Friday, June 11, 2010

Straw Bale Along the Coast to Slow the Oil

Interesting article by Andrew Morrison about using straw bales for helping slow the oil coming into the Gulf shores.
Read on:

As some of you may know, straw bales are used as erosion control all the time during construction projects. They are used to form silt traps, like the one shown here. The concept is that the water is slowed down, but still flows through the bale. The straw which is netted in a web within the bale, traps the silt and doesn’t allow it to move through. I believe the same system could work for the oil that is floating along the surface of the water. If bales were set all along the coast line, they would act like silt traps or sponges and soak up the oil. If they didn’t actually soak up the oil, they would certainly slow down the water and cause the oil to accumulate at the face of the bales. This would make it thicker and easier to collect, as one of the big issues with this spill is the fact that the oil itself is thin and does not collect easily.

I hope that somebody reading this can get it in front of the right people. The woman who originally asked the question has contacted the National Geographic Society, and as I said earlier, I’ve asked my friend who lives in New Orleans to contact people locally who may be interested in the idea. Please help us get the word out and create a line of defense along our coast lines in the South. Remember, you can still go to certain areas around Valdez, Alaska and find oil 6″ to 12″ down in hand dug holes. That’s a long term disaster I’d like to not see repeated.

About the Author
Andrew Morison is a specialist in straw bale and green construction. He has shown thousands of people how to build their own straw bale projects through his comprehensive series of instructional straw bale, concrete foundation, and plastering DVDs. You can check these out at

Thursday, June 10, 2010

Straw Bale Home for Sale

A friend of mine is selling her straw bale home in Winchester, CA. This is a wonderful home that she put a lot of love and passion into building. Anyone would be lucky to have it. This a very unique opportunity to purchase a completed straw bale home.

Here is the info from the MLS:

Built in 2004, this Wonderfully Unique and Custom Built Straw Bale Home rests on 4.82 Acres. This is a one of a kind opportunity to own an extremely energy efficient, country home with all the conveniences of the city just minutes away (Menifee Marketplace Shopping Center and Loma Linda Hospital). This Santa Fe style home makes use of a solar water heater and a solar wall heater. Two additional Solar panels generate electricity and significantly reduce electric bills. Property includes a permitted 12X32 workshop with a 35 AMP electrical outlet. Horses and/or other livestock are allowed. Live affordably in a house with some real character. See it today!

More Info:

Tuesday, May 25, 2010

Recycle Wine Corks at Whole Foods logoDid you know that you can recycle corks at Whole Foods?
Why recycle cork? Cork is a 100% natural, renewable, recyclable and biodegradable material that is obtained through an environmentally friendly harvesting process. It can be reused in numerous processes: Besides corks, cork is used in everything from shoes, to dart and bulletin boards, furniture, insulation, craft materials, buoys, instruments, fishing rods, tiles flooring, sports equipment and even to create a composite concrete. There is no need for them to end up in landfills.

Cork Tree Fact: Trees are not cut down to harvest cork, rather, the bark is stripped by hand every 9-12 years. Cork oak trees can live up to 300 years!

Monday, March 29, 2010

Earth Day 2010

April 22, 2010 marks the 40th anniversary of Earth Day 2010. How do you plan to celebrate?

Find an event that fits you:

* Global Days of Service - April 17-18 - Join millions around the globe to make your community and the world cleaner and more sustainable.
* The Climate Rally - National Mall, Washington DC - April 25th, 2010
* Environmental Arts
* Athletes for the Earth
* EarthFair 2010, April 18, San Diego, CA - EarthFair in Balboa Park is the largest free annual environmental fair in the world
* Earth Day Crafts for kids and families
* Find an event in your community

What do you plan on doing to celebrate Earth Day 2010?

Article © Lisa A. Swan, Design Forward

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Earth Hour 2010: Millions Turn off Lights for Earth Hour

Earth Hour, organized by the World Wildlife Fund (WWF), saw millions of people switch off their lights for an hour this weekend.

