I doubt geoengineering will ever be practical as a primary strategy for dealing with climate change (see here and here). That said, I don’t consider most of the efforts to pull CO2 out of the air geoengineering—that is ungeoengineering our self-inflicted climate wound. And those efforts are only plausible with super-aggressive mitigation that keeps concentrations close to 450 ppm.
It’s strategies like injecting sulfur into the atmosphere that should worry people the most. Those strategies have many flaws, but among the worst is that they do nothing to stop humanity from turning the oceans into one giant acidic deadzone.
A new study in Nature Geoscience, ($ub. req’d, abstract below) makes crystal clear why very serious mitigation must always be humanity’s primary strategy for averting climate catastrophe. As AFP reported on the study:
Global warming may create “dead zones” in the ocean that would be devoid of fish and seafood and endure for up to two millennia ...
Its authors say deep cuts in the world’s carbon emissions are needed to brake a trend capable of wrecking the marine ecosystem and depriving future generations of the harvest of the seas.
Precisely. This study makes a matching pair with NOAA stunner: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe.
Even worse, of course, is that while there are many plausible, albeit expensive and untried on large scale, strategies for removing CO2 from the atmosphere, it is far from clear how one does that from the ocean.
Here is more detail on this important study and on oceanic dead zones:
In a study published online by the journal Nature Geoscience, scientists in Denmark built a computer model to simulate climate change over the next 100,000 years.
At the heart of their model are two well-used scenarios which use atmospheric levels of carbon dioxide (CO2), the main greenhouse gas, as an indicator of temperature rise.
Under the worst scenario, CO2 concentrations would rise to 1,168 parts per million (ppm) by 2100, or about triple today’s level.
[This worst-case scenario is, of course, just the business-as-usual emissions scenario, see here.]
Under the more optimistic model, CO2 would reach 549 ppm by 2100, or roughly 50 percent more than today.
The temperature rise that either would yield depends on several factors: when the peak in carbon emissions is reached and how quickly it falls, and whether the warming unleashes natural triggers, or tipping points, that enhance or prolong the warming in turn.
Taking such factors into account, the scientists predict a possible rise of around five to seven degrees Celsius over pre-industrial times under the worst scenario. Under the other scenario, there would be warming of roughly between two to four degrees Celsius.
Either scenario spells bad news for the ocean, said Jens Olaf Pepke Pedersen, a physicist at the Technical University of Denmark.
Under the worst scenario, warmer seas and a slowdown of ocean circulation would lower marine oxygen levels, creating “dead zones” that could not support fish, shellfish and other higher forms of marine life—and may not revive for 1,500 to 2,000 years.
“They would start slowly by the end of this century, it’s not something that would happen tomorrow or in the near future but over the next few generations,” Pedersen told AFP.
“But because of the inertia in the ocean, once you have the process going, it’s not feasible to reverse it again just like that, so it would continue for hundreds of years ...
Wide oxygen depletion of the ocean, though, poses a far greater threat, touching at the heart of biodiversity, the paper warns.
Around 250 million years ago, a chemical change of the seas led to a massive wipeout of marine species.
Lead scientist Gary Shaffer of the Niels Bohr Institute at the University of Copenhagen said it was unclear, in the grim light of this study, whether future generations could look to the oceans as a major reserve of food.
“Reduced fossil-fuel emissions are needed over the next few generations to limit ongoing ocean oxygen depletion and acidification and their long-term adverse effects,” he said.
Here is the study abstract:
Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere. Future warming may have large global impacts including ocean oxygen depletion and associated adverse effects on marine life, such as more frequent mortality events, but long, comprehensive simulations of these impacts are currently not available. Here we project global change over the next 100,000 years using a low-resolution Earth system model, and find severe, long-term ocean oxygen depletion, as well as a great expansion of ocean oxygen-minimum zones for scenarios with high emissions or high climate sensitivity. We find that climate feedbacks within the Earth system amplify the strength and duration of global warming, ocean heating and oxygen depletion. Decreased oxygen solubility from surface-layer warming accounts for most of the enhanced oxygen depletion in the upper 500 m of the ocean. Possible weakening of ocean overturning and convection lead to further oxygen depletion, also in the deep ocean. We conclude that substantial reductions in fossil-fuel use over the next few generations are needed if extensive ocean oxygen depletion for thousands of years is to be avoided.
