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Thoughts on Geo-Engineering?

post #1 of 17
Thread Starter 

So we know that humans are unintentionally altering the planet's climate by increasing the atmospheric concentration of CO2.  The ideal solution to this would simply be to stop emitting so much CO2 and stabilize the atmospheric concentration at a safe level (and there is some debate what this level would be, likely in the 350-450 ppm range.  Currently it's around 385 ppm and rising at a rate of around 2 ppm per year).


Another possible solution is to introduce a second human-caused effect to counteract that of CO2.  For example, we could send a bunch of aerosols into the atmosphere (which block sunlight), or put some massive mirrors into orbit.


The problem with geo-engineering is that the solutions are generally very expensive, and could cause dangerous side effects that we don't anticipate.


After speaking at the AGU conference this week, James Hansen was asked “The genie is out of the bottle now — What do you think of geoengineering as a way to deal with global warming?”.  He responded that it would make sense to try “soft” geoengineering first, such as no-till agricutlure and afforestation. But as a last resort, Hansen admitted, more aggressive geoengineering schemes might be necessary.


Joseph Romm's take is that as a climate-saving strategy geo-engineering is largely somewhere between a dead end and a hoax — why would you choose chemotherapy that might make you sicker if your doctors told you diet and exercise would definitely work.


John Holdren, Obama's likely new science advisor has said The ‘geo-engineering’ approaches considered so far appear to be afflicted with some combination of high costs, low leverage, and a high likelihood of serious side effects.


More about this on ClimateProgress.


Personally, I tend to feel similarly to Romm and Holdren.  I don't like the idea of manipulating the Earth's climate because of the possibility of nasty unintended consequences.  But Hansen could also be right that if we fail to sufficiently reduce CO2 emissions, geo-engineering might become a last resort.


What are your thoughts on the subject?

post #2 of 17

Well, I like to think of geoengineering as falling under one of two categories: the untested, and the safe.

The untested are things like you mentioned, putting aerosols into the atmosphere (particularly sulfur, which of course contributes to acid rain), putting several thousand mirrors between the Earth and the Sun, putting buoys in the ocean that pull cooler ocean water (which can absorb more CO2) to the surface by wave action, creating artificial clouds...etc.


These are almost certain to have unintended consequences. On the other hand, things such as research in ways to suck carbon out of the air--like artificial photosynthesis, genetically engineering certain plants to grow faster, or perhaps just growing trees, condensing the carbon into charcoal and then burying the charcoal underground--are very likely NOT to have any unforeseen consequences, since we are simply reversing what has already been done.


If we continue this slow pace of emissions reductions, then geoengineering may be our only way out. It would be nice to have such a backup plan, even if it is only a hail marry pass.

post #3 of 17

You're driving down the road at 120 kph in a car with nonlinear controls that has all sorts of highly nonlinear feedbacks.  Some you know about, maybe some you don't, and even of the ones you know exist, you're not sure of the amplitudes and time constants of the responses.  Put another way, if you steer left, it might cause the brakes to heat cherry red and fail.  Stepping on the brakes may cause a shimmy in the right-front wheel.  You don't know, every system in the car affects every other system.  And the systems themselves are nonlinear.  The steering itself may respond linearly within a certain range, but get outside that range by a small amount and the wheel deflection increases exponentially with each further milliradian of change in the steering wheel (and this sensitivity is a function of speed, or throttle, or both). 


The smartest course of action is to not change anything for the time being, have someone get the damned manual out of the glovebox, and start reading.  If you have changed something, don't try fixing a vibration in the gearbox by opening the choke on the carburetor. 


-from old gcnp's almanac of climate parables


post #4 of 17
Originally Posted by dana1981:

why would you choose chemotherapy that might make you sicker if your doctors told you diet and exercise would definitely work.


I've never been able to say it so eloquently, but that's exactly how I feel about it. I am extremely pro-science, but there are too many examples of us as a civilization thinking we know exactly what's going on and the being proven utterly wrong.


gcnp is right on - let's continue to gather information and only make confident moves for a bit. At least with emission reduction we know how to do it, and we know we're moving in the right direction. Now we just have to do it...

post #5 of 17

With our dry lands becoming drier, we are progressively reducing the  volume of CO2 captured and oxygen released. We can reduce the amount of new CO2 we add to the atmosphere, and if we do so early and deeply enough, then we can hope that we will get a net reduction of CO2 in the atmosphere.


