Note  # 48:

While we claim no particular expertise in policy matters, we note expert opinion to the effect that   ''. . .stabilization [of atmospheric CO2 levels] requires an eventual and sustained reduction of emissions to   substantially below current levels'' [Wigley TML, Richels R and Edmonds J, Economic and environmental  choices in the stabilization of atmospheric CO2 concentrations, Nature 379, 240-3 (1996)] and we estimate  that ''substantial'' worldwide reduction in fossil fuel usage over the next several decades will not occur  without substantial likelihood of inducing major conflict.

JULES VERNE GUN

BY SCOTT R. GOURLEY

PM Illustrations by Harold Smelcer

Published on: April  1998

An ambitious plan to change the way we launch satellites will fulfill the science-fiction writer's dream.

In his 1865 novel From The Earth To The Moon, author Jules Verne describes a post-Civil War society in which the convened members of the fictitious Baltimore Gun Club lament the sudden lack of artillery activities. Their boredom is soon broken by a speech from the club's president, who outlines a bold plan to use a giant cannon to fire a projectile to the Moon. One of the fictional club members awed by the plan is named Tom Hunter. Coincidentally, a very real visionary with the same last name may make author Verne's fantasy come true.

"Jules Verne was a true visionary in an era when you needed visionaries," explains John Hunter. "Now, the problem is that we have too many visionaries and not enough doers." Hunter is standing in his cluttered Southern California office, where he has just drawn a diagram of comparative escape velocities on the blackboard. As president and founder of the Jules Verne Launcher Co., Hunter is combining Verne's vision with his own actions. Quite simply, he intends to use gas-powered launchers as an effective and inexpensive way of propelling satellites into orbit.

Hunter's quest began when he started working at Lawrence Livermore National Laboratory (LLNL) in 1985. One of his first projects at the lab involved the concept of an electromagnetic space launcher. "The cost per joule of just about any kind of electric gun is so high that it's basically prohibitive," Hunter says. During a technical discussion at Livermore Lab, it was suggested that he look at the potential of "gas guns," systems that utilize a pump tube filled with heated and pressurized gas to drive projectiles at extremely high velocities. In fact, Hunter's search of the library database revealed that a NASA gas gun had achieved a projectile speed of 6.84 miles per second back in 1966. But he knew that higher velocity was needed. "At that point I knew, just like particle theory, that 99% of the people were just going along the well-worn path because someone had money or a cool idea. But they weren't being rigorous thinkers about solving the problem."

The solution that emerged involved the use of a gas gun with multiple injectors. Hunter's computer simulations suggested that such a system would work very well. "The velocities I was getting to were much higher than had ever been done before with conventional gas guns." Hunter then conducted a 2-month lab project to demonstrate the antitank potential of a single-stage hydrogen gas gun operating at room temperature. "I got 1.5 miles per second. The results were within 1% of my code predictions on six data points." Based on the computer model's accuracy and the quick completion of the project, Hunter was funded for a 3-month effort to develop a 2-stage gas-gun precursor to a space launcher. The effort produced a 10-ft.-long gas gun that achieved a firing velocity of 5 miles per second.

"[That] still exceeds the velocity record for any rail gun ever built," Hunter says. "Gas guns routinely achieve 5 miles per second. That's what's so phenomenal about them. The beauty is that to access space, 4.35 miles per second is where the action really gets hot and heavy. At 4.35 miles per second, you can launch a 10-ton vehicle and get 33% fraction into LEO [low Earth orbit]. If you start with 11 tons, you're going to have 7275 pounds in LEO."

The success of the 10-ft. prototype justified additional LLNL research and development funding for a "space gun" project identified as Super High Altitude Research Project, or SHARP. (Hunter chose the name in recognition of the U.S. government's HARP Super Gun project, which was conducted during the mid-1960s with standard powder technology.)

Located at LLNL Site 300, SHARP is the world's largest gas gun. The 425-ft.-long system was built in a unique L-shaped design with a 270-ft.-long combustion section and pump tube mounted at a right angle to the 155-ft.-long launch tube. The original design was driven by a desire to minimize the height of any supporting gantry that would be required to elevate the tube for space launch.

