Earth Radiation Management strategies as alternatives to SRM techniques

Renaud de_RichterInstitut Charles Gerhardt Montpellier

UMR5253 CNRS-UM2 ENSCM-UM1 Ecole Nationale Supérieure de Chimie de Montpellier, 8 rue de l’Ecole Normale

34296 Montpellier Cedex 5, France

CEC14, Climate Engineering Conference 2014, Critical Global Discussions18-21 August, Berlin, Germany. Wednesday August 20th, 2014. Session:

Novel SRM Techniques: Cirrus Clouds Thinning and Marine Sky Brightening

SRM (sunlight reflection methods) SRM aims to reduce incoming Shortwave radiation

Earth Radiation ManagementThe notion of ERM was introduced in 2011 by Mitchell et al, with Modification of Cirrus Clouds to Reduce Global Warming

Mitchell DL, Mishra S, & Lawson RP. Cirrus clouds and climate engineering: new findings on ice nucleation and theoretical basis. Planet Earth, 2011, 257-288.

In (very) short: cirrus clouds trap Longwave radiation below them and contribute to warm the Earth by back radiation; dissipating cirrus clouds would increase outgoing longwave radiation, thus global warming is reduced.

Same thing for CO2: if we reduce it’s concentration we allow more heat energy (IR radiation) to escape out to the space.

=> Thus, for Mitchell et al, CDR belongs, together with Cirrus Clouds reduction, to ERM techniques which target to increase outgoing Longwave radiation

CDR

dissipating Cirrus clouds=> reducing

back radiation

For Mitchell et al, CDR belongs, together with Cirrus Clouds reduction, to ERM techniques which goal is to increase outgoing Longwave radiation

ERM aims to increase outgoing LW

SRM aims to reduce incoming SW

cloud whitening aerosols

Lagrange L1 reflectorsorbital mirrors

sea reflectivity land albedo

LandOceansurface

radiation

GHGR

+ Night Sky radiative cooling

By which mean can we enhance outgoing Earth LW radiation?

Let us start with thermals

Thermals: birds and sailplaners (gliders) know them well

one possibility for generation of thermals

urban heat islandalbedo change

Aufwindkraftwerk described in 1931 by German author Hanns Günther. The prototype was built under the

direction of a German engineer, Jörg Schlaich in Manzanares, Ciudad Real,

150 km south of Madrid Spain. The project was funded by the German

government and the power plant operated for 7 years.

Greenhouse effect+ Stack effect

Cost-competitive energy

if height > 700mArchitects say >1500m

height no problem!

A prototype with 200m high chimney built and fully tested 1982-1989

Updrafts generated by solar chimneys

the hot air is transferred from the surface and released much

higher, where it still rises high in the

troposphere where some of the heat can escape out to

the space

Something else on which we can act to increase OLWR?

CO2

CDR

Figure from NASA

DAC: CO2 direct capture in the Atmosphere• Adsorption on solids (similar to current methods being tested

for Carbon Capture & Sequestration)• Adsorption into alkaline solutions (or alkaline solid resins)• Resulting material must be transported and sequestered• Costs could be competitive since plants can be located near

the sequestration location…• The energy required

to capture 4 CO2 emits 1 CO2 (if done using FFPP)

All methods require energy to move air through the adsorption system EXCEPTED ONE!

http://www.sciencedirect.com/science/article/pii/S1364032112005680

In 2013 we proposed to use artificial trees from Lackner, with

his alkali solid resin, in synergy with a Solar

Updraft ChimneyDAC +25% efficiency using renewable energy

no more fans (investment savings & more energy savings) + other synergies

(resin regeneration…)

Do we forget something on which we can act to increase OLWR?

other GHGs

GHGR

Figure from NASA

Carbon dioxide removal (CDR) techniques aim to remove CO2, a major greenhouse gas, from the atmosphere, allowing more outgoing long-wave to escape (less back radiation).

… photocatalysis may be applied successfully to eliminate or transform all major long-lived well mixed GHGs, but also

soot, tropospheric ozone and other short-lived climate forcers.

by photocatalysis!All other GHGs, can also be removed from the atmosphere…

http://www.sciencedirect.com/science/article/pii/S1389556711000281

But such approaches are still in development

Next way of enhancing outgoing heat radiation

Latent heat

release

A solar chimney variant at the equator

Outside air temperature 35°C, 85% relative humidity. Sea water at 30°C is warmed to 85°C by the sun in black tubing and sprayed at the chimney entrance so has to obtain hot air 60°C / 95% RH The excess water is directed to a saline (salt deposit).

At some height inside the tower, an efficient heat exchanger with the outside air temperature cools the air => clear water condensates (20-30%, useful byproduct?) and the heat of condensation releases heat, warming the air above, making the air lighter… This warmed air in the tower rises and sucks the air column below by increased buoyancy. After the exit out of the tower, the warm and humid air still rises until the condensation releases more latent heat that escapes to the outer space.

Africa

Arabic peninsula

Red Sea averagesurface temperature

in August >30°C

Equatorial Solar chimney (Denis Bonnelle) with piece of cake collector

(initial Drawing: Janning Petersen)

Salt depositsea water is pumped, warmed and spayed

Next way of enhancing outgoing heat radiation

Latent heat

release

tornadoes

atmospheric vortex engine concept from Louis Michaud

(figure by Charles Floyd)

Hurricane Heat Engine close of a Carnot cycle

(image from Emmanuel)

http://vortexengine.caImage from Aqua CERES

Artificial

Are there other methods to help thermal infrared radiation to escape more easily to

the outer space?

YES ! There are many devices able to enhance atmospheric convection

Anymore things to enhance thermal IR out to space?

