Re: Cloud Albedo enhancement via Seeding: Re: very interesting article
Sam Carana
Thanks for your helpful comments, John, these topics do indeed deserve
a lot more attention.
The interaction between cloud brightness and pollution is important.
Note that I recommend vortex towers to be built in the desert, say in
places like Australia and the Sahara, where there's little or no
proximity to large pollution sources. The impact of pollution
particles on cloud brightness there would thus not be much different
from oceans. What does need to be studied more, though, is the impact
of dust on cloud formation and cloud brightness.
Assuming that there is little or no cloud coverage in the air above
deserts to start with, formation of any type of cloud there would be
welcome. The albedo of deserts is typically below 30%, whereas any
type of cloud coverage is likely to push the albedo above the 40%.
That said, I do acknowledge the important work by Stephen Salter on
creating tiny droplets (which I wrote about as far back as more than
three years ago) and I welcome Stephen's advise on this.
Building vortex towers in the desert has until now been proposed
primarily as a clean and safe way to produce electricity. Whilst this
is of course a vitally important part of the comprehensive approach we
need to tackle climate change, there are several additional ways in
which vortex towers could be beneficial in regard to climate change.
A vortex tower would push dry, hot air high up into the sky. Some of
that heat would escape into space. Furthermore, this updraft could
also establish an air circulation pattern in which hot air would move,
high up in the sky, towards the ocean. Simultaneously, as part of this
air circulation pattern, air from above the ocean would be drawn -
closer to the ground - towards the vortex tower. This air circulation
could bring cold and moist wind into the desert, which would benefit
vegetation growth and the associated drawing of CO2 from the
atmosphere.
The energy produced by the vortex towers could be used in a number of
further ways, each of which could have a beneficial impact regarding
climate change. As an example, the energy could be used to draw carbon
from the atmosphere, in ways as suggested by David Keith. While Klaus
Lackner has focused on reducing the energy required for this process,
David Keith's method seems fit to be used in combination with vortex
towers.
Similarly, strong bases could be used to draw carbon from seawater.
Such an agent could be reused within the device that uses temperature
change to draw CO2 to a binding agent and in turn split the binding
agent from the carbon, to start the process all over again. Granted,
this takes a lot of electricity, but this is precisely why it can best
be done close to vortex towers, for the very reason that vortex towers
can produce a huge amount of energy in places (deserts) that are
typically remote from where most demand for electricity is.
This could be combined with desalination. Energy produced by the
vortex towers could be used to pump seawater to the vortex towers. The
water could be used as potable water and for irrigation. Water could
also be sprayed into the sky, using the vortex tower's updraft, to
induce cloud forming with the associated albedo change and the
benefits of rain in regard to vegetation growth.
Energy produced by the vortex towers could also be used to split water
into hydrogen and oxygen, by means of electrolysis. The hydrogen could
then be used as fuel, or to produce ammonia by drawing nitrogen from
the air (which is also beneficial in regard to climate change). The
ammonia could then be used to produce fertilizer, replacing
fertilizers that are currently produced from fossil fuel.
Finally, carbon that is drawn from the atmosphere and/or from seawater
could be turned into char, similar to biochar, with its benefits as a
soil improver and as a safe way to store carbon. This char could be
applied to the soil simultaneously with fertilizer as produced in the
way described above. Application of such fertilizer together with char
could not only reduce the need for fertilizers made with fossil fuel,
it will also reduce runoffs that cause N2O emissions and dead zones in
the sea, since the char will improve retention of fertilizer in the
soil.
As a footnote, this hydrogen could also be released into the
atmosphere in order to - under the influence of UV light - produce
hydroxyl radicals, which would in turn speed up methane oxidation. As
I have been discussing with Andrew, this may be useful in the light of
looming emissions of methane, as more arctic permafrost keeps melting.
Cheers!
Sam Carana
On Sun, Apr 12, 2009 at 12:47 AM, John Latham
<john.l...@manchester.ac.uk> wrote:
> Hello Andrew, Sam et al,
>
> Enhancing the brightness of low-level stratiform clouds is much easier over
> the oceans than over land. This is because the extra brightness requires
> enhancement of the cloud droplet number concentration N (the Twomey effect)
> and the values of N over land can be one or two orders of magnitude greater
> than over the oceans, because of the greater proximity to pollution sources.
