Michael and list:
1. Below you closed, saying: “…. it may be possible to develop a
completely new SRM geoengineering regimen which can be governed at the local
level and would have an extremely short wave effect.
> Anyone in this group interested in signing on to that effort? "
2. My answer is “Yes” - as I think you have noticed a potentially
important link between CDR and SRM. I have since tried to follow this and now
see this is a large area, which the “Geo” group has already looked at a little
in talking briefly about the work of Professor Nadine Unger - through this cite:
http://blog.cifor.org/24311/on-forests-role-in-climate-new-york-times-op-ed-gets-it-wrong#.VfYVNmRVikp
3. Professor Unger’s “Nature” article, normally behind a pay wall is
free at: http://web.nateko.lu.se/courses/ngen03/nclimate2347.pdf. There is
a strong negative response by an impressive group also writing in the NYT,
shown at:
http://news.mongabay.com/2014/09/scientists-rebut-nytimes-op-ed-to-save-the-planet-dont-plant-trees/
4. I don’t think this “Geo” list has yet covered this mixed SRM-CDR
topic adequately. I have run out of time today, and will add more.
Ron
On Sep 12, 2015, at 3:21 PM, Michael Hayes <[email protected]> wrote:
> Nature is...never...that simple. Mr. Battersby is only telling half the story!
>
> Pseudomonas syringae elicits emission of the terpenoid
> (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene in Arabidopsis leaves via
> jasmonate signaling and expression of the terpene synthase TPS4. Attaran E,
> Rostás M, Zeier J. Mol Plant Microbe Interact. 2008 Nov;21(11):1482-97. doi:
> 10.1094/MPMI-21-11-1482.
>
>
> "[...] Inoculation of plants with virulent or avirulent P. syringae strains
> induces the emission of the terpenoids
> (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), beta-ionone and
> alpha-farnesene.[...]".
>
> In brief. the P.syringae bacterium has a remarkable high temperature ice
> (cloud) nucleation ability which is rather useful in cloud formation and
> artificial snow production. It is also somewhat remarkable at defending
> itself when it's hanging out in the forest. In that, it will exude toxins
> which basically kill off most any other bacteria around it. When these toxins
> irritate the plant, the plant in turn, turns up the production of terpenes
> which, in turn, helps the syringae migrate back up to the clouds.
>
> So, yes, Mr. Battersby is correct when he stated that "Bacteria have been
> found growing in clouds, and they may help seed cloud formation." and
> terpenes help that happen simply due to their volatile nature.
>
> Here is an interesting read on the details of this relationship:
>
> Biogenic volatile organic compounds in the Earth system - Jullada
> Laothawornkitkul, Jane E. Taylor, Nigel D. Paul and C. Nicholas Hewitt - New
> Phytologist (2009) 183: 27–51 doi: 10.1111/j.1469-8137.2009.02859.x
>
> "[...] biogenic volatile organic compounds mediate the relationship between
> the biosphere and the atmosphere. Alteration of this relationship by
> anthropogenically driven changes to the environment, including global climate
> change, may perturb these interactions and may lead to adverse and
> hard-to-predict consequences for the Earth system.".
>
> And so, if this phenomenon is seriously considered at the geoengineering
> level, it would not be hard to pull together a detailed proposal on just how
> both terpenes and P. syringae can be generated on a low cost and large scale
> so as to increase tropospheric cloud cover. Using this as an enhancement to
> the local Hydrologic Cycle, in areas which need the water/shade (i.e.
> glaciers, farmland and basically most of the planetary biosphere), it may be
> possible to develop a completely new SRM geoengineering regimen which can be
> governed at the local level and would have an extremely short wave effect.
>
> Anyone in this group interested in signing on to that effort?
>
> Best,
>
> Michael
>
>
> On Saturday, September 12, 2015 at 9:13:15 AM UTC-7, andrewjlockley wrote:
> Poster's note - this is an effect I've been thinking about for a long time.
> Can we manipulate trees (genetically or arboiculturally) to make them produce
> more secondary organic aerosols?
>
> https://www.newscientist.com/article/mg21829231-900-gaias-comeback-how-life-shapes-the-weather/
>
> Gaia’s comeback: How life shapes the weather
>
> The world would be warming even faster if forests weren't calling in the
> clouds. Could it be that Gaia is not so helpless after all?
>
> YOU’VE done it half a dozen times today without giving it a second thought.
