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Lecture „Climate Engineering“
1. Introduction
Ulrich Platt
Institut für Umweltphysik
Lecture Program of „Climate Engineering
2
Part 1: Introduction to the Climate System (4 sessions)1. Introduction and scope of the lecture2. The Climate System – Radiation Balance 3. Elements of the Climate System - Greenhouse Gases, Clouds, Aerosol4. Dynamics of the Climate System - Sensitivity, PredictionsPart 2: Climate Engineering Methods - Solar Radiation Management, SRM1. SRM – Reflectors in space 2. SRM – Aerosol in the Stratosphere3. SRM – Cloud Whitening4. SRM – Anything elsePart 3: Climate Engineering Methods – Carbon Dioxide Removal, CDR1. Direct CO2 removal from air2. Alkalinity to the ocean (enhanced weathering)3. Ocean fertilization4. Removal of other greenhouse gasesPart 4: CE – Effectiveness, Side Effects (3 sessions) 1. Comparison of Techniques, characterisation of side effects2. Other parameters than temperature3. Summary
Contents of Today's Lecture
• Global Warming - „Climate Change“
• What is Climate Engineering
• Why Climate Engineering?
• Physics of Climate – which knobs to turn?
• „Leverage“ of CE-Techniques
• Techniques to influence the climate, examples
• Even stranger ideas
• Conclusion
Literature
Bodansky, D. (1996), 'May we Engineer the Climate?', Climatic Change 33, 309-321.
Boyd, P. W. (2008), 'Ranking geo-engineering schemes', Nature Geoscience 1, 722-724.
Cicerone, R. J. (2006), Geoengineering: Encouraging research and overseeing implementation, National Academy of Sciences, Washington DC, chapter Climatic Change, pp. 221-226.
Crutzen, P. J. (2006), 'Albedo Enhancement by Stratospheric Sulfur Injections: A Contribution to Resolve a Policy Dilemma?', Climatic Change 77(3-4), 211--220.
Feichter, J. & Leisner, T. (2009), 'Climate engineering: A critical review of approaches to modify the global energy balance', The European Physical Journal - Special Topics 176(1), 81--92
Hegerl, G. C. & Solomon, S. (2009), 'Risks of Climate Engineering', Science 325, 955-956.
IPCC Climate Change 2014 Synthesis Report: https://www.ipcc.ch/site/assets/uploads/2018/02/SYR_AR5_FINAL_full.pdfLamb, H. H. (1971), 'Climate-Engineering Schemes to meet a Climatic Emergency', Earth-Science Reviews 7, 87-95.
Lenton, T. M. & Vaughan, N. E. (2009), 'The radiative forcing potential of different climate geoengineeringoptions', Atmos. Chem. Phys. 9, 5539-5561.
Robock, A. (2008), '20 reasons why geoengineeringmay be a bad idea', Bulletin of the Atomic Scientists 64(2), 14-18.
Society, The Royal (2009), Geoengineering the climate: Science, governance and uncertainty', Technical report, The Royal Society (RS Policy Document 10/09 ).
Wood, L.; Hyde, R. & Teller, E. (1997), 'Global Warming and Ice Ages: I. Prospects for Physics-Based Modulation of Global Change'.