> With seeding over land there is a considerable risk of REDUCING cloud
> brightness and longevity.
>
> Increasing the brightness of cumulonimbus clouds is a clear non-starter for
> several reasons. One is that their microphysical characteristics are
> dominated by ice processes which are very complex. Another is that the
> global area covered by these clouds is negligible vis-a-vis albedo
> enhancement.
>
> Spraying seawater droplets into the air beneath clouds cis likely to be
> counter-productive (i.e. cause a warming) unless: (1) the droplets are very
> small - around a micrometre in size, (2) the size-distribution is very
> narrow. To produce droplet size distributions meeting these criteria is
> extremely complicated, although Stephen Salter is making considerable
> progress in this arena, as a crucial part of our cloud albedo enhancement
> technique. If the spray droplets have a broad size-range and significantly
> larger sizes than the value mentioned above, the clouds are likely to have
> reduced brightness, if seeded, and also will have shorter lifetimes.
>
> Cheers, John.
>
> --
> John Latham
>
> lat...@ucar.edu & john.l...@manchester.ac.uk
>
> Tel. 303-444-2429 (H) & 303-497-8182 (W)
>
> Quoting "Sam Carana" <sam.c...@gmail.com>:
>
>>
>> Thanks Andrew,
>>
>> I had in mind adding a paragraph at the Wikipedia page on Cloud
>> reflectivity enhancement, under seawater spray.
>> http://en.wikipedia.org/wiki/Cloud_reflectivity_enhancement
>>
>> I have meanwhile added the following sentence:
>>
>> "Other proposals include the idea of making clouds with wind turbines
>> and building vortex towers in the desert to use the energy thus
>> generated (partly) to pump seawater to the towers and spray water into
>> the sky, as discussed at the Google Geoengineering group."
>>
>> http://groups.google.com/group/geoengineering/browse_thread/thread/9442d261d9de39be/
>>
>> Feel encouraged to add and make changes to that paragraph. I hope this
>> will lead to some further people taking note of such proposals and
>> pointing at research data that may be applicable.
>>
>> Cheers!
>> Sam Carana
>>
>>
>>
>> On Sat, Apr 11, 2009 at 6:33 PM, Andrew Lockley
>> <andrew....@gmail.com> wrote:
>>> Sam, there is already a Wikipedia article about this
>>> http://en.wikipedia.org/wiki/Hydraulic_geoengineering
>>> It would be great to see more contributions. I am happy to add them if
>>> you
>>> send me links to papers or to conference presentations. I'd be
>>> particularly
>>> interested in any forestry and cloud seeding projects that operate with
>>> this
>>> goal in mind.
>>> You can see the cloud seeding wiki
>>> at http://en.wikipedia.org/wiki/Cloud_seeding
>>> and the weather modification one
>>> at http://en.wikipedia.org/wiki/Weather_modification
>>> Here's an extract from the hydraulic geoeng wiki
>>>
>>> Australia
>>>
>>> In 1998, John West came up with the idea of a 2,300km canal to split
>>> Australia in two, from Darwin in the north to the Spencer Gulf in South
>>> Australia. The canal would allow ships to access the center of Australia
>>> and
>>> provide water for irrigation by means of desalination plants. Much water
>>> would evaporate inland from the canal and contribute to clouds and rain.
>>>
>>> Lawrence James Hogan described in his book "Man-made mountain", 1979
>>> (ISBN
>>> 0959557105) the idea to construct a mountain range, 2000km long, 10km
>>> wide
>>> at the base, 4 km tall and with a 2km plateau at the top, from the south
>>> of
>>> Australia to the Timor Sea in the north. The idea was that this could
>>> create
>>> rain in the dry interior of Australia, starting rivers that could
>>> fertilize
>>> large tracts of land.
