A team of researchers has come up with a simple plan to halt global warming: All we need to do is turn both the Sahara and the Australian outback into vast, shady forests.
While that might sound so ambitious as to be absurd, the climate scientists say the project would be no more expensive or technologically challenging than some of the other geoengineering schemes that are currently under discussion. And researcher Leonard Ornstein says it would certainly get results. Ornstein says that if most of the Sahara and Australian outback were planted with fast-growing trees like eucalyptus, the forests could draw down about 8 billion tons of carbon a year–nearly as much as people emit from burning fossil fuels and forests today. As the forests matured, they could continue taking up this much carbon for decades [ScienceNOW Daily News].
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The Republic of Maldives has big plans for discarded coconut shells: they can become both a fertilizer and a planet-cooler. The Maldivian government has announced plans to burn the shells and turn them into biochar, a form of high-carbon charcoal that takes a long time to decompose, and which can be used to nourish the soil. It’s one effort of many that the government of the Indian Ocean archipelago hopes will help it achieve carbon neutrality by the year 2020.
The “slow-cooked” organic waste project was launched through a partnership between the Maldives government and the British company Carbon Gold. The scheme would not only reduce organic garbage, it would also decrease dependence on imported fertilizer. Carbon Gold argues that the biochar is an effective way of removing CO2 from the atmosphere. The company says the fertiliser also improves soil fertility…. “Waste that would have rotted or been burnt before is now locked up and put very safely in the soil,” [BBC], says company cofounder Daniel Morrel. Researchers believe that biochar doesn’t break down (and therefore release its carbon) for hundreds of years.
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It would be funny if it weren’t so serious: While some skeptics are still ignoring the scientific evidence and insisting that global warming is a hoax, engineers and scientists are already looking for the best “plan B” that can help out humanity in the likely event that the world’s governments can’t agree to cut carbon dioxide emissions fast enough to prevent serious global consequences. Just last week Britain’s Institution of Mechanical Engineers released their picks for the most realistic geoengineering tactics, and now the Royal Society, Britain’s top science academy, has weighed in with its suggestions.
A 12-member working group of scientists, engineers, an economist, a social scientist, and a lawyer spent nearly a year examining technologies, such as fertilizing the oceans to suck down atmospheric carbon dioxide or orbiting giant mirrors to deflect sunlight [ScienceInsider]. The subsequent report (pdf) argues that many of the most-hyped geoengineering ideas are simply too risky, including the proposal to fertilize the ocean to create carbon-absorbing algae blooms. “Most of the things that have gone wrong in the past have happened when we’ve tampered with biological systems” [New Scientist], says John Shepherd, who chaired the report committee.
The report separates geoengineering tactics into two basic approaches: those that reflect sunlight back into space to cool down the planet, and those that remove the heat-trapping gas carbon dioxide from the air. Of the two strategies, the report concluded that those involving the removal of carbon dioxide were preferable, as they effectively return the climate system closer to its pre-industrial state. But the authors found that many of these options were currently too expensive to implement widely. This included “carbon capture and storage” methods, which require CO2 be captured directly from power plants and stored under the Earth’s surface [BBC News]. Yet carbon capture and storage projects have been touted as an important response to global warming by power plants and governments alike.
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The most practical and immediate steps we can take to slow global warming may be lining roadways with towering “artificial trees” and covering buildings with algae bioreactors, argues a new report from Britain’s Institution of Mechanical Engineers. The group believes that geoengineering (a broad term for climate-altering technologies) may be necessary to reduce carbon dioxide levels immediately, while governments continue to bicker about how to transition to a low-carbon future. “Geo-engineering is no silver bullet, it just buys us time,” said Tim Fox of the IME, who led the study [The Guardian].
Fox says the study (pdf) looked for techniques that could be rolled out with existing technology. The IME’s first suggestion is to construct hundreds of thousands of “artificial trees”, essentially building- or goalpost-sized structures through which the wind blows. As air passes through them, the “trees” extract CO2 from it for later sequestration [The Register]. The fake trees are intended to be much more efficient at absorbing CO2 than real, biological trees, with current designs estimated to remove one ton of CO2 from the air daily. But even if the devices could be made ten times more efficient, the study found that 100,000 fake trees would be required to absorb the CO2 emissions from all the cars and trucks in the United Kingdom.
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Five patent applications for technology that aims to control the weather bear the signature of a man who knows how to think big: Microsoft founder Bill Gates. The applications made public by the U.S. Patent Office last week describe floating devices that could reduce the strength of hurricanes by drawing warm water from the ocean’s surface and channeling it down to the depths through a long tube. A second tube would reverse the process and bring deep, cold water up to the surface.
The applications were filed by an entity called Searete, which is part of the company Intellectual Ventures that was founded by former Microsoft executives as an “invention business;” Bill Gates is an investor in the company. Gates is listed as one of the inventors on each hurricane-quelling patent application, along with scientists like the geoengineering expert Ken Caldeira. One of the patent applications describes how part or all of the cost of building and maintaining the hurricane-killer ships could be raised by selling insurance to coastal residents whose risk would be reduced by using the new system [New Orleans Times-Picayune].
