A Huge Pipe, a Balloon and Water

It sounds barmy, audacious or sci-fi: a tethered balloon the size of Wembley stadium suspended 20km above Earth, linked to the ground by a giant garden hose pumping hundreds of tonnes of minute chemical particles a day into the thin stratospheric air to reflect sunlight and cool the planet.

But a team of British academics will next month formally announce the first step towards creating an artificial volcano by going ahead with the world's first major "geo-engineering" field-test in the next few months. The ultimate aim is to mimic the cooling effect that volcanoes have when they inject particles into the stratosphere that bounce some of the Sun's energy back into space, so preventing it from warming the Earth and mitigating the effects of man-made climate change.

 

Before the full-sized system can be deployed, the research team will test a scaled-down version of the balloon-and-hose design. Backed by a £1.6m government grant, the team will send a balloon to a height of 1km over an undisclosed location. It will pump nothing more than water into the air, but it will allow climate scientists and engineers to gauge the engineering feasibility of the plan. Ultimately, they aim to test the impact of sulphates and other aerosol particles if they are sprayed directly into the stratosphere.

If the technical problems posed by controlling a massive balloon at more than twice the cruising height of a commercial airliner are resolved, then the team from Cambridge, Oxford, Reading and Bristol universities expect to move to full-scale solar radiation tests.

The principal investigator, Matthew Watson, a former UK government scientific adviser on emergencies and now a Bristol University lecturer, says the experiment is inspired by volcanoes and the way they can affect the climate after eruptions.

"We will test pure water only, in sufficient quantity to test the engineering. Much more research is required," he said, in answer the question of what effect a planetary-scale deployment of the technology could have.

Other leaders of the government-funded Stratospheric particle injection for climate engineering (Spice) project have investigated using missiles, planes, tall chimneys and other ways to send thousands of tonnes of particles into the air but have concluded that a simple balloon and hosepipe system is the cheapest. 

The research is paid for by the government-funded Engineering and Physical Sciences Research Council.

"The whole weight of this thing is going to be a few hundred tonnes. That's the weight of several double-decker buses. So imagine how big a helium balloon do you need to hold several double-decker buses – a big balloon. We're looking at a balloon which is possibly 100-200m in diameter. It's about the same size as Wembley stadium," said the Oxford engineering lecturer Hugh Hunt in an interview earlier this year.

"This hose would be just like a garden hose, 20km long and we pump stuff up the pipe. The nice thing about it is that we can really have a knob, if you like, which we can control to adjust the rate at which we inject these particles."

While the October experiment is expected to have no impact on the atmosphere, it could also be used to try out "low-level cloud whitening", a geo-engineering proposal backed financially by Microsoft chairman and philanthropist Bill Gates.

In this case, fine sea salt crystals would be pumped up and sprayed into the air to increase the number of droplets and the reflectivity in clouds. Together, many droplets are expected to diffuse sunlight and make a cloud whiter.

However, environment groups in Britain and the US said the government's experiment was a dangerous precedent for a full-scale deployment that could affect rainfall and food supplies. Even if the approach successfully cools the planet by bouncing some of the Sun's energy back into space, it would do nothing for the build up of CO₂ in the atmosphere, which leads to increased ocean acidity.

"What is being floated is not only a hose but the whole idea of geo-engineering the planet. This is a huge waste of time and money and shows the UK government's disregard for UN processes. It is the first step in readying the hardware to inject particles into the stratosphere. It has no other purpose and it should not be allowed to go ahead," said Pat Mooney, chair of ETC Group in Canada, an NGO that supports socially responsible development of technology.

Mike Childs, head of science, policy and research at Friends of the Earth UK, said: "We are going to have to look at new technologies which could suck CO₂ out of the air. But we don't need to do is invest in harebrained schemes to reflect sunlight into space when we have no idea at all what impact this may have on weather systems around the globe."

But the principle of large-scale geoengineering has been backed strongly by Sir Martin Rees, the former president of Royal Society, which in 2009 concluded in a report that it may be necessary to have a "plan B" if governments could not reduce emissions.

"Nothing should divert us from the main priority of reducing global greenhouse gas emissions. But if such reductions achieve too little, too late, there will surely be pressure to consider a 'plan B' – to seek ways to counteract the climatic effects of greenhouse gas emissions by 'geoengineering'," said Rees.

Members of the British public who were consulted by researchers in advance of the Spice experiment were broadly sceptical.

"Overall almost all of our participants were willing to entertain the notion that the test-bed as an engineering test – a research opportunity – should be pursued. Equally, very few were fully comfortable with the notion of stratospheric aerosols as a response to climate change," the Cardiff University-based researchers concluded.

by "environment clean generations"

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Posted in: air,balloon,clouds,environment,pipe,spray,water

Lasers Could Create Clouds and Rain, on Demand

Weather control freaks may get their next rainmaking tool in the form of an infrared laser. Scientists have successfully created small clouds by firing a laser both inside a lab and under the autumn skies of Berlin, Germany, New Scientist reports.