>>>
>>> Proposals to pipe or channel seawater into Lake Eyre were made as far
>>> back
>>> as 1883. Lake Eyre is a usually dry lake which at its lowest point is 15
>>> meter below sea-level. Flooding Lake Eyre could create clouds and rain
>>> for
>>> inland Australia, which could similarly turn desert into fertile land.
>>>
>>> [edit]China region
>>>
>>> For years there have also been fears in India that China would start
>>> diverting water from the Yarlung Zangbo River (upper reaches of
>>> the Brahmaputra) in the Himalaya to the north of China. In 2006[citation
>>> needed], China's Water Resources Minister Wang Shucheng, a hydraulic
>>> engineer, denied that there were such plans, but the fears continue in
>>> India
>>> and Bangladesh.
>>>
>>> Because such plans affect huge amounts of people and span huge amount of
>>> land, they are sometimes described as geoengineering projects. Similarly,
>>> the Three Gorges Dam, constructed along the Yangtze river, is - because
>>> of
>>> its huge scale - sometimes described as a hydrological geoengineering
>>> project.
>>>
>>> In 2003, the Chinese government announced plans for a $60-billion scheme
>>> to
>>> divert water from a tributary of the River Yangtze northwards from three
>>> different locations, partly using the old Grand Canal, which was built in
>>> imperial times to transport goods. Earlier this month, New
>>> Scientist reported that the completion date for the has been postponed
>>> and
>>> that the project is now in doubt. The eastern route, using the ancient
>>> Grand
>>> Canal, is held up because factories are polluting the canal. The western
>>> route, tapping the Yangtze headwaters in Tibet, has not been started.
>>> Officials also blame pollution for the latest delay to the middle route -
>>> a
>>> canal stretching more than 1200 kilometres from the Danjiangkou reservoir
>>> on
>>> the River Han.
>>>
>>> [edit]Russian region
>>>
>>> Map of Russia showing rivers that could be redirected from theArctic
>>> Main article: Northern river reversal
>>>
>>> These suggested projects are over a century old.
>>>
>>> The project to turn Siberian rivers South is well-known in Russia and the
>>> origin of the idea goes back as far as to the 1830s when a czarist
>>> surveyor
>>> named Alexander Shrenk first proposed it.[1] when the big canal
>>> engineering
>>> projects were conceived (i.e. the Suez and Panama canals).
>>>
>>> A century after Shrenk expressed his idea of redirecting Russia's rivers
>>> to
>>> the South, The USSR Academy of Sciences held a conference investigating
>>> his
>>> ideas in November 1933. This conference spun out interest that produced
>>> many
>>> serious engineering case studies trying to validate the possibility of
>>> the
>>> water return concept. The Hydroproject, the dam and canal institute, led
>>> by
>>> Sergey Yakovlevich Zhuk commenced many of these studies.[2]
>>>
>>> In 1970's construction started to divert the Pechora and Kama Rivers
>>> toward
>>> the Volga and the Caspian Sea in the south in western Russia. For the
>>> sake
>>> of cost-effectiveness, a 70-mile stretch was levelled with the help of
>>> nuclear explosives, this novel land clearance method drew sharp
>>> criticisms
>>> on environmental pollution grounds for fear of pollution. Three
>>> 15-kiloton
>>> devices were deployed and it was estimated that 250 more nuclear
>>> detonations
>>> was required to complete the levelling for the channel if the procedure
>>> had
>>> been continued. The pollution on surface was found to be manageable. In
>>> the
>>> US the expert opinion was divided with some endorsing this project like
>>> the
>>> physicist Glenn Werth, of the University of California's Lawrence
>>> Livermore
>>> Laboratory, as "both safe and economical".[3][1] Others feared climatic
>>> cooling from reduced river water flow, while others thought that
>>> increased
>>> salinity would melt ice and cause warming. Further work on this
>>> irrigation
>>> canal was soon stopped.
