Geoengineering side effects could be potentially disastrous, research shows
Comparison of five proposed methods shows they are ineffective, alter weather systems or could not be safely stopped
- theguardian.com, Tuesday 25 February 2014 11.41 EST
Geoengineering the planet’s climate: even when applied on a massive scale, the most that could be expected is a temperature drop of about 8%, new research shows. Photograph: Nasa/REUTERS
Large-scale human engineering of the Earth’s climate to prevent catastrophic global warming would not only be ineffective but would have severe unintended side effects and could not be safely stopped, a comparison of five proposed methods has concluded.
Science academies around the world as well as some climate activists have called for more research into geoengineering techniques, such as reflecting sunlight from space, adding vast quantities of lime or iron filings to the oceans, pumping deep cold nutrient-rich waters to the surface of oceans and irrigating vast areas of the north African and Australian deserts to grow millions of trees. Each method has been shown to potentially reduce temperature on a planetary scale.
But researchers at the Helmholtz Centre for Ocean Research Kiel, Germany, modelled these five potential methods and concluded that geoengineering could add chaos to complex and not fully understood weather systems. Even when applied on a massive scale, the most that could be expected, they say, is a temperature drop of about 8%.
The potential side effects would be potentially disastrous, say the scientists, writing in Nature Communications. Ocean upwelling, or the bringing up of deep cold waters, would cool surface water temperatures and reduce sea ice melting, but would unbalance the global heat budget, while adding iron filings or lime would affect the oxygen levels in the oceans. Reflecting the sun’s rays into space would alter rainfall patterns and reforesting the deserts could change wind patterns and could even reduce tree growth in other regions.
In addition, say the scientists, two of the five methods considered could not be safely stopped. “We find that, if solar radiation management or ocean upwelling is discontinued then rapid warming occurs. If the other methods are discontinued, less dramatic changes occur. Essentially all of the CO2 that was taken up remains in the ocean.”
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Geoengineering Ineffective Against Climate Change, Could Make Worse
By Charles Q. Choi
, Live Science Contributor | February 25, 2014 11:40am ET
| A diagram of the geoengineering projects people have proposed to combat climate change. The laws surrounding such projects are still uncertain.
Credit: Diagram by Kathleen Smith/LLNL
Current schemes to minimize the havoc caused by global warming by purposefully manipulating Earth’s climate are likely to either be relatively useless or actually make things worse, researchers say in a new study.
The dramatic increase in carbon dioxide levels in the atmosphere since the Industrial Revolution is expected to cause rising global sea levels, more-extreme weather and other disruptions to regional and local climates. Carbon dioxide is a greenhouse gas that traps heat, so as levels of the gas rise, the planet overall warms.
In addition to efforts to reduce carbon dioxide emissions, some have suggested artificially manipulating the world’s climate in a last-ditch effort to prevent catastrophic climate change. These strategies, considered radical in some circles, are known as geoengineering or climate engineering.
Many scientists have investigated and questioned how effective individual geoengineering methods could be. However, there have been few attempts to compare and contrast the various methods, which range from fertilizing the ocean so that marine organisms suck up excess carbon dioxide to shooting aerosols into the atmosphere to reflect some of the sun’s incoming rays back into space. [8 Ways Global Warming is Already Changing the World]
Now, researchers using a 3D computer model of the Earth have tested the potential benefits and drawbacks of five different geoengineering technologies.
Will it work?
The scientists found that even when several technologies were combined, geoengineering would be unable to prevent average surface temperatures from rising more than 3.6 degrees Fahrenheit (2 degrees Celsius) above current temperatures by the year 2100. This is, the current limit that international negotiations are focused on. They were unable to do so even when each technology was deployed continuously and at scales as large as currently deemed possible.
“The potential of most climate engineering methods, even when optimistic deployment scenarios were assumed, were much lower than I had expected,” said study author Andreas Oschlies, an earth system modeler at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany.
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According to a new study due to be published in 2014, Geoengineering field research is not only allowed, it is encouraged.
The study was authored by Jesse Reynolds at Tilburg Law School in the Netherlands. Reynolds researched the legal status of geoengineering research by analyzing international documents and treaties.
Geo-engineering is the science of manipulating the climate for the stated purpose of fighting mad made climate change. These include Solar Radiation Management (SRM), the practice of spraying aerosols into the sky in an attempt to deflect the Sun’s rays and combat climate change.
According to a recent congressional report:
“The term “geoengineering” describes this array of technologies that aim, through large-scale and deliberate modifications of the Earth’s energy balance, to reduce temperatures and counteract anthropogenic climate change. Most of these technologies are at the conceptual and research stages, and their effectiveness at reducing global temperatures has yet to be proven. Moreover, very few studies have been published that document the cost, environmental effects, socio-political impacts, and legal implications of geoengineering. If geoengineering technologies were to be deployed, they are expected to have the potential to cause significant transboundary effects.