Ross A & Matthews HD (2009) Climate engineering and the riskof rapid climate change. Environmental Research Letters 4, 045103 doi: 10.1088/1748-9326/4/4/045103
Web – Pages of Interest
Heidelberg Marsilius Project on Climate Engineering:http://www.climate-engineering.uni-hd.de/projects/
Asilomar Conference on Climate Intervention Techniques:http://www.climateresponsefund.org/
Report: Climate Engineering Responses to Climate Emergencies:http://arxiv.org/ftp/arxiv/papers/0907/0907.5140.pdf
Report of the Britischen Royal Society on CE:http://royalsociety.org/policy/publications/2009/geoengineering-climate/
David Keith‘s Home Page:http://keith.seas.harvard.edu/
Alan Robock‘s Home Page:http://www.envsci.rutgers.edu/~robock/
Intergovernmental Panel on Climate Change, IPCC:https://www.ipcc.ch/
YouTube CE-Playlist (CE-Related Video Clips):
http://www.youtube.com/playlist?list=PLF8369A27273314D8
Provided by: Andrew Lockley
Editors:Wilfried Rickels, Gernot Klepper, and Jonas DovernAuthors: Gregor Betz, Nadine Brachatzek, Sebastian Cacean, Kerstin Güssow, Jost Heintzenberg, Sylvia Hiller, Corinna Hoose, Gernot Klepper, Thomas Leisner, Andreas Oschlies, Ulrich Platt, Alexander Proelß, Ortwin Renn, Wilfried Rickels, Stefan Schäfer, Michael Zürn
From the Preface: …. Climate engineering raises numerous questions of fundamental importance: Which proposals are scientifically realistic? Can they be technically implemented, and how effective are they likely to be? What interactions and side-effects (e.g., in the climate system) are to be expected? How far do the efficiency advantages of individual measures go in a comprehensive macro-economic consideration? Will climate engineering become an endurance test for society and international relations? Is selective intervention in the Earth system ethically acceptable or justifiable?…
Dr. Georg SchütteState Secretary at the Federal Ministry of Education and Research (BMBF)
Interventions into the Climate
System?Assessing the Climate Engineering Debate
2011
Climate Engineering(frequently also called „Geoengineering“)
Intentional, large scale manipulation of the environment to counteract the unintended effects of anthropogenic climate change (D. Keith, 2000).
Absichtliche, großskalige Manipulation der Umwelt, um unerwünschten Effekten des anthropogenen Klimawandelsentgegenzuwirken (D. Keith, 2000)
Questions:
1) Is it actually possible and (if yes) affordable?
2) If 1) should be true, should we actually do it?
3) What are the side effects?
Geoengineering
Blasphemous - How can we dare to interfere with nature (or God)?
Hubris - How can we think that everything can beaccomplished by technology?
yet
We are modifying our climate already – not intentionally though - e.g. by releasing greenhouse gases to the atmosphere
The History of Weather Control
http://www.terraforminginc.com/weather-control/
Modifying Weather and Climate?
History of CE-Proposals (1)
Source: Climate engineering, Technical status, future directions, and potential responsesCenter for Science, Technology, and EngineeringUnited States Government Accountability Office, GAO, July 2011, GAO-11-71
September 29, 1921:End Of Iceberg Menace!
Nuke theArctic
Professor Julian Huxley. “Can We Atomize the Arctic?”, Jan. 1945
Wallace W. Ashley and Elmer V. Swan. According to them, Professor Julian Huxley had proposed the ideaof using nuclear bombs to melt thepolar ice caps. This would moderate our northern climate, eliminatingpesky cold snaps and opening up shipping across the top of the world.
History of CE-Proposals (2)
Source: Climate engineering, Technical status, future directions, and potential responses, GAO, July 2011, GAO-11-71
History of CE-Proposals (3)
Source: Climate engineering, Technical status, future directions, and potential responses, GAO, July 2011, GAO-11-71
0.8 ppm/Yr.
2.4 ppm/Yr.CO2-fraction in dry air, µmole/mole or ppm 400
320
340
360
380
The Atmospheric CO2 – Mixing Ratio During the last 60 Years
Scripps
Charles D. Keeling (1928-2005)
Mauna Loa, Hawaii, USA, 3397m a.s.l.
Source: World Meteorological Organization (WMO)
Cumulative Anthropogenic Carbon Emission to the Atmosphere 1850-2006 (in units of 109 tC)
Source: Carbon Dioxide Information Analysis Center (CDIAC.com) and values of atmospheric CO2 concentrations from Mauna Loa, as well as other locations.Carbon emissions from land use change and deforestation not included.