>>>
>>> In 1980's at least twelve the Arctic Ocean-bound rivers were proposed to
>>> be
>>> redirected back to the south. At that time it was estimated that an
>>> additional freeze-up would occur to cut the brief northern growing season
>>> by
>>> two weeks if 37.8 billion extra cubic meters of water was returned
>>> annually
>>> to the south in European side of Russia and 60 billion cubic meters in
>>> Siberia. The adverse effect of climatic cooling was feared very much and
>>> contributed much to the opposition at that time and the scheme was not
>>> taken
>>> up. Severe problems was feared from the thick ice expected to remain well
>>> past winter in the proposed reservoirs. By retarding the spring thaw, it
>>> was
>>> feared, the prolonged freeze-up could cut the already brief northern
>>> growing
>>> season by two weeks. The prolonged winter weather was also feared to
>>> cause
>>> increase in spring winds and reduce vital rains. More disturbing, some
>>> scientists cautioned that if the Arctic Ocean was not replenished by
>>> fresh
>>> water, it would get saltier and its freezing point would drop, the icecap
>>> would begin to melt, possibly starting a global warming trend. Other
>>> scientists feared that the opposite might occur: as the flow of warmer
>>> fresh
>>> water would be reduced, the polar ice may could expand. A British
>>> climatologist Michael Kelly of the University of East Anglia cautioned of
>>> the consequences: changes in polar winds and currents might reduce
>>> rainfall
>>> in the regions to benefit from the river redirection.[4][2] In a
>>> retrospect,
>>> this Arctic cooling fear has proven to be quite horribly misplaced advice
>>> as
>>> the north of Russia has had a significantly increased rainfall while the
>>> rains in the south have decreased without any helpful supply from the
>>> proposed supply of 100 billion cubic metres of water per annum as it was
>>> proposed.
>>>
>>> In 1986 a resolution "On the Cessation of the Work on the Partial Flow
>>> Transfer of Northern and Siberian Rivers" was passed by The Resolution of
>>> the Political Bureau of the Central Committee of the CPSU which halted
>>> the
>>> discussion on this matter for more than decade.[5] The Soviet Union and
>>> thenRussia have continued with the other regional powers these studies
>>> weighing in the costs and benefits of turning Siberia's rivers back to
>>> the
>>> south and using the redirected water in Russia, Central Asian countries
>>> plus
>>> nearby regions of China for agriculture, household and industrial use,
>>> and
>>> perhaps also for rehabilitating water inflow to the Aral Sea.
>>>
>>> According to Aleksey Yablokov, President of the NGO Center for Russian
>>> Environmental Policy, 5-7% redirection of the Ob's water could lead to
>>> long
>>> lasting might change the climate in the Arctic and elsewhere in Russia
>>> and
>>> opposes to these changes to change the environment by Siberian water
>>> redirections to the south.[6]. Despite the increase in Siberian rain
>>> fall,
>>> the redirection has become highly politicised and Yaroslav Ishutin,
>>> director
>>> of the Altai Krai Regional Department of Natural Resources and the
>>> Environment claims that the Ob has no water to spare and Siberia's water
>>> resources are threatened.[7][3]
>>>
>>> In early 21st century interest on this Siberian "water return" project
>>> was
>>> again resumed and the Central Asian states (President Nursultan
>>> Nazarbayev of Kazakhstan, President Islam Karimov of Uzbekistan as well
>>> as
>>> the Presidents of Kyrgyzstan and Tajikistan) held an informal summit
>>> with Russiaand China to discuss the project.[8][4]
>>>
>>> [edit]Large Water Bodies Oxygenation Projects
>>>
>>> Very large scale plans to oxygenate seas, oceans, and major river systems
>>> such as the Amazon river belong to realm of geoengineering projects due
>>> to
>>> nature of these large scale attempts to modify the oxygen, phosphate and
>>> organic matter composition of these water bodies to improve their
>>> ecosystems
>>> and make them more resilient against stresses such as pollution, climatic
>>> warming related weather events and other natural events such as sea
>>> currents
>>> that cause major losses of natural life. In the context of global warming
>>> these efforts aim to make the ecolocical systems more resilient to heat
>>> stresses, often amplified by direct human activity that provides the
>>> initial
>>> burdens.