> If it was chilly in the morning, you may have turned up the heating or put on
> another layer. As the day got warmer perhaps you opened a window to cool
> things down. We are adept at controlling our immediate environment.
>
> What about the living planet as a whole? Can the biosphere regulate the
> environment to suit itself, preventing the planet from freezing or boiling?
> This is the essence of the Gaia hypothesis proposed in the 1960s by James
> Lovelock, but climate scientists have never bought into it. They point out
> that there have been some wild swings in the climate, some of which were
> caused by life.
>
> Read more: “James Lovelock and the Gaia hypothesis“
>
> But now it appears the world would have warmed a bit more than it has were it
> not for the aromatic cocktail of chemicals emitted by plants. It turns out
> this can change the weather – and anything that changes the weather day after
> day and year after year changes the climate, too. While this new mechanism is
> nowhere near strong enough to save us from global warming, it may have been
> stronger in the past when the air was cleaner. So could it be that Gaia is
> not powerless after all?
>
> There is no doubt that life plays many key roles in the climate system. The
> air we breathe, rich in oxygen with only traces of carbon dioxide, is created
> by plants. Trees suck up huge quantities of rainwater that would otherwise
> flow back into the sea, and release it into the air. Much of the rain in the
> Amazon may come from the trees themselves.
>
> There are all kinds of other effects. Bacteria have been found growing in
> clouds, and they may help seed cloud formation. Blooms of plankton in the sea
> soak up the sun’s heat, warming the surface. The list goes on and on.
>
> The question is, how important are these processes? In particular, is life
> totally at the mercy of external influences such as the sun, or can it
> control the climate to some extent? Lovelock’s suggestion was that living
> organisms work in concert with nonbiological processes to regulate the
> environment. He pointed out that over the past 4 billion years the sun has
> become brighter, and yet the long-term temperature of Earth has remained
> suitable for life. Life might act as a planetary thermostat, Lovelock said,
> as well as maintaining the salinity of the oceans and other chemical balances.
>
> To this day, Lovelock regards Gaia’s existence as self-evident. “Earth’s
> atmosphere is so massively in chemical disequilibrium, for it to stay stable
> for any time requires a very powerful regulating system,” he says. But even
> if life does help control the composition of the air and seas, its ability to
> regulate temperature is much more dubious.
>
> We know now that there have been some violent swings in the climate,
> including a few “Snowball Earth” phases during which most of the planet
> froze, almost wiping out life. These super ice ages may well have been
> triggered by living organisms sucking the carbon dioxide out of the
> atmosphere and cooling the planet.
>
> It is now thought Earth was saved from an icy doom by a geological
> thermostat. When the planet gets hot, rocks break down faster, reacting with
> CO2 and removing it from the atmosphere. When it cools, this weathering
> process slows down, and the CO2 emitted by volcanoes begins to accumulate in
> the air.
>
> Gaia revisited
>
> This negative feedback keeps temperatures within the “just right” Goldilocks
> zone, but it takes many millions of years to kick in, which still leaves room
> for the living part of Gaia to step up. Perhaps life usually helps prevent
> swings on a shorter timescale, even if things do go catastrophically wrong on
> occasion? What would make the idea more convincing is a clear-cut mechanism.
> When the temperature starts to get too high or too low, then living organisms
> should respond in some way to move it in the opposite direction, back towards
> a happy medium.
>
> In 1987 Lovelock and others proposed one such mechanism. They pointed out
> that algae in the sea emit a gas called dimethyl sulphide, which can react
> with air to form sulphuric acid vapour and condense into small particles, or
> aerosols. Such aerosols can cool the planet by reflecting sunlight directly
> and also indirectly by making clouds whiter.
>
> Cloud formation requires more than just cooling moist air. Water droplets do
> not form and grow unless the air has suitable particles, or nuclei, for the
> water to condense onto. These nuclei must be upwards of 100 nanometres or so
> in size. The sulphuric acid aerosols from dimethyl sulphide could be just the
> ticket if they grow large enough. When temperatures rise, the group reasoned,
> algae should thrive and emit more dimethyl sulphide, seeding more cloud
> droplets. More droplets means whiter clouds, which reflect more sunlight and
> cool things down, completing the negative feedback loop.
>
> This idea, called the CLAW hypothesis after the initials of its four authors,
> inspired a lot of research – but it appears to be feeble at best.
