What is the StratoShield?
The StratoShield is one possible way to respond to a climate emergency in which greenhouse warming becomes intolerable. The StratoShield would reverse greenhouse warming by slightly reduc¬ing the amount of solar radiation that hits the Earth. The shield does this by increasing the amount of sulfur aerosols injected into the atmosphere by about 1%, a process that happens naturally whenever volcanoes erupt. The aerosols reflect incoming sunlight back into space. Although the change in sunlight would be imperceptible to human eyes—and probably beneficial for plants—it would have a substantial cooling effect for the part of the Earth under the shield.

How much aerosol would the StratoShield put into the stratosphere?
The reference system we’re studying would inject 100,000 metric tons of sulfur dioxide a year into the stratosphere, which at a constant flow rate works out to only about 34 gallons (130 liters) a per minute. About 100 million tons of sulfur dioxide already rises into the stratosphere each year, about half from manmade sources (such as power plants) and half from natural processes (such as volcanoes) . One StratoShield installation would thus increase annual aerosol input to the atmosphere by about one part in 1,000. Scientific studies so far have concluded that a worldwide system (which would require a dozen or more StratoShield installations) would probably have to spread several million metric tons a year of sulfur dioxide throughout the stratosphere to reduce solar radiation hitting the entire planet by about 1.8% (4 W/m²) globally. Climatologists believe that small reduction in sunlight would be adequate (if it occurred equally around the globe) to counter all of the warming caused by a doubling of CO₂ over preindustrial levels. A StratoShield placing 100,000 metric tons of aerosol a year into the upper atmosphere would be expected to reduce incoming solar radiation by less than half a watt per square meter, averaged over the globe. More research is needed to confirm these estimates.

What is the aerosol made of?
The aerosol would likely be made of sulfur dioxide (SO₂), a natural component of volcanic ash that is present in the air we all breathe every day. Another possibility is to use SO3 instead. Engineered aerosols, not found naturally in the atmosphere, could be more efficient at reflecting certain parts of the solar spectrum, but their benefits over SO₂ might not be worth the cost of development and production—or the uncertainties about their environmental effects. Science has produced a good understanding of both the global sulfur cycle (which includes volcanic ash) and the safety of sulfur dioxide at the very low concentrations required for geoengineering. A good deal more research would be required to establish the safety and environmental life cycle of customized aerosol particles.

Why not just use airplanes to disperse the aerosols?
Others have proposed this approach; we also gave it serious consideration. We concluded that airplanes may not be the best solution, for a number of reasons. Some existing military aircraft do fly high enough to reach the stratosphere, and in principle could be re-tasked to deliver sulfur-bearing aerosols in the event of a climate emergency—which would after all constitute a threat to international security. Calculations so far suggest the operating costs to use aircraft could be quite high, however, and if the required altitude for aerosol injection is beyond the bottom of the stratosphere (due to stratospheric wind patterns), the cost would go up dramatically.

A second concern with using military aircraft as delivery vehicles is the emissions of carbon dioxide and other greenhouse gases that they would produce, exacerbating the very problem they were deployed to solve. If fighter jets were used, 167 jets would each have to make three flights a day, 250 days a year to deliver the amount of aerosol required, according to one recent study [Robock et al. 2009].

A related, more promising idea is to adjust the fuel mixture in commercial airplanes to generate the needed aerosols in their ex¬haust (rather than flying a cargo hold full of aerosols). Unfortunately, this option would reduce their fuel efficiency and is not likely to be accepted by stakeholders in commercial airplane operations.

Aren’t there other ways of achieving the same effect?
There are many other ways of enhancing Earth’s albedo to reduce average global insolation. I.V. has been collaborating with Professors John Latham and Stephen Salter on one very promising idea of theirs to increase marine cloud cover by spraying salty sea water into the air. The small droplets would serve to nucleate more clouds, which increases the albedo of that area. U.S. Secretary of Energy Steven Chu has advocated painting roofs white to increase their reflectivity. Our inventors have begun exploring ways to brighten ground cover such as asphalt by, for example, incorporating crushed glass into the mix.
Many of these ideas will no doubt prove ineffective or impractical for one reason or another when they are fully studied, but there does seem to be a wide array of options still to explore. It is an area ripe for invention.

What is the lifetime of the aerosols in the stratosphere?
The eruption of Mt. Pinatubo in 1991 gave us an opportunity to learn many things about using sulfur-based aerosols to cool the Earth. The aerosols it spewed into the stratosphere remained there for an average of 1-2 years before falling down through the troposphere.