>>>
>>> Large scale perennial and temporary oxygen depletions are observed in the
>>> Baltic Sea, the Black Sea, Chesapeake Bay, the Pacific Ocean on the
>>> coasts
>>> of Washington and Oregon states, the Atlantic Ocean around St. Lawrence,
>>> and
>>> the Amazon river in South America. One of the principal contributors has
>>> been the increased water temperatures that reduce amount of the oxygen
>>> that
>>> is dissolving as well as the disappearance of rains that create air
>>> bubbles
>>> onto the surface of water (which is important in the tropical rain forest
>>> river systems thus oxygenating them, but not in the oceans or lakes away
>>> from these types of rainy regions).
>>>
>>> [edit]The Baltic Sea Oxygenation Projects
>>>
>>> From the large water body oxygenation projects the oxygenation studies on
>>> the Baltic Sea are the most advanced, and varied, in the world of the
>>> various large water bodies' oxygenation projects conceived or already in
>>> various degrees of trials.
>>>
>>> Matti Lappalainen began series of studies to establish possibilities to
>>> scale up artificial oxygenation from small water bodies such as ponds,
>>> lakes
>>> and rivers to much large water bodies such as oceans, seas and very large
>>> rivers. Artificial oxygenation often reveals a set of feedbacks while it
>>> is
>>> helpful in cutting off other feedbacks. In some instances, the water
>>> bodies
>>> store or accumulate away problems (i.e. phosphate load on sediments) and
>>> when oxygen is then added, these accumulated problems that had been
>>> salted
>>> away in the bottom sediments are gradually started to be sorted out and
>>> re-emerge, this slows the initial recovery as the old dirt and
>>> un-decomposed
>>> materials come visible from 'under the carpet' and re-circulate back into
>>> system before their final disposal, increasing the cost and reducing
>>> perceived recovery speed of the systems. The experiments were made in
>>> small
>>> Lake Särkinen, Sotkamo, Finland and medium-size Lake Pyhäjärvi, Tampere,
>>> Finland using Mixox hypolimnetic oxygenation method developed by Matti
>>> Lappalainen assessing the changes in organic and phosphate loads and how
>>> the
>>> water quality was eventually improving in these.[9]
>>>
>>> The artificial oxygenation methods have since then been expanded to
>>> larger
>>> scale projects with the objective of resolving the oxygen depletion and
>>> associated phosphate and organic decomposable nutrient related pollution
>>> problems in the Baltic Sea that are influenced by nutrient run off,
>>> increasing water temperatures, and changes in the ocean circulation
>>> (until
>>> now perhaps the most important factor in the Baltic Sea)[10], residue
>>> from
>>> treated or untreated sewage flow from conurbations and agricultural
>>> fertilisation. Atmosmare Foundation is separately investigating and
>>> testing
>>> methods of cutting off agricultural fertilisation phosphate and
>>> biomaterial
>>> runoff from the Aurajoki Basin to the Baltic Sea, at Savijoki,
>>> Lieto.[11][5], [12][6]. According to Matti Lappalainen, the principal
>>> difficulty in the scale-up from the lake to sea environment has been the
>>> issue of allocating the responsibility and ownership of the problem when
>>> seas, oceans or transnational river basins lose their health due to human
>>> pollution often in combination with the acts of nature and when the
>>> harmful
>>> consequences are manifested across the border or on the international
>>> waters.
>>>
>>> The initial project to learn how it would be possible to oxygenate the
>>> Baltic Sea was conducted at Pohjanpitäjänlahti, Finland which is often
>>> referred as a ‘Mini-Baltic Sea’ due to similarity of its ecosystems to
>>> the
>>> structures of the Baltic Sea as a whole. [13]
>>>
>>> Naturvårsverket, 'the Swedish Environmental Protection Agency' (in
>>> English),
>>> Verket för Innovationssystem (VINNOVA) 'Swedish Governmental Agency for
>>> Innovation Systems' (in English) and The Baltic Sea 2020 are funding
>>> PROPPEN[14]The Biological Pilot Research Project to Oxygenate the Deep
>>> Water
>>> Sites of the Baltic Sea, a €1,000,000 sea-scale oxygenation research
>>> project[14] that started 9.1.2009. The project uses Mixox hypolimnetic
>>> oxygenation method and is led by Dr. Heikki Pitkänen.[15] with Vesi-Eko
>>> Oy,
>>> Water-Eco Ltd[16][www.vesieko.fi] The site to be oxygenated is
>>> Sadöfjärden
>>> (17 km2), at Hanko Archipelago near Tammisaari, Finland to learn benefits
>>> from large area oxygenation with a smaller €200,000 project site
>>> Lännertasundet (1.9 km2) in Stockholm Archipelago,
>>> Sweden.[17]VINNOVA[7][8][18][19][9][10] A second project BOX funded by
>>> same
>>> consortium is headed by Professor Anders Stigebrand of University of
>>> Gothenburg starts €2,000,000 oxygenation project with different method
>>> takes
>>> place also in Stockholm Archipelago in the Baltic Sea.
