Delivering solar geoengineering materials may be feasible and affordable

Aug 31, 2012

A cost analysis of the technologies needed to transport materials into the stratosphere to reduce the amount of sunlight hitting Earth and therefore reduce the effects of global climate change has shown that they are both feasible and affordable.

Published today in Environmental Research Letters, the study has shown that the basic technology currently exists and could be assembled and implemented in a number of different forms for less than USD $5 billion a year.

Put into context, the cost of reducing is currently estimated to be between 0.2 and 2.5 per cent of GDP in the year 2030, which is equivalent to roughly USD $200 to $2000 billion.

management (SRM) looks to induce the effects similar to those observed after ; however, the authors state that it is not a preferred strategy and that such a claim could only be made after the thorough investigation of the implications, risks and costs associated with these issues.

The authors caution that reducing incident sunlight does nothing at all to reduce in the atmosphere, nor the resulting increase in the of the oceans.

They note that other research has shown that the effects of solar radiation management are not uniform, and would cause different temperature and precipitation changes in different countries.

Co-author of the study, Professor Jay Apt, said: "As economists are beginning to explore the role of several types of , it is important that a cost analysis of SRM is carried out. The basic feasibility of SRM with current technology is still being disputed and some and policy makers are concerned about unilateral action."

In the study, the researchers, from Aurora Flight Sciences, Harvard University and Carnegie Mellon University, performed an engineering cost analysis on six systems capable of delivering 1 million metric tonnes of material to altitudes of 18 km: existing aircraft, a new airplane designed to perform at altitudes up to 30 km, a new hybrid airship, rockets, guns and suspended pipes carrying gas or slurry to inject the particles into the atmosphere.

Based on existing research into solar radiation management, the researchers performed their cost analyses for systems that could deliver around one million tonnes of aerosols each year at an altitude between 18 and 25 km and between a latitude range of 30°N and 30°S.

The study concluded that using aircraft is easily within the current capabilities of aerospace engineering, manufacturing and operations. The development of new, specialized aircraft appeared to be the cheapest option, with costs of around $1 to $2 billion a year; existing aircraft would be more expensive as they are not optimised for high altitudes and would need considerable and expensive modifications to do so.

Guns and rockets appeared to be capable of delivering materials at high altitudes but the costs associated with these are much higher than those of airplanes and airships due to their lack of reusability.

Although completely theoretical at this point in time, a large gas pipe, rising to 20 km in the sky and suspended by helium-filled floating platforms, would offer the lowest recurring cost-per-kilogram of particles delivered but the costs of research into the materials required, the development of the pipe and the testing to ensure safety, would be high; the whole system carries a large uncertainty.

Professor Apt continued: "We hope our study will help other scientists looking at more novel methods for dispersing particles and help them to explore methods with increased efficiency and reduced environmental risk."

The researchers make it clear that they have not sought to address the science of aerosols in the stratosphere, nor issues of risk, effectiveness or governance that will add to the costs of solar radiation management geoengineering.

Explore further: NASA balloons begin flying in Antarctica for 2014 campaign

More information: The published version of the paper 'Cost analysis of stratospheric albedo modification delivery systems' (Justin McClellan, David W Keith and Jay Apt 2012 Environ. Res. Lett. 7 034019: iopscience.iop.org/1748-9326/7/3/034019/article

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User comments : 9

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Birger
5 / 5 (1) Aug 31, 2012
While this effort might be justified to reduce the warming of the Arctic -thus preventing the permafrost from releasing methane, which is an even stronger greenhouse gas than carbon dioxide- it is no substitute for reducing emissions.

Geoengineering may slow warming, but as mentioned in therarticle it has drawbacks. It will alter rainfall patterns. Also, the CO2 buildup in the oceans is increasing the acidity of the water, making it harder for marine organisms to build shells.
wgard
5 / 5 (1) Aug 31, 2012
I find the concept of geoengineering very frightening. First, there is the thought that, like many other things, there is a very tenuous understanding of consequences. While the mechanism of desired consequences may be well mapped, it is the danger of unforeseen or unknown consequences, both in the here-and-now and in the long term that weight against it, IMO. Then there is the aspect of reversibility. If the results are not as expected, how do you reverse them? I firmly believe the cautionary principle holds true with respect to any attempts at geoengineering or climate modification in any form.
Eikka
not rated yet Aug 31, 2012
It's better to adapt to existing conditions than rely on artifically moderated climate, because a failure of the system will have catastrophic consequences.

It's the same principle everywhere. It's pointless to build dams and pumps to keep the sea back, because you know they will break some day and then your whole city will drown.
jimbo92107
5 / 5 (1) Aug 31, 2012
The question, "What could possibly go wrong?" just popped into my head.
DavidW
not rated yet Aug 31, 2012
Excellent comments.

"...thus preventing the permafrost from releasing methane, which is an even stronger greenhouse gas than carbon dioxide- ..."

Yet, it may not be as bad as the recent article on Antarctica: http://phys.org/n...tic.html
In South America the loss of rain forests are now dwarfed by the tar sands destruction of the Canadian Boreal Forest. It goes on and on...

This is true; however the leading cause of methane release is unnecessary consumption of animal products. We will have to get everything right or the best we can hope for is a police state and what follows that if we continue this direction. The unnecessary suffering is going to end one way or another and that is where the line of new beginning starts. Either that happens, or the government(s) will do as they please. Any attempts to repair the problems we face that are not based in truth will fail, as they must and all that challenges the truth.
cantdrive85
1 / 5 (1) Aug 31, 2012
Does anybody ever look up any more? The geo-engineering of the lower atmosphere has been going on for quite sometime now.
Caliban
not rated yet Aug 31, 2012
Rank idiocy, and nothing more than the most transparent of bids to vacuum up some of those sweet, sweet taxpayer dollars.

There is so much money to be made in questionable efforts like this by corporate parasites that it is absolutely dizzying to contemplate.

Just think of it -the perfect opportunity to make billions from a taxpayer-funded enterprise of highly questionable efficacy, without risking a cent of their own capital, and with the pre-assurance that if it doesn't work, there will be no repercussions, no demands of repayment, reparations, and zero liability for any and all consequences.

All this, while Rome Burns...

Any who get involved in this "geoengineering" scheme(or should we term it a "racket") will do nothing but pocket $$$$$.

For these reasons --and very carefully mark my words-- we can all expect to see a very strong push to see this plan put into action.
ValeriaT
not rated yet Sep 01, 2012
Some consequences are already predictable. The sulphate aerosols contribute to the destruction of the ozone layer, acid rains and into droughts and spreading of deserts, because they cause condensation of watter into form of many tiny droplets, which cannot coalesce into rain. Whether the small particles of aerosols are really reflected with long-wavelength infrared radiation is disputable too.
MikPetter
not rated yet Sep 02, 2012
From the article.. nuff said "The researchers make it clear that they have not sought to address the science of aerosols in the stratosphere, nor issues of risk, effectiveness or governance that will add to the costs of solar radiation management geoengineering."

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