Last month the National Academy of Sciences released two reports calling for experiments to test technologies for mitigating global warming caused by greenhouse gas emissions. The technologies in question are part of a controversial form of planet-wide doctoring called geoengineering. While geoengineering has garnered most of its media attention since the late 2000s, the topic and its methods have a long history.
Since the mid-1960s scientists have known that the burning of fossil fuels has a tremendous effect on the Earth’s climate. In fact, after being briefed by his science advisors President Lyndon Johnson delivered a warning to Congress in February 1965 saying, “This generation has altered the composition of the atmosphere on a global scale through … a steady increase in carbon dioxide from the burning of fossil fuels."
Though the Johnson administration took no actions to curb the increase of carbon flooding into the atmosphere, President Johnson’s advisors did float the idea of dispersing reflective particles over a 13 million square kilometer area above the world’s ocean. At the time it was thought that seeding the atmosphere with reflective particles would reflect an extra 1 percent of sunlight away from Earth, offsetting some of the heat that was being trapped by carbon pollution.
Today, some scientists are singing a very similar tune. But what technologies do we have at our disposal to counter climate change? Have we advanced geoengineering in the last half-century? Is geoengineering safe or even ethical?
First, let’s take a look at the technologies we have at our disposal.
Carbon Dioxide Removal
Currently, the most researched and vetted branch of geoengineering falls under the wide category of carbon dioxide removal. Through a number of different processes, CO2 removal is an attempt to directly remove carbon gasses from the environment to counter the effects of global warming and ocean acidification.
As it stands now, CO2 removal technology ranges from high-tech to low, making it a very adaptable method of geoengineering. On the low-tech side of things researchers believe that Afforestation, the process of planting vast swaths of tree, could lock up massive amounts of carbon for the lifetime of the plants. Equally low-tech is a process called Biocharring where biomass is burned and buried, keeping that material out of the atmosphere.
Moving on to more complex methods of CO2 removal, researchers have also explored the idea of Ocean Fertilization, whereby select regions of the world’s waterways would be seeded with nutrients that would promote “primary production” that would draw CO2 into their depths.
As for the high-tech options, Carbon Capture and Sequestration appears to be king in this arena. Carbon sequestration, which is used in some power plants and oil refineries, seeks to siphon carbon emissions before they reach the open environment and store them in containers or deep in the Earth so that they cannot add to the concentration of carbon in the atmosphere.
Unfortunately for all of these technologies the CO2 we’re producing is never really removed from the planet, it’s only hidden. That brings up the unpleasant fact that it could, one day, break free of its bonds and wreak havoc on the planet.
Solar Radiation Management
The second and more controversial method for climate modification is Solar Radiation Management (SRM), sometimes referred to as Albedo Modification. The thinking behind this idea is that foreign materials could be introduced to reflect a small portion of the Sun’s light back into space, countering the warming effects of increased concentrations of carbon pollution.
To date, three albedo modification methods have been identified.
The first method, which was presented to President Johnson, would see stratospheric aerosols (small, reflective particles) sent into the upper atmosphere to reflect sunlight before it hits earth.
The second method, which sounds a bit similar, involves seeding clouds over vast swaths of the globe to blot out some of the sun’s light.
As for the third method, some have suggested that large reflectors could be launched into space where they would act as global parasols, shading large swaths of the Earth from far afield. Of all of the ideas posited by the albedo modification supporters, the space reflector idea seems the most consequential and least permanent. In fact, there’s no reason to think that space reflectors couldn’t be controlled on an on-demand basis. However, it’s still unknown if a reflector would act as well in practice is it does in theory.
According to University of Chicago geophysical researcher Raymond T. Pierrehumbert, “The nearly two years’ worth of reading and animated discussions that went into this study have convinced me more than ever that the idea of ‘fixing’ the climate by hacking the Earth’s reflection of sunlight is wildly, utterly, howlingly barking mad.” He isn’t alone in that opinion, either.
The U.S.’s National Research Council (NRC) has highlighted a number of issues it sees as problematic with albedo and carbon dioxide modification. In essence, the NRC thinks that albedo modification introduces too many risks to our planet, doesn’t address carbon-based climate change and lacks any real technological underpinnings. The NRC also feels that CO2 removal is expensive and will have little impact on long-term global warming.
The Near & Distant Future
What’s been missing in this exploration of geoengineering is the most obvious solution: cut carbon emissions. In fact, in one Academy of Science report experts agreed, “There is no substitute for dramatic reductions in the emissions of CO2 and other greenhouse gases to mitigate the negative consequences of climate change, and concurrently to reduce ocean acidification.”
While that may be the case, it appears that the world cannot or will not be capable of curbing emissions in any meaningful way. Granted, fuel economy standards are increasing and renewable energy production is at an all-time high. However, given that projections show a continual rise of carbon concentrations through 2100, people are unlikely to give up on the idea of geoengineering.
In the end, the potentially devastating effects of man-made climate change will likely cause nations to undertake some form of geoengineering. It’s ironic to think that today’s climate issues may touch off a possibly never-ending process of climate tweaking that will perpetuate the man-made nature of this dilemma.
Still, it could be argued that man-made climate change was destined to happen one way or another and that the underlying science will be useful in the future. While it’s probably still a millennia off, the lessons we learn about modifying the climate may help us expand our species’ footprint throughout the Universe, giving us the tools to terraform other worlds and shape them into imitation Earths. That process, called Terraforming, will be the subject of my next article.
Images Courtesy of Wikipedia, Oxford University, The National Research Council & NASA GISS