date: Fri, 16 Feb 2007 16:44:19 +0000
from: Phil Jones <p.jones@uea.ac.uk>
subject: Fwd: FYI: Futuristic fleet of 'cloudseeders'
to: cru.internal@uea.ac.uk

    WRT our coffee time discussion this AM.
    There will be a TV program about it !
    Phil

     Date: Fri, 16 Feb 2007 10:27:47 -0600
     To: schlesin@atmos.uiuc.edu
     From: Michael Schlesinger <schlesin@atmos.uiuc.edu>
     Subject: FYI: Futuristic fleet of 'cloudseeders'
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     [1]http://news.bbc.co.uk/2/hi/programmes/6354759.stm
     Futuristic fleet of 'cloudseeders'
     VIEWPOINT
     Professor John Latham
     Some experts are proposing radical ideas to save us from disastrous climate change. But
     would they work? Professors John Latham and Stephen Salter have designed a fleet of
     yachts that would pump fine particles of sea-water into clouds, thickening them to
     reflect more of the Sun's rays. Here, Professor Latham talks about the proposal.
     Five Ways To Save The World
     Monday 19 February 2007
     2100 GMT on BBC Two
     Programme preview
     It was in 1946 that scientists first began trying to manipulate clouds.
     They found that by firing tiny particles of silver iodide into rain-bearing clouds, they
     could induce rainfall.
     Our idea of a fleet of "cloudseeders", however, was largely born from a remark made by
     my son Mike, decades ago.
     We were on a mountainside in North Wales, looking west towards Ireland.
     He asked why clouds were shiny at the top but dark at the bottom.
     I explained how they were mirrors for incoming sunlight.
     He pondered for a while, then grinned: "Soggy mirrors, Dad," he said.
     The idea my colleagues and I are pursuing is to increase the amount of sunlight
     reflected back into space from the tops of thin, low-level clouds (marine stratocumuli,
     which cover about a quarter of the world's oceanic surface), thereby producing a cooling
     effect.
     Calculations show that if we can increase the reflectivity by about 3%, the cooling will
     balance the global warming caused by increased CO2 in the atmosphere (resulting from the
     burning of fossil fuels).
     Cloud-seeding yachts
     In order to deploy our scheme and produce adequate cooling, we would need to spray
     sea-water droplets continuously over a significant fraction of the world's oceanic
     surface, at a total rate of around 50 cubic metres per second.
     Professor Stephen Salter has developed plans for a novel form of spray-droplet
     production (involving high-velocity propulsion of sea-water droplets), and has designed
     a wind-powered unmanned vessel which can be remotely guided to regions where cloud
     seeding is most favourable.
     Instead of sails, these vessels use a much more efficient technique to power the yacht -
     Flettner rotors.
     These spinning vertical cylinders mounted on the deck, are named after their inventor
     Anton Flettner. They also house the spraying system which sprays sea water droplets from
     the top of the rotors.
     The power required for spraying, communications and so on, comes from electricity
     generated by turbines dragged along by the vessels.
     We envisage that about 1,000 such vessels would be required to make the scheme
     effective.
     Under control
     The ideal solution to the global warming problem is that the burning of fossil fuels be
     drastically reduced.
     But our scheme offers the possibility that we could buy time within which catastrophic
     warming could be staved off while carbon dioxide levels are being reduced to acceptable
     levels.
     One advantage of our plan is that it is ecologically benign, the only raw material
     required being sea-water.
     The amount of cooling could be controlled, via satellite measurements and a computer
     model, and if an emergency arose, the system could be switched off, with conditions
     returning to normal within a few days.
     In addition to global temperature stabilisation, we also envisage that the technique
     could be used to remedy more regional problems, such as the dying of the coral reefs as
     a result of ocean warming.
     Long road ahead
     But while it is all very well spraying the clouds, what effect will this have on the
     world's fragile eco-system, and do we have the right to interfere with the planet in
     this way?
     Before we could justify deploying such a scheme on a global scale we would need to do
     several things.
     We would have to complete the development of the required technology, and conduct a
     limited-area field experiment in which the reflectivity of seeded clouds is compared
     with that of adjacent unseeded ones.
     We would also have to perform detailed analysis to establish whether there might be
     serious or harmful meteorological or climatological ramifications (such as reducing
     rainfall in regions where water is scarce) and if so, to find a solution for them.
     But bearing all this in mind, we have been encouraged by the consistent response we have
     received to our scheme - for example at a recent Nasa meeting - and it seems likely to
     be a strong contender in the fight to improve the current global warming problem
     worldwide.
     When the planet is in such a dire situation, I am convinced it is simply irresponsible
     not to at least examine our options.

     Professor John Latham is an atmospheric physicist at the University of Manchester &
     NCAR, Colorado, US. Professor Stephen Salter is an engineer at the University of
     Edinburgh.
     Story from BBC NEWS:
     [2]http://news.bbc.co.uk/go/pr/fr/-/2/hi/programmes/6354759.stm
     Published: 2007/02/15 14:25:07 GMT
      BBC MMVII

   Prof. Phil Jones
   Climatic Research Unit        Telephone +44 (0) 1603 592090
   School of Environmental Sciences    Fax +44 (0) 1603 507784
   University of East Anglia
   Norwich                          Email    p.jones@uea.ac.uk
   NR4 7TJ
   UK
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