Some of the world's best known landmarks -- including the Eiffel Tower, Big Ben and Rome's Colosseum -- participated on March 27, 2010 at 8:30pm local time, following Sydney's Opera House and Beijing's Forbidden City. In the United States, the lights went out at the Empire State Building in New York, the National Cathedral in Washington, D.C., and the Coca-Cola headquarters in Atlanta, among many other sites in the Eastern time zone.

Earth Hour was considered success on west coast. Symbolic lights turned off on Las Vegas Strip and LAX entrance.

Anyone who has been to Los Angeles International Airport in the evening knows about the pillars of light that stand at the beginning of the property. These lights normally portray the different colors and give the passing people something interesting to view. On Saturday for an hour, in a symbolic gesture, the lights were turned off for 'Earth Hour.'

In Las Vegas, many of the lights on the Strip were flipped off at 8:30 too. Again showing the power of shutting down the lights for 60 minutes to stress conservation and participate in the 'Earth Hour.'

In the end, it is not about the energy saved during that hour. It's about the message of awareness that will be spread. From a child asking why the lights are off, to leaders who read the message loud and clear. As more and more people join the effort, the awareness grows... and hopefully people will continue to understand that energy saving measures can be made by each and every one of us.

The image above shows the Empire State Building (L) in New York, Big Ben (C) in London and the Eiffel Tower (R) in Paris with lights turned off during "Earth Hour". -Photo by AFP

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Sunday, February 28, 2010

Solar Roads: The Greatest Pipe Dream Yet

Over 5.7 million miles of highway stretch across America alone. The carbon footprint produced by the machinery needed for salting and snow removal of these paved roads is almost immeasurable. With the world's attention focused on the climate crisis industry has shifted toward developments in renewable resources.

The sun, which is an unequivocal provider of all life energy, is now the inspiration behind an ambitious project one small Idaho company hopes will someday be responsible for cutting greenhouse gases in half. The project, which is already in phase I of its development is to create "a series of structurally-engineered solar panels that are driven upon", or ‘solar-roadways', as creators Scott and Julie Brusaw have dubbed them.

The idea is to replace all current petroleum-based asphalt roads, parking lots, and driveways with Solar Road Panels that collect and store solar energy to be used by our homes and businesses. This renewable energy replaces the need for the current fossil fuels used by the generation of electricity. Getting the project off the ground was no easy task and securing funding, even for Phase I of production was a challenge. "Getting the Phase I contract was mainly about physically writing the proposals to get it approved for funding; to prove that these panels were feasible. When I first came up with the idea, my team was invited by the Department of Transportation in Virginia to come out and present for them, and so we did. They were excited about the project and asked a lot of questions, soon after we applied for funding", says co-creator, Scott Brusaw. The funding they received was a $100,000 grant from the Dept of Transportation to build a prototype, "I'm madly ordering parts as fast as I can," says Scott.

As asphalt and tar have never been credited as unparalleled engineering it is easy to understand that solar panel highways will require a level of complexity not yet considered for roadways. The panels are said to consist of three layers. The base will contain power and data lines and is overlaid with the electronics strata that contain solar cells, LEDs and super-capacitors which would produce and store electricity.

The LED's would provide ‘paint' for the highways and be able to communicate messages such as ‘slow' or ‘detour ahead' with the use of lights brought to the surface. The top layer will be made of glass that would provide the same traction as asphalt.

Even more impressive would be their ability to heat up, melting ice from the road, "Our target date to finish Phase I is February 12, 2010. During this demonstration the snow should be falling where we are, allowing us to demonstrate how the panels' heating elements can melt snow or ice. We will videotape everything and put it up on our website."