Any geoengineering strategy that lets the oceans die is no cure at all.
This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.
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Comments
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amazingdrx Posted 11:25 pm
18 Feb 2009
Latest figures have chemical ag and its unintended effects contributing over 50% of human caused GHG. Organic ag takes carbon back out of the atmosphere and builds soil, that gives it the potential on a world wide scale of acomplishing ungeoengineering.
The other big effect of organic ag/waste biomass biodigestion is to produce biogas for distributed backup power generation for varible renewable sources like wind and solar energy. That could make 100% renewable energy possible.
Then organic ag would start to help civilization go carbon negative. Building up the soil based carbon sink to its pre-industrial levels.
Another scenario to consider is ocean based algae farming and aquaculture, on a large scale it could also remove carbon from the atmosphere and ocean.
There is hope that exponential commercial mass production of organic ag and renewable energy devices could match and neutralize exponential GHG climate change. The power of compound growth could be on the side of maintaining/restoring a human friendly climate.
A volcanic eruption ot two or three could buy some breatrhing room. World wide dust storms might block solar energy like volcanic dust clouds tend to. Human tinkering on that scale is not a good idea, the sulfur plan for instance.
Ungeoengineering better get off the ground sometime really soon to avoid climate disaster. Since science just got around to aknowledging postive feedback effects on climate, new estimates of the climate tipping point are needed.
Have we already passed the point at which feedback effects are larger than the cancellation effect of renewable energy/organic ag build out? This also involves estimates of how fast ungeoengineering could happen. That makes it very tricky as it involves economics and politics, where science has to tread lightly in terms of certianty. Only a range of possibilities is possible, not specific times versus GHG levels/temperature change.
http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin
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dicynodont Posted 6:34 am
19 Feb 2009
Ocean Anoxic Events (OAE) are caused by radiative forcing imbalances that produce changes in climate which alters ocean circulation and hence oxygen penetration. Ocean acidification has absolutely nothing to do with this process (and may even help if less organic carbon is exported to the deep ocean). It is very possible that radiative forcing management techniques (e.g. stratospheric aerosols, marine cloud seeding, DMS production) could actually maintain or restore natural ocean circulation patterns, which would prevent OAE from occuring. Researching how this could be done should be one of the highest priorities.
My personal opinion is that if radiative forcing geoengineering techniques reduce the threat of ocean anoxia, then a little bit of enhanced acidifcation is an acceptable outcome. Even better are those techniques that remove atmospheric CO2, since these both solve the OAE problem as well as the ocean acidification problem. (...and yes, ocean iron fertilization can help in both of these aspects)
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macmardg Posted 7:01 am
19 Feb 2009
There is no actual connection between whether or not sulfur is injected into the atmosphere and whether humanity continues kill the oceans (etc); I do believe that when the time comes for a serious discussion, that humans are smart enough to understand more than the false choice between either emission reductions or geoengineering, but that we might consider both (and on the direct subject of the post, its certainly true that it won't help the oceans.)
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christophersj Posted 8:01 am
19 Feb 2009
This is all developing but I am sure the information coming from places like Scripps, Stanford, and the Monaco Declaration indicate that ocean acidification is anything but minor, and is in fact the largest threat to the oceans and to many human's food supply.
Those "some species" make up much of the base of the food chain of the worlds oceans. They are literally talking about most calcium based life forms, from phytoplankton to pteropods to to coral to shellfish being radically affected if not made entirely extinct.
Fin fish and whales eat and rely upon many of those species.
