Further comment here: http://www.commondreams.org/headline/2014/01/08-4
Greg >________________________________ > From: Angus Ferraro <[email protected]> >To: [email protected] >Cc: [email protected]; Angus Ferraro <[email protected]> >Sent: Wednesday, January 8, 2014 4:24 AM >Subject: Re: [geo] Plan to avert global warming by cooling planet artificially >'could cause climate chaos' - The Independent > > > >Hi all, > > >I think the media spin wasn't ideal as well. The paper took a while to appear >on the ERL website but it's up now (though only in PDF form - the HTML form is >not working as yet). Here's the link: >http://iopscience.iop.org/1748-9326/9/1/014001/pdf/1748-9326_9_1_014001.pdf > > >Abstract >Geoengineering by injection of reflective aerosols into the stratosphere has >been proposed as a way to counteract the warming effect of greenhouse gases by >reducing the intensity of solar radiation reaching the surface. Here, climate >model simulations are used to examine the effect of geoengineering on the >tropical overturning circulation. The strength of the circulation is related >to the atmospheric static stability and has implications for tropical >rainfall. The tropical circulation is projected to weaken under anthropogenic >global warming. Geoengineering with stratospheric sulfate aerosol does not >mitigate this weakening of the circulation. This response is due to a fast >adjustment of the troposphere to radiative heating from the aerosol layer. >This effect is not captured when geoengineering is modelled as a reduction in >total solar irradiance, suggesting caution is required when interpreting model >results from solar dimming experiments as analogues for stratospheric aerosol geoengineering. > >Cheers > > >Angus > >On Wednesday, 8 January 2014 10:07:51 UTC, matthew watson wrote: >Hi all, >> >> >>I liked the paper (I did not review it for the journal but was asked to >>provide comment for the media). I did not like the press release or the >>'spin' at all. Whilst I am not a fan of SRM particularly, the 'nail in the >>coffin' framing doesn't quite convince me. The paper was a model run of 4 X >>CO2 (1020 ppm) and 5 X Pinatubo (I assume using 20 MT SO2 for that, so 150 MT >>sulphate). That, to me, is a little like saying 'this car failed it's safety >>test after I dropped it from 30,000 ft'.I don't doubt that rainfall would be >>affected, we saw that after Pinatubo (and other eruptions). Here's what Piers >>Forster and I wrote... >> >> >>Dr Matt Watson, Senior Lecturer in Natural Hazards at the University of >>Bristol, said: >>"The paper draws two conclusions. Firstly, models that simply dim the Sun as >>an approximation for global cooling by aerosols do a poor job of capturing >>rainfall changes compared with those that model stratospheric aerosols >>explicitly. Secondly, that rainfall is strongly affected, particularly in >>the tropics. >> >>"However, the authors chose an extreme climate scenario (4x CO2) so we should >>not be surprised if that, and any geoengineering attempt to counter it (also >>extreme, requiring 100 million tonnes of SO2 per year), had severe and uneven >>impacts. >> >>“I found the press release particularly unhelpful. Exploratory science is >>rarely as definitive as this. To state that Solar Radiation Management (SRM) >>won't work based upon one extreme scenario smacks of hype rather than a >>serious discussion. I know of no serious scientist who would advocate >>introducing 100 megatonnes of sulphur dioxide in a four degree warmer world. >> >>"This new research will doubtless be seized upon by those opposing >>geoengineering research and rebutted by those that support it, in an >>unhelpful, adversarial tit-for-tat. A more realistic scenario might have >>been to try with 2x CO2 or a specific IPCC projection, and possibly simply >>stabilize (rather than attempt to return to pre-industrial) temperatures. >>That would probably produce less dire predictions. >> >> >>"It remains the case that our only guaranteed way forward is to reduce the >>record levels of greenhouse gases we continue to pump into the atmosphere. >>It's vital that scientists continue researching geoengineering; but no >>government serious about climate change should see it as a quick fix." >> >>Prof Piers Forster, Professor of Climate Change at the University of Leeds, >>said: >> “In climate model simulations, aerosol injection into the stratosphere has >>been shown to temporarily suppress CO2-driven temperature change but also >>altering rainfall patterns - a so-called side effect. >> “This paper comes up with another possible side effect of injecting aerosol >>into the stratosphere. Earlier work has found that injection can affect the >>location of tropical rainfall. This work hints at a more general suppression >>of tropical rainfall. >> “At present these injection technologies do not exist, even on paper, and >>this precludes an evaluation of realistic effectiveness or side effects. If >>we want to suppress global warming the only game in town at present is >>reducing greenhouse gas emissions.” >>I would have attached the paper also, but can't really because I only have >>the early 'not for circulation' copy provided by SMC. The article is supposed >>to be up at ERL today, but isn't yet. I'm sure Angus can provide one... >> >> >>Matt >> >> >> >> >> >>On Wed, Jan 8, 2014 at 9:31 AM, Andrew Lockley <[email