"SHARP has only gotten to 1.92 miles per second because we're launching fairly big masses and we haven't jacked up the pressures very high," Hunter says. He adds that achieving the requisite 4.35 miles per second is "totally doable," based on both computer-model and lab-gun experience.

First, Hunter will build and fire a prototype system dubbed the "Micro Launcher." "Our Micro Launcher design is so small that you'll hardly see the projectile-maybe only 50 mils or one-twentieth of an inch," Hunter says. "That sounds crazy, right? I helped build the world's biggest gun," he says jokingly, clearly aware of the irony.

Hunter is also devoting considerable attention to the design of specially hardened satellite packages and has recruited experienced satellite designers for his team of engineers. They will use the prototype systems to ensure satellite stability as it leaves the launch tube, as well as to address g-force hardening. The largest commercial guns will subject the satellites to 1000 g's for approximately 1 second. Although this is easily met by circuit designs, it may require hardening of components like solar cells or deployable antenna structures.

Based on SHARP experience, Hunter's engineers predict that the guns can easily be fired once per working day. Given a rate of 300 launches per year and a payload of 10,000 pounds per launch, the system has the potential of placing approximately 1500 tons a year into LEO. Moreover, at a target launch cost per pound of about one-twentieth of a modern rocket launch, the company estimates a breakeven point between the first 50 and 100 launches.

"The house odds wouldn't bet on us," Hunter says. "That's not a condemnation of house odds. That's just the way that the house works. But this is going to happen."

The SHARP firing sequence begins with the ignition of a methane gas mixture at one end of the steel pump tube. That explosion drives a 1-ton steel piston down the pump tube, which has been filled with pressurized hydrogen gas. The piston rapidly compresses the gas to 60,000 psi in the high-pressure section (below), destroying a coupling holding the projectile in the attached depressurized launch tube. The projectile is driven down the 4-in.-dia. tube at an extremely high speed and it bursts through a thin plastic sheet covering the end of the gun. All recoil forces are absorbed through the use of three sleds-two 100-ton sleds and one 10-ton sled-mounted on railroad tracks.

Stu Hutson
for National Geographic News

August 25, 2005

Why not just take an elevator instead? Thanks to a new development in the manufacture of molecule-size cylinders known as carbon nanotubes, that may one day be a viable option.

In theory, space elevators need a fixed line, or cord, that stretches from an anchor on Earth to a station out in space. The station acts like a counterweight, forever "held" above the planet by the centrifugal force from Earth's rotation.

A tram-like vehicle equipped with electric motors could climb this tether from Earth's surface into space at a safer speed than rocket alternatives.

In theory, space elevators would need far less energy than conventional space launches. As a result, the cost of transporting matter could drop from U.S. $20,000 a kilogram (the going rate for the space shuttle) to as little as $250 a kilogram.

"This is a trillion-dollar moneymaker for a ten billion dollar investment," said Bradley Edwards, whose work with Los Alamos National Laboratory and the NASA Institute for Advanced Concepts has made him a go-to expert on space elevators. "Some of the largest companies in the world are just waiting for the word that this is possible."

Conquering Carbon

The word on cheap space freight rates won't be sounded until at least one major obstacle is overcome: developing a strong enough material for the tether. Scientists believe they found the fibers for that material—carbon nanotubes—in 1991.

The tubes are molecules of carbon linked together in a shape that resembles a Chinese finger trap. Carbon is among the stickiest elements, and these tubes hold together hundreds of times better than Kevlar, the material used to make bullet-proof vests.

In theory, a space elevator tether made of carbon nanotubes would look and feel like a span of three-foot-wide (one-meter-wide) plastic wrap that stretched skyward as far as the eye could see. It could be rolled up and simply dropped to the ground from space-based orbit.

The problem with this scenario is that individual carbon nanotubes are only millimeters tall and nanometers wide. (A nanometer is a billionth of a meter.) No one has successfully woven the tubes together in a way to make sheets that are as strong as their individual fibers.

But Ray Baughman, who directs the Nanotech Institute at the University of Texas at Dallas, and his team have developed what could be a first step.

The technique, which is described in the August 19 issue of the journal Science, begins by building nanotubes. Gaseous carbon atoms are coaxed to deposit themselves onto a specially prepared surface in an oven. The surface "catches" the atoms in such a way that they cling to each other and form into tubes.