>>>
>>> [edit]The Amazon River Oxygenation
>>>
>>> Veli Albert Kallio[20] and Matti Lappalainen proposed oxygenation of the
>>> Amazon river at World Water Week in August 2006.[21] There were sustained
>>> draught event from 2005 to 2006 that influenced much of the north and
>>> central parts of South America leading much of the Amazon becoming anoxic
>>> and dead. Their brief paper discussed dangers of sudden swings in the
>>> Amazon’s climate and how these ecological risks might be reduced to
>>> secure
>>> the future of the Amazon river system in a warming climate by some
>>> large-scale engineering and land management processes that also included
>>> oxygenation of the Amazon river water.[22][11]
>>>
>>> 2009/4/11 Sam Carana <sam.c...@gmail.com>
>>>>
>>>> Making rain is an important issue for further discussion by this group
>>>> and it should qualify as a separate geoengineering project and added
>>>> as such to Wikipedia.
>>>>
>>>> Making rain can be done artificially in several ways, such as by cloud
>>>> seeding and by spraying seawater into the sky.
>>>>
>>>> This can have the dual benefits of albedo change and soil fertility,
>>>> which leads to more carbon being drawn from the atmosphere.
>>>>
>>>> Proposals to spray seawater into the sky include Stephen Salter's
>>>> self-navigation ships, my own proposal to use wind turbines and
>>>> another proposal I am working on, which is to build vortex towers in
>>>> the desert and use the energy thus generated (partly) to pump seawater
>>>> to the towers and spray water into the sky.
>>>>
>>>> Cheers!
>>>> Sam Carana
>>>>
>>>>
>>>>
>>>> On Sat, Apr 11, 2009 at 3:43 AM, Andrew Lockley
>>>> <andrew....@gmail.com> wrote:
>>>> > This isn't applied to geo-eng yet, but I can think of a plethora of
>>>> > geoeng
>>>> > opportunities arising from this effect. I find it amazing that such a
>>>> > fundamental effect has apparently been missed.
>>>> >
>>>> >
>>>>
>>>> http://www.newscientist.com/article/mg20227024.400-rainforests-may-pump-winds-worldwide.html?full=true
>>>> >
>>>> > THE acres upon acres of lush tropical forest in the Amazon and
>>>> > tropical
>>>> > Africa are often referred to as the planet's lungs. But what if they
>>>> > are
>>>> > also its heart? This is exactly what a couple of meteorologists claim
>>>> > in
>>>> > a
>>>> > controversial new theory that questions our fundamental understanding
>>>> > of
>>>> > what drives the weather. They believe vast forests generate winds that
>>>> > help
>>>> > pump water around the planet.
>>>> >
>>>> > If correct, the theory would explain how the deep interiors of
>>>> > forested
>>>> > continents get as much rain as the coast, and how most of Australia
>>>> > turned
>>>> > from forest to desert. It suggests that much of North America could
>>>> > become
>>>> > desert - even without global warming. The idea makes it even more
>>>> > vital
>>>> > that
>>>> > we recognise the crucial role forests play in the well-being of the
>>>> > planet.
>>>> >
>>>> > Scientists have known for some time that forests recycle rain. Up to
>>>> > half
>>>> > the precipitation falling on a typical tropical rainforest evaporates
>>>> > or
>>>> > transpires from trees. This keeps the air above moist. Ocean winds can
>>>> > spread the moisture to create more rain. But now Victor Gorshkov and
>>>> > Anastassia Makarieva of the St Petersburg Nuclear Physics Institute in
>>>> > Russia say that forests also create winds that pump moisture across
>>>> > continents.
