Fwd: White/Cool Roofs Memo to MEF (Major Economies Forum)

[Ken Caldeira]

Should albedo be taken into account in meeting CO2 emissions reduction targets?

[ I assume that since Art's email was sent to a broad group, there is no presumption of confidentiality.]

___________________________________________________
Ken Caldeira

Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA

kcal...@ciw.edu; kcal...@stanford.edu
http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1 650 704 7212; fax: +1 650 462 5968  

---------- Forwarded message ----------
From: Arthur Rosenfeld <Aros...@energy.state.ca.us>
Date: Thu, May 14, 2009 at 5:05 PM
Subject: White/Cool Roofs Memo to MEF (Major Economies Forum)
To: Anthony Eggert <AEg...@arb.ca.gov>, Bart Croes <BCr...@arb.ca.gov>, "Mary Nichols," <MNic...@arb.ca.gov>, John Harte <JHa...@berkeley.edu>, Matthew Elliott <Mat...@ceaconsulting.com>, Cathy Zoi <cath...@climateprotect.org>, And...@climateworks.org, H...@climateworks.org, Michael MacCracken <MMac...@comcast.net>, jo...@ef.org, Arthur Rosenfeld <Arosenfe.H...@energy.state.ca.us>, Cheri and John Holdren <John_H...@harvard.edu>, Steve Chu <The.Se...@hq.doe.gov>, Alan Meier <AKM...@lbl.gov>, Hashem Akbari <H_Ak...@lbl.gov>, Jayant Sathaye <JASa...@lbl.gov>, Mark Levine <MDLe...@lbl.gov>, Ken Caldeira <KCal...@stanford.edu>, S...@stanford.edu
Cc: Devorah / Devi Eden <DEden.HQ...@energy.state.ca.us>, David Hungerford <Dhungerf.H...@energy.state.ca.us>, Pat Flint <Pflint.HQ...@energy.state.ca.us>



In preparation for the Dec. climate change summit in Copenhagen, the US
has been working with MEF (Major Economies Forum), where it has been
challenged to set a CO2 emissions goal for 2020 of 20% below 1990.    At
a recent meeting of MEF, John Holdren (Pres. Science Advisor) and Energy
Sec’y Steve Chu suggested informally that the US might consider a
commitment to white/cool roofs, and this idea excited some hallway
interest from the UK, China, India, Brazil, …

Accordingly Hashem Akbari and I decided to write the attached memo to
our Climate Team at the State Department.    Pls. take a look and
consider whether you have high-level contacts with any of those
countries, or more likely with Todd Stern and Jonathan Pershing at
State.   If so, we’d be grateful for some support.

Cheers,  Art


============================
Art Rosenfeld,    Commissioner
California  Energy  Commission
1516 9th St,. Sac'to CA 95814
(916)654-4930,    fax 653-3478
Cell-phone         (916)205-3965
Berkeley Home  (510)527-1060
ARos...@Energy.State.CA.us
     www.Energy.CA.gov
http://www.energy.ca.gov/commission/commissioners/rosenfeld.html
===========================================================================

[Ray Taylor]

I'm troubled that the authors quote Ashkabari's figues on tonnes of
CO2 equivalent, which seems to imply albedo INSTEAD of CO2. I would
much prefer to see W/sq m and a BOTH AND commitment.

This is exactly the kind of thing that would bring geoengineering into
disrepute, ie geoengineering being seen as a way to avoid serious
reductions in petrochemical burning for heat, power and short/medium-
distance transport.

Petrochemicals are too precious to burn, except for long distance
travel. Future generations (2040-2100) will need them for other
things.

Ray T

[Alvia Gaskill]

Albedo should only be taken into account in meeting emission reduction targets if the concerns I discuss below are properly addressed.

 

http://www.nature.com/climate/2008/0812/full/climate.2008.122.html

 

I brought this up before several weeks ago and have some other information to share later this weekend, but as the above article indicates, the atmospheric lifetime of CO2 emitted today is variable, with about half gone in 30 years, 30% in several hundred and the remainder taking up to 30,000 years to be removed from the atmosphere.

 

Unlike a cap and trade program where actual emissions are being prevented from entering the air, the albedo program would only temporarily offset the warming due to the GHGs already in the air in the year the surface is put into service.  The effectiveness wouldn't increase over time as the solar forcing would remain constant even as the GHGs continue to pile up.

 

While the calculations presented appear correct, they only apply for the time period that the albedo of the surface is as white as anticipated and that also includes the lifetimes of the roof and the building or road surface.   If the roofs and road surfaces are not maintained or they cease to exist and are not replaced by sunlight reflecting surfaces of equal albedo, then the millions and billions of tons of offsets cited will no longer apply. 

 

Practically speaking, the offsets can only be projected for about 30-50 years, the lifetime of most buildings constructed today.  Because of that, at most half of the CO2 forcing can be permanently offset.  We'll have to leave it up to air capture or some new set of buildings and roads to continue the offset for the remaining 200 years (75% CO2 gone).  I don't think obsessing on the final 20% of CO2 is meaningful.  Either we will have perfected air capture by the end of the 21st century or we never will. 