Why are you building this now?
We are not building or even planning to build the StratoShield. Intellectual Ventures is simply urging that research on geoengineering options, including stratospheric aerosol enhancement, begin in earnest now. We share with many others a concern that the massive scale of technological development, deployment, investment, and lifestyle changes required to bring greenhouse gas levels down to sustainable levels will take more time to implement than we have before the climate starts changing in intolerable ways.

If that happens, geoengineering options could buy humanity additional time to complete the shift to a cleaner energy system. The solution to the problem of climate change is new energy systems, not geoengineering. But we may find that we need geoengineering technologies as stop-gap responses if the transition to these cleaner energy systems takes too long, or if abrupt changes in climate occur unexpectedly.

Why did you choose this idea to study?
If the world decided that it had to use geoengineering as a stop-gap solution, the goal would be to deploy it quickly but also to phase it out relatively quickly. That leads us to prefer geoengineering approaches that are less expensive and that require little or no new technology, so are easier to deploy quickly. It also leads us to prefer approaches whose cooling effects are well understood and readily controlled, and which dissipate quickly once the system is turned down or turned off.

The StratoShield is an example of a geoengineering system that draws on existing technology and has deployment and annual operation costs amounting to millions of dollars, rather than billions. Although we have explored the general principles of how a system like this would operate, many technical details would have to be worked out. The detailed R&D is not something that IV currently contemplates doing, although if a responsible research program on geoengineering is launched, we may participate and collaborate with others in inventing and refining a variety of technical options.

In concert with technical development, a great deal of environ¬mental science must be done to identify possible side effects. There may be work-arounds to avoid some side effects, but others could be show-stoppers. Much more intellectual effort needs to be applied to this area so that a body of scientific and engineering knowledge exists, should it ever be needed to address a climate emergency.

1. What is geoengineering?

“Geoengineering” describes how the earth’s systems can be influenced by engineering solutions. There are many historic examples of how humans have used technology to change geological systems. From using fire to drive game to building irrigation for agriculture, seeding clouds during droughts, reversing the Chicago River to building the Hoover dam, the term can encompass all sorts of ideas. Today, options discussed often include large-scale engineering of the environment in order to combat or counteract the adverse effects of human-induced changes in the atmosphere and climate.

2. Why is Intellectual Ventures researching geoengineering technologies?

Intellectual Ventures looks at hard problems facing the world and brainstorms ideas and technologies that can lead to better solutions. Global warming is a very significant problem, but it won’t be solved with old ideas and old technology alone. We believe that the solution to this crisis will involve new ideas and new technologies.

Intellectual Ventures recognizes that the process of bringing new global warming ideas to the surface can be challenging and controversial. But as an invention company, we believe research needs to be done now, rather than after the full complications of global warming are upon us.

3. What makes Intellectual Ventures’ approach to climate change different from the research that is already being done elsewhere?

Some people think that global warming can be solved purely by policy means: taxes, renewable requirements, or cap-and-trade systems. While such moves may be helpful, we are not convinced that they are sufficient for several reasons.

The first is that current climate science cannot say with certainty what level of CO2 can be tolerated by the climate system without severe consequences. Some scientists believe that even the current level of CO2 is dangerously high, while others are relatively comfortable with far higher levels. This matters because the more sensitive the climate is to CO2, the quicker and deeper cuts in emissions must be in order to avoid harmful environmental changes. We may be lucky, and the climate system may be relatively tolerant, or we may be unlucky and find that the necessary cuts must be deeper, or occur quicker, than the world can manage to do.

Second, there has been more talk than action. The world has made little progress in curbing large scale emissions of CO2 and other greenhouse gases. In order to make meaningful cuts in CO2 emissions there would need to be comprehensive and effective international agreements in place. So far, these have proven elusive.

Third, the task of retooling our energy infrastructure away from fossil fuels is a massive task, which is going to take a long time to accomplish. Indeed most of the world has not even made a meaningful start. New technology will speed the transition to a carbon-free energy infrastructure, but it is hard to estimate or have confidence in that can be accomplished quickly.

Fourth, and perhaps the most important, by the time if we should discover that the factors above are not favorable – and serious environmental harm starts to occur, it will be too late for conventional approaches to work. Once there is too much CO2 in the atmosphere, even if you stop emissions entirely, you will have problems for many decades to come. It is possible that this unhappy situation will not occur, either because the climate can tolerate a lot more CO2, or because the world achieves very significant emission reductions. However, if we do find ourselves in a bad scenario, geoengineering is one of the few alternatives for reducing harm to both human society and the environment.

