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A 2009 editorial in the journal Nature Geoscience, opined that, if participants at the Copenhagen Climate Conference failed to map out a path for future greenhouse-gas emissions that is both effective and feasible, then humanity might have to consider turning to “geoengineering.” Geoengineering, a term unfamiliar to most, is the deliberate manipulation of Earth's climate system to control global warming. Since Copenhagen was a resounding flop, new geoengineering proposals have been springing up in a number of scientific journals. Science is still struggling to understand how climate works and what accidental impacts human activities have on that system. Now a number of “visionaries” want to mess with the planet on purpose—what could possibly go wrong with that?
Alarmed by the failure of international political and scientific organizations to agree on an approach for global reduction of carbon emissions, concerned scientists are now asking whether intentional, large-scale alteration of the climate system might be a way to limit climate change. Recent prominent reviews have emphasized that such schemes are fraught with uncertainties and potential negative effects. A policy forum editorial in Science by Jason J. Blackstock and Jane C. S. Long states that, as plans for such schemes begin to take form, a process for ensuring global transparency and cooperation is needed. It would seem that Blackstock and Long are masters of understatement.
Propelling aerosols into the upper atmosphere or pumping carbon dioxide into the deep ocean are just two schemes that have been proposed to repair the Earth's climate through geo-engineering. We discussed past proposals for warming the planet in Chapter 3 of The Resilient Earth and this blog has reported on several cooling schemes in previous posts. We gave the coveted Crank of the Week award to John Latham for suggesting the creation of a fleet of 1500 robot sailing ships to combat global warming. A later award went to Tom M. L. Wigley, Senior Scientist at the National Center for Atmospheric Research, for suggesting that global warming be curbed by releasing sulfur dioxide (SO2) into the stratosphere. If these climate manipulation projects are so far out why do such respected scientific journals as Science and Nature publish articles describing them? According to the Nat. Geosci. editorial:
The topic of geoengineering—the deliberate manipulation of the Earth's climate system to moderate global warming—is fraught with hysteria and uncertainty, primarily because of the sparseness of peer-reviewed literature on the subject, the colossal unknowns when it comes to consequences and the outlandishness of some of the ideas. Launching giant mirrors into space and filling the landscape with fake forests evokes images of a world gone awry. But given that our choices for avoiding the dangerous effects of climate change are running out, we can no longer afford to ignore engineering options.
A Royal Society report identified two general types of geoengineering schemes — those that remove carbon dioxide from the atmosphere (CDR), and those that reflect sunlight back to space (solar radiation management or SRM). A number of different schemes were ranked according to effectiveness, affordability, timeliness and safety in commentary by Philip W. Boyd (see “Ranking geo-engineering schemes”). No overall winner emerges and, as the report stresses, there is no 'silver bullet'. But the evidence suggests that techniques that remove carbon dioxide from the atmosphere are preferable, as they involve fewer uncertainties and risks.
Various geoengineering schemes for cooling the climate. Image B. Matthews/Nature.
CDR schemes such as direct air capture or ocean fertilization would remove the supposed cause of climate change. However, technical challenges and large uncertainties surrounding large-scale CDR deployment, along with long delays in the climatic response to carbon forcing, mean that it would take decades to have a noticeable effect. Given that climate change alarmists are constantly shouting that we only have another decade or so to “take action,” this approach doesn't much appeal to them.
By comparison, SRM could substantially influence the climate in months. SRM schemes such as stratospheric aerosols and cloud brightening aim to cool the planet by reflecting a fraction of the incoming sunlight away from Earth. Volcanic eruptions, which inject large amounts of aerosols into the stratosphere, have demonstrated the rapid impact potential of SRM. Many think that such schemes would be technically simple, low cost and easy to deploy. As was stated in another editorial in Nat. Geosci., we need to keep in mind that the most technologically spectacular proposals—such as mimicking a volcanic eruption—are not necessarily the best.
Unfortunately, there is a great deal of uncertainty about the side effects of such meddling. SRM may have serious unintended consequences that could produce droughts and damage the ozone layer. It might affect different regions unevenly and would do doing nothing to address ocean acidification. Some researchers have even suggested that such measures might come with a rebound effect, meaning that discontinuing the artificial cooling could cause renewed warming even worse than that initially averted.
Geoengineers hope to do this on purpose.
