review Report: Geoengineering The Ozone Layer By David Stephen College grad in Physics [email protected] October 2011.

Review Report: Geoengineering The Ozone Layer

ByDavid StephenCollege grad in [email protected]

October 2011

Geoengineering• Geoengineering has been in the news in recent weeks after the

announcement of Stratospheric Particle Injection for Climate Engineering (SPICE) by UK scientists and a report by the US Bipartisan Policy Center on Climate Remediation Research.

• Geoengineering is seen as the way out from likely effects of global warming; Geoengineering or climate engineering can be described as an artificial procedure directed at excesses responsible for global warming to reduce or prevent its effects.

Table of Contents Geoengineering The Ozone Layer The Ozone Layer Hole & Why it came Ozone Recovery & Projections Ozone Layer Geoengineering: A background Ozone Layer Geoengineering: The Need The Proposal Aerostat Aerodyne Discussions Conclusion References Downloads

The Ozone Layer• The ozone layer is a layer of gas present in an upper part of the atmosphere

called the stratosphere; the stratosphere is roughly between 20-48km above sea level.

• The ozone layer helps to protect planet earth from harmful Ultra Violet (UV) radiations, it does this in a series of reactions involving UV light and allotropes of oxygen; allotropes of oxygen involved are ozone, O3; oxygen molecule, O2 and oxygen atom, O

NASA’s Aura satellite image of the ozone layer over Antarctica in 2005

• Heat intensity in the ozone layer dissociates oxygen molecule to oxygen atoms,

O2 + solar energy of wavelength less than 242nm → O + O• Each oxygen atom released from the reaction reacts separately with oxygen

molecules in the ozone layer to form ozone molecules O + O2 → O3

O + O2 → O3

• Ozone molecules formed in this process are individually dissociated by UV light,

O3 + solar energy of wavelength less than 336nm → O2 + O [1]

• These reactions screen out harmful UV radiation from reaching the earth surface.

The Ozone Layer Hole & Why it came• The ozone layer contain gases, these gases are constantly reacting in the

presence of light, they can also react with some other gases if encountered at that level.

• Ozone Depleting Substances (ODSs) are class of gases used in several utilities by man and are harmful to the ozone layer because of reactions they prompt with ozone gas at that altitude to form compounds that cannot protect against harmful UV rays.

• A large depleted part or ‘hole’ was noticed in the ozone layer over Antarctica in late 1970’s which studies linked to ODSs. This observation lead to moves to reduce the use of these gases and sustain the ozone layer useful to protect us from UV radiations that are capable of causing skin cancer, cataract and immune system suppression with increased exposure.

• Chlorofluorocarbons or CFCs are common examples of ODSs, they are used in some of man’s necessary utilities like fire extinguishers, refrigerators and aerosols. CFCs mainly contain chlorine, fluorine and carbon.

• When CFCs escape to the ozone layer, they are dissociated by UV light to release chlorine, Cl- , this chlorine reacts with ozone, O3 produced from the combination reaction stated earlier to form chlorine monoxide, ClO and one oxygen molecule, O2

Cl- + O3 → ClO + O2 ----- equation (i)

ClO + O3 → Cl- + 2O2 ----- equation (ii)

• ClO produced in equation (i) reacts with another O3 to produce Cl- and 2O2 as shown in equation (ii). Chlorine produced from equation (ii) continue in reaction with ozone as in equation (i), occurring thousands of times again.[1] This reduces ozone relevant to protection over the part where these reactions occur.

Ozone Recovery & Projections• Ozone layer depletion is usually considered as a settled matter because of

efforts from international agreements directed to stop the use of ODSs.• The Montreal Protocol is the major international agreement binding Nations

to stop the use of ODSs and replace with substances that are not harmful to the ozone layer.

• The ozone layer is projected to return to pre-1980 levels around mid-century when ODSs at that level will fizzle out and lost ozone molecules will be replaced naturally in reactions.

Ozone Layer Geoengineering:A background

• Weather anomalies occurring across the globe of late is linked to global warming, contribution from other processes is researched in studies.