 

Attempting to apply this to offsetting methane or nitrous oxide forcing or other GHGs would, I believe be equally problematic due to their variable lifetimes.  If one wanted to make this a program relevant to gases of lifetimes comparable to that of the roofs, then methane is the one to use, not CO2 as all of the methane emitted today will be gone in about 20 years, about the lifetime of a roof.

 

In earlier representations of this, it was suggested that carbon credits could be counted based on the increased whitening of these surfaces.  In the present document, temporary tax credits are proposed, while the carbon credit potential is simply mentioned as an example of its value.  Whatever the final form, the timescales of CO2 and surface lifetime have to be considered as does the logistics of ensuring that the surfaces continue to meet the original requirements.  In the U.S., this could take the form of the annual property tax assessment where "the man" drives by your home or business and would note the change in albedo from previous years.

 

I agree that CO2 equivalent is a murky term.  If CO2  or methane offsets were to be sold, they would have to be based on a single gas only and amortized over the agreed upon lifetime of the surface.  Parties could agree, however, to assume that all the forcing is CO2 forcing.

 

The overall result of the proposed global program would still be beneficial without taking into account any CO2 offsets.

 

http://money.cnn.com/2007/05/09/pf/gas_myths/index.htm

 

Requiring the purchase of automobiles with light or white colored roofs as suggested in a government program would result in minimal savings as even run all the time, A/C uses about 1 mpg gas equivalent.  The bleed through of heat into the passenger compartment is different with a black or dark roofed vehicle, but probably not significant.  This should be studied further before such a program is proposed. 

 

News Feature

Nature Reports Climate Change
Published online: 20 November 2008 | doi:10.1038/climate.2008.122

Carbon is forever

Carbon dioxide emissions and their associated warming could linger for millennia, according to some climate scientists. Mason Inman looks at why the fallout from burning fossil fuels could last far longer than expected.

Distant future: our continued use of fossil fuels could leave a CO₂legacy that lasts millennia, says climatologist David Archer

123RF.COM/PAUL MOORE

After our fossil fuel blow-out, how long will the CO₂ hangover last? And what about the global fever that comes along with it? These sound like simple questions, but the answers are complex — and not well understood or appreciated outside a small group of climate scientists. Popular books on climate change — even those written by scientists — if they mention the lifetime of CO₂ at all, typically say it lasts "a century or more"¹ or "more than a hundred years".

"That's complete nonsense," says Ken Caldeira of the Carnegie Institution for Science in Stanford, California. It doesn't help that the summaries in the Intergovernmental Panel on Climate Change (IPCC) reports have confused the issue, allege Caldeira and colleagues in an upcoming paper in Annual Reviews of Earth and Planetary Sciences². Now he and a few other climate scientists are trying to spread the word that human-generated CO₂, and the warming it brings, will linger far into the future — unless we take heroic measures to pull the gas out of the air.

University of Chicago oceanographer David Archer, who led the study with Caldeira and others, is credited with doing more than anyone to show how long CO₂ from fossil fuels will last in the atmosphere. As he puts it in his new book The Long Thaw, "The lifetime of fossil fuel CO₂ in the atmosphere is a few centuries, plus 25 percent that lasts essentially forever. The next time you fill your tank, reflect upon this"³.

"The climatic impacts of releasing fossil fuel CO₂ to the atmosphere will last longer than Stonehenge," Archer writes. "Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far."

The effects of carbon dioxide on the atmosphere drop off so slowly that unless we kick our "fossil fuel addiction", to use George W. Bush's phrase, we could force Earth out of its regular pattern of freezes and thaws that has lasted for more than a million years. "If the entire coal reserves were used," Archer writes, "then glaciation could be delayed for half a million years."

Cloudy reports

"The longevity of CO₂ in the atmosphere is probably the least well understood part of the global warming issue," says paleoclimatologist Peter Fawcett of the University of New Mexico. "And it's not because it isn't well documented in the IPCC report. It is, but it is buried under a lot of other material."

It doesn't help, though, that past reports from the UN panel of climate experts have made misleading statements about the lifetime of CO₂, argue Archer, Caldeira and colleagues. The first assessment report, in 1990, said that CO₂'s lifetime is 50 to 200 years. The reports in 1995 and 2001 revised this down to 5 to 200 years. Because the oceans suck up huge amounts of the gas each year, the average CO₂ molecule does spend about 5 years in the atmosphere. But the oceans also release much of that CO₂ back to the air, such that man-made emissions keep the atmosphere's CO₂ levels elevated for millennia. Even as CO₂ levels drop, temperatures take longer to fall, according to recent studies.

"The climatic impacts of releasing fossil fuel CO₂ to the atmosphere will last longer than Stonehenge, longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far."

David Archer

Earlier reports from the panel did include caveats such as "No single lifetime can be defined for CO₂ because of the different rates of uptake by different removal processes." The IPCC's latest assessment, however, avoids the problems of earlier reports by including similar caveats while simply refusing to give a numeric estimate of the lifetime for carbon dioxide. Contributing author Richard Betts of the UK Met Office Hadley Centre says the panel made this change in recognition of the fact that "the lifetime estimates cited in previous reports had been potentially misleading, or at least open to misinterpretation."

