Clouds Closer to Earth

Chicken Licken was right, the sky really is falling. Nasa satellite data has shown that the Earth's cloud tops have been lowering over the last decade.

 Cloud-top height fell one percent on average between March 2000 and February 2010, according to measurements from the multi-angle imaging spectroradiometer mounted on Nasa's Terra satellite. That one percent means a reduction of 30 to 40 metres in the average maximum height of clouds, during the 00s.

While the short record means it's difficult to draw any strong conclusions from the data, it does hint towards a longer-term trend. Roger Davies, the lead researcher on the project, warns that it's something that should be monitored in the coming decades to determine how significant it is for global temperatures.

If there is indeed a consistent reduction in cloud height, and this isn't just natural variability, then Earth would begin cooling to space more efficiently, reducing the surface temperatures and slowing the effects of climate change. 

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"We don't know exactly what causes the cloud heights to lower," says Davies. "But it must be due to a change in the circulation patterns that give rise to cloud formation at high altitude." The Terra spacecraft, which launched in 1999 and records three-dimensional images of clouds around the globe, will continue gathering data in the coming years.

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"

Can We Count On Weather Machines?

An NAS workshop looks to offset the effects of global warming with intensive, large-scale engineering projects to intentionally alter the climate. Does anyone think this is a good idea?

Ever since prehistoric man first set fires to drive game towards hunters and cliffs, humans have altered their environment for their own gain. No more so than in the years since the Industrial Revolution, when carbon emissions began to drastically alter Earth's climate and atmosphere.

And now that we know definitively that humans can alter Earth's climate, some scientists have begun investigating ways to deliberately change the weather to offset the negative impact of a century of inadvertent human generated climate change.

 

The name for that deliberate, targeted climate change is geoengineering, and its on the mind of everyone from the National Academy of Sciences to Barack Obama's science adviser.

On Monday, the National Academy of Sciences held a workshop on geoengineering, following an interview where White House Science Adviser John Holdren recommended increased research into the subject. While the scientists at the workshop agreed that it was possible, there was disagreement about when to start testing the ideas, and whether or not the cure might be worse than the problem.

According to National Public Radio, one of the more popular ideas involves seeding the sky with sulfur particulate to reflect the rays of the sun and cool the Earth. This solution mimics the changes in climate that follow large volcanic eruptions. In a recent article, The Atlantic Monthly deemed this the "Blade Runner scenario," and listed some other possible geoengineering schemes, including pouring huge amounts of iron into the ocean to encourage carbon-absorbing algae blooms and using a fleet of 1,500 ships to churn up seawater to create more light reflecting clouds.

As Matt Springer at ScienceBlogs notes, no one is sure if any of these plans will work, if geoengineering is even legal, or what unintended nightmare consequences may result from wholesale disruption of the Earth's carefully balanced ecosystem.

The global warming that results from man-made carbon emissions has shown that we can profoundly alter the climate. But the scientists interviewed in all those articles seem torn by the question of whether or not more human generate change is the appropriate, cheapest, and safest way to address the climate problem.

by "environment clean generations"

CERN, Cosmic Rays and Climate Change

Not content with just stirring the pot in particle physics, CERN has embarked on an experiment aimed at addressing whether or not comic rays from deep space might be seeding clouds in Earth’s atmosphere, influencing climate change. The early findings are far from deciding the issue of whether climate change is man made or otherwise, but they have borne some interesting results. It turns out that cosmic rays could be influencing temperatures on Earth. Perhaps even more groundbreaking, it turns out they also might not. Welcome to climate science.

The notion is this: Cosmic rays that we know are bombarding our planet from the far reaches of space are pelting the atmosphere with protons, and those protons can ionize some compounds that in turn condense into aerosols, basically droplets in the atmosphere. Clouds might in turn build around those droplets, and those clouds shield the Earth, reducing temperatures.

But our dosing of cosmic rays is dependent on the sun. When the sun is emitting lots of radiation during high points in the solar cycle, its magnetic field shields us from some of those cosmic rays. An active sun spells fewer rays spells fewer clouds, and hence warming temperatures on Earth.

So, are cosmic rays (or the lack thereof) to blame for our current spate of rising temperatures? Of course/not/maybe.

The experiment at CERN is fabricating the upper atmosphere in the lab by trapping ultra-pure air and things like water vapor, ozone, ammonia, and sulphur dioxide in a chamber. They are then bombarding that air with protons from the same generator that supplies the Large Hadron Collider. Preliminary results show that these faux cosmic rays indeed have an effect on the atmosphere: When high energy protons stream in, production of nanometer-sized particles in the atmosphere increases by more than ten times.

Case closed. But not really. Those particles that are forming are far too small to actually seed a cloud. So while CERN has proven that cosmic rays are definitely influencing the upper atmosphere, the connection between warming and cosmic rays is far from firmly established.

Naturally, different scientists are reaching different conclusions, but all seem to think this experiment is a worthwhile idea, even if it basically asks more questions than it answers. So, just to recap, the whole climate change argument has not been put to rest. 

 by "environment clean generations"

Clouds Can Make Warming Worse

Researchers are making headway against one of the most deceptively difficult problems in climate science: What happens to clouds in a warming world? Are there more, or fewer, and do they make matters better or worse?

A team of University of Hawaii-Manoa researchers from the U.S. and Japan report that a regional atmospheric model has achieved a breakthrough in the depiction of the impact of warming temperatures on cloudiness in the eastern Pacific Ocean, something that large global climate models have failed to accomplish.

It doesn't qualify as a dramatic Eureka! moment, but in climate science, progress on this front is a big deal, because this failure of the large, supercomputer-driven global climate models to accurately capture the role of clouds in our changing climate is a major source of uncertainty in their forecasts.

"All the global climate models we analyzed have serious deficiencies in simulating the properties of clouds in present-day climate," said lead author Axel Lauer in a statement released by UHM. "It is unfortunate that the global models' greatest weakness may be in the one aspect that is most critical for predicting the magnitude of global warming."

Unfortunately, the news from the University of Hawaii team, reporting in the Journal of Climate, apparently confirms earlier estimates that the response of clouds to rising sea surface temperatures amplifies the warming trend, leading scientists to suggest that our future lies at the warmer high end of the spread of model uncertainty rather than the cooler low end.

Higher sea surface temperatures cause low-level marine clouds to dissipate, the thinking goes, allowing more of the sun's warming rays to break through, causing a further rise in ocean temperatures. . . and so on.

In the same stretch of the eastern North Pacific, similar "positive feedback" results were reported last summer by a team led by Amy Clement of the University of Miami, who compared observations made by sailors with measurements taken by satellite-borne instruments, but is the first report of a model successfully capturing the effect.

"If our model results prove to be representative of the real global climate, then climate is actually more sensitive to perturbations by greenhouse gases than current global models predict, and even the highest warming predictions would underestimate the real change we could see," said co-author Kevin Hamilton.

 by "environment clean generations"