In my opinion, the threat is so large, and so "permanent", that, by itself, it is reason enough to bring CO2 emissions to zero as fast as possible -- besides global warming.
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dobermanmacleod Posted 5:29 pm
19 Feb 2009
"Few seem to realise that the present IPCC models predict almost unanimously that by 2040 the average summer in Europe will be as hot as the summer of 2003 when over 30,000 died from heat. By then we may cool ourselves with air conditioning and learn to live in a climate no worse than that of Baghdad now. But without extensive irrigation the plants will die and both farming and natural ecosystems will be replaced by scrub and desert. What will there be to eat? The same dire changes will affect the rest of the world and I can envisage Americans migrating into Canada and the Chinese into Siberia but there may be little food for any of them." --Dr James Lovelock's lecture to the Royal Society, 29 Oct. '07
"The alternative (to geoengineering) is the acceptance of a massive natural cull of humanity and a return to an Earth that freely regulates itself but in the hot state." --Dr James Lovelock, August 2008
What is the short-term alternative to geoengineering, a carbon diet? CO2 stays in the air hundreds of years, so even if we do start reducing our emissions (very unlikely in my opinion), we are stuck with global warming for generations.
There is a cheap and simple way to immediately cool the Earth: just add a little sun dimming aerosol to the upper atmosphere. That sun dimming aerosol doesn't have to be sulfur for goodness sakes. In fact, according to the paper "The Incredible Economics of Geoengineering" an engineered aerosol would be much more efficient that the stuff volcanoes spew out anyway.
Furthermore, there is a practical mechanical method of deacidifying the ocean and removing the excess CO2:
"Researchers at Harvard University and Pennsylvania State University have invented a technology, inspired by nature, to reduce the accumulation of atmospheric carbon dioxide (CO2) caused by human emissions. By electrochemically removing hydrochloric acid from the ocean and then neutralizing the acid by reaction with silicate (volcanic) rocks, the researchers say they can accelerate natural chemical weathering, permanently transferring CO2 from the atmosphere to the ocean. Unlike other ocean sequestration processes, the new technology does not further acidify the ocean and may be beneficial to coral reefs. The innovative approach to tackling climate change is reported in the Nov. 7 issue of the journal Environmental Science and Technology..." --"Engineered weathering process could mitigate global warming," EurekAlert, 7 Nov '07
It simply amazes me the misconceptions and flawed reasoning so-called experts are still clinging to. What do you think people will do, just sit back and starve to death when record high temperatures start causing the routine failure of crops? Have you ever seen a person starve to death? I would rather quickly burn to death or even die on a cross than slowly starve to death.
The Greens' resistance to geo-engineering sits very uncomfortably with its message that the planet is screwed and we're all going to die. It suggests that Environmentalism has less to do with saving the planet than it does with reining in human aspirations. It suggests that they don't actually believe their own press releases, and that they know the situation is not as dire as they would like the rest of us to think it is. And that Environmentalists are cutting off their noses to spite their faces - "we'll save the planet our way or not at all." It suggests that Environmentalists regard science and engineering as the cause of problems, and not the solution. --Climate Resistance, Mar '08
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dicynodont Posted 5:32 pm
19 Feb 2009
Joe is right to point out the threat of ocean anoxia -- I read the cited paper when it came out and shuddered -- but Joe is wrong to connect it with geoengineering. Geoengineering is perhaps one of the primary solutions to this problem.
My secondary point is that ocean anoxia is a BIG problem, in fact, probably the single greatest threat from climate change. It dwarfs the threat of ocean acidification. Widespread "Ocean Anoxic Events" are strongly implicated as the primary cause of mass extinctions on earth, particularly the great Permo-Triassic mass extinction where 95% of all species in the ocean and land went extinct. Ocean acidification, while bad for calcareous life in the ocean, cannot cause a dead zone let alone a mass extinction.