Instead of pinning an absolute value on the atmospheric lifetime of CO₂, the 2007 report describes its gradual dissipation over time, saying, "About 50% of a CO₂ increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within a few centuries. The remaining 20% may stay in the atmosphere for many thousands of years." But if cumulative emissions are high, the portion remaining in the atmosphere could be higher than this, models suggest. Overall, Caldeira argues, "the whole issue of our long-term commitment to climate change has not really ever been adequately addressed by the IPCC."

The lasting effects of CO₂ also have big implications for energy policies, argues James Hansen, director of NASA's Goddard Institute of Space Studies. "Because of this long CO₂ lifetime, we cannot solve the climate problem by slowing down emissions by 20% or 50% or even 80%. It does not matter much whether the CO₂ is emitted this year, next year, or several years from now," he wrote in a letter this August. "Instead ... we must identify a portion of the fossil fuels that will be left in the ground, or captured upon emission and put back into the ground."

Slow on the uptake

Unlike other human-generated greenhouse gases, CO₂ gets taken up by a variety of different processes, some fast and some slow. This is what makes it so hard to pin a single number, or even a range, on CO₂'s lifetime. The majority of the CO₂ we emit will be soaked up by the ocean over a few hundred years, first being absorbed into the surface waters, and eventually into deeper waters, according to a long-term climate model run by Archer. Though the ocean is vast, the surface waters can absorb only so much CO₂, and currents have to bring up fresh water from the deep before the ocean can swallow more. Then, on a much longer timescale of several thousand years, most of the remaining CO₂ gets taken up as the gas dissolves into the ocean and reacts with chalk in ocean sediments. But this process would never soak up enough CO₂ to return atmospheric levels to what they were before industrialization, shows oceanographer Toby Tyrrell of the UK's National Oceanography Centre, Southampton, in a recent paper⁴.

Finally, the slowest process of all is rock weathering, during which atmospheric CO₂ reacts with water to form a weak acid that dissolves rocks. It's thought that this creates minerals such as magnesium carbonate that lock away the greenhouse gas. But according to simulations by Archer and others, it would take hundreds of thousands of years for these processes to bring CO₂ levels back to pre-industrial values (Fig. 1).

Figure 1: Long lifetime.

Model simulation of atmospheric CO₂ concentration for 40,000 years following after a large CO₂ release from combustion of fossil fuels. Different fractions of the released gas recover on different timescales. Reproduced from The Long Thaw³.

Full figure and legend (18 KB)

Several long-term climate models, though their details differ, all agree that anthropogenic CO₂ takes an enormously long time to dissipate. If all recoverable fossil fuels were burnt up using today's technologies, after 1,000 years the air would still hold around a third to a half of the CO₂ emissions. "For practical purposes, 500 to 1000 years is 'forever,'" as Hansen and colleagues put it. In this time, civilizations can rise and fall, and the Greenland and West Antarctic ice sheets could melt substantially, raising sea levels enough to transform the face of the planet.

New stable state

The warming from our CO₂ emissions would last effectively forever, too. A recent study by Caldeira and Damon Matthews of Concordia University in Montreal found that regardless of how much fossil fuel we burn, once we stop, within a few decades the planet will settle at a new, higher temperature⁵. As Caldeira explains, "It just increases for a few decades and then stays there" for at least 500 years — the length of time they ran their model. "That was not at all the result I was expecting," he says.

But this was not some peculiarity of their model, as the same behaviour shows up in an extremely simplified model of the climate⁶ — the only difference between the models being the final temperature of the planet. Archer and Victor Brovkin of the Potsdam Institute for Climate Impact Research in Germany found much the same result from much longer-term simulations⁶. Their model shows that whether we emit a lot or a little bit of CO₂, temperatures will quickly rise and plateau, dropping by only about 1 °C over 12,000 years.

"The longevity of CO₂ in the atmosphere is probably the least well understood part of the global warming issue."

Peter Fawcett

Because of changes in the Earth's orbit, ice sheets might start to grow from the poles in a few thousand years — but there's a good chance our greenhouse gas emissions already may prevent that, Archer argues. Even with the amount of CO₂ emitted so far, another ice age will almost certainly start in about 50,000 years. But if we burn all remaining fossil fuels, it could be more than half a million years before the Earth has another ice age, Archer says.

The long-term effects of our emissions might seem far removed. But as Tyrrell says, "It is a little bit scary, if you think about all the concerns we have about radioactive wastes produced by nuclear power. The potential impacts from emitting CO₂ to the atmosphere are even longer than that." But there's still hope for avoiding these long-term effects if technologies that are now on the drawing board can be scaled up affordably. "If civilization was able to develop ways of scrubbing CO₂ out of the atmosphere," Tyrrell says, "it's possible you could reverse this CO₂ hangover."

Top of page

References

1. Flannery, T. The Weather Makers: The History and Future Impact of Climate Change 162 (Atlantic Monthly Press, New York, 2005).
2. Archer, D. et al. Ann. Rev. Earth Pl. Sc. (in the press).
3. Archer, D. The Long Thaw: How Humans Are Changing the Next 100,000 Years of Earth's Climate (Princeton Univ. Press, 2008).
4. Tyrrell, T., Shepherd, J. G. & Castle, S. Tellus 59, 664–672, doi:10.1111/j.1600-0889.2007.00290.x (2007).
5. Matthews, H. D. & Caldeira, K. Geophys. Res. Lett. 35, L04705, doi:10.1029/2007GL032388 (2008).
6. Archer, D. & Brovkin, V. Climatic Change 90, 283–297 (2008).

