Their argument may be counter factual as reducing trop sulfur causes warming, so there's some pressure to maintain S emissions to avoid warming shocks. Adding strat S will reduce this pressure to maintain emissions.
A On Feb 19, 2013 9:27 AM, "Chris Vivian" <[email protected]> wrote: > Andrew, > > I think that ocean acidification is widely accepted scientifically as the > chemistry is well understood (and has been for many decades). What is much > less well understood is is the impacts of ocean acidification on biota. You > may find this FAQ about ocean acidification of interest > https://darchive.mblwhoilibrary.org/bitstream/handle/1912/5373/OAFAQ_V2_Sept15_2012.pdf?sequence=1 > and > this website http://www.whoi.edu/OCB-OA/FAQs/. > > The Skeptical Science article grossly exagerates the significance of > injecting sulphur aerosol into the stratosphere for ocean acidification. As > I understand it, the amounts of sulphur aeosol that might be injected into > the stratosphere for geoengineering purposes is only a few percent of the > sulphur aerosols put into the troposphere by human activities, particularly > through burning fossil fuels. > > Chris. > > On Monday, 18 February 2013 22:15:26 UTC, andrewjlockley wrote: > >> As previously pointed out on this list, monsoon disruption and ocean >> acidification are not widely accepted as being the certainties claimed >> below. >> >> A >> On Feb 18, 2013 6:13 PM, "Rau, Greg" <[email protected]> wrote: >> >>> >>> http://www.skepticalscience.**com/print.php?n=1785<http://www.skepticalscience.com/print.php?n=1785> >>> No >>> alternative to atmospheric CO2 draw-down >>> >>> This article suggests that the current atmospheric CO2 level is already >>> triggering amplifying feedbacks from the Earth system and therefore, in >>> themselves, efforts at reduction in atmospheric CO2-emission are no >>> longer sufficient to prevent further global warming. For this reason, along >>> with sharp reductions in carbon emissions, efforts need to be undertaken in >>> an attempt to reduce atmospheric CO2 levels from their current level of >>> near-400 ppm to well below 350 ppm. NASA-applied outer space-shade >>> technology may buy time for such planetary defense effort. >>> >>> The scale and rate of modern climate change have been greatly >>> underestimated. The release to date of a total of over 560 billion ton of >>> carbon through emissions from industrial and transport sources, land >>> clearing and fires, has raised CO2 levels from about 280 parts per >>> million (ppm) in pre-industrial periods to 397-400 ppm and near 470 ppm CO >>> 2-equivalent (a value which includes the CO2-equivalent effect of >>> methane), reaching a current CO2 growth rate of about 2 ppm per >>> year<http://www.globalcarbonproject.org/> >>> >>> *Figure 1: Part A. Mean CO2 level from ice cores, Mouna Loa observatory >>> and marine sites; Part B (inset). Climate forcing 1880 - >>> 2003<http://pubs.giss.nasa.gov/abs/ha06510a.html>. >>> Aerosol forcing includes all aerosol effects, including indirect effects on >>> clouds and snow albedo. GHGs include ozone (O3) and stratospheric H2O, >>> in addition to well-mixed greenhouse gases.* >>> >>> *Figure 2: Relations between CO2 rise rates and mean global temperature >>> rise rates during warming >>> periods<http://cci.anu.edu.au/files/download/?id=4951> >>> *, including the Paleocene-Eocene Thermal Maximum, Oligocene, Miocene, >>> glacial terminations, Dansgaard-Oeschger cycles and the post-1750 period. >>> >>> These developments are shifting the Earth's climate toward Pliocene-like >>> (5.2 - 2.6 million years-ago; mean global temperatures of +2-3oC above >>> pre-industrial temperatures) and possibly toward mid-Miocene-like >>> (approximately 16 million years-ago; mean global temperatures +4oC >>> above pre-industrial >>> temperatures<http://www.nature.com/ngeo/journal/v4/n7/fig_tab/ngeo1186_ft.html>) >>> conditions within a few centuries--a geological blink of an eye. >>> >>> The current CO2 level generates amplifying feedbacks, including the >>> reduced capacity of warming water to absorb CO2 from the atmosphere, CO2 >>> released >>> from fires, droughts, loss of vegetation cover, disintegration of methane >>> released from bogs, permafrost and methane-bearing ice particles and >>> methane-water molecules. >>> >>> With CO2 atmospheric residence times in the order of thousands to tens >>> of thousands >>> years<http://www.pnas.org/content/early/2009/01/28/0812721106.abstract>, >>> protracted reduction in emissions, either flowing from human decision or >>> due to reduced economic activity in an environmentally stressed world, may >>> no longer be sufficient to arrest the feedbacks. >>> >>> Four of the large mass extinction of species events in the history of >>> Earth (end-Devonian, Permian-Triassic, end-Triassic, K-T boundary) have >>> been associated with rapid perturbations of the carbon, oxygen and sulphur >>> cycles, on which the biosphere depends, at rates to which species could >>> not >>> adapt<http://theconversation.edu.au/is-another-mass-extinction-event-on-the-way-5397> >>> . >>> >>> Since the 18th century, and in particular since about 1975, the Earth >>> system has been shifting away from Holocene (approximately 10,000 years to >>> the pre-industrial time) conditions, which allowed agriculture, previously >>> hindered by