My strong desire is to have neither issue exist, but if I had to choose one... I would accept some acidification if it meant preventing widespread ocean anoxia.
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Pangolin Posted 8:16 pm
19 Feb 2009
Just drop a big enough rock into the South Pacific to replicate the Krakatoa event. Instant global cooling and ocean fertilization. Also a quick cull of excess human population as crops failed.
Or we could stop burning fossil fuels and start sequestering atmospheric carbon in soils. I think the asteroid strike is more likely.
Put the Carbon Back
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2wheeler Posted 1:12 am
20 Feb 2009
Such an application may be better than merely burning all the fixed carbon biomatter as "biogas" (returning it instantly to the atmosphere from whence it came).
Normally we haven't considered biologically cycling carbon to be able to be geologically fixed or locked up for much of a time. Bacteria and all are pretty good at chewing it up and digesting all but the tiniest fraction, back down again. But the bacteria have a hard time eating charcoal, for some reason.
I'm more interested in mitigation approaches that don't mess with the oceans integrity as well as the atmosphere simultaneously (through runoff, acid rain, weathering and the like). Needless to say, asteroid impact-like albedo changes, etc. with aerosols, particulates or space mirrors are also off the deep end of anyone's preference scale.
The application of biochar technology approaches bears further investigation for this purpose. I understand that biochar fixed carbon remains and enriches soils in the top meter or so of ground (adding to fertility and agricultural productivity in an organic gardening type of approach). This type of carbon can apparently remain for 500 years or more in the soils. It beats deep well injection or other exotic schemes, imho.
Why not pursue biochar? It could also benefit local sustainable agriculture. Humankind has been depleting the soils for many years, investing in them at this time could make a lot of sense.
Geoengineering ain't all bad if it goes along this type of ecological path in partnership rather than monkey wrench opposition to the planet's natural tendencies. Just sayin'.
Moving toward sustainability with hopefulness, one revolution at a time.
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amazingdrx Posted 3:02 am
20 Feb 2009
Biochar is based on combustion.
A pyrolisis system based on fuel cell cogeneration could produce biochar much more efficiently, generating a lot of grid backup power in the process.
Still it would probably be better to biodigest most wood waste, here in Wisconsin wood chips are used for dairt bedding and sent through the biofigestor over and over, the cycle could be interupted to inject soil ammendment along with tree planting, for instance. Or serve as carbon sink enhancing organic fertilizer.
By halting the use of chemical fertilizer, this produces huge GHG reduction. Biochar just can't match these acomplishments.
There are a lot of other pollutants from combustion to produce biochar, it comes from burnimg compounds that should return to the soil to feed roots. Bacterial action returns them with a fenntle break down. Combustion turns them into compunds that cause cancer and increase atmospheric GHG effect 100s of times.
Is it worth building portable biodigestion fuel cell systems to recycle wood waste at risk of massive forest firestotms? Or should we just butn it and make some biochar to bury?
I think it is worth adding one part manure to 30 parts wood waste (the optimum ratio) and making biogas and organic soil ammendment. Then adding a nice blob of it around tree seedlings to help them get through drought and beat the odds.
A new CCC could turn tinder dry dying drought, disease, and insect ridden trees into clean energy, organic fertilizer, and healthy forests again. Using waste biomass to biogas.
The total waste stream useful for biodigestion consists of manure, garbage, sewage, food waste, crop waste, waste wood, algae and weed overgrowth choking lakes and waterways, and so forth. It's a huge source of GHG left to emit very intense greenhouse gases like nitrous oxide and methane, accounting for over 50% of human produced GHG.
And that also make it a huge backup power source, as it is easily stored in biodigestors and biogas tanks. Also it is natural gas, methane, so it is compatible. Biogas can run in any natural gas powered equipment and natural gas runs in fuel cell cogebneration systems. With this ultra high efficiency clean power backup, renewables (and conservation savings) can supply all the extra power we need.