Though entirely ingenious the project has some obvious flaws, for which solutions are being furiously researched. Solar panels are notoriously fragile and would not be able to withstand the weight of even light vehicles. "We are trying to work on developing a type of glass that would be able to withstand the pressure of trucks and other vehicles driving over it daily. This glass that we're going to be layering over the panels needs to have enough grip and not be slippery, especially in rain or snow. We have partnered with Pennsylvania State University to develop the glass surface for our panels, and they're going to be testing it using 80,000-lb. trucks."

Though the price tag for implanting solar roads throughout the country is estimated at an unworldly $35 trillion, the Brusaw's hope that funding from Phase II of their contract will allow them to start implementing solar panels in parking lots of businesses, and possibly begin mass-producing them shortly after.

The product has received widespread interest globally from countries wanting to build plants. "We're getting requests from all around the world, from countries in Africa, Asia, and Europe. The Czech Republic contacted us just last week about possibly having some of their people visit our site, and once this project here gets off the ground, and we have plants that are mass-producing the panels for the roads, they would like to have some of their employees come over here for 2-3 years and see how everything works, and to gain confidence in getting the project off the ground over there as well."

Sure they will be ploughing the snow from our roads this year, but keep in mind they laughed at the light bulb and said man was never meant to fly.

Jennifer Maclellan is the Senior Writer for the Green Guide Network. You can contact her at


Interview with Scott Brusaw conducted by Danielli Marfori, Creative Intern for the Green Guide Network.

Article & Picture ©

Tree Selection Guide

The Urban Forest Ecosystems Institute at Cal Poly San Luis Obispo has a tree selection application available on the web:

SelecTree for California is an interactive tree selection program designed to match specific trees to specific applications such as Max Height, Flower Color, Longevity, Disease Resistance, Attracts Wildlife, etc. The Tree Selection Guide listis 1,481 trees with up to 49 attributes and over 6,050 photos for 1,068 trees available from tree detail records. Search by tree attribute or by name.

Article © Lisa A. Swan, Design Forward

Wednesday, December 30, 2009

Building With Whole Trees

Roald Gundersen, an architect who may revolutionize the building industry, shinnied up a slender white ash near his house here on a recent afternoon, hoisting himself higher and higher until the limber trunk began to bend slowly toward the forest floor.

"Look at Papa!" his life and business partner, Amelia Baxter, 31, called to their 3-year-old daughter, Estella, who was crouching in the leaves, reaching for a mushroom. Their son, Cameron, 9 months, was nestled in a sling across Ms. Baxter's chest.

Wild mushrooms and watercress are among the treasures of this 134-acre forest, but its greatest resource is its small-diameter trees - thousands like the one Mr. Gundersen, 49, was hugging like a monkey.

"Whooh!" he said, jumping to the ground and gingerly rubbing his back. "This isn't as easy as it used to be. But see how the tree holds the memory of the weight?"

The ash, no more than five inches thick, was still bent toward the ground. Mr. Gundersen will continue to work on it, bending and pruning it over the next few years in this forest which lies about 10 miles east of the Mississippi River and 150 miles northwest of Madison.

Loggers pass over such trees because they are too small to mill, but this forester-architect, who founded Gundersen Design in 1991 and built his first house here two years later, has made a career of working with them.

"Curves are stronger than straight lines," he explained. "A single arch supporting a roof can laterally brace the building in all directions."

The firm, recently renamed Whole Tree Architecture and Construction, is also owned by Ms. Baxter, a onetime urban farmer and community organizer with a knack for administration and fundraising. She also manages a community forest project modeled after a community-supported agriculture project, in which paying members harvest sustainable riches like mushrooms, firewood and watercress from these woods, and those who want to build a house can select from about 1,000 trees, inventoried according to species, size and shape, and located with global positioning system coordinates, a living inventory that was paid for with a $150,000 grant from the United States Department of Agriculture.