protected]> wrote: >> >>Poster's note : paper seemingly not released yet. Hopefully authors will >>provide a copy. >>>http://www.independent.co.uk/ news/science/plan-to-avert- >>>global-warming-by-cooling- planet-artificially-could- >>>cause-climate-chaos-9043962. html >>>Plan to avert global warming by cooling planet artificially 'could cause >>>climate chaos' >>>Proposal to inject tiny reflective particles into the upper atmosphere to >>>block out sunlight could lead to droughts, warn scientists >>>Wednesday 08 January 2014 >>>A controversial proposal to cool the planet artificially by injecting tiny >>>reflective particles into the upper atmosphere which block out sunlight >>>would cause droughts and climate chaos in the poorest countries of the >>>world, a study has found. >>>One of the more serious plans to “geoengineer” the global climate would in >>>effect create another climate catastrophe that would result in misery for >>>millions of people, according to a computer model of the plan.Some climate >>>researchers have suggested that mimicking the cooling effects of volcanic >>>eruptions with massive injections of sulphate particles into the atmosphere >>>may be necessary in an emergency if global temperatures and carbon dioxide >>>levels continue to rise unabated.It is known that the sulphate particles >>>produced by volcanoes, which are relatively quickly washed out of the >>>atmosphere, can reduce incoming solar radiation significantly, and so cause >>>average global temperatures to dip.However, a study by scientists at Reading >>>University has found that the effect of a massive and continuous injection >>>of sulphates into the air would be to alter the rainfall patterns over vast >>>regions of the world, notably Africa, South America and Asia which could as a result be devastated by drought.“We have shown that one of the leading candidates for geo-engineering could cause a new unintended side-effect over a large part of the planet,” said Andrew Charlton-Perez of the University of Reading, a co-author of the study published in the journal Environmental Research Letters.“The risks from this kind of geo-engineering are huge. A reduction in tropical rainfall of 30 per cent would, for example, quickly dry out Indonesia so much that even the wettest years after a man-made intervention would be equal to drought conditions now,” Dr Charlton-Perez said.“The ecosystems of the tropics are among the most fragile on Earth. We would see changes happening so quickly that there would be little time for people to adapt.“Discussion of geo-engineering often prompts heated debate, but very often there is a lack of understanding of what putting large amounts of aerosol in the stratosphere will do to the complex climate system. Our findings should help to fill in some of the gaps about one of the leading candidates,” he said.Volcanoes, such as the Mount Pinatubo eruption in 1991, can cool average global temperatures significantly for short periods, but to reverse the expected 4C rise in global temperatures as a result of global warming would need large quantities of sulphate aerosols to be injected into the upper atmosphere over the course of several years.“To reduce global temperatures enough to counter effects of global warming would require a massive injection of aerosol – the small particles that reflect sunlight back into space. This would be equivalent to a volcanic eruption five times the size of that of Mount Pinatubo every year,” said Angus Ferraro of Exeter University.“Previous predictions of how stratospheric aerosol injection would affect climate were based on a number of assumptions. By actually modelling what would happen if aerosol were to be pumped into the atmosphere around the equator, we have revealed a new impact of geo-engineering on tropical climate,” Dr Ferraro said.“As well as reflecting some of the incoming energy from the sun and cooling surface temperature, the aerosol also absorbs some of the heat energy coming from the surface which warms the stratosphere. We have shown for the first time that warming the stratosphere makes the troposphere below more stable, weakening upward motion and reducing the amount of rainfall at the surface,” he said.Professor Ellie Highwood of University of Reading, a co-author of the study said that there is an understandable desire to explore alternatives to deep-cuts in carbon dioxide emissions, which do not seem to be materialising as a result of the failure of countries to reach a binding international agreement.“Climate scientists agree that cutting carbon emissions is still necessary to curb the damaging effects of future climate change. However, since such cuts are far from certain to materialise, proponents of geo-engineering research argue that whatever the world decides on its carbon emissions, it would be prudent to explore alternatives that might help us in the decades ahead,” Professor Highwood said.“On the evidence of this research, stratospheric aerosol geo-engineering is not providing world leaders with any easy answers to the problem of climate change,” she said. -- >>>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. >>>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. >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. >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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