Flooding in Piazza San Marco, Venice

Venice is sinking, and the nearby Adriatic sea—like the global sea level—is rising. The city could, some estimates suggest, be underwater by the end of the century. Much of the trouble is due to Venice’s precarious, low-lying position in the middle of a lagoon, but human activity in the area has played a role in the city’s subsidence, as well. As Scott K. Johnson explains at Ars Technica:

The pumping of shallow groundwater in the mid-1900s also contributed to the problem. Water in the pores between grains of sediment provides pressure that bears some of the load. When pore pressure decreases, or water is removed completely, grains can be packed together more tightly by collapsing the pore spaces. As sediment is compacted, the land surface drops. While the effect was small (less than 15cm), Venice doesn’t have much wiggle room.

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A naled, or aufeis, in the flesh. Er, ice.

It sounds like science fiction, but, like so many science fiction-ish ideas in the age of radical adaption to climate change, it’s real: Mongolia is launching a $750,000 geoengineering project to freeze vast quantities of the Tuul River in order to cool its capital city of Ulan Bataar during the sweltering summer, and to provide drinking water as the ice melts, as well. While specifics about exactly how the cooling will work are scarce, details about the freezing process are not, as it will mimic a natural process that already occurs on rivers in the north.

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A recent volcanic eruption let scientists watch Mother Nature try out one of the geoengineering schemes that has been proposed to reduce the amount of carbon dioxide in the air, and therefore cool the planet. But the results of this natural experiment left a lot to be desired.

The geoengineering technique known as ocean fertilization calls for scientists to dump iron into the ocean to “fertilize” it and spur blooms of phytoplankton. These tiny photosynthetic organisms will suck up CO2 as they grow, the thinking goes, but will then die and tumble down to the sea floor, where the CO2 will be safely stored in the heaps organic matter.

The same thing can happen naturally, though, if a volcano happens to erupt and spews iron particles over the ocean. That’s exactly what happened in the summer of 2008.

In August 2008, scientists in the northeastern Pacific Ocean were shocked to witness a sudden, huge spike in the area’s plankton population. Their investigation traced the bloom to an ash cloud from a volcano that had erupted in the Aleutian Islands only a few days before. The ash, it turned out, had fertilized the ocean with thousands of tons of iron, on which the plankton gorged. [ScienceNOW]

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Has climate skeptics’ favorite Danish statistician, Bjørn Lomborg, changed his stance? In the forthcoming book edited by Lomborg, Smart Solutions to Climate Change, he calls climate change one of the world’s “chief concerns” and suggests investing $100 billion annually on climate change solutions.

The suggestion certainly comes as a surprise. In his previous books, like The Skeptical Environmentalist and Cool It, Lomborg argues that anthropogenic climate change is real but that it isn’t a “catastrophe”–that the associated “hysteria” was causing us to spend money trying to curb the globe’s warming where it would have been better spent, say, feeding the hungry or curing HIV.

Understandably, that stance has made his work appealing to climate skeptics who don’t want to spend money on curbing emissions–and unpopular among those who see Lomborg as a distraction who misrepresents the science and confuses the issue. In his new book, the statistician apparently reorders his priorities, now arguing that climate change solutions should get more cash.

What’s not a surprise: opinions vary as to the merits of this new book and as to whether it’s a shift, a drastic shift, not a shift, or a publicity stunt. Here, we share some.

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You could plant huge new forests where none have been before. You could blast particles into the sky to block the sun’s radiation. You could put mirrors in space. These planetary hacks could slow global warming, but one thing that none of them could do, most likely, is to stop the rising sea levels that a warming planet will bring.

That’s the contention of John Moore, lead author of a study out in the Proceedings of the National Academy of Sciences. Moore’s team examined five different means that scientists have proposed to hack the planet and save ourselves from anthropogenic global warming. The geoengineering schemes—forestation, atmospheric aerosols, space mirrors, biochar, and the use of biofuels plus carbon sequestration—are focused either on reducing the amount of energy the Earth absorbs or pulling carbon out of the atmosphere. So Moore wanted to see what they could do about a side effect of the extra heat: melting ice raising the global average sea level.

The results weren’t terribly encouraging. Sea levels respond slowly to changes in the planet’s temperature, Moore told Nature News, so “you can’t just slam on the brakes.”

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Schemes to hack the planet and save us from global warming have two layers of obstacles to overcome. First, is it technologically and physically possible to do what’s proposed? And then there’s the second: Is it politically possible to tinker with the planet?

Those who would argue “absolutely not” to the latter got a boost by a new study out in Nature Geoscience. Katharine Ricke and her team modeled the effects of one of the most popular geoengineering plans: seeding the atmosphere with aerosols to reflect away some of the sun’s rays, mimicking the way a massive volcanic eruption can cool the Earth. Ricke found that the effects on rainfall and temperature could vary wildly by region—and that what’s best for one country could spell disaster for another.