Figure from NASA

Heat Pipes or Thermosyphons

Half million thermosyphons

are already used

to prevent permafrost

melting

0IL

Half million heat pipes are used to prevent permafrost melting

along roads, railways, oil pipelines… in Siberia, Tibet, Alaska…

Are there credible proposals against the vicious cycle due to loss of polar reflectivity (albedo)?

A melting glacier surface cannot raise its temperature and thus not increase outgoing longwave radiation; any surplus of radiation is thus used for additional meltingOerlemans, J. A projection of future sea level. Climatic change,  1989, 15(1-2), 151-174.

D. Bonnelle has proposed a device transferring sea water in altitude where chilling air makes ice, which is returned to the ocean.

The latent heat of freezing warms the air inside a tall tower anddrives turbines to produce renewable electricity.

The hot air coming out of the chimney enhances atmospheric convection… and the humidity released will produce high albedo fresh

snowhttp://data.solar-tower.org.uk/thesis/2004-Denis-BONNELLE_Solar-chimneys_Energy-towers_etc.pdf

Both a SRM technique by ALBEDO effect and a ERM method by heat transfer from the ocean to the atmosphere

D. Bonnelle also proposed a giant closed heat pipe thermosyphon (book ISBN: 978-2729854072)

top ofa hill

Proposal by: S. Zhou, P.C. Flynn; Geoengineering downwelling ocean currents: a cost assessment.

Clim Change 2005, 71(1-2), 203–220

Both a SRM: by ALBEDO effect and ERM: by heat transfer from the ocean to the atmosphere

SNOW CANONS

Other ways of enhancing outgoing IR radiation?

Emitted by surface and preferably by the atmospheric window

by the atmospheric window8-13 µm

Complementarity between cool roofs…reflective coatings on top of buildings => .SRM

…and night sky radiative coolingradiant materials on top of buildings => ERM

University of Central FloridaParker, D. S., Sherwin, J. R., Hermelink, A. H., & Center, F. S. E. (2008). NightCool: A Nocturnal Radiation Cooling Concept. 2008 ACEEE Summer Study on Energy Efficiency in Buildings, 209-222.

Improved by cold water storage tank

=> reduces even more the cooling costs

Remark: SRM is only possible 12 h/day… SRM

or on one half of the planet at the same time

Outgoing longwave radiation, March 18, 2011 from Aqua CERES data

…meanwhile outgoing Longwave radiation is permanent

Some recentprogress done by researchers in Stanford and Harvard universities

Geoengineering SRM diverts sunlight radiation back into space by increasing albedo, increasing short wave radiation reflection (parasol effect): thus less light reaches the Earth surface.

But blocking the sun will not help the humans to stop spewing billions of tons of CO2 into the atmosphere

ERM consists to increase longwave outgoing radiation, by the use of atmospheric convection devices, which are a full set of unusual renewable energies, which allow more heat to leave the Earth surface and at the same time cool the Planet, provide humans with all their energy needs and progressively de-carbonize the energy sector

Pros and Cons of SRM and ERMSRM ERM

FAQ• Q1: isn’t it like science fiction?

Science fiction??? what about orbital mirrors?and reflector arrays at the Lagrange (L1) point? and millions of artificial trees? …and… and …

• Q2: if so perfect and so good, … why aren’t they already built and in operation?

Behind “atmospheric convection devices”, the science is strong and they are proven technologies!They are worth being studied to help cool the Earth by ERM

Answer later, after the talk…

• Q3: are there complementarities between: SRMERM & ?Yes! Some examples, after the talk…

More information on

Open Access: http://www.sciencedirect.com/science/article/pii/S1364032113008460

Thank you for your attention

QUESTIONS?

Additionnal slides

SRM Advantages: It can be cheap Rapid deployment is possible It allows to “buy time” It is often presented as a “last resort”, in case

of climate emergency

SRM Drawbacks: Imperfectly compensates for CO2 driven warming Doesn’t stop ocean acidification, nor CO2 emissions May introduce new environmental risks like affecting

precipitation patterns and volumes... Treats the symptoms rather than cure the illness

Comments on SRM

Solar updraft tower and downdraft energy tower are under industrial development in the US (Texas & Arizona)

Atmospheric vortex engine found funding for the next prototypes in Canada. The development plan is going on.

Heat pipes are widely used in several industrial sectors and prevent permafrost melting on the Trans Alaska Pipeline and the Qinghai-Tibet Railway.

Radiative cooling technologies and new materials are available for heat transfer by the atmospheric window during clear sky nights.

Future ERM prospects

How can we cool the Earth surface?

Some examples of convection towers and devices:• http://en.wikipedia.org/wiki/Energy_tower_(downdraft)

http://www.solarwindenergytower.com/the-tower.html• http://en.wikipedia.org/wiki/Solar_updraft_tower

http://www.solar-updraft-tower.com/en#commercial_sut/index http://www.theengineer.co.uk/energy-and-environment/news/per-lindstrand-

plans-1km-high-inflatable-solar-energy-chimney/1017508.article• http://en.wikipedia.org/wiki/Vortex_engine http://www.fmrl.gatech.edu/drupal/projects/solarvortex Georgia Institute of Technology

http://phys.org/news/2012-12-entrepreneur-funding-tornado-power.html• http://en.wikipedia.org/wiki/Radiative_cooling Harvard University, Cambridge

http://www.pnas.org/content/early/2014/02/26/1402036111.short • http://en.wikipedia.org/wiki/Heat_pipe

There exist many convection devices are able to break the GHGs insulating envelope surrounding the Earth and create thermal bridging, thus increase outgoing longwave radiation

Conclusion: by progressively replacing fossil fuel power plants, these unusual renewable energies will produce electricity with no CO2 emissions and thus will reduce global warming, cool the Planet, stop sea level rise, stop ocean acidification…