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In large industrial experiments across the globe, factories and power plants are trying to capture the carbon dioxide that streams out of their flues in order to bury it deep underground. Researchers believe the greenhouse gas will stay put for thousands of years and therefore won’t contribute to global warming, but the costs and long-term effects of the procedure are still unclear. The experiments currently underway are expected to determine whether carbon capture and storage will allow nations to continue burning fossil fuels for energy without ill effects.
In France this month, the first retrofitted power plant will begin to use its new carbon capture and storage technology. The system used by the natural gas-burning power plant will transport and store 60,000 tonnes of carbon dioxide every year in the nearby depleted gas field at Rousse – once the biggest onshore natural gas field in Europe, but which is now almost empty [The Guardian]. The carbon dioxide will flow through existing pipelines that once brought natural gas to the power plant. While the first new power plant using carbon capture and storage opened last year in Germany, some environmentalists say that the French plant’s retrofit is an important example of how existing industries can be adapted to a future that requires clean energy.
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President Obama’s science adviser John Holdren has given his first round of interviews, and he immediately caused a ruckus by airing his thoughts on geoengineering–the large-scale climate hacks that could potentially slow or reverse global warming. Tinkering with Earth’s climate to chill runaway global warming — a radical idea once dismissed out of hand — is being discussed by the White House as a potential emergency option, the president’s new science adviser said…. “It’s got to be looked at,” he said. “We don’t have the luxury … of ruling any approach off the table” [AP].
However, the day after that Associated Press article appeared, Holdren came back to say that the article had misrepresented his statements. Dr. Holdren said that the Associated Press article implied incorrectly that this strategy for climate management was under serious consideration at the White House…. “Asked whether I had mentioned geo-engineering in any White House discussions, though, I said that I had. This is NOT the same thing as saying the White House is giving serious consideration to geo-engineering – which it isn’t — and I am disappointed that the headline and the text of the article suggest otherwise” [The New York Times blog], he wrote in an email to journalists and colleagues.
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A controversial geoengineering experiment that Greenpeace campaigned against (to little avail) has concluded, and researchers say their findings deal a major blow to the geoengineering technique known as ocean fertilization. As 80beats explained in January, the researchers dumped 20 tons of iron sulfate in the ocean near Antarctica in an effort to spur enormous blooms of phytoplankton, a type of algae; researchers theorized that when that plant life died and sank to the seabed it would lock away the carbon dioxide it had absorbed while growing. They hoped that widespread use of this technique could slow global warming.
While the iron did prove an algae bloom, researchers involved in the Lohafex project found that little biomass sunk down to the sea floor. Their results, announced in a press release, suggest that iron fertilisation could not have a major impact, at least in that region of the oceans. “There’s been hope that one could remove some of the excess carbon dioxide – put it back where it came from, in a sense, because the petroleum we’re burning was originally made by the algae,” said [researcher] Victor Smetacek…. “But our results show this is going to be a small amount, almost negligible” [BBC News]. Researchers also announced the surprising reason for that result: The plankton bloom wasn’t a carbon sequestration hot spot, instead it was an all-you-can-eat marine buffet.
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As global warming’s effects become evident researchers have turned to geoengineering schemes that could slow the warming process, like a global “sunshade” produced by spraying sulfur aerosols into the atmosphere to reflect sunlight back into space. But a new study points out an (obvious in retrospect) drawback of that idea: It would seriously reduce the effectiveness of some solar energy facilities, which proponents hope would reduce our dependence on fossil fuels and thus prevent further global warming.
Researchers from the National Oceanic and Atmospheric Administration went back and examined data from 1991, when Mount Pinatubo erupted. The Philippine volcano ejected about 15 million metric tons of sulfur-dioxide–laden dust into the air, cooling the planet’s average temperature by about 0.6°C for nearly 2 years [ScienceNOW Daily News]. The researchers found that the eruption also reduced peak power output at a California solar-thermal plant by 20 percent. Solar thermal plants use arrays of mirrors to concentrate sunlight and turn it into a heat source for a conventional power plant; they are generally cheaper than traditional photovoltaic systems.
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A climate scientist in England has invented a new process for turning wood into charcoal with giant microwaves, and says that the technique may be the best tool humans have for sequestering carbon and slowing global warming. The “biochar” created in the process locks in carbon from the wood, and sequesters it for thousands of years before the charcoal finally decomposes.
Biochar received new attention recently when researchers ranked geoengineering schemes based on their ability to slow global warming, and listed biochar as one of the most effective (and cheapest) approaches. The English scientist, Chris Turney, is eager to move from theory to practice, and has founded a company called Carbonscape that set up a microwave-powered kiln in Blenheim, in New Zealand’s South Island, in October last year…. The stove the Carbonscape directors call the Black Phantom can fix up to one tonne of carbon a day [The Australian].
Charcoal is typically produced by slowly heating wood in industrial ovens, but Turney says his microwave process is cleaner and more efficient. The idea came from a cooking accident when he was a teenager, in which he mistakenly microwaved a potato for 40 minutes and found that the vegetable had turned into charcoal. “Years later when we were talking about carbon sequestration I thought maybe charcoal was the way to go,” he said [The Guardian].