According to research by the Forest Products Laboratory in Madison, run by the USDA, a whole, unmilled tree can support 50 percent more weight than the largest piece of lumber milled from the same tree. So Mr. Gundersen uses small-diameter trees as rafters and framing in his airy structures, and big trees felled by wind, disease or insects as powerful columns and curving beams.

Taking small trees from a crowded stand in the forest is much like thinning carrots in a row: the remaining plants get more light, air and nutrients. Carrots grow longer and straighter; trees get bigger and healthier.

And when the trees are left whole, they sequester carbon. "For every ton of wood, a ton and a half of carbon dioxide is locked up," he said, whereas producing a ton of steel releases two to five tons of carbon. So the more whole wood is used in place of steel, the less carbon is pumped into the air.

These passive solar structures also need very little or no supplemental heat.

Tom Spaulding, the executive director of Angelic Organics Learning Center, near Rockford, Ill., northwest of Chicago, knows about this because he commissioned Mr. Gundersen to build a 1,600-square-foot training center in 2003. He said: "In the middle of winter, on a 20-below day, we're in shorts, with the windows and doors open. And we don't burn a bit of petroleum."

"It's eminently more frugal and sustainable than milling trees," he added. "These are weed trees, so when you take them out, you improve the forest stand and get a building out of it. You haven't stripped an entire hillside out west to build it, or used a lot of oil to transport the lumber."

Mr. Gundersen had a rough feeling for all of this 16 years ago, when he started building a simple A-frame house here for his first wife and their son, Ian, now 15. He wanted to encourage local farmers to use materials like wood and straw from their own farms to build low-cost, energy-efficient structures. So he used small aspens that were crowding out young oaks nearby.

"I would just carry them home and peel them," said Mr. Gundersen, who later realized he could peel them while they were standing, making them "a lot lighter to haul and not so dangerous to fell."

Mr. Gundersen, who built most of the house singlehandedly, also recognized the beauty of large trees downed by disease or wind, and used the peeled trunks, shorn of their central branches a few feet from the crook, as supporting columns in the house. "I thought they were beautiful, but I didn't think how strong they were," he said

Article © Anne Raver, NY Times. Picture © Paul Kelley, NY Times

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Christmas Tree Recycling

What Are Your Recycling Choices?

After the holidays, don't throw your natural tree away! Here are some tips on what to do with your tree after the holidays. In general, you have these options:

1. Curbside pick-up for recycling - Most areas will collect trees during their regular pickup schedules on the 2 weeks following Christmas. There are often requirements for size, removing ornaments, flocking, etc.
2. Call for an appointment to have a non-profit in your area pickup your tree. Some boy scout troops are offering a pickup service for a small donation (often $5).
3. Take your tree to a drop off recycling center. Most counties have free drop-off locations throughout the county. Usually, you may take up to two trees to any of the following drop-off locations at no charge.
4. Cut the tree to fit loosely into your yard waste container.