Even so, while climate science is slowly unraveling the mysteries of how the atmosphere works, other scientists who style themselves “geoengineers” are busy hatching schemes to inject aerosols into the stratosphere in an effort to cool the planet. In the January 29 issue of Science, Alan Robock et al. have penned a perspective article titled “A Test for Geoengineering?” The authors address concerns about suggestions that aerosol injection could be tested safely over the Arctic, since that area is already frozen. Here is what they concluded:
Some authors have argued that the effects of polar testing could be confined to the Arctic. However, we have shown, on the basis of analogs from past volcanic eruptions and climate model experiments, that Arctic injection would cool the atmosphere down to latitude 30°N, weakening the summer monsoon over Africa and Asia and reducing precipitation, just like tropical injections of stratospheric aerosols. Indeed, any high-latitude sulfate aerosol production would affect large parts of the planet.
This geoengineering suggestion is based, naturally, on climate models. The same models that have been shown to be unable to predict climate change correctly even without humans intentionally messing with the stratosphere. Climate model simulations suggest that the equivalent of one Pinatubo sized volcanic eruption every four years could counteract global warming for the next few decades. The cloud would have to be maintained in the stratosphere to allow the climate system to cool fully. There are, however, a few problems with this scheme:
- No matter what the results, it would be difficult to stop such an experiment quickly.
- All model simulations conducted so far indicate that upon ending the project, the climate would warm much more rapidly than if no geoengineering had been conducted in the first place.
- People being what they are, the geoengineering infrastructure, including different industrial interests involving many jobs, would lobby to keep the program going.
- No stratospheric aerosol observing system exists to monitor the effects of any in testing so judging the results would be difficult.
- Finally, local impacts are particularly difficult to predict.
The authors report that “modeling to date has raised concerns that large-scale sulfur insertion might produce untoward local climate responses affecting both temperature and moisture.” As has recently been reported, moisture (water vapor) in the stratosphere has greater impact on global temperature variation than has previously been accounted for in climate models. SRM efforts are directed at countering greenhouse warming only, the potential ramifications for the hydrological cycle are being ignored.
Potential techniques for producing aerosols in the stratosphere. Robock et al./Science.
Any engineered change in incoming solar radiation cannot totally compensate the effects of increasing levels of greenhouse gases. A change in incoming solar radiation that exactly offsets the warming effect of greenhouse gases is expected to overcompensate their effect on the hydrological cycle (see “Impact of geoengineering schemes on the global hydrological cycle”). So if temperature is brought back to pre-industrial levels, global rainfall totals could decline well below the levels of the early nineteenth century. The Asian and African summer monsoons on which billions of people's livelihoods rely could potential be derailed by geoengineering.
As you can tell from all these warnings, geoengineering has the potential to cause as much international tension as nuclear proliferation—perhaps even more. Having nuclear weapons is not the same as using them and any nation that did would face the wrath of all other nations on Earth. Trying out one of these engineered schemes to “save the planet” is a different proposition all together. Blackstock and Long summed up the political aspects of geoengineering this way:
Emerging national research programs—and even individual scientists—must forswear climatic impacts testing and carefully restrict subscale field-testing until approved by a broad, legitimate international process. All SRM research should be in the public domain and should be integrated into any subsequent international research framework. Programs should include international collaboration, communicate with developing nations, and prioritize research that has global versus national benefits. These steps will limit the new problems geoengineering research heaps on an already strained global climate agenda, preserving options for future international cooperation.
While the history of modern science is rife with suggested projects to modify the earthly environment, most of these suggestions have come from serious scientists and engineers thinking large thoughts about large problems. That, in part, is what they get paid for. What is disturbing with this recent interest in geoengineering is that it comes from bureaucrats and policy wonks, the political portion of the scientific establishment. They are concerned with setting agendas and establishing frameworks, not doing science or designing experiments.
Fake trees fight global warming but they are not pretty. Image IMechE.
Could it be that, in this post Climategate, post Glaciergate world, those on the global warming gravy train are looking for new schemes to keep the government largess flowing? Not that we don't need a formal review before some overeager geoengineer attempts an experiment on the living Earth, but seeking a “broad, legitimate international process” sounds more like the kind of intellectual dross put out by the IPCC than serious working science.
Why are scientists earnestly thinking about geoengineering? “It is essential that we have a back-up plan,” the Nature Geoscience editorial concluded, “if geoengineering is that plan, it had better be well researched, well ahead of time.” It is good that this discussion is taking place in the open, but if this is the best that science can offer then we are all in trouble. Not from global warming, but from the fools trying to fix it.
The rational approach is to work on solving the world's growing need for environmentally sound energy while being prepared to deal with the possible negative effects of climate change, if there are any. Thinking “outside the box” can be a good thing for scientists and engineers, but if that box happens to be the planet we live on they had better come up with a way to test outside the box as well—in other words, not on this planet.
Be safe, enjoy the interglacial and stay skeptical.
The ultimate in geoengineering, a totally fake planet. Image Lucasfilm Ltd.