By 2011: 360 GtCequiv. to 1.31022JHeat Air by 3K Average Power: 510-3W
Global Annual Mean Surface Air Temperature Change
Recovery from volcanic eruptions dominates
Tropospheric aerosols mask
warming(global dimming)
Greenhouse gases dominate
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.pdf
The Challenge: Limit CO2-Growth
From: Klaus Lackner
Constant emissions at 2010 rate
10% of 2010 rate
0% of 2010 rate
33% of 2010 rate
Will We Manage to Reduce CO2 –Emissions?
Will We Manage to Reduce CO2 – Emissions?Example: Germany
Emission of greenhouse gases regulated by UNFCC
Mt CO2equiv.
100%
-31%
-40%
-55%
-70%
-95%
Radiative Climate Forcing Components
Source: IPCC-AR5, Fig. SPM.5
Problem beyond Gradual Changes: „TippingElements“
Timothy M. Lenton, Hermann Held, Elmar Kriegler, Jim W. Hall, Wolfgang Lucht, Stefan Rahmstorf, and Hans Joachim Schellnhuber(2008), Tippingelements in the Earth’sclimate system, PNAS 105(6), 1786–1793.
Climate subsystems where anthropogenic climate forcing could cause threshold-type behavior. small perturbation at a critical point qualitatively alters the future fate of the system. They could be triggered this century and would undergo a qualitative change within this millennium. (“Tipping Elements” in colour, overlain on global population density)
Climate Change – what to do?
Mitigation (Abwendung )
Rapid reduction of greenhouse gas emissions
Adaptation (Anpassung )
Relocate population, change structure of
agriculture, higher levies...
Climate Engineering
Reduction of solar radiation, removal of greenhouse gases
from the atmosphere, …
From: nature reports climate change, Vol. 4, p. 5, Jan. 2010,
Climate Engineering
• Serious discussions sinceabout the mid-1960ties (basic ideas shade sun, raise Earth‘salbedo)
• Increasing number of publications since about 2006
• Today there are manyproposed techniques, moreand more problems are noticed
- Geoforming, GeoengineeringBering straight - dam or diversion of large sibirian rivers forirrigation of central asia make the North Polar See ice-freeP.M. Borisov, Bulletin of the Atomic Scientists, March, 1969, pp. 43-48
- Weather and precipitation control for commercial andmilitary purposes (USA, UdSSR, China, 1950 ~ 1980)
As our civilization steadily becomes more mechanized and as ourpopulation density grows the impact of weather will become evermore serious. ...The solution lies in ... intelligent use of more preciseweather forecasts and, ideally, by taking the offensive throughcontrol of weather... I shudder to think of the consequences of a priorRussian discovery of a feasible method for weather control.Henry Houghton, MIT, 1957
Historical Background
- “Can We Atomize the Arctic?”, Jan. 1945, Prof. Julian HuxleyIdea of using nuclear bombs to melt the polar ice caps. This would moderate the northern climate, eliminating pesky cold snaps and opening up shippingacross the top of the world.
Geo-EngineeringIntentional change of climate parameters (to compensate forthe consequences of the antropogenic greenhouse effect)
P. CrutzenClimatic Change, 2006
34
Save The
World?
Forget about a future filled with wind farms and hydrogen cars. The Pentagon's top weaponeer
says he has a radical solution that would stop global warming now --no matter how much oil we burn.
Jeff GoodellRolling Stone
November 3, 2006
Attempting to Modifying the Climate -Why?
• Annual anthropogenic emissions: 9 Gt of carbon (equivalent to 33 Gt of CO2)
• It is clear that our climate is changing and will even more rapidlychange in the coming decades (if projections are correct).
• Stabilizing the atmmospheric CO2 level would require about 80% cutin global emissions.