In general, geoengineering technologies are categorized as either a carbon dioxide removal (CDR) method or a solar radiation management (SRM) method. CDR methods address the warming effects of greenhouse gases by removing carbon dioxide (CO2) from the atmosphere. CDR methods include ocean fertilization, and carbon capture and sequestration. SRM methods address climate change by increasing the reflectivity of the Earth’s atmosphere or surface.
Aerosol injection and space-based reflectors are examples of SRM methods. SRM methods do not remove greenhouse gases from the atmosphere, but can be deployed faster with relatively immediate global cooling results compared to CDR methods.“
Reynolds’ study will be published in the Journal of Energy, Climate and the Environment around the same time that the Intergovernmental Panel on Climate Change presents its Fifth Assessment Report. The study continues the calls for an international body to regulate the controversial weather modification techniques.
Some believe the answer is international agreement for international tests but low-risk domestic research should continue to assist in the overall decision of what to do with geoengineering.
One of the many dangers of manipulating the weather are the loss of blue skies. According to a report by the New Scientist, Ben Kravitz of the Carnegie Institution for Science has shown that releasing sulphate aerosols high in the atmosphere would scatter sunlight into the atmosphere. He says this could decrease the amount of sunlight that hits the ground by 20% and make the sky appear more hazy.
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09 Jan 2014: Report
Solar Geoengineering: Weighing
Costs of Blocking the Sun’s Rays
With prominent scientists now calling for experiments to test whether pumping sulfates into the atmosphere could safely counteract global warming, critics worry that the world community may be moving a step closer to deploying this controversial technology.
In 1991, Mount Pinatubo in the Philippines erupted in one of the largest volcanic blasts of the 20th century. It spat up to 20 million tons of sulfur into the upper atmosphere, shielding the earth from the sun’s rays and causing global temperatures to drop by nearly half a degree Celsius in a single year. That’s more than half of the amount the planet has warmed
Studies have shown that such a strategy would be powerful, feasible, fast-acting, and cheap.
due to climate change in 130 years.
Now some scientists are thinking about replicating Mount Pinatubo’s dramatic cooling power by intentionally spewing sulfates into the atmosphere to counteract global warming. Studies have shown that such a strategy would be powerful, feasible, fast-acting, and cheap, capable in principle of reversing all of the expected worst-case warming over the next century or longer, all the while increasing plant productivity. Harvard University physicist David Keith, one of the world’s most vocal advocates of serious research into such a scheme, calls it “a cheap tool that could green the world.” In the face of anticipated rapid climate change, Keith contends that the smart move is to intensively study both the positive and negative effects of using a small fleet of jets to inject
Arlan Naeg/AFP/Getty Images
The 1991 Mount Pinatubo eruption lowered temperatures nearly half a degree Celsius.
sulfate aerosols high into the atmosphere to block a portion of the sun’s rays.
Yet even Keith acknowledges that there are serious concerns about solar geoengineering, both in terms of the environment and politics. Growing discussion about experimentation with solar radiation management has touched off an emotional debate, with proponents saying the technique may be needed to avert climate catastrophe and opponents warning that deployment could lead to international conflicts and unintended environmental consequences — and that experimentation would create a slippery slope that would inevitably lead to deployment. University of Chicago geophysicist Raymond Pierrehumbert has called the scheme “barking mad.” Canadian environmentalist David Suzuki has dismissed it as “insane.” Protestors have stopped even harmless, small-scale field experiments that aim to explore the idea. And Keith has received a couple of death threats from the fringe of the environmentalist community.
Clearly, there are good reasons for concern. Solar geoengineering would likely make the planet drier, potentially disrupting monsoons in places like India and creating drought in parts of the tropics. The technique could help eat away the protective ozone shield of our planet, and it would cause air pollution. It would also do nothing to counteract the problem of ocean
Some worry that solar geoengineering would hand politicians an easy reason to avoid emissions reductions.
acidification, which occurs when the seas absorb high levels of CO2 from the atmosphere.
Some worry that solar geoengineering would hand politicians an easy reason to avoid reducing greenhouse gas emissions. And if the impacts of climate change worsen and nations cannot agree on what scheme to deploy, or at what temperature the planet’s thermostat should be set, then conflict or even war could result as countries unilaterally begin programs to inject sulfates into the atmosphere. “My greatest concern is societal disruption and conflict between countries,” says Alan Robock, a climatologist at Rutgers University in New Jersey.