Other tips and ideas

* Removing the tree: The best way to avoid a mess removing your tree is to place a plastic tree bag (which are available at hardware stores) underneath the stand when you set the tree up! You can hide it with a tree skirt. Then, when the holidays are done, pull the bag up around the tree, stand and all, and carry it outside. Obviously, you will want to remove the stand before recycling the tree. If some needles do scatter inside, it is better to sweep them up; as needles can clog vacuum cleaners.
* Tree Recycling / Mulching programs are a fast-growing trend in communities throughout the nation. Check below on this page or with your local department of public works for information. They chip and shred the trees, then make the mulch available for use in your garden. Your hauler will notify you of pick-up dates in your area. There are a few things you must do to make your tree ready for RECYCLING. Here are some general tips - but be sure to check with your local hauler - these are just general guidelines! To find your local hauler:
If it is Waste Management Inc (WM), click here to find your Local WM Service Provider's Website - or click here to contact your Local WM Customer Service Center by Phone - find the 1-800 number of your Local Customer Service Center
If your local hauler is AW / BFI (Allied Waste) - Click here to locate the contact information for your local hauler.
* Soil erosion barriers: Some communities use Christmas trees to make effective sand and soil erosion barriers, especially at for lake and river shoreline stabilization and river delta sedimentation management (Louisiana does both).
* Fish feeders: Sunk into private fish ponds trees make excellent refuge and feeding area for fish.
* Bird feeders: Place the Christmas tree in the garden or backyard and use it as a bird feeder and sanctuary. Fresh orange slices or strung popcorn will attract the birds and they can sit in the branches for shelter. (Make sure all decorations, hooks, garland and tinsel strands are removed). Eventually (within a year) the branches will become brittle and you can break the tree apart by hand or chip it in a chipper. See this article from Perdue University for more information.
* Mulch: A Christmas tree is biodegradable; its branches may be removed, chipped, and used as mulch in the garden. If you have a neighbor with a chip, see if he will chip it for you.
* Paths for Hiking Trails: Some counties use the shredded trees as a free, renewable and natural path material that fits both the environment and the needs of hikers!
* Living, rooted trees: Of course, next year, you could get a rooted (ball and burlapped or containerized) tree and then plant it in your yard after Christmas (It's a good idea to pre-dig the hole in the late Fall while the soil is still soft, then plant the tree into that hole immediately after Christmas.) NOTE: Living trees have a better survival rate in mild climates, than in a northern area.
* Important: Never burn your Christmas tree in a fireplace or wood stove. Pines, firs and other evergreens have a high content of flammable turpentine oils. Burning the tree may contribute to creosote buildup and risk a chimney fire.

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Sunday, November 29, 2009

Eco Gift Ideas: Beyond the Stores

This holiday season, remember there are more options than just what you can find in the stores. Here are some ideas for the socially conscious person on your list this year.

Offer gifts that don't involve buying anything. For example, time together, a back rub, babysitting, offer to teach something you know how to do (e.g., making candles), donation to charity, seeds from your garden, tickets to an event (musical, lecture series, play, concert, etc.), organic house cleaning service, gift certificates for spas, music downloads, movie downloads, etc.

Other gift ideas:

* Give the gift that keeps on growing -- a tree!
* Buy gifts from Fair Trade Shops.
* Give alternative charity gifts or donate to your favorite charity in honor of someone
* Feed a child in honor of someone you love and support organization for fighting hunger.
* Consider purchasing gifts from companies focused on providing products which use renewable energy sources (i.e., solar powered radio or outdoor lighting).
* Purchase gifts made from reused and natural materials or find ideas for making your own eco gifts.
* Shop for gifts at antique stores, estate sales or flea markets.
* Donate to a local charity that is distributing holiday gifts for underprivileged children.
* Create sustainable gift baskets filled with sustainable gift items (e.g., compact fluorescent light bulbs, plastic bag dryer, organic cotton socks/scarfs/hats/etc., shower head with mist setting for lowest flow showers, organic and/or vegan snack items, organic cotton towels, shade grown coffee, fair trade gifts, solar battery charger, solar radio/flashlight, etc.)

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Eco Friendly Holiday Gifts

This holiday season we have our top ten gifts ideas for 2009. Everything for the green geek to the eco baby, see what tops our list:

  • iPhone Solar Skin From NovoThink ($69.95) - Charge your iPhone from the sun with this innovative skin cover from

  • SIGG Water Bottles ($21.99) - Swiss-made, leach-proof, safe water bottles. SIGG bottles are manufactured in an ecologically-friendly environment and are 100% recyclable after their very long lives.

  • bumGenius 3.0 One-Size Cloth Diapers ($17.95) - It easy to switch to cloth diapers for your baby with washable, reusable diapers from Cotton Babies

  • Cascata Rain Water Collection and Storage System from Algreen ($199) - 65-gallon rain barrel makes saving rain water easy.

  • pb Bamboo Travel Blanket ($39.95) - Perfect for the traveler in your life. Bamboo is a
    soft and smooth fabric that provides superior ventilation and wicking.