• Negotiations to reduce CO2-emissions have had dissapointingresults
• In addition there is the danger of „Tipping Elements“
So our options appear to be:
• Adapt to climate warming or
• Actively change the climate
Some Question
s:
• Is CE technologicallyfeasible?
• Do we actually need to apply CE?
• Who decides on application of CE?
• Who decides on theglobal temperature?
Reasons why Geoengineering may be a Good Idea
1. Cool the planet
2. Reduce or reverse ice melting
3. Reduce or reverse land ice sheetmelting
4. Reduce or reverse sea level rise
5. Increase plant productivity
6. Increase terrestrial CO2 sink
Robock et al. 2009, GRL
Reasons why Geoengineering may be a Bad Idea
1. Effects on regional climate (temperature, precipitation, other para.)2. Continued ocean acidification3. Rapid warming when CE stops 4. Stratospheric Ozone depletion5. Effects on plants (less solar radiation and lower direct/diffuse ratio)6. Enhanced acid precipitation7. Whitening of the sky (but nice sunsets)8. Effects on cirrus clouds as aerosols fall into the troposphere9. Less solar radiation for solar power (especially less direct radiation)10. Environmental impacts of aerosol injection (production and delivery)11. There’s no going back (how rapidly could effects be stopped?)12. Human error13. Undermining emissions mitigation. 14. Cost15. Commercial control of technology16. Military use of technology17. Conflict with current treaties18. Control of the thermostat?19. Question of moral authority20. Unexpected consequences
Robock, Alan, 2008: 20 reasons why geoengineering may be a bad idea. Bull. Atomic
Scientists, 64, No. 2, 14-18, 59, doi:10.2968/064002006.
Two Types of „Climate Engineering“
2) Carbon cycle engineering (CDR)• Direct capture of CO2 from air• Ocean fertilization• Alkaline material into the ocean• bury charcoal „Bio-char“• Alkaline material into the soil
Slow and expensive,But the cause (the CO2) is actuallyremoved from the air
1) Solar radiation management (SRM)• Sulfate aerosol in the stratosphere• Cloud whitening• Change surface albedo of Earth
and/or ocean• Special particles in the mesosphere• Scatterers in space
Fast, cheap, imperfect and unsafe, littleinfluence on atmospheric CO2
Greenhousegases reduceIR-emission
The „Leverage“ of CE - Techniques
Leverage Ratio:
Lev
Mass of Greenhouse Gas the effect of which is neutralizedR
Mass of material needed for the measure
Examples:1) Mankind emitted about 370 Gt carbon (1357 Gt CO2) since 1750. About 1 Mt of sulfur would be required to offset the warming effect of that much CO2 (for one year) Rlev 1.4106
2) In order to induce ocean uptake of the same amount of CO2 about 3100 Gt of CaCO3 (carbonate) would be required Rlev 0.44
(CO2 + CaCO3 + H2O Ca(HCO3)2)
3) Iron Fertilization of the ocean requires 1 atom of Fe for 105 atoms of C in algalbiomass (Redfield ratio) mass ratio Rlev 2.5104
Climate-Engineering (Geo-Engineering)
Adapted from Thomas Leisner42
04 4S A
A A
S 2 1 A2LT 2 T
2 2
Simple Global Radiation Balance:
• Scattering surfaces in space
Change of Solar constant (S0)Increase of Planetary Albedo (A) Reduction of atmospheric (IR) absorption (A)
• Scattering surfaces in thestratosphere(e.g. sulfate aerosol)
• Absorber in the Stratosphere
• Scattering surfaces in theTroposphere(e.g. whiter clouds)
• Change of Albedo of Land-and Ocean – surfaces
• Geochemical CO2 –sequestration in the ocean
• Ocean Fertilization
• CO2 – sequestration from theair (air capture)
• CO2 – uptake by terrestrialecosystems(new forests, biochar)
Climate-Engineering
Climate Engineering Techniques ...
