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Geoengineering Is No Replacement For Reducing Carbon Emissions

A National Research Council committee concluded that there is no substitute for “dramatic reductions” in greenhouse gas emissions to mitigate the negative consequences of man-made climate change.

MIT uses greenhouse gas technology for low cost concentrated solar systemTheir findings were published in a two-volume evaluation of proposed climate intervention techniques — also known as geoengineering — a study that was sponsored by the US National Academy of Sciences.

The idea of geoengineering is very much like that annoying uncle so often used in analogies like these — it just keeps coming back and back, no matter how many times it is rejected or dismissed. Geoengineering is based around the idea that, if it was man that put the harmful extra greenhouse gas emissions into the atmosphere, logic dictates we should therefore be able to do something about it. Projects such as seeding clouds with tiny droplets of seawater in an attempt to make clouds thicker and therefore more reflective.

The report explains that “some carbon dioxide removal strategies seek to enhance or mimic the natural processes that already remove about half of the world’s carbon emissions from the atmosphere each year” — see cloud seeding, enhancing the reflectivity of clouds. However, the authors explain further that these techniques are either decades away, technologically, or would only mask the warming effect and “present serious known and possible unknown environmental, social, and political risks, including the possibility of being deployed unilaterally.”

These two separate impediments — technological and negative effects — forced the authors to split their research into two different approaches in two companion reports. They also make the distinction between using the term “geoengineering” — which denotes some measure of precise control over the climate — and the more accurate terminology, “climate intervention,” which they describe as “purposeful actions intended to curb the negative impacts of climate change.”

“That scientists are even considering technological interventions should be a wake-up call that we need to do more now to reduce emissions, which is the most effective, least risky way to combat climate change,” said committee chair Marcia McNutt, editor-in-chief of Science and former director of the U.S. Geological Survey. “But the longer we wait, the more likely it will become that we will need to deploy some forms of carbon dioxide removal to avoid the worst impacts of climate change.”

The idea of geoengineering has been around forever — like the aforementioned analogous uncle. I’ve been covering the topic for over 5 years at a number of different outlets. And while each new or revived technique bears some immediate promise, the unknowns are horrifying.

To Research or to Hide Away Forever?

Interestingly, there seems to be some disagreement over just what should happen next — further research, or burying all research entirely?

“If the world cannot slow emissions or the effects of climate change are more extreme or occur sooner than expected, there may be demands to pursue additional climate-intervention technologies about which scientists need a better understanding,” said National Academy of Sciences President Ralph J. Cicerone.

“Although riskier ideas to lessen the amount of energy absorbed from the sun should not be considered for deployment, they should be studied so that we can provide answers if someday these ideas begin to be considered in attempts to avert catastrophe. These reports should guide federal agencies in supporting research on climate-intervention technologies, while keeping separate any decision-making about their implementation.”

PierrehumbertHowever, as The Register picked up on, one of the authors of the report — Raymond T. Pierrehumbert, the Louis Block professor in geophysical sciences at the University of Chicago (pictured right) — wrote an article for, in which he concluded that “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.”

Which, seems to leave no real room for disagreement, considering that Pierrehumbert was also a lead author on the IPCC Third Assessment Report and a co-author of the National Research Council report on abrupt climate change.

Pierrehumbert went on to say in his article that “the report is couched in language more nuanced than what I myself would prefer.”

Technology or Climate Mimicry

As already mentioned the study was split into two separate reports to better explain what the authors thought to be the two streams of climate intervention — carbon dioxide removal and sequestration and albedo-modification research.

Simply put, carbon dioxide removal intends to do just that, mimicking or enhancing natural processes that already remove approximately half the world’s carbon emissions each year. There are environmental risks for most all of these ideas, though these risks are relatively low and understood. But these techniques have a relatively limited technical capacity, and unless some technological innovation takes the world by storm by the time I finish writing, large-scale deployment would be astronomical (which is to say, would cost more than simply transitioning to renewable energy generation).

Map of earth's permafrost at 3 density levels.On the other hand is albedo-modification research — investigating the idea of enhancing our planet’s natural albedo (the fraction of solar energy reflected back into space by ‘lighter’ surfaces (such as snow)) — and it is these techniques that Raymond T. Pierrehumbert is terrified of.

The idea stems from the idea that our planet already reflects a certain percentage of the sun’s energy back into space — the same way a white surface reflects more glare into your face than a black one (needless to say, the melting polar caps — which are both uniformly white — is a problem). Pierrehumbert explains:

If the Earth had 100 percent albedo, it would reflect all sunlight back to space and be a frozen ice ball some tens of degrees above absolute zero, heated only by the trickle of heat leaking out from its interior. Earth’s current albedo is about 30 percent, with much of the reflection caused by clouds and snow cover.

Another report co-author and colleague of Pierrehumbert, James Fleming, described albedo modification as “untested and untestable, and dangerous beyond belief.”

Such strong language is offset by the report’s less strict language — in the press release accompanying the publication of the reports:

The committee said it would be “irrational and irresponsible” to implement sustained albedo modification without also pursuing emissions mitigation, carbon dioxide removal, or both.  It opposed deployment of albedo-modification techniques, but recommended further research, particularly “multiple-benefit” research that simultaneously advances basic understanding of the climate system and quantifies the technologies’ potential costs, intended and unintended consequences, and risks.

My understanding of Pierrehumbert’s opinion on the matter suggests that he would have preferred language something along the lines of “Oh hell, NO!” instead.

Let’s stick to Renewables

Reports such as these will almost always be the result of a compromised average of the author’s opinions. However, the recognized possible “legal, ethical, social, political, and economic ramifications” of albedo modification seems to suggest that the best idea is to focus our attention on switching to renewable energy generation techniques rather than trying to hack our planet.

Instead, the committee (though obviously not all of it) recommend “the initiation of a serious deliberative process to examine what international research governance structures may be needed beyond those that already exist, and what types of research would require such governance.”

Without a doubt, international oversight of climate intervention is absolutely necessary — if only to stop unilateral actions taken that might do catastrophic harm to the environment. However, I’m going to agree with Pierrehumbert and suggest that maybe we don’t need oversight and research.

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I'm a Christian, a nerd, a geek, and I believe that we're pretty quickly directing planet-Earth into hell in a handbasket! I also write for Fantasy Book Review (, and can be found writing articles for a variety of other sites. Check me out at for more.


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