The concept works because laser pulses strip electrons from atoms in the air and promote formation of hydroxyl radicals. Those in turn make sulfur and nitrogen dioxides into particles which can form the basis for water droplets -- not unlike how current cloud seeding methods use silver iodide crystals as the "seeds" for water droplets.

But rather than seeding the air with crystals delivered by airplanes or artillery rockets, the Swiss, German and French researchers used a laser which could generate 220-millijoule pulses within 60 femtoseconds, where one femtosecond is one millionth of one billionth of a second. That's as much power as what 1,000 power plants could generate, according to Jérôme Kasparian at the University of Geneva, Switzerland.

A lab experiment involved the laser firing inside water-saturated air to create tiny clouds similar to airplane contrails. The outdoor experiment did not produce visible clouds, but clearly boosted the density and size of water droplets according to weather LIDAR measurements.

Cloud seeding has had plenty of critics voice their doubts over its effectiveness. Still, China has used the weather-control tactic for its hosted Olympics, and even delivered snowstorms to weary Beijing residents on multiple occasions. Russia has also prominently used cloud seeding in an attempt to make snow fall on the outskirts of Moscow rather than on the city itself.

Nations intrigued by the idea of more high-tech cloud seeding shouldn't abandon their silver iodide just yet. Researchers need to work on tuning their laser in the hopes of creating large enough water droplets which could fall as rain.

 by "environment clean generations"

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Posted in: air,crystals,Giant Solar-Powered Artificial Waterfall,high-tech,Lasers Could Create Clouds and Rain,on Demand

Dust Level High

There is twice as much desert dust in the atmosphere now than a century ago. Particles of dust in the air affect climate and ocean ecology. A better understanding of changing dust levels should help scientists make more accurate climate predictions. 

The amount of dust in the atmosphere has doubled over most of the planet since the last century, finds a new study.

As wind blows through the world's deserts, it whisks dust up into the air and down into the oceans and can significantly affect climate and the environment in all sorts of ways. 

Understanding the changing patterns of dirt particles in the atmosphere could help scientists improve the accuracy of climate predictions. Tracing swirls of dust to their roots could also lead to better land management practices that might mitigate the flow of dust from Earth to sky and sea.

But first, researchers need to figure out why dust levels are rising in the first place. 

"We don't know," said Natalie Mahowald, an atmospheric scientist at Cornell University in Ithaca, N.Y. "It's probably a combination of agriculture and pasture-usage as well as climate change because a lot of regions are getting drier, and that would increase desert dust."

"We put big uncertainty bars on everything," she added. "We need more data."

Climate researchers have spent a lot of time worrying about the effects of particles that human actions release into the atmosphere. Known as anthropomorphic aerosols, these include sulfates from coal-fired power plants and nitrogen oxides from automobile exhaust. 

Mahowald is more interested in desert dust, which can also affect climate in a number of ways. For one thing, particles of soil that are suspended in the air alter the way the atmosphere absorbs and reflects energy from the sun. Dust also changes the properties of clouds, which play a big role in climate patterns. Overall, rising levels of dust tend to cool the atmosphere down.

Dust also affects the chemistry of the oceans. That's because dust contains iron, which boosts growth of plankton, allowing the oceans to pull a little more carbon out of the air. 

To piece together a history of Earth's blowing dust, Mahowald and colleagues compiled a wealth of published data, which included analyses of layered ice cores and sediment samples taken from more than a dozen sites around the world. Most of these cores held specks of dust that had blown in from somewhere else. 

In ice cores from Antarctica, for example, scientists identified soil from South America. Lake sediments in Colorado's San Juan Mountains contained soil particles originally from the Mojave Desert in California, 1,000 kilometers (600 miles) away. Each layer was dated so the researchers could tell how the levels of blowing dust changed over time. 

For the 100-year span from about 1900 to 2000, levels of dust fluctuated quite a bit and patterns differed in different regions, the researchers reported in the journal Atmospheric Chemistry and Physics. Overall, though, levels of dust around the globe doubled everywhere except above North America, where levels dropped a little bit. 

By comparing dusty periods with periods that weren't so dusty, the researchers were able to show that dusty skies lead to lower temperatures -- masking some of the warming effects of greenhouse gasses. As dust accumulates in the air, it also affects clouds enough to move storms away from desert areas, possibly propelling droughts that, in turn, lead to even more dust. 

In the oceans, dust boosts productivity and sucks up more carbon from the air, which can also cool the climate. But that may be offset by erosion and the loss of plant cover on land.

In satellite images of Earth, you can see three obvious colors, said Joseph Prospero, an atmospheric scientist at the University of Miami in Florida: The blue of oceans, the white of clouds and the brown of massive desert dust storms. 

Those images, Prospero said, clearly show that dust is a major player that needs to play a more significant role in climate models as one of a multitude of fluctuating and complicated factors. 

"When climate changes, you get a tremendous amount of variability in dust output," he said. "There is a strong possible loop where the climate becomes drier and windier causing more dust, and more dust affects radiation, so it feeds back on climate."

"There is a lot of uncertainty about how that works," he added. "That's why we focus on dust."

 by "environment clean generations"

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Posted in: air,desert,drought,dust,earth,Mahowald,ocean,particles,satellite