>>>> >
>>>> > How can forests create wind? Water vapour from coastal forests and
>>>> > oceans
>>>> > quickly condenses to form droplets and clouds. The Russians point out
>>>> > that
>>>> > the gas takes up less space as it turns to liquid, lowering local air
>>>> > pressure. Because evaporation is stronger over the forest than over
>>>> > the
>>>> > ocean, the pressure is lower over coastal forests, which suck in moist
>>>> > air
>>>> > from the ocean. This generates wind that drives moisture further
>>>> > inland.
>>>> > The
>>>> > process repeats itself as the moisture is recycled in stages, moving
>>>> > towards
>>>> > the continent's heart (see diagram). As a result, giant winds
>>>> > transport
>>>> > moisture thousands of kilometres into the interior of a continent.
>>>> >
>>>> > Coastal forests create giant winds that push water thousands of
>>>> > kilometres
>>>> > inland
>>>> >
>>>> > The volumes of water involved in this process can be huge. More
>>>> > moisture
>>>> > typically evaporates from rainforests than from the ocean. The Amazon
>>>> > rainforest, for example, releases 20 trillion litres of moisture every
>>>> > day.
>>>> >
>>>> > "In conventional meteorology the only driver of atmospheric motion is
>>>> > the
>>>> > differential heating of the atmosphere. That is, warm air rises,"
>>>> > Makarieva
>>>> > and Gorshkov told New Scientist. But, they say, "Nobody has looked at
>>>> > the
>>>> > pressure drop caused by water vapour turning to water." The
>>>> > scientists,
>>>> > whose theory is based on the basic physics that governs air movement
>>>> > have
>>>> > dubbed this the "biotic pump" and claim it could be "the major driver
>>>> > of
>>>> > atmospheric circulation on Earth". This is a dramatic claim. The two
>>>> > Russians argue that their biotic pump underlies many pressure-driven
>>>> > features of the tropical climate system, such as trade winds, and
>>>> > helps
>>>> > create intense local features like hurricanes.
>>>> >
>>>> > To back up their hypothesis they show how regions without coastal
>>>> > forests,
>>>> > such as west Africa, become exponentially drier inland. Likewise, in
>>>> > northern Australia, rainfall drops from 1600 millimetres a year on the
>>>> > coast
>>>> > to 200 mm some 1500 kilometres inland. In contrast, on continents with
>>>> > large
>>>> > forests from the coast to interior, rainfall is as strong inland as on
>>>> > the
>>>> > coast, suggesting the trees help shuttle moisture inland (Ecological
>>>> > Complexity, DOI: 10.1016/j.ecocom.2008.11.004, in press). In the
>>>> > Congo,
>>>> > for
>>>> > instance, around 2000 mm of rain falls each year at the coast and the
>>>> > same
>>>> > amount falls inland. The same is true in the Amazon, the Siberian
>>>> > Arctic
>>>> > and
>>>> > the Mackenzie river basin in northern Canada. But the US, largely
>>>> > forested
>>>> > until recently, now seems be headed for desert. Makarieva and Gorshkov
>>>> > told New Scientist that without rapid reforestation "the degrading
>>>> > temperate
>>>> > forests of North America are on their way to desertification".
>>>> >
>>>> > The Russians' ideas have languished since they were published in a
>>>> > small
>>>> > journal in 2007. "We are facing enormous difficulties in overcoming
>>>> > the
>>>> > initial resistance of the scientific community," they say. Antoon
>>>> > Meesters
>>>> > of the Free University in Amsterdam, the Netherlands, recently
>>>> > described
>>>> > it as "an untenable result of confused principles". Meesters does not
>>>> > dispute the physics behind the Russians' theory but claims the effect
>>>> > is
>>>> > negligible.
>>>> >
>>>> > This week, a leading British forest scientist based at the Institute
>>>> > of
>>>> > Tropical Forest Conservation in Kabale, Uganda, came to the Russians'
>>>> > aid.