instabilities in the climate and by extreme weather events. The >>> shift is most clearly manifested by the loss of polar >>> ice<http://www.agu.org/pubs/crossref/2011/2011GL046583.shtml>. >>> Sea level rises have been accelerating, with a total of more than 20 cm >>> since 1880 and about 6 cm since >>> 1990<http://www.eea.europa.eu/data-and-maps/indicators/sea-level-rise-1/assessment> >>> . >>> >>> For temperature rise of 2.3oC, to which the climate is committed if sulphur >>> aerosol emission discontinues<http://pubs.giss.nasa.gov/abs/ha06510a.html> >>> (see >>> Figure 1), sea levels would reach Pliocene-like levels of 25 meters plus or >>> minus 12 meters, with lag effects due to ice sheet hysteresis (system >>> inertia). >>> >>> With global atmospheric CO2-equivalent (a value which includes the >>> effect of methane) above 470 ppm, just under the upper stability limit >>> of the Antarctic ice >>> sheet<http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf>, >>> with current rate of CO2 emissions from fossil fuel combustion, cement >>> production, land clearing and fires of ~9.7 billion ton of carbon in >>> 2010<http://www.science.org.au/natcoms/nc-ess/documents/GEsymposium.pdf>, >>> global civilization faces the following alternatives: >>> >>> 1. With carbon reserves sufficient to raise atmospheric CO2 levels >>> to above 1000 >>> ppm<http://www.columbia.edu/~jeh1/mailings/.../20120130_CowardsPart2.pdf>, >>> continuing business-as-usual emissions can only result in advanced >>> melting >>> of the polar ice sheets, a corresponding rise of sea levels on the scale >>> of >>> meters to tens of meters, on a time scale of decades to centuries, and >>> high >>> to extreme continental temperatures rendering agriculture and human >>> habitat over large regions >>> unlikely<http://www.ccrc.unsw.edu.au/staff/profiles/sherwood/wetbulb.html> >>> . >>> 2. With atmospheric CO2 at about 400 ppm, abrupt decrease in carbon >>> emissions may no longer be sufficient to prevent current feedbacks >>> (melting of ice, methane release from permafrost, fires). Attempts to >>> stabilize the climate require global efforts at CO2 draw-down, using >>> a range of methods, including global reforestation, extensive biochar >>> application, chemical CO2 sequestration (using sodium hydroxide, >>> serpentine and new innovations) as well as burial of >>> CO2<http://www.science.org.au/natcoms/nc-ess/documents/GEsymposium.pdf> >>> . >>> >>> As indicated in Table 1, the use of short-term solar radiation shields >>> such as sulphur aerosols cannot be regarded as more than a band aid, with >>> severe deleterious consequences in terms of ocean acidification and >>> retardation of the monsoon and of precipitation over large parts of the >>> Earth. >>> >>> By contrast, retardation of solar radiation through space sunshade >>> technology<http://www.sciencedaily.com/releases/2006/11/061104090409.htm> >>> may >>> allow time for CO2 draw-down. Unlike sulphur dioxide injections this >>> will not have ocean acidification effects - an effort requiring a planetary >>> defense project by NASA. >>> >>> Dissemination of ocean iron >>> filings<http://newswatch.nationalgeographic.com/2012/10/18/iron-fertilization-savior-to-climate-change-or-ocean-dumping/> >>> aimed >>> at increasing fertilization by plankton and algal blooms, or temperature >>> exchange through vertical ocean pipe >>> systems<http://www.realclimate.org/index.php/archives/2007/04/ocean-cooling-not/>, >>> are unlikely to constitute effective means of transporting CO2 to >>> relatively safe water depths. >>> >>> By contrast to these methods, CO2 sequestration through fast track >>> reforestation, soil carbon, biochar and possible chemical methods such as >>> "sodium >>> trees"<http://www.realclimate.org/index.php/archives/2007/04/ocean-cooling-not/> >>> and >>> serpentine (combining Ca and Mg with >>> CO2<http://onlinelibrary.wiley.com/doi/10.1002/cjce.5450810373/abstract>) >>> may be effective, provided these are applied on a global scale >>> >>> Such efforts will require an effective planetary defense effort on the >>> scale currently expended on military spending (totaling more than $20 >>> trillion since WWII). >>> >>> It is likely that a species which decoded the basic laws of nature, >>> split the atom, placed a man on the moon and ventured into outer space >>> should also be able to develop the methodology for fast sequestration of >>> atmospheric CO2. The alternative, in terms of global heating, sea level >>> rise, extreme weather events, and the destruction of the world's food >>> sources is unthinkable. >>> >>> Good planets are hard to come by. >>> >>> Posted by Andrew Glikson on Thursday, 14 February, 2013 >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "geoengineering" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to geoengineerin...@**googlegroups.com. >>> To post to this group, send email to geoengi...@googlegroups.**com. >>> Visit this group at http://groups.google.com/** >>> group/geoengineering?hl=en<http://groups.google.com/group/geoengineering?hl=en> >>> . >>> For more options, visit >>> https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> >>> . >>> >>> >>> >> -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/geoengineering?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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