We should definitely not trust that this will be adequate. Previous warming periods even without human intervention have gone on to completion. We should expect that once global warming has proceeded to some level, reducing our input will place us at the stage earth has been before, ready to go right on warming without our assistance, or we could describe this as the phase I call the self fueling furnace. Warming causing release of CO2, methane, and of course water vapor faster than we can reduce our CO2 output.


I am not sure that merely supplying water to irrigate our dry lands will be enough.  We may have to use our ocean surfaces to capture CO2 as well. Simply planting forests in dry land does not look to be enough. Plants need water to convert CO2 to O2 and sugar.


We will have passed the tipping point before we realize that we have to do more, and the futher past the tipping point, the less likely we will be able to bring the warming to an end. But the warming phase is not the ultimate disaster. The warming period will bring on an earlier onset of an ice age. Incidentally, the early part of the ice age will correct the dry land's lack of rainfall. If we correct this early, we may not have a major ice age.


Using water to grow more wood and food is not entirely  a losing effort.

post #6 of 17

i'm wary of the 'geoengineering' tag. it does imply big, hitech, invasive solutuions, and we really dont know enough yet to give a good guess on the side effects. too many unknown unknowns in how th eearth system would react, as well as the effects we can predict.

theres plenty of more natural processes we can harness first while we learn how to drive this thing.

re-forestation, and saving and rehabilitating peatlands and salt marshes are obvious ones, and have added benefits to help pay for them.

growing algae in more controlled conditions; rather than random dumping in deep ocean; of course for the next few decades this will be for fuel to replace fossil oil, but maybe eventually we can lay down 'new oil'. we can use sewage as the nutrients, another 'kill 2 birds' thing.

whiteshell mentioned growing cyanobacteria, which dont get eaten, and i should go find out more about that.

post #7 of 17

It of course depends on how bad the situation gets whether we will be required to intervene on the planet’s natural ability to offset our human errors. There may come a time when geo-engineering is no longer an option if real action to counter climate change isn’t taken seriously by the world’s governments. 

I see two problems with geo-engineering. First of all we have in the past tried manipulating nature on small scales. We do this when we replant forests, re-stock lakes and release species into the environment to control non-indigenous species accidentally released into the environment by human actively. Historically our efforts often result in failure. Forests lose biodiversity, fish species lose immunity to disease and species introduced to control other species become invasive.  We simply are not good at doing nature’s job and may end up creating a bigger problem than we started with. We will be gambling with the planet if we make attempts to purposely control the climate.
The second and in my opinion the greater threat from geo-engineering comes from the fossil fuel industry and their cravings for profits. If we can geo-engineer a planet to counter emissions of fossil fuels in the past, then we can geo-engineer a planet to counter emissions of fossil fuels in the future. Oil and coal companies will see geo-engineering as nothing more than a chance to emit if they believe any climate problem can be countered by artificial means.  As long as profits remain in the ground and governments can be lobbied, geo-engineering will be a license to assault nature.


Edited by gwens - Tue, 23 Dec 2008 19:14:39 UTC
post #8 of 17

i agree on borh counts gwens.

i do permaculture, in which the first step is to observe how natural ecosystems in a similar situation do things, then trying to set up a near natural self organising system. they can be incredibly productive for the effort put in, and by their natrure improve things like soil carbon and biodiversity.

and as for the big boys, yes, the more pressure on the slippery buggers the better.



the only time i flew over spain, a few years ago, i was struck by the reflectivity of the miles of polytunnels, i thought then that it would be well possible to alter albedo quite significantly by this method. i saw this today;

Fix For Global Warming? Scientists Propose Covering Deserts With Reflective Sheeting

ScienceDaily (Dec. 23, 2008)

well, far inland it would be good, but anywhere within pumping distance of the sea and/or a city (sewage - yum), why not use polytunnels, and grow food at the same time. (and probably be able to create little oases with the overspill). like all my schemes (and like nature of course), it soon gets complicated; get an algae plant in there and use the pressed algae as compost, a co2 pipe as well.......

post #9 of 17


Fix For Global Warming? Scientists Propose Covering Deserts With Reflective Sheeting

ScienceDaily (Dec. 23, 2008)


This concept looks quite feasible, but the price tags seems to be a bit higher than necessary.  Mylar (2 mil) is >90% reflective and costs about $0.15 per m^2 in small quantities.  The cost quoted in the article works out to $464.50 per m^2.  A supporting frame would add to the cost, but $464.35 seems excessive. 


A less expensive option could be to increase the albedo in cities.  A large city like New York is about 1000 km^2.  The role of urban albedo is discussed here

post #10 of 17

When we think of making the Sahara more reflective, consider the temperature difference between the Sahara and the Congo.