4. Aren’t there other solutions to global warming already in the mix?

Yes, there are political and technological answers to climate change that are being considered right now. Policy solutions requiring international agreements continue to evolve. New technological answers emerge every day, at Intellectual Ventures and throughout the world. Our work is deeply involved in new energy system inventions, including invention in energy conservation technologies – better batteries, hybrid engines, and electrical transmission systems for renewable power – plus a new type of nuclear reactor designed by the team at TerraPower.

5. Could we use geoenginnering technologies now, in place of cutting emissions?

Geoengineering is not a substitute for reducing our CO2 emissions. There are many good reasons for working hard to reduce CO2 emissions, so we do not endorse geoengineering simply to allow further emissions. We believe that geoengineering should be viewed as a last resort to prevent irreparable harm to the environment and human society. However, we can’t wait to develop that last resort until we need it – we must begin the research work to understand it now. Research and better understanding must precede any decision to deploy geoengineering.

6. Why is global warming such a threat?

Global warming has characteristics that make it extremely challenging for the world’s political and policy framework. Indeed, it is about the worst possible case. The easiest threats to solve are localized, quick and predictable. Global warming, however, is the opposite. It’s not local; it’s global, so the whole world needs to cooperate in order to solve it. The resulting environmental problems may have broad impacts and occur slowly without a clear cause and effect. The onset of symptoms is slow, so it is easy to doubt. The solutions on the table so far involve financial pain today, in exchange for a benefit decades away – longer than most people plan, and much longer than most politician’s terms. Each of these properties make it hard for human nature to deal with global warming decisively. It also is difficult for our policy making and governance institutions. As a society, we are not good at making very long term tradeoffs of this sort.

7. Won’t geoengineering detract from renewable and green energy solutions?

Some people worry that geoengineering will be used as an excuse to continue emitting CO2. That is a valid concern, but it is not a reason to stop research and development efforts.

Given the size of the potential harm, the uncertainty in how much harm for how much CO2, and the political risk that governments and individuals will not do enough, it is hard to feel good about our current course and speed. We think it is only prudent to start now on the research that could offer a way to “buy time.” If the global warming threat is serious – and we believe that it is – all options must remain on the table, and we must invest in pursuing them.

8. What is the greatest potential benefit you see from geoengineering? What about possible harms?

Realistically, geoengineering could offer us a way to buy time by preventing the worst effects of global warming while society gets its act together on a carbon-emission free energy infrastructure. We are continuing to work with experts in the climate sciences to further advance the technology. If we are effective in cutting emissions, and lucky in how much CO2 the climate system can tolerate, then it may not be needed at all.

Other people worry that geoengineering may not work, or that it could provide a false hope. That is an argument for more research and development, not less. At the present time there is almost no research and development funding for geoengineering, which seems foolish given what is at stake.

Another concern is that there might be unforeseen consequences of geoengineering. This is also a topic which research can address. Geoengineering is only under consideration to combat the vastly more harmful effects that are predicted from severe climate change.

9. Will Intellectual Ventures make money from geoengineering?

Intellectual Ventures invents new technology as its main business, but we do not expect or intend that our climate technology inventions will make money. Rather, they are part of our work applying the brain power and creativity of our inventors to the serious problems confronting society. Other efforts like this include active programs in eliminating malaria, delivering vaccine to remote areas without refrigeration and purifying food and water to prevent illness in the developing world.

10. When will your inventions be built?

We say geoengineering “might” offer a solution, because we advocate only research and development on geoengineering and not deployment at this time. None of the approaches that we are familiar with, such as our ocean cooling or stratospheric shield approaches, are ready for prime time yet. They need to get much more attention and funding to experiment with them and prove them out. That’s why, as part of our climate change strategy, R&D in geoengineering has its place.

HD quality m4v.

For the first time we’ve got some technical details to share publicly.  Please take a look at this StratoShield White Paper if you’d like to know more.

“When you read the actual scientists’ reasoning for how [geoengineering] could work, and might need to work, it’s really hard not to come to the conclusion that it’s idiotic to discount it. Not to say it’s a slam dunk to do it, but idiotic to discount it entirely.”

A great quote from Stephen Dubner in this Guardian interview with him and Steven Levitt. We’re big fans of Freakonomics and delighted to have some of our climate science inventions featured in their upcoming sequel – Superfreakonomics. The new book is already starting to make some headlines even though it’s not due out until October 20.

Another U.K. paper, The Independent, also published a review that mentions our “hose-to-the-sky” concept.  This is an idea for pumping sulfur dioxide into the stratosphere to cool the planet.  The Independent calls it “the outer limits of freakonomics.”

We’ll post a lot more about our climate science projects soon.