T.M. Lenton and N.E. Vaughan, The radiative forcingpotential of different climate geoengineering options, Atmos. Chem. Phys., 9, 5539–5561, 2009
Are there no better ideas?
Keith, David, 2001: Geoengineering, Nature, 409, 420. 45
SRM
CDR
r
rE
ME
1. Site: 1. Lagrange-point (L1-point) (unstable)
2. Implementation: Cloud of many thin discs, stabilised by
modulation of radiation pressure, disk size: ~1 m,
Weight: 1g, Number: 1.61013
3. Optical Design: Transparen refracting material, low areal
density, total mass: 20 Mt
4. Transport: elektromagnetic accelerator,
Ionen thrusters, Cost: 50 $/kg (zur Zeit 20000 $/kg)
Total cost several Trillion $
(100 billion $/a)
Change of the Solar constant: (Angel, PNAS, 2006)
How much shading is Needed?
Example: We whish to offset temp. change due to 2xCO:
Primary forcing: 3.7 W (there will be little or no feedback if wecompensate primary forcing)
Incident Radiation on Earth: 1372 W/m2
minus reflection (A=0.7): 960 W/m2
We need to shade an area of: 3.7/960 x cross section of Earth (πR2)
0.0038 x 1.29108 km2 5105 Km2
Assumin a sheet of 0.1 mm thickness would have a volume of 5107
m3
Stratospheric Particle Injection – Inspired by VolcanicEruptions
Explosive
NET COOLING
Stratospheric aerosols
(Lifetime 1-3 years)
Ash
Effectson cirrusclouds
absorption (IR)
IR
Heating
emission
emission
IR Cooling
More
Downward
IR Flux
Less
Upward
IR Flux
forward scatter
Enhanced
Diffuse
FluxReduced
Direct
Flux
Less TotalSolar Flux
Heterogeneous LessO3 depletion Solar Heating
H2S
SO2
NET HEATING
Tropospheric aerosols
(Lifetime 1-3 weeks)
Quiescent SO2 H2SO4
H2SO4
CO2
H2O
backscatter
absorption
(near IR)Solar Heating
More Reflected
Solar Flux
Indirect Effects on
Clouds
Stratospheric Sulfate Aerosol
from a presentation by Alan Robock, Heidelberg 2010 49
Mount Pinatubo (1)Eruption June 1991
before
after
Photo: NASA
WMO (2003)
NASA
Mount Pinatubo (2)
Effects of Mount Pinatubo, Philipines volcanic eruption (June 1991) on the radiation balance and on the hydrological cycle as an analog of geoengineering
Trenberth and Dai (2007)Geophys. Res. Lett.
from a presentation by Alan Robock, Heidelberg 2010
Mount Pinatubo (3)
52
Reflection
Surface
Optimal Particle Size?
Small Particles More Surface/Mass (less mass needed)
But at size parameter x < 1 rapidlydecreasing scattering efficiency
But more scattering in backward direction
also: particles settle less rapidly
However, the useful lifetime of particles is also limitedby the stratospheric circulation
1 large particle, 8 small particles, radius r/2, same total volumeradius r but twice the total surface area
Why Endanger Particles the Ozone Layer? (1)
Katalytic Ozone destruction:
X + O3 XO + O2
XO + O X + O2
net: O + O3
2O2
X/XO: „Katalyst“(e.g. OH/HO2, NO/NO2, Cl/ClO, Br/BrO)
HOX (Bates and Nicolet, 1950)NOX (Crutzen, 1970)ClOX (Stolarski and Cicerone, 1974;
Molina and Rowland, 1974)
Katalytic ozone destruction explainsdifference between measured (lower) and calcualted (ca. 3x higher) O3 –concentrations and their dependence on.
Particles?
How could Particle Sedimentation be prevented?
Prinziple of the „Light-Mill“(Lichtmühle)?