• The ozone hole is linked to climate change and may also influence certain weather anomaly; studies for exactness of the ozone hole to these are continuous.

• The ozone layer should naturally recover around mid-century, this is many years from now even as what may come in weather deviations due to its depleted parts are not exactly clear.

• Geoengineering the ozone layer may be necessary in future if the ozone hole expands and poses more risk to man and the environment.

• Geoengineering the ozone layer is a workable experiment because of acquaintance of man with outer space and the mix of gases involved in protection reactions in the stratosphere.

• Objects known to fly to stratospheric height are mainly rockets, aerostats and aerodynes. Most of these objects have been used in missions around and beyond stratospheric region showing their competence to travel there with a certain amount of load.

• Oxygen will be used for this recovery and will be conveyed from planet earth as liquid and discharged as gas to depleted parts of the ozone layer.

• Discharged gas is expected to join in reactions occurring for protection at the stratosphere. This recovery is not expected to close the whole depleted portion of the ozone layer (which is about 3%) but will be used for parts measurements show to contain fewer ODSs to avoid destruction of incoming oxygen molecules when they become ozone.

• Arctic ozone depletion in 2011; Image Credit: NASA/JPL-Caltech.

• The images above show the distribution of ozone gas and chorine monoxide in the ozone layer over Arctic at a stratospheric altitude of 20km in mid-march 2011.

• It shows the hole over Arctic and how chlorine monoxide surrounds it. The purple & grey part show a low ozone distribution for the image on the left and the blue part for the image on the right show a high chlorine monoxide distribution. [2]

• For the image on the left, areas with light blue, dark blue and sky blue depict points of low ozone, it also depicts points of low chlorine monoxide shown from the image on the right. These are choice points to discharge oxygen using this distribution as reference.

• Oxygen gas when discharged will provide more molecules for reactions and join in reactions to close the hole to a targeted extent.

Ozone Layer Geoengineering:The Need

• Adding oxygen to depleted parts of the ozone layer may be necessary in future. This may come towards the middle of the first half of this century if the ozone hole clearly pose threats to man and the environment in health concerns and devastation respectively.

• Geoengineering for global warming may be likely soon, some of the procedures suggested will further deplete the ozone layer according to certain reviews. These reviews should not stop a process that may be the last resort to save planet earth from global warming. Effects to the ozone layer observed after geoengineering for global warming can be repaired by geoengineering the ozone layer.

• Geoengineering the ozone layer will also be necessary to further understand the impact of artificial input to a natural cycle in the atmosphere.

The Proposal• A tank of volume of around 500m3 full of liquid oxygen will be conveyed

using an aerostat or aerodyne from the surface of the earth to the stratosphere. The tank will have a chamber where it is expected to vaporize before discharge under high pressure to trigger reactions immediately. This process is similar to the combustion process in rocket engines.

• The gas should be discharged at a low stratospheric altitude where wind and turbulence is bearable. Discharged gas should be carried higher by stratospheric winds and other air motion for thoroughgoing; reaction of discharged gas for protection however does not depend on this.

• Liquid oxygen is preferred for this procedure because more volume of the same mass of oxygen can be carried as liquid than as gas.

• Oxygen instead of ozone is preferred for a number of reasons; ozone gas is unstable and dissociates at high concentration to oxygen under atmospheric conditions in a short time. For ozone, large amount will be manufactured and transported, this is practically difficult and financially guzzling. Ozone molecules that protects in the ozone layer where formed from a process which ‘prepares’ them for the next; this may not be the same for freshly discharged ozone that is ‘not prepared’ for the process and may be inactive for a while before possible eat up by ODSs. These are the basic reasons for preference of oxygen to ozone for this research.

• Discharged oxygen can undergo two reactions because of the condition in the ozone layer and discharge of the gas at high pressure.

• Discharged oxygen released under high pressures can react with natural oxygen atoms to form ozone molecules. i.e.