Biochar just can't compete with this.
http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin
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MarkCapron Posted 11:35 pm
21 Feb 2009
Go to http://www.PODenergy.org for an Ocean/Wastewater engineer's explanation on harnessing this process to remove carbon dioxide from both ocean and air. Fund the process with production of biomethane, food, increased species diversity, and fresh water.
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MarkCapron Posted 11:42 pm
21 Feb 2009
To grow biofuel equivalent to the gasoline used in California, we'd need to irrigate land with about half the flow of the Mississippi River.
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amazingdrx Posted 12:34 am
22 Feb 2009
Excellent argument against biomass powered gas guzzling.
Waste biomass is only enough to provide grid backup for a 90% wind, water, and solar powered energy economy.
With plugin hybrid and renewable electric mass transit and freight transportation, 90% of oil use could be eliminated.
Biodigestion also recycles water and saves aquifers from contamination due to sewage, manure, landfill, and chemical fertilizer run off.
Pretty interesting idea Mark:
http://www.podenergy.org/
When the removable molecule concentration exceeds the salt concentration, the osmotic pressure works to draw pure water through the membrane. Forward osmosis researchers are using carbon dioxide and ammonia for the removable molecules. Carbon dioxide will dissolve in sufficient concentrations for seawater forward osmosis at about 50 atmospheres pressure. Not including the cost of dissolving the initial carbon dioxide supply, the energy cost of recycling and recompressing carbon dioxide in a seawater forward osmosis process is about 0.4 kWh/m3 of fresh water produced. The bacteria in high-pressure anaerobic digestion may produce the dissolved carbon dioxide at the necessary concentration and pressure and avoid the 0.4 kWh/m3 energy cost. Also, a high-pressure anaerobic digestion biomethane production facility would require relatively little additional structure to incorporate forward osmosis
I am kind of skeptical of deep ocean CO2 sequestration though. Would it stay put given radical climate change ocean current/temperature effects?
Osmotic processes are problematic as far as membrane replacement and chemical additives. Desaliniaztion can remove CO2 by greening desert area using photosynthesis. Vacuum pump evaporation and heat pump energy recovery coupled with direct solar heating with the pumps powered by wind or wave power might win the prize.
Water is the oil of the renewable energy age. As oil and fossil fuels fade and renewables grow, water will be the limiting factor on human prosperity.
http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin
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MarkCapron Posted 12:50 pm
25 Feb 2009
I'm not real happy with deep ocean encased liquid CO2 storage either. But we need to pull a lot of CO2 out of the atmosphere and stash it, quickly. Mineralization is good, but uses a lot of minerals. Char decomposes. We might even change the chemistry of the ocean, as much as we are already.
Liquid CO2 in a plastic bag is inert. A deep ocean temperature change (in the climate change range) won't make a bag more than 3,000 meters deep less dense than seawater. The bag of liquid won't be turning to gas unless elevated to only 500 meters deep.
We can create a "liquid" denser than seawater and less dense than the 3,000 meter deep liquid CO2 to act as a self-repairing skin over the liquid CO2 bags. (The skin is further described on the http://www.PODenergy.org site.) We can perform maintenance by adding plastic and ooze lid over multiple bags. Ooze over the liquid CO2 also increases pressure, further increasing the CO2 density over seawater density.
There are a lot of realatively easy and cheap ways to ensure liquid CO2 stored below 3,000 meters will be safe for millenia. We have a hard time saying the same for the high-temp deep-aquifer CO2 satuation being considered for "clean coal."
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amazingdrx Posted 2:33 pm
25 Feb 2009
These other sequestration schemes sound like mega-underwater or underground landfills for cO2. An earthquake could release it all. It's too expensive and too dangerous. Soil carbon sinks are cash flow positive. Actually stimulating the economy and productivity and lowering production costs.
If you want to get enamored of ocean GHG remediation solutions I think the algae farming energy systems look pretty good.
http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin
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