Baughman likens the result to a tiny bamboo forest. The researcher catches the row of tubes from the "forest edge" with an adhesive strip. As the first row is pulled away, the second row clings to its neighbor and is also pulled away. Eventually, enough of a sheet is pulled away that it can be reeled up with a plastic roller.

But for now, the resulting "fabric" isn't nearly as strong as Kevlar.

Versatile Tubes

Other scientists have experimented with producing nanotube-based materials by embedding the tubes in polymers—large, chain-like molecules made from repeating links of smaller molecules. Rodney Andrews from the University of Kentucky has produced fibers this way that are five times stronger than Baughman's.

"What's good about Ray's [product] is that it's made entirely out of nanotubes," Edwards said. "And the final material that will make up the [space elevator] tether will probably have to be at least 50 percent nanotubes."

Making the new carbon nanotube sheets stronger is a matter of finding better pulling methods and more advanced surfaces. Still, research won't produce a viable tether for some time, probably a few decades, Baughman said.

Edwards's own company, Carbon Designs Inc., also develops nanotube-based materials. He and other experts are slightly more optimistic, putting the estimated time of arrival of a space elevator tether at less than 20 years.

So don't pack your bags for the first space elevator trip anytime soon. But in the near future you might see carbon nanotubes coming to more commonplace products.

Carbon nanotubes have other interesting properties besides their strength, and Baughman has already demonstrated that their conductivity can make his sheets glow, providing whole surfaces that give light.

He's also shown that a sheet placed between pieces of glass will heat up when electrified, and may make for the perfect in-glass radio antenna.

Sea Salt Inhibits Global Warming

University Of Manchester

02-23-2005

Scientists at The University of Manchester are examining a novel idea for delaying the effects of climate change using a combination of clouds and sea salt.

Atmospheric experts Professor Tom Choularton and Dr. Keith Bower, who are working with a team of leading scientists around the world on the theory, have developed a computer simulation which shows how adding sea salt to clouds can slow global warming.

The idea, conceived by Professor John Latham, an Emeritus Professor at the University, now based at National Centre for Atmospheric Research in Colorado, is to use clouds as natural heat shields which when injected with salt reflect more sunlight and therefore protect against the greenhouse effect.

Professor Choularton, said: 'What our simulation shows is that if you artificially inject sea salt into clouds it not only increases the amount of heat which is reflected back into space, creating a cooling effect, but it also inhibits the formation of drizzle, which means the clouds last longer, more heat is reflected, and the cooling effect lasts longer.'

Professor Choularton's principal role is to understand the effect artificially injecting salt will have on the clouds, in particular whether it will cause any adverse effects. This information will then be used to plan small-scale pilot projects to see how the clouds react in the field.

One of the challenges the team faces is how to get salt into the clouds, in particular low level lumpy grey clouds, known as stratocumulus, which are the only type of clouds which will produce this cooling effect.

One idea, developed by Professor Stephen Salter of the University of Edinburgh, is to use high-frequency generators on board yachts to convert sea water into a very fine mist of salt particles which rise up and embed themselves in the clouds.

'If all of this is successful then it may be possible to have an operational system which over a small area of the globe would have the effect of off-setting global warming and reducing global temperature,' says Professor Latham.

'This would not be an ultimate solution to global warming but it would be a way of buying more time if the worst impacts of global warming start to manifest themselves over the next couple of decades,' he added.

The team is now hoping to gain funding to carry out pilot projects designed to test this theory.

Editor's Note: The original news release can be found here.

This story has been adapted from a news release issued by University Of Manchester.

Sea salt inhibits global warming (21 Feb, 2005)

Scientists at The University of Manchester are examining a novel idea for delaying the effects of climate change using a combination of clouds and sea salt.

Atmospheric experts Professor Tom Choularton and Dr. Keith Bower, who are working with a team of leading scientists around the world on the theory, have developed a computer simulation which shows how adding sea salt to clouds can slow global warming.

The idea, conceived by Professor John Latham, an Emeritus Professor at the University, now based at National Centre for Atmospheric Research in Colorado, is to use clouds as natural heat shields which when injected with salt reflect more sunlight and therefore protect against the greenhouse effect.