O2 + O → O3

• Or be split by UV rays as in the reactions below *O2 → O + O

O + ‘ O2 → O3

O + ‘ O2 → O3

• *O2 is one of the injected oxygen molecules split by UV rays to oxygen atoms. ‘ O2 is part of the injected oxygen molecules in reaction with the oxygen atoms to form ozone molecules.

• This shows that injected oxygen molecules can protect from harmful UV rays in reactions within their cycle.

Aerostat• Aerostats can be defined as powered, gases filled balloons which can be

steered not requiring movement through surrounding air. They are also known as airships, blimps and dirigibles. They were used for transportation many years back but have been modernized of late for high altitude and better transport capabilities.

• Aerostats can be used for this research, they present an advantage for little or negligible pollution and capability to fly to low stratospheric altitude. [3] Their load capacity is a challenge but can be possible in a specially built system.

• Balloon-like discharge as in the SPICE project is possible for this research if adjustment is made for oxygen discharge in a desired fashion.

Aerodyne• Aerodynes are class of aircrafts made of metals and can fly around

stratospheric heights. Unmanned Aerial Vehicles (UAVs) are examples of aerodynes, they are powered aerial vehicles that does not carry a human operator.

• UAVs can be used to deliver oxygen as this research submits because of their altitude and load capabilities.

• RQ-4 Global Hawk is an example of a UAV used by the US Air Force that flew around 21km above sea level with a certain amount of load [4]; Boeing X-37B, was similarly used and is powered by batteries.[5]

• UAVs are options for this research but are very expensive to build and maintain, before experimentation of this research, chances exist to extemporize for UAV usage.

Discussions• This research is a basic scenario, further scientific and technical review

should channel it for solutions with regards to the ozone hole.• Some factors aside ODSs are also necessary to determine parts or regions

where this procedure will be used. Since most ozone is made around the equator and its distribution varies seasonally and geographically, target points for this procedure will include points where models show will impact more and movement of stratospheric winds will draw more natural ozone molecules close after some time.

• The mode & approach of this research is workable, and should be viable when used. This research presents an option for ozone layer repair aside the sole hope of natural repair to come around 2050.

Conclusion• Experimentation of this research may not come anytime soon but review is

necessary for thoughts in this line and to broaden options in this direction.• Geoengineering the ozone layer may never come as we remain hopeful that

effects due to depleted ozone stay within a bearable range. Options as this however will prepare us for the challenge if things suddenly or gradually tilt towards an undesired end.

• Geoengineering the ozone layer is here and this research presents a starting point, execution is not so close but may be likely in 2-3 decades. Rather than look critically for reasons why this will not work, it is preferable that those reasons are highlighted for observation and solution within 15-20years to prepare this procedure for use anytime it is needed.

References1. Wilkins J (2006), How the Earth Got its Ozone Layer. Energy publication of

Department of Physics, Ohio State University, E01.1.2. Manney G.L. et al (2011), Unprecedented Arctic Ozone Loss in 2011 http://

www.nature.com/nature/journal/vaop/ncurrent/full/nature10556.html3. Smith S Jr., and L. Michael (2007), The HiSentinel Airship, presented paper

at the 7th AIAA Aviation Technology, Integration and Operation (ATIO) 2nd C, Belfast, Northern Ireland.

4. United States Air Force, (2009) RQ-4 Global Hawk, Fact Sheet by the Air Combat Command, Public Affairs Office, Virginia, United States of America.

5. United States Air Force, (2010) X-37B Orbital Test Vehicle, Fact Sheet from the Office of the Secretary of the Air Force (Public Affairs), Washington, USA.

Downloads• Please download the research paper from which this report was developed

from: http://trpns.com/wp-content/uploads/2011/09/Ozone-Hole-Repair.pdf

• For more information about the ozone layer, please download documents from the links below:

• http://ozone.unep.org/Assessment_Panels/SAP/Scientific_Assessment_2010/SAP-2010-FAQs-update.pdf

• http://downloads.climatescience.gov/sap/sap2-4/sap2-4-final-all.pdf • http

://www.physics.ohio-state.edu/~wilkins/energy/Companion/E01.1.pdf.xpdf

THANK YOU