Mason Inman is a freelance science writer currently based in Pakistan.

[Peter Read]

I do not like to query anything that Ken says because he seems to know so much about absolutely everything

 

But I do not think we should support doom and gloom reporting of the extremely long life of CO2 without pointing out that we can get it out of the atmosphere quite simply.  And without very costly artificial trees. 

 

A programme of commercial reforrestation, that goes about half way to restoring global preindustrial forrest cover, makes a daunting mangerial task but involves no rocket science and can store about 100Gt C out of the atmosphere.  It is an investment not a cost, after maturity yielding a flow of timber that can contribute to REDD objectives and a co-produced flow of bioenergy raw material that can keep a mounting stock of fossil carbon in the ground, 500Gt by mid around mid century on one (my) calculation.  When used in large point sources, it can be linked to CCS giving a system that extracts energy while pumping CO2 underground.  CCS is about 85 % efficient so that mixing 15 % biomass raw material with coal yields a genuinely zero emissions system and I see no reason why coal should not continue to be used if it is sufficiently cheap to carry the CCS cost.  And there is the lately emerged biochar technology that can eventually store several more 100Gt of C in the soil through intervening in the careless disposal of biotic wastes from farm, forestry, food processing and households.

 

Mason Inman's piece falls into the category of porno-climate reporting and we should should not allow ourselves to be quoted unless also saying that the problem is perfectly soluble if the political-diplomatic process can weaned off its emissions reductions baby food and onto an adult diet of biotic carbon stock management (BCSM).  Nor, I think, should we write papers of the kind reported by him without making very clear that the assumption is that the policy process continues to do nothing effective about the problem.  But, as I think I said on this blog a little while back, BCSM needs to be matched by ocean surface cooling to sustain monsoon systems, where the feasible technologies urgently need demonstration.  

 

Peter

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[xben...@aol.com]

Peter:

I might point out that commercial reforrestation works hand in hand
with deep ocean sequestration as well. Forest growth can hold CO2 for
centuries, but when the trees die, much of their debris can be
sequestered in deep water, a la the CROPS program. Chipping away at the
CO2 yearly makes sense, and each seasonal year we neglect doing it,
that CO2 will be with us a long time: Sequestration by installment.

Gregory Benford

-----Original Message-----
From: Peter Read <pre...@attglobal.net>
To: agas...@nc.rr.com; kcal...@stanford.edu; geoengineering
<geoengi...@googlegroups.com>
Sent: Sat, 16 May 2009 6:01 am
Subject: [geo] Re: [clim] Fwd: White/Cool Roofs Memo to MEF (Major
Economies Forum)

I do not like to query anything that Ken says
because he seems to know so much about absolutely everything
 
But I do not think we should support doom and gloom
reporting of the extremely long life of CO2 without pointing out that
we can get
it out of the atmosphere quite simply.  And without very costly
artificial
trees. 
 
A programme of commercial reforrestation, that goes
about half way to restoring global preindustrial forrest cover, makes a
daunting
mangerial task but involves no rocket science and can store about 100Gt
C out of
the atmosphere.  It is an investment not a cost, after maturity
yielding a
flow of timber that can contribute to REDD objectives and a co-produced

flow=2
0of

=2
0 only apply for the time period that the albedo of the surface is as

will be gone20in about 20 years, about the lifetime of a roof.

CO2 hangover."0D

To: Anthony Eggert &lt;AEg...@arb.ca.gov&gt;, Bart Croes
&lt;BCr...@arb.ca.gov&gt;, "Mary
Nichols," &lt;MNic...@arb.ca.gov&gt;, John Harte
&lt;JHa...@berkeley.edu&gt;,
Matthew Elliott &lt;Mat...@ceaconsulting.com&gt;,
Cathy Zoi &lt;cath...@climateprotect.org&gt;,
And...@climateworks.org, H...@climateworks.org, Michael
MacCracken &lt;MMac...@comcast.net&gt;, jo...@ef.org, Arthur
Rosenfeld &lt;Arosenfe.H...@energy.state.ca.us&gt;,
Cheri and John Holdren &lt;John_H...@harvard.edu&gt;,
Steve Chu &lt;The.Se...@hq.doe.gov&gt;,
Alan Meier &lt;AKM...@lbl.gov&gt;,
Hashem Akbari &lt;H_Ak...@lbl.gov&gt;, Jayant Sathaye
&lt;JASa...@lbl.gov&gt;, Mark
Levine &lt;MDLe...@lbl.gov&gt;, Ken
Caldeira &lt;KCal...@stanford.edu&gt;, S...@stanford.edu
Cc: Devorah / Devi
Eden &lt;DEden.HQ...@energy.state.ca.us&gt;,
David Hungerford &lt;Dhungerf.H...@energy.state.ca.us&gt;,
Pat Flint &lt;Pflint.HQ...@energy.state.ca.us&gt;

In
preparation for the Dec. climate change summit in Copenhagen, the US
has

=2
0been working with MEF (Major Economies Forum), where it has

[Peter Read]

Gregory
Many thanks.