Professor Choularton, said: 'What our simulation shows is that if you artificially inject sea salt into clouds it not only increases the amount of heat which is reflected back into space, creating a cooling effect, but it also inhibits the formation of drizzle, which means the clouds last longer, more heat is reflected, and the cooling effect lasts longer.'

Professor Choularton's principal role is to understand the effect artificially injecting salt will have on the clouds, in particular whether it will cause any adverse effects. This information will then be used to plan small-scale pilot projects to see how the clouds react in the field.

One of the challenges the team faces is how to get salt into the clouds, in particular low level lumpy grey clouds, known as stratocumulus, which are the only type of clouds which will produce this cooling effect.

One idea, developed by Professor Stephen Salter of the University of Edinburgh, is to use high-frequency generators on board yachts to convert sea water into a very fine mist of salt particles which rise up and embed themselves in the clouds.

'If all of this is successful then it may be possible to have an operational system which over a small area of the globe would have the effect of off-setting global warming and reducing global temperature,' says Professor Latham.

'This would not be an ultimate solution to global warming but it would be a way of buying more time if the worst impacts of global warming start to manifest themselves over the next couple of decades,' he added.

The team is now hoping to gain funding to carry out pilot projects designed to test this theory.

For further information please contact Simon Hunter, Media Relations Officer, on telephone: 0161 2758387

Notes to Editors:

Professor Choularton is Professor of Atmospheric Physics at The University of Manchester in the School of Earth, Atmospheric and Environmental Sciences.

Professor Choularton's collaborators include Professor John Latham, National Centre for Atmospheric Research in Colorado, Professor Stephen Salter, University of Edinburgh, Professor Mike Smith, University of Leeds and Dr Andy Jones, Hadley Centre at the Meteorological Office.

By The Associated Press    from Live Science .com

posted: 24 July 2005
11:17 am ET

PDF] Why is the global warming proceeding much slower than expected
L Bengtsson, E Roeckner, M Stendel - View as HTML - Cited by 29
... BENGTSSON ET AL.: WHY IS THE GLOBAL WARMING SLOWER THAN EXPECTED? ... Doiron, CC Schnetzler,
AJ Krueger, and LS Walter, Global tracking of the SO 2 clouds from the ...
J. Geophys. Res, 1999 - glwww.dmi.dk - agu.org - agu.org - adsabs.harvard.edu 

Clearing smoke may trigger global warming rise

18:59 29 June 2005

NewScientist.com news service

http://www.newscientist.com/article.ns?id=dn7607

Fred Pearce

Global warming looks set to be much worse than previously forecast, according to new research. Ironically, the crucial evidence is how little warming there has been so far.

Three top climate researchers claim that the greenhouse gases already in the atmosphere should have warmed the world more than they have. The reason they have not, they say, is that the warming is being masked by sun-blocking smoke, dust and other polluting particles put into the air by human activity.

But they warn that in future this protection will lessen due to controls on pollution. Their best guess is that, as the mask is removed, temperatures will warm by at least 6°C by 2100. That is substantially above the current predictions of 1.5 to 4.5°C.

“Such an enormous increase would be comparable to the temperature change from the previous ice age to the present,” says one of the researchers, Meinrat Andreae of the Max Planck Institute for Chemistry in Mainz, Germany. “It is so far outside the range covered by our experience and scientific understanding that we cannot with any confidence predict the consequences for the Earth.”

Cool estimate

The calculations assume a doubling of greenhouse gases such as carbon dioxide (CO2) in the atmosphere by 2100 compared to pre-industrial levels.

Andreae and his two British colleagues, Peter Cox and Chris Jones, are leading authors from the UN’s Intergovernmental Panel on Climate Change. These new findings are likely to be reflected in the IPCC’s next assessment of climate change science, scheduled for 2007.

The cooling effect of aerosols has been known for some time. But, says Andreae, past assessments have underestimated its influence. Because of this, they have also underestimated the sensitivity of the atmosphere to the warming effect of greenhouse gases.

The new modelling study finds that only high estimates of both aerosol cooling and greenhouse warming can explain the history of global temperatures over the past 50 years.

One foot on the gas

The problem for future climate is that the cooling aerosols only stay in the air for a few days, whereas the warming gases stick around for decades or centuries. So while the cooling effect is unlikely to grow much, the gases will accumulate and have an ever-bigger effect on global temperature.