Congo on average is warmer, but never as hot as the Sahara. Having jungles fed with water, Congo does not cool down as far at night and does not heat up as much in the daytime. Of course it is more equatorial. But would we not expect those dark green forests to get hotter than the reflective desert when the sun is blazing down?


Well, no. Equatorial rain forests put up a cloud cover that cuts off a lot of the heat of the sun. If we were able to pump excess Niger and Congo water into the deserts to grow trees the desert would cool down first from transpiration, then from cloud cover.


We can make parts of a city more reflective, as in by placing light colored sand all over parking lots, driveways, even black topped buildings. The wind would then clean the buildings by sand blasting.


But cities are hotter than surrounding lands not because  of solar gain. Farm lands have at least as much solar gain. Rather cities consume more energy, and most of that, perhaps all of it,  is released as heat.  Task one for cities is to cut energy consumption.  Task 2 is to lose that heat efficiently, as by sending it out to the oceans. The energy cost to dump heat into the ocean is so much less than the energy cost to just shove it out of my building into the alley  beside it.


Instead of using energy to heat the city we need to do a better job of saving the energy we already get from sun even if that does not make the city more reflective.

post #11 of 17

interesting article

What can we do to save our planet?

The Independent asked the world's leading climate scientists whether we should prepare a 'Plan B' to curb the worst effects of global warming. Their responses are fascinating – and sobering

Friday, 2 January 2009


i agree with;

Jim Lovelock, author of the Gaia theory

I never thought that the Kyoto agreement would lead to any useful cut back in greenhouse gas emissions so I am neither more nor less optimistic now about prospect of curbing CO2 compared to 10 years ago. I am, however, less optimistic now about the ability of the Earth's climate system to cope with expected increases in atmospheric carbon levels compared with 10 years ago. I disagree that geoengineering the climate is a dangerous distraction and I disagree that on no account should it ever be considered. I strongly agree that we now need a "plan B" where a geoengineering strategy is drawn up in parallel with other measures to curb CO2 emissions. However, climate change is an Earth system problem and the UN is not a suitable body to host or organise it.


strongly agree with;

Professor Chris Rapley, director of the Science Museum, London

"help the Earth help itself"; i.e. by amplifying carbon sequestration processes that the Earth already practises – in the ocean and on land.


and this warning;

Kevin Walsh, University of Melbourne

The fundamental problem with geoengineering is that we are already undertaking our own geoengineering experiment, namely global warming due to man-made greenhouse gas production. This current experiment has already thrown up some nasty surprises. Why should we try another experiment when it could cause additional unintended consequences? Why not try to fix the fundamental problem instead?


and this;

Steven Ghan, Pacific Northwest National Laboratory

Any geoengineering solution should focus on removing CO2. Any other solution is bound to introduce changes in the distribution of radiative heating that would change the climate in undesirable and perhaps unexpected ways.


not to mention not adressing ocean acidification.

post #12 of 17

another interesting article; air scrubbers


Can technology clear the air?

from new scientist.


i like the low energy one, that could be fab. usual problem, no funding.

post #13 of 17
Thread Starter 

Yeah air scrubbers are a cool idea.  They're good because they can remove CO2 as a last ditch effort with minimal side-effects, unlike geo-engineering proposals.  It's just a matter of getting them to work in a cost-effective manner on a sufficiently large scale.

post #14 of 17

eh? do they not count as geo-engineering then?



another reason against suphate release;



The Sensitivity of Polar Ozone Depletion to Proposed Geoengineering Schemes


article here;

Stratospheric Injections to Counter Global Warming Could Damage Ozone Layer


post #15 of 17
Thread Starter 

I don't know, technically it may be, but personally I wouldn't consider removing CO2 with scrubbers to be geo-engineering.  It's more like removing the geo-engineering of the CO2 emissions in the first place!

post #16 of 17

This issue is not going to be decided by people with no interest in the methods used.

It will be decided by industries dealing with cap and trade if they are discussing using a membrane to remove CO2 from the air. It will be decided by companies supplying sulphate particles and promoting their use with clever sales pitches, put out in such a way that those who oppose them will be portrayed as reckless, as criminal, given the  increasing level of global warming.


If you plan to educate the population about these things, you need to do it before those with an economic interest paint you into a corner. I say you, because I will not live that long.

post #17 of 17

don, that is my fear also.


here is a study that compares different geoengineering ideas, i was pleased to see 'my' biochar came in above ocean seeding.

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