I would like to know more about the CROPS program if you have a reference

But a propos "when the trees die", they don't die under commercial
forrestation but get cut down when growth slows and the rate of increase of
value falls below the operator's cost of borrowing. When that happens, if
there is co-produced fuel and timber, is that some fossil fuel gets left in
the ground and some other timber elsewhere gets left standing (hopefully in
natural biodiverse forest), an ongoing process for "chipping away at
atmospheric CO2 yearly" that can also support both REDD and biodiversity
objectives.

In a 'normal' commercial plantation there are equal area stands of all ages
of maturity from just planted to due to be felled next year. Annual growth
shifts each stand one year towards maturity, so that the average age of
stand is half the maturity age and there is a total standing stock of carbon
equal to approximately half of the maximum possible if all the stands were
left unfelled after growing to maturity and then left to die (which would
yield a zero return on investment).

While a new forest is growing towards the maturity of its first stand, and a
new stand is planted each year so as to eventually result in a normal
forest, the "chipping away" comes from annual average growth of the forest,
which ceases when the first stand is felled since thereafter annual felling
removes as much C as is captured by the annual growth of the rest of the
forest.

Increased "chipping away" results from routing the fuel fraction through one
of the negative emissions systems, biochar or BECCS, which results in C
being stored as nearly pure C in the soil or as CO2 deep underground, as
well as in leaving fossil fuel underground.

Decreased chipping away results if the trees left standing in natural
forests die off. A forthcoming paper by Len Ornstein suggests (from
memory - some time since I saw the draft) that about 1Gt of carbon annually
could be kept from the atmosphere if an organised program existed for
sequestering C that would otherwise be returned to atmosphere following
natural treefall.

Peter

----- Original Message -----
From: <xben...@aol.com>
To: <pre...@attglobal.net>; <agas...@nc.rr.com>; <kcal...@stanford.edu>;
<geoengi...@googlegroups.com>
Sent: Sunday, May 17, 2009 4:20 AM
Subject: Re: [geo] Re: [clim] Fwd: White/Cool Roofs Memo to MEF (Major
Economies Forum)

Peter:

I might point out that commercial reforrestation works hand in hand
with deep ocean sequestration as well. Forest growth can hold CO2 for
centuries, but when the trees die, much of their debris can be
sequestered in deep water, a la the CROPS program. Chipping away at the
CO2 yearly makes sense, and each seasonal year we neglect doing it,
that CO2 will be with us a long time: Sequestration by installment.

Gregory Benford
.
.
.
(snipped by PR)

[Ken Caldeira]

In response to Peter's earlier comment:

Our studies on the long lifetime of CO2 emissions considered only natural and not engineered CO2 removal mechanisms.

As Peter points out, several engineered CO2 removal approaches have been proposed, with biomass co-firing of power plants combined with carbon capture and geologic disposal perhaps being the most plausibly cost effective approach.

One could look at engineered CO2 removal as a negative emission, with positive consequences equal and opposite to the negative consequences of a CO2 emission -- so the positive consequences of CO2 removal are similarly long-lived.

Nevertheless, I think we need to be wary of suggestions, such as those made by Roger Pielke Jr and others (eg http://sciencepolicy.colorado.edu/admin/publication_files/resource-2716-2009.03.pdf), that it is OK to pollute today because others can clean it up tomorrow.

On the other hand, the idea that we would continue using petroleum products as transportation fuels (especially for aviation) and then negate those emissions with near-simultaneous air capture may be a plausible and cost effective path forward.

That said, we should be aware that biomass options are all plagued by low areal power densities, and so require large land areas to be quantitatively important -- and large land areas often come with large transportation and processing costs (not to mention costs associated with competing uses of that land for food production, biodiversity, etc).

Best,

Ken

PS. I am a little suspicious about biochar, because I am skeptical that the best thing to do with reduced carbon is bury it underground (especially while we still have a coal mining industry trying to remove reduced carbon from underground), but that is another discussion and I haven't really investigated biochar carefully yet.

___________________________________________________
Ken Caldeira

Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA

kcal...@ciw.edu; kcal...@stanford.edu
http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1 650 704 7212; fax: +1 650 462 5968  

[Peter Read]

Thanks Ken,

 

I think you are absolutely right re the Pielke approach.  I think we are possibly quite near the edge of some tipping point precipice [and of course quite possibly not, but inaction is not a rational response to uncertainty]  What I estimate could be done by mid century with a huge effort, using 1Gha of land, could have been done much more easily using 600 MHa starting 15 years ago, when my book "Responding to Global Warming" was published. Pielke is just being silly.

 

We shouldn't be too despondent about the areal power density of bioenergy.  In good conditions Eucalypts can do 1000Gj/Ha-yr and sugar cane 1300.  Over a decade or so of technolgical improvement, and with irrigation, biomass can likely supply most of the world's fuel demands.  Add a bit of zero emissions coal-and-biofuel co-fired generation, then maybe the fat can be pulled from the fire despite Einsteins view that "only two things are infinite, the universe and mankind's stupidity - and I not sure about the universe". 

 

What I am concerned about is that scientists should be careful what they say to the media, and clarify the assumptions behind their work, maybe reminding journalists that studies of how the natural earth system works do not preclude geo-engineering options to forestall unwanted outcomes

 

Peter

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[Ken Caldeira]

To put Peter's numbers into SI units:

1000Gj/Ha-yr = 3.2 W / m2
1300Gj/Ha-yr = 4.1 W / m2

These numbers seem mighty optimistic (are they supposed to include losses from inputs, processing etc?).