> Observations show that as much as 60 per cent of the cloud condensation
> nuclei above the oceans are provided by salt spray, and most of the rest are
> solid organic compounds also sprayed directly from the sea surface. That
> leaves little room for the involvement of sulphate aerosols, as Patricia
> Quinn and Timothy Bates of the Pacific Marine Environmental Laboratory in
> Seattle pointed out in a 2011 review (Nature, vol 480, p 51).
>
> Another stage in the proposed feedback loop is also doubtful. “People go out
> on ships and incubate algae to look at their response to an increase in
> temperature or radiation,” says Quinn. The algae do emit more dimethyl
> sulphide when the sea warms up, but only slightly; not enough to whitewash
> the sky.
>
> So the CLAW effect seems too weak to pull Earth’s climate levers. Maybe that
> job can be done by a green tendril instead. In 2004 Markku Kulmala at the
> University of Helsinki suggested a new feedback loop. In a pine forest in
> southern Finland, he and his team had been measuring the concentration of a
> group of chemicals called terpenes. Terpenes are produced by many plants and
> they evaporate readily into the air – they are volatile, in other words. We
> perceive terpenes as part of that pleasant smell of pine forests, and they
> are the main constituents of genuine turpentine distilled from pine resin.
>
> “The chemicals that give pine forests that pleasant smell could have a huge
> influence on cloud formation”
>
> As they float about in the air, terpene molecules and other volatile organic
> compounds become oxidised, making them less volatile. They then condense onto
> any tiny aerosol particles already in the air, making them larger. That means
> more aerosols grow to a given size. Over several years, Kulmala’s group
> monitored terpenes and the number of aerosol particles about 3 nanometres
> across above a Scots pine forest in Finland. They found a strong correlation
> between the two, with both peaking in summer when plants are growing most
> vigorously. This led Kulmala to suggest that if the climate warms, plants
> might emit even more volatiles and make more planet-cooling aerosols – a
> negative feedback that would counteract the warming.
>
> But this was only an educated guess. Kulmala’s studies did not show that
> forests emit more volatiles as the temperature rises. Nor did it show whether
> the aerosol particles could grow large enough for them to seed cloud droplets
> – at least 100 nanometres across. And the data came from just one site –
> hardly evidence of a worldwide phenomenon.
>
> Meanwhile, far from the forests of Finland, Jasper Kirkby and his team were
> busy making clouds in a large stainless steel chamber at the CERN particle
> physics laboratory near Geneva, Switzerland. In some of the experiments, the
> CERN team tried to recreate the first step in cloud formation: how gases
> condense to form embryonic aerosol particles. “If you look to the mountains
> one day after a rainstorm has cleansed the atmosphere, there is already a
> blue haze. Those are new aerosol particles that have formed from trace gases,
> scattering light into your eye,” says Kirkby. New particles require sulphuric
> acid vapour to form. That comes from sulphur dioxide, a by-product of human
> industry as well as those marine algae.
>
> Stick’em together
>
> It had been thought that sulphuric acid vapour could condense on its own, but
> the results of Kirkby’s studies, released in 2011, proved otherwise. A few
> molecules might stick together, but these embryonic aerosols are unstable.
> They almost always evaporate instead of growing larger.
>
> When the team added traces of ammonia to the air, however, it stabilised the
> growing sulphuric acid cluster, increasing the number of viable aerosol
> particles by as much as 1000 times. Yet this is still just a thousandth of
> the formation rate of sulphuric acid aerosols actually seen in our
> atmosphere, so something else must be stabilising their growth.
>
> “After we ruled out ammonia, the only other possibility was organic
> compounds,” says Kirkby. “We have now made a series of measurements with
> several different organics.” Those results are under review, so Kirkby will
> not comment further except to say that they are “very interesting” and due
> out later this year.
>
> Nevertheless, his team’s published work suggests that volatile organic
> compounds could have a huge influence on clouds by helping sulphate aerosols
> to form in the first place, in addition to making existing aerosol particles
> grow larger.
>
> And volatile organic compounds could influence clouds in a third way,
> according to Gordon McFiggans’s team at the University of Manchester, UK. As
> cloud-condensation nuclei collect water and grow into a droplet, volatiles
> are absorbed along with the water, changing the chemistry of the drop to
> attract more water. In May this year, the team published a paper showing that
> this effect might substantially increase the number of droplets (Nature
> Geoscience, vol 6, p 443). And a cloud with more droplets per cubic metre is
> a whiter, fluffier cloud, reflecting more solar heat away from the Earth.