As Keith himself summarizes, “Solar geoengineering is an extraordinarily powerful tool. But it is also dangerous.”
Studies have shown that solar radiation management could be accomplished and that it would cool the planet. Last fall, Keith published a book, A Case for Climate Engineering, that lays out the practicalities of such a scheme. A fleet of ten Gulfstream jets could be used to annually inject 25,000 tons of sulfur — as finely dispersed sulfuric acid, for example — into the lower stratosphere. That would be ramped up to a million tons of sulfur per year by 2070, in order to counter about half of the world’s warming from greenhouse gases. The idea is to combine such a scheme with emissions cuts, and keep it running for about twice as long as it takes for CO2 concentrations in the atmosphere to level out.
Under Keith’s projections, a world that would have warmed 2 degrees C by century’s end would instead warm 1 degree C. Keith says his “moderate, temporary” plan would help to avoid many of the problems associated with full-throttle solar geoengineering schemes that aim to counteract all of the planet’s warming, while reducing the cost of adapting to rapid climate change. He estimates this scheme would cost about $700 million annually — less than 1 percent of what is currently spent on clean energy development. If such relatively modest cost projections prove to be accurate, some individual countries could deploy solar geoengineering technologies without international agreement.
‘The thing that’s surprising is the degree to which it’s being taken more seriously,’ says one scientist.
The idea of solar geoengineering dates back at least to the 1970s; researchers have toyed with a range of ideas, including deploying giant mirrors to deflect solar energy back into space, or spraying salt water into the air to make more reflective clouds. In recent years the notion of spraying sulfates into the stratosphere has moved to the forefront. “Back in 2000 we just thought of it as a ‘what if’ thought experiment,” says atmospheric scientist Ken Caldeira of the Carnegie Institution for Science, who did some of the first global climate modeling work on the concept. “In the last years, the thing that’s surprising is the degree to which it’s being taken more seriously in the policy world.”
In 2010, the first major cost estimates of sulfate-spewing schemes were produced. In 2012, China listed geoengineering among its earth science research priorities. Last year, the Intergovernmental Panel on Climate Change’s summary statement for policymakers controversially mentioned geoengineering for the first time in the panel’s 25-year history. And the National Academy of Sciences is working on a geoengineering report, funded in part by the U.S. Central Intelligence Agency.
Solar geoengineering cannot precisely counteract global warming. Carbon dioxide warms the planet fairly evenly, while sunshine is patchy: There’s more in the daytime, in the summer, and closer to the equator. Back in the 1990s, Caldeira was convinced that these differences would make geoengineering ineffective. “So we did these simulations, and much to our surprise it did a pretty good job,” he says. The reason is that a third factor has a bigger impact on climate than either CO2 or sunlight: polar ice. If you cool the planet enough to keep that ice, says Caldeira, then this dominates the climate response.
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Geoengineering could bring severe drought to the tropics, research shows
Study models impact on global rainfall when artificial volcanic eruptions are created in a bid to reverse climate change
- theguardian.com, Wednesday 8 January 2014 00.59 EST
A view from the space shuttle Atlantis of three layers of volcanic dust in the Earth’s atmosphere, following the 1991 eruption of Mount Pinatubo in the Philippines. Photograph: ISS/NASA/Corbis
Reversing climate change via huge artificial volcanic eruptions could bring severe droughts to large regions of the tropics, according to new scientific research.
The controversial idea of geoengineering – deliberately changing the Earth’s climate – is being seriously discussed as a last-ditch way of avoiding dangerous global warming if efforts to slash greenhouse gas emissions fail.
But the new work shows that a leading contender – pumping sulphate particles into the stratosphere to block sunlight – could have side-effects just as serious as the effects of warming itself. Furthermore, the impacts would be different around the world, raising the prospect of conflicts between nations that might benefit and those suffering more damage.
“There are a lot of issues regarding governance – who controls the thermostat – because the impacts of geoengineering will not be uniform everywhere,” said Dr Andrew Charlton-Perez, at the University of Reading and a member of the research team.
The study, published in the journal Environmental Research Letters, is the first to convincingly model what happens to rainfall if sulphates were deployed on a huge scale.
While the computer models showed that big temperature rises could be completely avoided, it also showed cuts in rain of up to one-third in South America, Asia and Africa. The consequent droughts would affect billions of people and also fragile tropical rainforests that act as a major store of carbon. “We would see changes happening so quickly that there would be little time for people to adapt,” said Charlton-Perez.
Another member of the research team, Professor Ellie Highwood, said: “On the evidence of this research, stratospheric aerosol geoengineering is not providing world leaders with any easy answers to the problem of climate change.”
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