(Most estimates I see are an order of magnitude lower [cf. http://www.biofuel2g.com/Ponencias/wim_corre.pdf].) How to reconcile this difference?

How much land is there with "good conditions" that would not be better allocated to other purposes [food, biodiversity, etc]?

Even so, land requirements are substantial for a high energy lifestyle ... And efficiency improvements only help bring about a low energy lifestyle if they are coupled to (or brought about by) strong incentives to reduce energy use. ( Remember James Watt and his steam engine !! )

[Peter Read]

Where I got those numbers from I can't remember but have carried around for some years

The best I could easily find for eucalypts, googling yesterday, were outliers described as "extraordinary" from about 20 years ago and without comment in a 3 yr old article, both about 750 GJ per Ha per yr

The amount of land good enough for trees depends mainly on water, which is why I tend to say there's no shortage of land but of investment in land. If you drop water 300 m down a hydro system you get one tenth the energy you get from putting it on water constrained land to grow biofuel.  At 40 per cent generation efficiency thats one quarter the amount of electricity and a lot of waste heat if you can find a use for it.

Think the sugar figure came from Zambia but google just told me how much is produced there, not productivity.

What can be done if we know what we are trying to do, and get focused on achieving technological progress in that direction - e.g. the Manhattan project - is very different from statistics of past performance

[Alvia Gaskill]

The 11-year offset from cars is quite misleading considering how
difficult it would be and how long it would take. I still can't get
over calling this geoengineering when the term has such a negative
connotation. However, it does fit my definition of mitigating warming
without reducing source emissions. I also would still need to be
convinced that having the government purchase white colored cars would
make any difference at all.

http://news.yahoo.com/s/afp/20090526/sc_afp/climatewarmingusbritainchu

US wants to paint the world white to save energy
1 hr 35 mins ago

LONDON(AFP) (AFP) – US Energy Secretary Steven Chu said Tuesday the
Obama administration wanted to paint roofs an energy-reflecting white,
as he took part in a climate change symposium in London.

The Nobel laureate in physics called for a "new revolution" in energy
generation to cut greenhouse gas emissions.

But he warned there was no silver bullet for tackling climate change,
and said a range of measures should be introduced, including painting
flat roofs white.

Making roads and roofs a paler colour could have the equivalent effect
of taking every car in the world off the road for 11 years, Chu said.

It was a geo-engineering scheme that was "completely benign" and would
keep buildings cooler and reduce energy use from air conditioning, as
well as reflecting sunlight back away from the Earth.

For people who found white hard on the eye, scientists had also
developed "cool colours" which looked to the human eye like normal
ones, but reflect heat like pale colours even if they are darker
shades.

And painting cars in cool or light colours could deliver considerable
savings on energy use for air conditioning units, he said.

Speaking at the start of a symposium on climate change hosted by the
Prince of Wales and attended by more than 20 Nobel laureates, Chu said
fresh thinking was required to cut the amount of carbon created by
power generation.

He said: "The industrial revolution was a revolution in the use of
energy. It offloaded from human and animal power into using fossil
fuels.

"We have to go to a different new revolution that can severely
decrease the amount of carbon emissions in the generation of energy."

On May 17, 3:50 pm, "Peter Read" <pre...@attglobal.net> wrote:
> Where I got those numbers from I can't remember but have carried around for some years
> The best I could easily find for eucalypts, googling yesterday, were outliers described as "extraordinary" from about 20 years ago and without comment in a 3 yr old article, both about 750 GJ per Ha per yr
> The amount of land good enough for trees depends mainly on water, which is why I tend to say there's no shortage of land but of investment in land. If you drop water 300 m down a hydro system you get one tenth the energy you get from putting it on water constrained land to grow biofuel.  At 40 per cent generation efficiency thats one quarter the amount of electricity and a lot of waste heat if you can find a use for it.
> Think the sugar figure came from Zambia but google just told me how much is produced there, not productivity.
> What can be done if we know what we are trying to do, and get focused on achieving technological progress in that direction - e.g. the Manhattan project - is very different from statistics of past performance

> Peter...
>
> read more »

>
>
>
>   ----- Original Message -----
>   From: Ken Caldeira
>   To: Peter Read
>   Cc: xbenf...@aol.com ; geoengi...@googlegroups.com ; Leonard Ornstein
>   Sent: Sunday, May 17, 2009 9:36 AM
>   Subject: [geo] Re: [clim] Fwd: White/Cool Roofs Memo to MEF (Major Economies Forum)
>
>   To put Peter's numbers into SI units:
>
>   1000Gj/Ha-yr = 3.2 W / m2
>   1300Gj/Ha-yr = 4.1 W / m2
>
>   These numbers seem mighty optimistic (are they supposed to include losses from inputs, processing etc?).
>

>   (Most estimates I see are an order of magnitude lower [cf.http://www.biofuel2g.com/Ponencias/wim_corre.pdf].) How to reconcile this difference?

