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What Is Geoengineering And How Does It Work?

By ITHP Staff

03 October, 2013

Interview with expert

It shouldn't come as a surprise that planet Earth is heating up. Though many of us would applaud the idea of getting out our shorts and tank tops a few days early, we'd quickly change our minds after examining the consequences of global warming. Scientists looking for ways to combat increasing temperatures are now exploring new innovative possibilities of cooling the planet through modern technology.

One such scientist is Ben Kravitz. Dr. Kravitz is part of a group of scientists researching geoengineering and hoping to prevent the future negative effects of global warming. ITHP got to interview Dr. Kravitz about his work in climate modeling and research. Enjoy.

What is geoengineering and how does it work?

That's actually a more difficult question than it sounds. But before I begin answering that, I want to be perfectly clear. The only research anyone has done on geoengineering has been using computer models or inside lab space.

There are two broad categories of geoengineering research, which are known as Solar Reduction Methods (SRM) and Carbon Dioxide Removal (CDR). These two technologies are really different, and they're really only related in that they are ways people might intervene to reduce the effects of global warming. SRM tries to reduce the amount of sunlight that reaches the planet. There are several proposed ideas, such as putting reflectors in space, making Earth's surface brighter, or putting a layer of sulfate aerosols in the stratosphere. (The last one on that list is what large volcanic eruptions do, and we know that volcanic eruptions can cool the surface.) CDR attempts to reduce the amount of CO2 in the atmosphere by preventing its emission or by extracting it from the atmosphere and sequestering it. There are other technologies that don't really fall neatly into either category. My expertise is in SRM, so that's what I'll focus on.

The problem with all of those technologies is they're purely technical. They don't say what geoengineering is supposed to do or how much geoengineering would be done. Should geoengineering cool the planet by a certain number of degrees? Should it change the hydrological cycle? Should it restore sea ice? Should it prevent ocean acidification? All of these questions (and a lot more) need to be answered by society, not by scientists, before a technology or set of technologies is chosen, should society decide it wants to pursue geoengineering.

Another problem that should be addressed is how geoengineering should be used. SRM is not a permanent "fix" for climate change. It's imperfect and temporary (blocking sunlight does different things to the climate than reducing CO2), and if SRM is suddenly stopped, the climate will rebound very quickly to a warmer one. The only permanent solution to climate change is to stop emitting CO2. Geoengineering might be used as a way of temporarily keeping temperatures below a dangerous level (I repeat might, since that hasn't been determined) while efforts to reduce climate change's effects are ramped up. But that too needs to be decided before geoengineering is used. Essentially, if society decides to start geoengineering, it needs to have a plan for when and how to stop.

Geoengineering researchers such as myself are pursuing a better understanding of geoengineering in case society comes up with such a plan.

What is your present role relating to geoengineering?

I am a climate modeler, which means I take computer models of the climate and "ask" them what the effect of geoengineering might be if geoengineering is done in a certain way. I'm currently coordinating the Geoengineering Model Intercomparison Project (GeoMIP), which is an organized group of climate modeling centers around the world who are conducting the same simulations of geoengineering. We've just completed a round of simulations in which we looked at very idealized simulations ("turning down" the sun in response to an increase in CO2) and a few more realistic ones involving stratospheric sulfate aerosols. We've just designed some new experiments that will look at the effects of brightening marine low clouds, like the kind you can see off the coast of California.

What are the dangers of geoengineering? Publications such as the New York Times have claimed the potential consequences of geoengineering to be detrimental citing potential shifts in the ozone and rainfall levels being adversely affected?

That really depends on how geoengineering is done. We're still learning a lot about the potential effects, and it's fair to say there is quite a lot we don't know. It has been shown in climate models that stratospheric sulfate aerosols could cause changes in ozone and precipitation patterns. CDR has its own risks, although I know a lot more about SRM. Even beyond the climatic consequences, there are many potential geopolitical consequences of geoengineering, on which I'm also not an expert. Geoengineering is a large, multi-disciplinary issue, and it's taking a lot of work from a lot of very smart people to figure out all of the questions that need to be answered.

Since geoengineering most likely will affect the entire world who will vote on this? The United Nations? Are we waiting on a global governance system?

I'm not an expert on the governance of geoengineering, so all I can say is there are a lot of very complex issues involved. Researchers can explore if and how geoengineering can help, but policymakers have to take the lead on if and how to put it into action.

At present is there any form of geoengineering currently going on in the U.S? Most Americans by now have seen planes spraying cities with large contrails that can turn the entire sky white. Is this normal? As a scientist do you know why this spraying will happen than cease completely for weeks?

There is no form of geoengineering currently going on in the U.S., and airplanes are not "spraying" anything. Contrails are basically just a specific type of cloud. You get them when you mix warm, moist air (jet exhaust) with cold, dry air (the atmosphere at those high altitudes). You can see the same effect on a cold day, when you can see your breath. Contrails form when conditions allow those clouds to form. If the atmosphere where the plane is flying isn't cold or dry enough, a contrail won't form and you won't see the plane's exhaust. But the air changes a lot (there are winds, and air moves around), which is why you might see a patchy looking contrail.

What progress are other countries making such as China in controlling the weather?

I really don't know enough about weather control to be able to answer this question. Geoengineering is designed to affect the climate, not the weather, and weather is not my area of expertise.

In your opinion why are military strategists are taking a close interest in geoengineering?

As I'm not affiliated with any military organization, I cannot say whether any military strategists are interested in geoengineering or why they would be interested.

© 2010 International Human Press


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