Radiation-source
Reflecting cold
Black warm
Wrong explanation 1:
Radiation pressure, Photons have momentum (p=E/c) but it is too small:
solar radiation: 10-4 W/cm2 3·1014 Photons/s, Momentum of a photon 10-27 kgm/s Force 3·10-13 Newtons (for 1 cm2)
Moreover: Momentum transfer to black surface: p, reflecting surface: 2p wrong rotational direction
Wrong explanation 2 (Wikipedia):
Warm layer of air at black surface provides larger pressure ...
low altitude Stratocumulus- clouds cover about 30% of the sea surface
A 2% enhancement of their albedo would provide a radiative forcing of -4 W/m². (Latham 2002)
Enhanced Cloud Reflectivity due to Ship Traffic
Scheme by John Latham (University of Manchester, NCAR) and SteveSalter (University of Edinburgh) to increasing cloud albedo by injecting more sea salt cloud condensation nuclei into marine stratus clouds.
from a presentation by Alan Robock, Heidelberg 2010
Cloud Whitening
57
more condensationnuclei same amount of condensing waterproduces more (and smaller) clouddroplets more surface area more scattering higher cloud
albedo Cools Earth
Primary Susceptible Regions for Cloud Whitening
Jones et al. 2009
Spatial and temporal distribution of forcing caused by x4 CO2
(negative) Radiation forcing due to stratospheric aerosol
Govindasamy et. al. Global and Planetary Change 37 (2003) 157–168
Problem: Side-Effects regarding the Spatial and Temporal Distribution of Climate Forcing
Govindasamy et. al. Global and Planetary Change 37 (2003) 157–168
Consequences of CE Offseting 2xCO2 on the Global Temperature Distribution
oC
Consequences of CE on Global Precipitation Patterns
Change in daily precipitation column, (mm), J. Feichter et al. submitted
Blackstock et al. 2009
CE-measuresoffsetting the meanglobal temperature risecaused by 2xCO2
Ocean (Iron) Fertilization: Enhance CO2-Uptake
Redfield Ratio: C:N:P:Fe 106:16:1:0.001 (e.g. Sarmiento&Gruber 2006)
5
C6.6
N
C1
P
C10
Fe
S.W. Chisholm, Nature 407, (2000)
CO2 – Uptake in the Ocean: The “Biological Pump”
Boyd, 2007
… it is difficult to see how ocean iron fertilization with such a low Csequestered: Feadded
export efficiency would easily scale up to solve our larger global C imbalance problems…
It would scale up to a region of 109 km²—more than an orderof magnitude larger than the entire area of the Southern Ocean.
K. O. Buesseler et al., Science 2002 and 2008
Side Effects:
enhanced production of greenhouse gases like DMS, COS, organic halogen species
M. Lawrence, Science, 2001
CO2 Sequestration by Fertilization of Suitable Ocean Areas
CO2 – Removal from theAtmosphere
Art: Stonehaven CCS, Montreal,
from Klaus Lackner, Columbia University
“Synthetic Tree”
Unconventional CE-Techniques
„Immaterial“ transport of Sulfur to the stratosphere
Terramobile – LASER: Make Aerosol out of Air
Bubbles in the ocean:Bright water
And more ...
Climate Engineering is based on innovative technology
Enhancing the Natural Sulfur Cycle to Slow Global Warming?
Wingenter O.W., Elliot S.M., Blake D.R. (2007),New Directions, Atmospheric Environment, 41 (34), 7373-7375, ISSN: 13522310, +Atmos. Env. 2008, 42, (19), 4806-4809, ISSN: 13522310.