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Sunshades in the stratosphere to reflect sunlight away from our planet. Dumping iron into the oceans to encourage algae blooms that would take up carbon dioxide. Painting every rooftop white. These are just a few of the geoengineering schemes that have been suggested to artificially alter the planet’s climate and counteract global warming.
Now researchers have helpfully ranked 17 proposals on their possible efficacy, saying that it’s past time to take a hard look at the ambitious ideas. “There is a worrying feeling that we’re not going to get our act together fast enough,” says [coauthor Tim] Lenton, referring to international efforts to limit greenhouse gas emissions. Scientists have reached a “social tipping point” and are starting to wonder which techniques might complement emissions cuts, he says [New Scientist]. The study, published in Atmospheric Chemistry and Physics, didn’t include an analysis of costs and environmental impacts.
Lenton says there has been too much hype and not enough analysis regarding geoengineering schemes, so he decided to start by asking a straightforward question. At the most basic level, earth’s surface temperature is governed by a balance between incoming Solar radiation and outgoing terrestrial radiation [Physics World]. The researchers examined how each of the geoengineering schemes would sway that balance, either by reflecting away solar radiation or reducing carbon dioxide that traps heat in the atmosphere. They found that a few proposed technologies could have a planet-wide cooling impact, but say those would be extremely hard to pull off.
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One of the most controversial geoengineering schemes that has been proposed to slow the course of global warming, ocean fertilization, received mixed reviews from a new study. The idea involves dumping iron into the ocean to nourish plankton and spur enormous blooms, which would then die off and fall to the sea floor, bringing the carbon dioxide they’d absorbed with them. Now, researchers studying natural plankton blooms near Antarctica have new evidence to fuel the debate over the efficacy of the process, and whether or not it can get our planet out of hot water.
Scientists took measurements around the Crozet Islands, where there are naturally occurring fluxes in iron levels. To the north of the islands levels of iron are boosted each year as iron-rich volcanic rocks are eroded and the nutrients are carried off by the current [Times Online]. Researchers observed a huge plankton bloom there that covered an area the size of Ireland and lasted for more than two months, while also studying the water to the south of the islands, where the prevailing ocean currents don’t carry dissolved iron and therefore plankton blooms don’t form naturally. The results, to be published tomorrow in Nature [subscription required], showed that iron-enriched waters do, as hoped, encourage more carbon to be stored on the ocean floor. But the efficiency of artificial iron fertilisation could be as much as 50 times lower than previous estimates [New Scientist].
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The ravages of global warming could be mitigated by convincing farmers around the world to plant slightly different varieties of corn, barley, and millet, according to a new study which examines the reflective properties of crop plants.Plants reflects short wave energy back out to space much like snow and other light surfaces do. This is known as the albedo effect and is a key component of calculating the effects of climate change. As Arctic ice melts and is replaced by dark water, for instance, the region’s warming is expected to accelerate. Plants have higher or lower reflectivity depending on things like the shape and size of their leaves and how waxy they are [New Scientist].
Lead researcher Andy Ridgwell and his colleagues were inspired in their work by the growing talk of geoengineering fixes for global warming, including ambitious and large-scale projects like seeding the Southern Ocean with iron to encourage algae blooms or building a huge sunshade in the Earth’s orbit. The researchers say their proposal, which they call bio-geoengineering, is more realistic because it uses existing infrastructure. “Arable agriculture is already a global-scale undertaking,” Dr. Ridgwell said. “We wondered whether you might grow slightly different crops and have some sort of climate impact.” … [I]t wouldn’t cost much, and it wouldn’t require much international cooperation. “It’s very practical, and it could just be done,” he said. “It’s not some trillion-dollar pie-in-the-sky idea” [The New York Times].
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A German research ship carrying 20 tons of iron sulfate is currently motoring towards the South Atlantic, and the crew plans to dump its mineral cargo into the ocean in a controversial science experiment. The researchers will be testing a technique called ocean fertilization, in which iron is dumped into nutrient-poor waters to induce a huge blooms of phytoplankton. After the photosynthesizing plankton grows and absorbs carbon dioxide, researchers hope it will die and sink down to the seafloor still bearing that greenhouse gas in a natural form of carbon sequestration. Ocean iron fertilization is considered one of the more promising options for global-scale geoengineering, which aims to slow or reverse the effects of climate change caused by man’s burning of fossil fuels [Wired News].
But the so-called LOHAFEX experiment has raised the ire of some environmentalists, who worry about unknown consequences of interfering with the marine ecosystem. Ocean fertilisation experiments have been carried out on a few occasions in the past, but became controversial in 2007 when a company called Planktos announced it would dump iron fillings [sic] off the coast of the Galapagos islands. Some environmental organisations … expressed concerns that this was tantamount to pollution and, by affecting plankton at the bottom of the food chain could have unforeseen consequences [New Scientist]. The company Planktos went out of business and never conducted its experiment (largely due to the bad publicity), but the incident caused the UN Convention on Biological Diversity to ask countries not to permit ocean fertilization experiments.
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