The world, says Andreae, is “driving the climate with one foot on the gas and the other on the brake. When the brake comes off, it makes a hell of a difference".

The authors have added another previously unrecognised element to the temperature forecast - the effect of all this on nature and the natural carbon cycle.

Natural ecosystems are currently absorbing up to half of the CO2 that humans put into the atmosphere. Most climate models assume this will continue. But there is growing evidence that from about 2050, soils and forests will stop absorbing CO2 and start releasing it instead.

The authors calculate that this switch in the natural carbon cycle could accelerate the build-up of CO2 in the air by more than 50%, producing a total warming that “may be as high as 10°C” by 2100.

9/11 study:

Air traffic affects climate

August 8, 2002

By Richard Stenger

(CNN) -- The thin wisps of condensation that trail jet airliners have a significant influence on the climate, according to scientists who studied U.S. skies during a rare interruption in national air traffic after the September 11 terrorist attacks.

During the three-day commercial flight hiatus, when the artificial clouds known as contrails all but disappeared, the variations in high and low temperatures increased by 1.1 degrees Celsius (2 degrees Fahrenheit) each day, said meteorological researchers.

While the temperature range is significant, whether the jet clouds have a net effect on global warming remains unknown.

"I think what we've shown are that contrails are capable of affecting temperatures," said lead scientist David Travis of the University of Wisconsin, Whitewater. "Which direction, in terms of net heating or cooling, is still up in the air."

In many ways, contrails behave in the same manner as cirrus clouds, thin high-altitude floaters that block out solar energy from above and trap in heat below.

As a result, they help reduce the daily range in daytime highs and nighttime lows. Contrails, by providing additional insulation, further reduce the variability.

With air traffic growing and contrails becoming more prevalent, the natural variation will further decline and could disrupt regional ecosystems, some scientists speculate.

Certain trees, crops and insect species depend on specific daily temperature variations for their survival.

In some ways, contrails differ from their natural brethren. Cirrus clouds let less heat out than in overall, producing a net increase in the Earth's temperatures, according to climate scientists. With contrail clouds, they said they are not so sure.

"Contrails are denser and block sunlight much more than natural cirrus clouds," said Travis, who conducted the study with Andrew Carleton of Penn State University in University Park, Pennsylvania. They reported the findings this week in the journal Nature.

"And contrails are much more prevalent when the sun is out," he said. "When this is factored in, there is a possibility that they offset global warming, and this is what we are trying to determine now."

The researchers plan more studies to tackle that question, but they said they expect to rely on circumstantial evidence only.

"We can only hope that the September 11 tragedy never happens again," Travis said.

Cosmic dirt makes deep climate impact
Christine White
August 25, 2005

The Australian

A MASSIVE 40,000 tonnes of space dust and debris rain down on Earth every year - and the particles are big enough to affect the planet's climate.

"Cosmic dust" from a recent meteoroid explosion was studied by a team of researchers, including Andrew Klekociuk from the Australian Antarctic Division in Kingston, Tasmania.

Published in Nature today, scientists found the dust particles from the spectacular explosion over Antarctica last September were about 1000 times bigger than previously thought. "And bigger particles have a much greater climate impact potential," Dr Klekociuk said.

After the explosion, dust rained down on the area for several weeks. "Most of the dust would have ended up in the stratosphere - 10km to 50km up - where it could reside for months," he said.

Researchers warn this could contribute to climate change, as dust particles can reflect sunlight, promote cloud formation and even cause ozone depletion.

Duncan Steel, space researcher with Ball Aerospace in Canberra, said: "It's obvious that our climate is largely controlled by the sun, but there are other off-planet factors that can affect the environment. This seems to be one of them."

The meteoroid studied by Dr Klekociuk and colleagues originally weighed about 1million kilograms, making it one of the biggest chunks of space rock to enter Earth's atmosphere in the past decade.

When it exploded, it released a similar amount of energy to the nuclear bomb that destroyed Hiroshima.

"I can almost guarantee that everyone has at least one tiny micrometeorite - cosmic dust particle - in their hair," Dr Steel said.

Smithsonian/NASA ADS Physics/Geophysics Abstract Service

pdf download of this paper :  (http://eed.llnl.gov/cccm/pdf/Govindasamy_etal_2003.pdf)

Abstract