>
>   How much land is there with "good conditions" that would not be better allocated to other purposes [food, biodiversity, etc]?
>
>   Even so, land requirements are substantial for a high energy lifestyle ... And efficiency improvements only help bring about a low energy lifestyle if they are coupled to (or brought about by) strong incentives to reduce energy use. ( Remember James Watt and his steam engine !! )
>
>   On Sat, May 16, 2009 at 2:11 PM, Peter Read <pre...@attglobal.net> wrote:
>
>     Thanks Ken,
>
>     I think you are absolutely right re the Pielke approach.  I think we are possibly quite near the edge of some tipping point precipice [and of course quite possibly not, but inaction is not a rational response to uncertainty]  What I estimate could be done by mid century with a huge effort, using 1Gha of land, could have been done much more easily using 600 MHa starting 15 years ago, when my book "Responding to Global Warming" was published. Pielke is just being silly.
>
>     We shouldn't be too despondent about the areal power density of bioenergy.  In good conditions Eucalypts can do 1000Gj/Ha-yr and sugar cane 1300.  Over a decade or so of technolgical improvement, and with irrigation, biomass can likely supply most of the world's fuel demands.  Add a bit of zero emissions coal-and-biofuel co-fired generation, then maybe the fat can be pulled from the fire despite Einsteins view that "only two things are infinite, the universe and mankind's stupidity - and I not sure about the universe".
>
>     What I am concerned about is that scientists should be careful what they say to the media, and clarify the assumptions behind their work, maybe reminding journalists that studies of how the natural earth system works do not preclude geo-engineering options to forestall unwanted outcomes
>
>     Peter
>       ----- Original Message -----
>       From: Ken Caldeira
>       To: pre...@attglobal.net
>       Cc: xbenf...@aol.com ; geoengi...@googlegroups.com ; Leonard Ornstein
>       Sent: Sunday, May 17, 2009 8:26 AM
>       Subject: [geo] Re: [clim] Fwd: White/Cool Roofs Memo to MEF (Major Economies Forum)
>
>       In response to Peter's earlier comment:
>
>       Our studies on the long lifetime of CO2 emissions considered only natural and not engineered CO2 removal mechanisms.
>
>       As Peter points out, several engineered CO2 removal approaches have been proposed, with biomass co-firing of power plants combined with carbon capture and geologic disposal perhaps being the most plausibly cost effective approach.
>
>       One could look at engineered CO2 removal as a negative emission, with positive consequences equal and opposite to the negative consequences of a CO2 emission -- so the positive consequences of CO2 removal are similarly long-lived.
>

>       Nevertheless, I think we need to be wary of suggestions, such as those made by Roger Pielke Jr and others (eghttp://sciencepolicy.colorado.edu/admin/publication_files/resource-27...), that it is OK to pollute today because others can clean it up tomorrow.

>
>       On the other hand, the idea that we would continue using petroleum products as transportation fuels (especially for aviation) and then negate those emissions with near-simultaneous air capture may be a plausible and cost effective path forward.
>
>       That said, we should be aware that biomass options are all plagued by low areal power densities, and so require large land areas to be quantitatively important -- and large land areas often come with large transportation and processing costs (not to mention costs associated with competing uses of that land for food production, biodiversity, etc).
>
>       Best,
>
>       Ken
>
>       PS. I am a little suspicious about biochar, because I am skeptical that the best thing to do with reduced carbon is bury it underground (especially while we still have a coal mining industry trying to remove reduced carbon from underground), but that is another discussion and I haven't really investigated biochar carefully yet.
>
>       ___________________________________________________
>       Ken Caldeira
>
>       Carnegie Institution Dept of Global Ecology
>       260 Panama Street, Stanford, CA 94305 USA
>

>       kcalde...@ciw.edu; kcalde...@stanford.edu

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[Alvia Gaskill]

Predictably, the media is already misrepresenting and ridiculing the
proposal from the Energy Sec'y. On the CBS Morning Show (before they
start up with the cooking, lose weight segments and celebrity
interviews), co-host Harry Smith mentioned before a break that the
plan would emulate the light colored roofs of Mediterranean countries
and that roads would be painted white. Julie Chen then chirped in
that the roads wouldn't stay white very long in NYC. She then said it
would however, be good for manufacturers of sunglasses. Yuk yuk yuk.
Now just imagine how stratospheric aerosols, OIF, or cloud whitening
would be treated.

[Alvia Gaskill]

http://cosmos.bcst.yahoo.com/up/ylocalnews;_ylt=Au35Abw4T5NsZkt91yh3xGKr_aF4;_ylu=X3oDMTFhdDVrbm50BHBvcwMzBHNlYwN5bl9yXzNzbG90X3ZpZGVvBHNsawN2aWQtZXYtbGluaw--?ch=4226712&cl=13692400&lang=en

Climate Change Video:White Paint A Weapon Against Climate Change? CBS 13 /
CW 31 Sacramento

Caif. TV reporter on top of the roof of the TV station discusses the
advantages of white roofs in reflecting sunlight. Notes that white roofs
for commercial buildings are required in Calif. A more balanced and
accurate report than from the CBS Early Show that I renamed the Morning
Show. Morning, Good Morning, Early, Today, it's all the same. One person
commented that I shouldn't be watching this crap, but bad as it is, millions
of people do and their opinions are largely formed by what they see and hear
on these general interest programs, moreso now with the demise of print
newspapers. The local TV news briefly mentioned Chu's statement on this, so
it has been fairly widely disseminated, although I don't think the public or
the media actually understands the potential limits to it or the time scales
and effort involved.

