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 <[email protected]> To: [email protected]; [email protected]; geoengineering <[email protected]> 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 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 mo nsoon systems, where the feasible technologies urgently need demonstration. Peter ----- Original Message ----- From: Alvia Gaskill To: [email protected] ; geoengineering Sent: Saturday, May 16, 2009 2:38 AM Subject: [geo] Re: [clim] Fwd: White/Cool Roofs Memo to MEF (Major Economies Forum) 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 =2 0 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 gone20in 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 suggest ed 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 t hat 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. Over all, 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 t he 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 u sing 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 sho ws 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."0D Top of page References Flannery, T. The Weather Makers: The History and Future Impact of Climate Change 162 (Atlantic Monthly Press, New York, 2005). Archer, D. et al. Ann. Rev. Earth Pl. Sc. (in the press). Archer, D. The Long Thaw: How Humans Are Changing the Next 100,000 Years of Earth's Climate (Princeton Univ. Press, 2008). Tyrrell, T., Shepherd, J. G. & Castle, S. Tellus 59, 664–672, doi:10.1111/j.1600-0889.2007.00290.x (2007). Matthews, H. D. & Caldeira, K. Geophys. Res. Lett. 35, L04705, doi:10.1029/2007GL032388 (2008). Archer, D. & Brovkin, V. Climatic Change 90, 283–297 (2008). Mason Inman is a freelance science writer currently based in Pakistan. ----- Original Message ----- From: Ken Caldeira To: Climate Intervention ; geoengineering Sent: Thursday, May 14, 2009 11:50 PM Subject: [clim] Fwd: White/Cool Roofs Memo to MEF (Major Economies Forum) 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 [email protected]; [email protected] http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab +1 650 704 7212; fax: +1 650 462 5968 ---------- Forwarded message ---------- From: Arthur Rosenfeld <[email protected]> Date: Thu, May 14, 2009 at 5:05 PM Subject: White/Cool Roofs Memo to MEF (Major Economies Forum) To: Anthony Eggert <[email protected]>, Bart Croes <[email protected]>, "Mary Nichols," <[email protected]>, John Harte <[email protected]>, Matthew Elliott <[email protected]>, Cathy Zoi <[email protected]>, [email protected], [email protected], Michael MacCracken <[email protected]>, [email protected], Arthur Rosenfeld <[email protected]>, Cheri and John Holdren <[email protected]>, Steve Chu <[email protected]>, Alan Meier <[email protected]>, Hashem Akbari <[email protected]>, Jayant Sathaye <[email protected]>, Mark Levine <[email protected]>, Ken Caldeira <[email protected]>, [email protected] Cc: Devorah / Devi Eden <[email protected]>, David Hungerford <[email protected]>, Pat Flint <[email protected]> In preparation for the Dec. climate change summit in Copenhagen, the US has =2 0been 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 [email protected] www.Energy.CA.gov http://www.energy.ca.gov/commission/commissioners/rosenfeld.html ========================================================= ================ == No virus found in this incoming message. 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