  • El Naturalista Women's Pump ($182) - A vegetable-tanned leather shoe with microfibra lining that is antibacterial, antimicrobial and anti-odor.

  • Samsung Reclaim ($29.99 and up with contract) - The eco-friendly cell phone made from 80%
    recycled materials.

  • Triple Home Recycle Bin from Get Organized ($75.88) - Stainless steel bin with color coded foot petals to keep your paper, plastic and glass separate.

  • Cork Furniture - Cork is a natural, sustainable, renewable, non-toxic material. Check out the designs by Corque

  • Sport Solar Oven ($135) - Solar cooking will roast meats, bake fish and chicken, steam veggies,
    it can even bake cookies and cooks rice and pasta with only solar energy.

  • Article © Lisa A Swan, Design Forward

    Saturday, October 31, 2009

    Green Investing

    This column by Yahoo's David Jackson, "The Green Investor" is a great place to start looking for a new way to invest your money.

    Investing in green can improve our quality of life and improve the environment, while helping our bottom line. Green investing is becoming more mainstream everyday, and with it brings a host of financial opportunities.

    By investing Green, you can support the companies and the technologies that are helping the environment while (hopefully) increasing your personal wealth. On a wider scale the growing trend of Green Investing can go so far as to influence policy decisions public companies make.

    As with any investing, you can WIN or LOSE so do your research, but whether you are trying to save the world or looking for the next big Growth Industry to ignite your portfolio reading The Green Investor.

    Article © greenUPGRADER

    The Green Investor...

    Waste Less Living

    Waste Less Living is a 'Zero-Waste' service that has an effective system for distributing, collecting, and then composting your waste from your next party or event.

    They take the the waste generated at your party or event and turn it into a compost, instead of sending it to the trash. They help you identify potential sources of trash and recommend viable and economical alternatives to reduce your waste up-front. They then provide and deliver all the necessary tableware to your event site. Once the party is over, they collect all the tableware and food waste and compost it off-site for you.

    So how does it work:
    The kit contains biodegradable and 100% compostable plates, cups, utensils, napkins and trash bags. They deliver the kits, you use them, and they take your waste (tableware and food scraps) away for composting and not landfilling.

    Their products are:

    * Boidegradable and 100% compostable
    * Made from renewable resources (i.e. corn, sugar, potatoes, post-consumer-waste paper, wheat, rice, bamboo)
    * Eco-friendly alterantive to plastic, Styrofoam, and paper disposable tableware
    * Reduce green house gases and other enviormental impacts
    * Affordable

    No more guilt about using disposables because your waste will be used to make more of the stuff. It's the perfect solution that is sustainable!

    Article © Lisa A. Swan, Design Forward


    Monday, September 28, 2009

    Natural Insecticides

    As you may be experiencing a increase of ants in your house or getting ready to plant a winter garden, here are some tips on natural pest control:

    * Garlic control
    * Orange Oil
    * Mint, cloves, rosemary & thyme can be used as insecticides
    * Insecticidal Soaps
    * Neem Oil - Neem oil is used in gardens and landscapes against insects that chew on plants such as black vine weevil.
    * Diatomaceous Earth - Diatomaceous earth is a dry, powdery material derived from the shells of marine organisms. It is used mainly to deter and kill crawling pests both indoors and outdoors.
    * Boric Acid - Boric acid is used mainly in structural pest control against insects like termites, carpenter ants and powderpost beetles, and in baits for cockroaches. Boric acid is generally used in the borate form, often sodium borate.
    * Vinegar and Salt

    Article © Lisa A. Swan, Design Forward

    Cloud-seeding ships could combat climate change

    It should be possible to counteract the global warming associated with a doubling of carbon dioxide levels by enhancing the reflectivity of low-lying clouds above the oceans, according to researchers in the US and UK. John Latham of the National Center for Atmospheric Research in Boulder, US, and colleagues say that this can be done using a worldwide fleet of autonomous ships spraying salt water into the air.