I've also attached some pictures I shot in early April of the roof of a
local Sam's Club warehouse building in Durham, NC (501, 502, 503) to
illustrate some of the problems with white roofs, namely that while they
start out white, they don't stay that way. This particular building is part
of a large shopping center that sits on the site of the former South Square
Mall for those of you familiar with the area. A Target and some other
stores make up the rest of the structure which is nearly a quarter of a mile
from one end to the other. It's about 5-years old and I estimate the total
roof area to be around 300,000 SF.

When the building was new, the roof was quite white and shiny, much like
virgin white polyethylene sheeting (see my Roomba videos at weatherman2050
on YouTube for comparison shots of new and used white plastic.) Today,
however, the roof is a dingy light gray in color which seems to revert back
to white again when it rains or of course, snows. I don't think management
makes any effort to clean the roof, relying on the wind and rain to do the
job. To be fair about this, I've seen the roofs of other commercial
buildings in this area that do appear white, but without knowing their age
or when the roof was installed which may be different, it is difficult to
tell the history.

Also shown are shots of the nearby sidewalk where the pictures of the roof
were taken. The roof is now about the same whiteness as the concrete
sidewalk (505), but brighter than the adjacent asphalt (506). According to
the Akbari/Rosenfeld plan, as I understand it, degradation of the roof
albedo to around 0.6 total solar is factored into the estimates for the
lifetime of the roof amd associated reduced CO2eq forcing and washing is not
a requirement. Correct me on this if I'm wrong guys. The Sam's Club roof
is still probably within the 0.6-0.8 range, although without measurements,
it is impossible to know for certain.

Most commercial buildings have flat roofs, but as Akbari/Rosenfeld
indicates, residential roofs are sloped. In NC and throughout most of the
country, home roofs tend to be slate gray or black, red or some other dark
color. Since homeowners don't want white roofs (or white cars either) due
to the fact that when they get dirty it is much more noticeable, roofs made
of darker materials that reflect more light in the near (solar) IR are
proposed for them.

I once tried an experiment where I completely covered my car in aluminum
foil (no pictures available, unfortunately) to see the effect on inside
temperature. It did make a difference of around 10-15 degrees F. White
painted metal on the roof or hood of a car is quite a bit cooler than darker
colors, though, at least 10-15degrees F. White car advocates should note
that a great deal of the heating in the passenger compartment is through the
windshield and windows and depends on the sun angle, so white paint alone
won't solve the problem.

Cars are a lot like little houses, with windows, roofs and doors. The foam
material in the roof known as the headliner or roof liner is analogous to
the insulation in the attic of a home. If it can be shown that significant
reductions in GHG emissions are possible by reducing the heat gain inside a
vehicle, the type headliner material may be as important or more so than the
exterior paint color. Those expandable Al windshield sun shades also help
and keep the interior from getting as hot as it would otherwise, requiring
less AC to cool the car on startup.

[Alvia Gaskill]

A little informal research on the white vs. dark car theory conducted this
morning. All readings were taken on the roof of the vehicles using a non
contact thermometer. Internal measurements would have been a little hard to
explain as readings through the glass are biased and I don't have permission
to enter other people's cars and SUVs. Colors refer to color of vehicles.

1. 7:45 am, overcast, ambient sun temperature 71F
a. white 70F
b. white 70F
c. black 73F
d. dark blue 73F
e. dark blue 74F
f. dark green 74F

2. 9:10 am, partly sunny, ambient sun temp. 77F
a. white 87F
b. white 83F
c. black 98F (same as in 1, but in partial shade)
d. black 110F (not in shade)
e. dark blue 118F
f. dark green 116F

3. 12:10pm, sunny, ambient sun temp. 81F
a. white 107F
b. white 109F
c. black 145F
d. black 145F
e. dark blue 143F
f. dark blue 143F
g. dark green 146F

4. ranges:
white 70-108F
black 73-145F
dark blue 73-144
dark green 74-146

So the white car roof temperature was about 37F lower than the black, dark
blue or dark green, quite a bit more than my estimate. But, since we don't
travel on top of the car, these numbers are less informative than if they
were correlated with internal measurements.

One interesting side note is the potential for offsetting CO2eq forcing from
making all surface passenger vehicles in the world white. Assuming one
billion vehicles (cars, busses and trucks), an average reflectable surface
area of 50SF per vehicle, and a starting albedo of 0.2 going to 0.8, the
estimated area would be around 1800 square miles or about enough to offset
7% of the global GHG forcing expected to be added in 2009 (pre-recession
estimate). These are very fuzzy numbers as most of the vehicles are out of
the tropics and wouldn't receive as much sunlight as in the case of a
tropical desert with generally clear skies. And of course, like with the
roofs and pavement, the offset only occurs as long as the surface exists
with that level of reflectivity, while the CO2eq forcing will be around much
longer, from decades to centuries. So, should EPA include tax credits for
purchases of white vehicles along with all the other tax incentives to
encourage the CO2eq offset as well as lowered emissions from reduced A/C?
And as for the clunker program, a clunker is a clunker, but should they and
new cars also have color ratings?