The Idea:
Iron-fertilize about 5% of the southern ocean area (1nM, 3 x per week)(don‘t care about C-fixation)
Enhance dimethyl-slufide (DMS) concentration by 20%
Enhanced DMS leads to +10% CCN (since ½ of CCN are due to DMS-oxidation)
≈0.8% albedo increase due to „cloud whitening“ (from 46.0% to 46.4%)
Negative forcing of 3 W/m2 (summer)
See also: „The Iron CLAW“ (M. Harvey, Environmental Chemistry 4 (6), 396-399, 2007)
Conclusions (Unconventional Techniques)
• There are many new ideas to facilitate CE
• Some of them may actually work
• It is likely that more ideas will emerge ... We should not prematurely settle with the presently
discussed techniques
• In fact it could be that – should CE measures ever beimplemented – none of the presently discussedtechniques are actually used
Efficiency – Cost – Safety - Timeliness of CE-Measures
source: Geoengineering the climate: Science, Governance and Uncertainty,The Royal Society, 2009
Robock et al. JGR 2008
What Happens if we stop Climate Engineering Measures?
How to Test Climate Engineering Measures?
The Role of Field Trials
Sooner or later, the improvement of our understanding of CE technologies will necessitate large-scale field trials that come very close to an actual application of the technologies. Such field trials should be accompanied by comprehensive monitoring programs. Even if we assume the best possible design for large-scale trials, unequivocal identification and quantification of the effects and side-effects of particular technologies would take many years or even decades. In the course of a field trial extending over such a long period, apparent effects and side-effects unrelated to the application of the technology would also occur.
The conduct of such a large-scale trial without the occurrence of significant social and political impacts must be considered one of the major challenges of climate engineering.
Questions beyound Technological Feasibility and Cost of CE-Measures
CE in cases of severe emegency (Crutzen)?
CE could give a feeling of false scurity (we continue as usual, apply CE if thereshould be a problem)
CE could be used as excuse for neglecting mitigation and adapatation?
Some CE-measures appear to be very cheap in comparison to mitigation
Danger of unilateral application?
Ethics of CE?
Legal questions (precautionary principle, compensation for damages)
Political enforceability?
Who decides on termination or continuation of CE – measuresin case of problems?
Who can guarantee the continuation of CE-measures over centuries (or millennia)?
What happens if CE-measures are (or have to be) terminated?
Teilprojekte (Work Packages)
A: Umweltphysik: Profs. Leisner, Platt, Aeschbach, S. Müller-Klieser
B: Philosophie: Prof. M. Gessmann, H. Fernow
C: Humangeographie: Prof. H. Gebhardt, T. Wiertz
D: Umwelt-Ökonomie: Prof. T. Goeschl, D. Heyen
E: Psychologie: Prof. J. Funke, S. Wüstenberg
F: Internat. öffentl.Recht: Prof. R. Wolfrum, D. Reichwein
G: Politische Wissenschaft: Prof. S. Harnisch, S. Uther
H: Politische Ökonomie: Prof. S. Walter, W. Dietz
Marsilius Projekt der Univ. Heidelberg:„The Global Governance of Climate Engineering“ RNZ v. 1.12.2009
Really Roughly Estimated Cost of CE-measures(109 US$ per W/m2)
Reduction of CO2 Emission: 200 (forcomparison)
Urban albedo reduction: 2000
Desert albedo reduction: 1000
Cloud Whitening:0.135 (or more)
Stratospheric S-Aerosol: 2-67
Space Shades:1700 (L1)
Source: Rickels et al. 2011 (BMBF-Report)
Summary
• Climate modification measures are already being applied to our planet (Emission of greenhouse gases, deforestation, etc.) – although notdeliberate.
• The idea to add deliberate Climate Engineering to these measures mayappear blasphemic, however there might be emergency situationswhere CE may be the only solution (e.g. because of time scales).
• CE might not be feasible at all or much more difficult (and expensive) to implement than anticipated.
• There are great dangers associated with CE:- Moral dangers – less incentive for mitigation(„Climate Sceptics“: „Climate change is not a problem and CE is the solution“)
- Side effects and unwanted effects- Political disturbances
• However, research can answer some of these questions and reducesome of the uncertainties.
“Time Magazin24. 3. 2008