>>>> > In a review of the work in the journal Bioscience (DOI:
>>>> > 10.1525/bio.2009.59.4.12), Doug Sheil and his co-author Daniel
>>>> > Murdiyarso
>>>> > underline the importance of the idea. "Conventional models typically
>>>> > predict
>>>> > a 20 to 30 per cent decline in rainfall after deforestation," Sheil
>>>> > says.
>>>> > "Makarieva and Gorshkov suggest even localised clearing might
>>>> > ultimately
>>>> > switch entire continental climates from wet to arid, with rainfall
>>>> > declining
>>>> > by more than 95 per cent."
>>>> >
>>>> > Sheil explains that current theory doesn't explain clearly how the
>>>> > lowlands
>>>> > in continental interiors maintain wet climates. "There is a missing
>>>> > element," Sheil says. The biotic pump "may be the answer". He calls
>>>> > the
>>>> > Russians' findings "a most profound insight into the impact of forest
>>>> > loss
>>>> > on climate. They will transform how we view forest loss, climate
>>>> > change
>>>> > and
>>>> > hydrology."
>>>> >
>>>> > Many forest scientists are intrigued by the idea. "It makes perfect
>>>> > sense,"
>>>> > says Andrew Mitchell, director of the Global Canopy Programme, Oxford,
>>>> > UK.
>>>> > "We know that coastal rainforests are critical to maintaining rainfall
>>>> > deep
>>>> > inland." He says it could offer a more convincing explanation for how
>>>> > Amazon
>>>> > rainfall is typically recycled six times.
>>>> >
>>>> > The implications are global, he adds. "We think some of the recycled
>>>> > Amazon
>>>> > moisture is taken on a jet stream to South Africa, and more maybe to
>>>> > the
>>>> > American Midwest. Gorshkov and Makarieva are looking at the front end
>>>> > of
>>>> > an
>>>> > absolutely critical process for the world's climate." If their theory
>>>> > is
>>>> > correct, it means that large forests help kick-start the global water
>>>> > cycle.
>>>> > However, because forest models do not include the biotic pump, it is
>>>> > impossible to say what wiping the Amazon off the map would mean for
>>>> > rainfall
>>>> > worldwide.
>>>> >
>>>> > The theory suggests that past civilisations could have had a much
>>>> > greater
>>>> > impact on global climate than we thought. Australia once had forests
>>>> > but
>>>> > is
>>>> > now largely desert. Gorshkov and Makarieva argue that Aborigines
>>>> > burning
>>>> > coastal forests may have switched the continent from wet to dry by
>>>> > shutting
>>>> > down its biotic pump.
>>>> >
>>>> > Climatologists are already worried about the state of the Amazon
>>>> > rainforest.
>>>> > Last month, the UK's Met Office warned that if the planet warms by 4
>>>> > degrees, 85 per cent of the forest could dry out and die. If Gorshkov
>>>> > and
>>>> > Makarieva are right, the Amazon will be gone before warming kicks in.
>>>> > They
>>>> > predict that even modest deforestation could shut down the pump and
>>>> > reduce
>>>> > rainfall in central Amazonia by 95 per cent.The same could happen in
>>>> > the
>>>> > world's other large rainforest regions, such as central Africa.
>>>> >
>>>> > According to Richard Betts, head of climate impacts at the Met Office,
>>>> > "The
>>>> > jury is still out on whether the mechanism is significant or not. But
>>>> > the
>>>> > role of tropical forests in protecting us against climate change is
>>>> > severely
>>>> > underrated."
>>>> >
>>>> > It's not all bad news. If natural forests can create rain, then
>>>> > planting
>>>> > forests can, too. Sheil says, if forests attract rain, then replanting
>>>> > deforested coastal regions could re-establish a biotic pump and bring
>>>> > back
>>>> > the rains. "Once forests are established, the pump would be powerful
>>>> > enough
>>>> > to water them. Could we one day afforest the world's deserts?
>>>> > Makarieva
>>>> > and
>>>> > Gorshkov's hypothesis suggests we might."