Geoengineering May Be Necessary, Despite Its Perils

Wednesday, September 02, 2009
Geoengineering May Be Necessary, Despite Its Perils

A Royal Society study sorts through the potential of technologies aimed at offsetting climate change.
By Kevin Bullis

Geoengineering might be a terrible idea, but it could also be the only option if efforts to slow carbon dioxide emissions continue to fail, according to a new report by the Royal Society in London.

Broadly defined, geoengineering is any attempt to counteract climate change on a massive scale. It includes two main approaches: pulling carbon dioxide out of the atmosphere (such as by increasing the growth of algae that take up carbon dioxide) or somehow decreasing the rate at which the sun heats the earth (such as by shading the planet or increasing the reflectivity of clouds).

In both cases, scientists don't know what might go wrong with the proposed schemes--their scale is unprecedented. According to John Shepherd, who chaired the Royal Society's study, "used irresponsibly or without regard for possible side effects, geoengineering could have catastrophic consequences similar to those of climate change itself."

Yet if climate change starts to get out of control, we may be left with no alternatives. "Geoengineering and its consequences are the price we may have to pay for failure to act on climate change," Shepherd adds.

The study analyzed the proposed geoengineering alternatives to decide which are most likely to work without disastrous consequences. Notably, one approach advocated publicly by U.S. Energy Secretary Steven Chu--painting roofs white to reflect sunlight--didn't come out well.

Here's a summary of what the Royal Society study found.

Regarding carbon capture methods:

· CO2 capture from ambient air: This would be the preferred method of geoengineering, as it effectively reverses the cause of climate change. At this stage no cost-effective methods have yet been demonstrated and much more research and development is needed.

· Enhanced weathering: This technique, which utilizes naturally occurring reactions of CO2 from the air with rocks and minerals, was identified as a prospective longer-term option. However, more research is needed to find cost-effective methods and to understand the wider environmental implications.

· Land use and afforestation: The report found that land-use management could and should play a small but significant role in reducing the growth of atmospheric CO2 concentrations. However, the scope for applying this technique would be limited by land-use conflicts, and all the competing demands for land must be considered when assessing the potential for afforestation and reforestation.

Should temperatures rise to such a level that more rapid action needs to be taken, the following solar radiation management techniques were considered to have most potential:

· Stratospheric aerosols: These were found to be feasible, and previous volcanic eruptions have effectively provided short-term preliminary case studies of the potential effectiveness of this method. The cost was assessed as likely to be relatively low and the timescale of action short. However, there are some serious questions over adverse effects, particularly the depletion of stratospheric ozone.

· Space-based methods: These were considered to have potential for long-term use, if the major problems of implementation and maintenance could be solved. At present the techniques remain prohibitively expensive and complex and would be slow to implement.

· Cloud albedo approaches (e.g., cloud ships): The effects would be localized and the impacts on regional weather patterns and ocean currents are of considerable concern but are not well understood. The feasibility and effectiveness of the technique is uncertain. A great deal more research would be needed before this technique could be seriously considered.

The following techniques were considered to have lower potential:

· Biochar (carbon dioxide reduction technique): The report identified significant doubts relating to the potential scope, effectiveness, and safety of this technique and recommended that substantial research would be required before it could be considered for eligibility for U.N. carbon credits.

· Ocean fertilization (carbon dioxide reduction technique): The report found that this technique had not been proved to be effective and had high potential for unintended and undesirable ecological side effects.

· Surface albedo approaches (solar radiation management technique, including white-roof methods, reflective crops, and desert reflectors): These were found to be ineffective, expensive, and, in some cases, likely to have serious impacts on local and regional weather patterns.

Tags: carbon dioxide, climate change, geoengineering, albedo, white roofs

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[no subject]
Despite two world wars and several pandemics, human population has quadrupled in the past one hundred years and this was the result of only one thing: "the industrialization of agriculture". So whether we like it or not, we have been engaged in unintentional destructive geoengineering for quite some time. Polar ice and mountain snow, which help to buffer intermediate spikes in environmental temperature, are currently melting at an unprecedented rate. Part of this might be natural but human activity has definitely tilted the balance. Whether we like it or not, we need to engage in constructive geoengineering to set things right. Unfortunately, individual nations have their own economic agendas which is why geoengineering efforts need to be coordinated through an international body like the UN/IPPC.
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neilrieck
09/03/2009
Posts:17Avg Rating:

Re:
I'm not sure all of that CO2 we've added, about 3% more than the natural cycle annually, has been as destructive as you assume. It's certainly beneficial for the plants that are necessary for all types of food production, and retreating glaciers and warmer temperatures in the North mean more farms and longer growing seasons. It could also mean larger deserts, but I think it's important to understand both the costs and benefits of increased CO2 in our atmosphere.

There was 5 times more CO2 in our atmosphere during the Triassic caused by volcanic eruptions, and it benefited the dominant life forms of the time with increased plant production. Oxygen levels were much lower at the time, but the increase in plant life is largely to thank for the atmospheric oxygen we have today.

Further, there is yet no concrete evidence supporting the notion that increased CO2 necessarily is the primary cause of recent warming, which I will note has been in decline for over ten years now. There are only computer models which lack the ability to model cloud formation and its effects on global temperature, a significant deficiency in the computer programs. The predictions of these models have failed to be realized, and that simple fact alone should give you pause.
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kstauff
09/03/2009
Posts:57Avg Rating:


Ocean fertilization with iron
Iron fertilization of the oceans are a form of "CO2 capture from ambient air: This would be the preferred method of geoengineering, as it effectively reverses the cause of climate change." Fertilization has been demonstrated, a dozen times on intermediate scale (scores of km2), to be a cost-effective method. "Recent marine trials suggest that one kilogram of fine iron particles may generate well over 100,000 kilograms of plankton biomass. . . The maximum possible result from this technique, assuming the most favourable conditions and disregarding all practical considerations,is 0.29W/m2 of globally-averaged negative forcing[5], which is almost sufficient to reverse the warming effect of about 1/6th of current levels of anthropogenic CO2 emissions." http://en.wikipedia.org/wiki/Iron_fertilization

The technique has been tried and found to be effective more than every other technique mentioned except land use and forestation.

Fertilization also has great potential to sequester carbon, build a much larger and robust ocean ecosystem, provide biofuels, slow ocean acidification, reverse many of the bad effects of overfishing, and increase cloud cover and albedo. These benefits will, if fertilization is carefully implemented, outweigh any "unintended and undesirable ecological side effects," and research should proceed.

co2
Ok, you say man did not put all the co2 into the air. Well thats true. So, would we be better off if we worked to get whats there out, no matter what put it there. Or see how bad it gets? Back in the 70s it was said that if we did not start then we would have fires and floods. So many that we could not pay for doing anything about co2.
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d4d
09/07/2009
Posts:1Avg Rating:

Re: co2
Back in the 70's we were told we were entering a new ice age. Fires and floods have been natural occurrences for hundreds of millions of years on planet Earth; they're not new just because the media and Al Gore would like you to believe they are. In fact, the very conservation efforts of some overzealous environmentalists have contributed to the amount of fuel available to wild fires