>
> McFiggans is now starting experiments in Manchester to try to find out more.
> “We have a new photochemical chamber where we can process an atmospheric soup
> of gases, hit it with an arc lamp to mimic sunlight and cook up an aerosol
> population, then squirt it into a cloud chamber,” he says. “Then we should
> see if we get denser clouds in the presence of organic vapours.”
>
> So several lines of evidence suggest organic compounds might have a big
> effect on clouds (see diagram). The clincher comes from a study involving 11
> weather stations around the planet. A team including Kulmala and led by Pauli
> Paasonen, also at Helsinki, sampled aerosols at these stations, counting the
> concentration of particles large enough to form a cloud droplet. They also
> monitored levels of a range of volatile organic compounds.
>
> In April, the team reported that they had found a strong pattern (Nature
> Geoscience, vol 6, p 438). In places such as Finland and eastern Siberia,
> where the air is clean, the number of cloud condensation nuclei rose markedly
> when the temperature went up. Paasonen calculates that over these unpolluted
> regions, the cooling effect could be powerful, offsetting up to a third of
> any local temperature rise. This might be enough to protect some forested
> areas from the worst climate swings.
>
> “In unpolluted regions, the cooling effect is powerful. It’s as if we could
> cool the world by sweating”
>
> “But in more polluted areas, the feedback is not significant,” says Paasonen.
> That makes sense, as in these spots there is already a dense haze of
> aerosols. The volatiles would make those particles slightly larger but have
> little affect on the overall number.
>
> Curiously, terpenes are thought to be involved in protecting individual
> plants from heat stress, because their release is so strongly linked to
> temperature. So it seems a strange coincidence that collectively they might
> act to cool an entire region. “It’s as if we could cool the weather by
> sweating,” says Paasonen. “That would be useful!”
>
> “It’s as if we could cool the weather by sweating. That would be useful!”
>
> Lovelock thinks it could be an evolutionary adaptation, as organisms that can
> regulate their climate should boost their survival. “If successful, they will
> spread,” he says.
>
> Globally, this cooling power of plants may not be so profound. Paasonen
> estimates that the feedback should offset around 1 per cent of global
> warming, although there is a huge uncertainty because the full effect on
> clouds is not well understood, and its global importance will not be clear
> until more sites have been studied. The true figure could be as high as 5 or
> 10 per cent, or much less than 1 per cent.
>
> “It does not save us, that’s for certain,” says Paasonen. Nor will it be easy
> to indulge in a little geoengineering to boost this effect by planting
> certain kinds of plants, as his results suggest that the effect is just as
> strong over farmland as over virgin forest. But once upon a time, before
> human pollution overwhelmed this feedback in many parts of the world, it
> could have been more powerful. “One thing the authors don’t go into is deep
> prehistory,” says Tim Lenton of the University of Exeter, UK. “When land
> plants first evolved, this could have had a significant cooling effect.”
>
> And there may be other feedbacks working in the same direction. “When you add
> them up it begins to amount to something,” says Lovelock. For example,
> volatiles may play a role at sea as well as over land, says Quinn. Salt spray
> is still likely to be the dominant source of cloud nuclei, but organic
> vapours could condense onto small salt particles to boost them to an
> effective size. A few teams have made observations at sea, but it is
> difficult to get the kind of long-term coverage that enabled Paasonen to spot
> the feedback on land.
>
> So in a small way at least, Gaia can influence the temperature.
> Unfortunately, not only have we poisoned her and sapped her power, we have
> also unleashed her evil twin. As the Arctic warms, vegetation is starting to
> replace snow and ice, and dark vegetation soaks up more of the sun’s heat – a
> positive feedback that is accelerating the warming in the Arctic. According
> to a study out earlier this year, this feedback is much stronger than
> previously thought (Nature Climate Change, doi.org/k27).
>
> It is not clear how all this stacks up. The positive feedbacks involving
> living organisms may well outweigh the negative ones, undermining the notion
> of life making a cosy nest for itself. And even if Gaia turns out to have
> more power than we realised, we cannot rely on her helping hand – we still to
> have to save ourselves.
>
> This article appeared in print under the headline “Call in the clouds”
>
> By Stephen Battersby
>
> Stephen Battersby is a consultant for New Scientist based in London
>
> Magazine issue 2923 published 29 June 2013
>
>
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