For example, Ricke says, her study found that levels of sulphate that kept China closest to its baseline climate were so high that they made India cold and wet. Those that were best for India caused China to overheat. She notes, however, that both countries fared better either way than under a no-geoengineering policy [Nature].

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Bill Gates is getting serious about geoengineering. Back in January, after the failure of governments at the Copenhagen Climate Change summit to do anything serious, the billionaire former head of Microsoft announced he’s give nearly $5 million of his fortune to fund research into geoengineering projects. Recently he announced his first concrete foray into the field: giving $300,000 to project that would spray seawater into the sky, seeding clouds that would hopefully block some of the sun’s UV rays.

The machines, developed by a San Francisco-based research group called Silver Lining, turn seawater into tiny particles that can be shot up over 3,000 feet in the air. The particles increase the density of clouds by increasing the amount of nuclei contained within. Silver Lining’s floating machines can suck up ten tons of water per second. If all goes well, Silver Lining plans to test the process with 10 ships spread throughout 3800 square miles of ocean [Inhabitat].

Most of the major geoengineering ideas that have been proposed—launching a reflective shield into space, artificial trees to pull carbon dioxide out of the air—are extremely expensive and difficult.

However, a study last year calculated that a fleet of 1,900 ships costing £5 billion (about $7.5 billion) could arrest the rise in temperature by criss-crossing the oceans and spraying seawater from tall funnels to whiten clouds and increase their reflectivity [The Times].

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As heated global warming debates continue, scientists are also investigating ways to get our planet to cool off if the politicians can’t figure out how to reduce greenhouse gas emissions. The latest geoengineering scheme involves turning the world’s oceans into a giant bubble bath, with hundreds of millions of tiny bubbles pumped into the seas. This would increase the water’s reflectivity and bring down ocean temperatures, according to Harvard University physicist Russell Seitz. As the creative physicist said to the assembled crowd at an international meeting on geoengineering research: “Since water covers most of the earth, don’t dim the sun…. Brighten the water.”

Seitz explained that micro-bubbles already occur naturally, with bubbles under the ocean’s surface reflecting sunlight back into space and mildly brightening the planet. What Seitz imagines doing now is artificially pumping many more bubbles into the sea. These additional micro-bubbles would each be one five-hundredth of a millimeter and would essentially serve as “mirrors made of air.” The scientists say they could be created off boats by using devices that mix water supercharged with compressed air into swirling jets of water. “I’m emulating a natural ocean phenomenon and amplifying it just by changing the physics—the ingredients remain the same” [ScienceNOW], Seitz said.

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Of all the planet hacking possibilities floated as last-minute ways to stave off a climate catastrophe (building a solar shade for the Earth, injecting the atmosphere with sunlight-reflecting aerosols, etc.), iron seeding seems one of the more practical and feasible ideas. The scheme calls for the fertilization of patches of ocean with iron to spur blooms of plankton, which eventually die, sink, and sequester carbon at the seafloor.

However, worries over the consequences of tinkering with the ocean ecosystem have held up plans to attempt this. And now, in a study in the Proceedings of the National Academy of Sciences, researchers claim that such a plan could risk putting a neurotoxin into the food chain.

Iron seeders have targeted the large swaths of ocean surface with high levels of nitrate and low chlorophyll, where an injection of iron could potentially turn a dearth of plankton into a bloom. But too many phytoplankton can be a bad thing, especially when it comes to members of the genus Pseudonitzschia. This alga produces domoic acid, which it spews into the surrounding seawater to help it ingest iron [ScienceNOW]. Sea lions off California have gotten sick from the toxin. In Canada, three people died in the 1980s from eating shellfish that themselves had eaten Pseudonitzschia.

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If climate-watchers found no solutions in December’s failed Climate Change Summit in Copenhagen, then they might be heartened by the fact that billionaire philanthropist Bill Gates thinks there needs to be a greater focus on researching technologies that can slow global warming.

ScienceInsider reports that the Microsoft founder had provided at least $4.5 million of his own money to be distributed over 3 years for the study of methods that could alter the stratosphere to reflect solar energy, techniques to filter carbon dioxide directly from the atmosphere, and brighten ocean clouds [ScienceInsider]. These and other geoengineering techniques have been hotly debated in the scientific world, with some critics arguing that tinkering with Earth’s natural systems could do more harm than good.

Methods that divert some incoming solar energy, like spraying reflective aerosols into the stratosphere or making clouds more reflective, have been deemed potentially effective but also risky; the abrupt halt of a large-scale project would result in sudden, extreme warming. On the other hand, techniques that reduce the amount of carbon dioxide already in the atmosphere are considered less risky, but they’re currently too expensive to implement widely.

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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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