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" <[email protected]> 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: [email protected] ; [email protected] ; 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 <[email protected]> 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: [email protected] > Cc: [email protected] ; [email protected] ; 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 > > [email protected]; [email protected] > http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab > +1 650 704 7212; fax: +1 650 462 5968 > > On Sat, May 16, 2009 at 12:11 PM, Peter Read <[email protected]> > wrote: > > 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: <[email protected]> > To: <[email protected]>; <[email protected]>; > <[email protected]>; > <[email protected]> > 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) > > -------------------------------------------------------------------------- > > No virus found in this incoming message. > Checked by AVG -www.avg.com > > Version: 8.0.238 / Virus Database: 270.12.32/2118 - Release Date: > 05/16/09 17:05:00 > > ------------------------------------------------------------------------------ > > No virus found in this incoming- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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