    Clouds are a key component of the Earth's climate system. They can both heat the planet by trapping the longer-wavelength radiation given off from the Earth's surface and cool it by reflecting incoming shorter wavelength radiation back into space. The greater weight of the second mechanism means that, on balance, clouds have a cooling effect.

    'Twomey effect' boosts reflectivity

    Latham's proposal, previously put forward by himself and a number of other scientists, involves increasing the reflectivity, or "albedo", of clouds lying about 1 km above the ocean's surface. The idea relies on the "Twomey effect", which says that increasing the concentration of water droplets within a cloud raises the overall surface area of the droplets and thereby enhances the cloud's albedo. By spraying fine droplets of sea water into the air, the small particles of salt within each droplet act as new centres of condensation when they reach the clouds above, leading to a greater concentration of water droplets within each cloud.

    Latham and co-workers, including wave-energy researcher Stephen Salter of Edinburgh University, claim that such spraying could increase the rate at which clouds reflect solar energy back into space by as much as 3.7 Wm-2. This is the extra power per unit area that scientists say will arrive at the Earth's surface following a doubling of the concentration of atmospheric carbon dioxide compared to pre-industrial levels - 550 ppm vs 275 ppm (Phil. Trans. R. Soc. A DOI:10.1098/rsta.2008.0137).

    New spin on sailing

    The 300-tonne unmanned ships used to seed the clouds would be powered by the wind, but would not use conventional sails. Instead they would be fitted with a number of 20 m-high, 2.5 m-diameter cylinders known as "Flettner rotors" that would be made to spin continuously. This spinning would generate a force perpendicular to the wind direction, propelling the ship forward if it is oriented at right angles to the wind (Phil. Trans. R. Soc. A DOI: 10.1098/rsta.2008.0136).

    These rotors would be easier to operate remotely than sails and would also serve as the conduits for the upward spray, with the spray consisting of droplets 0.8 ┬Ám in diameter generated by passing sea water through micro nozzles. The power for the spray and the cylinder rotation would be provided by oversized propellers operating as turbines.

    The immediate effect of seeding clouds in this way would be a local cooling of the sea surface, and as such the technique could be targeted at coral reefs, diminishing polar ice sheets or other vulnerable regions. However, the great thermal heat capacity of the ocean and the currents within it mean that these initial effects would eventually spread across the globe.

    Fleet of 1500

    Latham and colleagues calculate that, depending on exactly what fraction of low-level maritime clouds are targeted (with some regions, notably the sea off the west coasts of Africa and North and South America, more susceptible to this technique than others), around 1500 ships would be needed altogether to counteract a carbon doubling, at a cost of some £1m to £2m each. This would involve an initial fleet expanding by some 50 ships a year if the scheme is to keep in step with the current rate of increase in atmospheric carbon-dioxide levels.

    This cloud-seeding proposal is one of a number of ideas put forward by scientists in recent years to "geoengineer" the Earth in response to climate change rather than, or as well as, deal with the causes of the change. A series of papers on several proposals, including Latham's, have been published in a recent issue of the journal Phil. Trans. R. Soc. A entitled Geoscale engineering to avert dangerous climate change.

    Latham maintains that his group's idea is not pie in the sky and that its feasibility is supported by two of the world's leading computer climate models, as well as recently obtained experimental cloud data. He points out that, unlike rival techniques, the system could be used to vary the degree of cooling as required and could be switched off instantaneously if needed. However, he adds more research must be done to find out a number of unknowns - such as exactly what fraction of spray droplets will reach the clouds - and to establish that the technique would not create any harmful climatic side effects. More work must also be done on the spray technology, he says.

    About the author

    Edwin Cartlidge is a science journalist based in Italy

    Article © Edwin Cartlidge,