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All-out geoengineering still would not stop sea level rise

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p>Mimicking volcanoes by throwing particles high into the sky. Maintaining a floating armada of mirrors in space. Burning plant and other organic waste to make charcoal and burying it—or burning it as fuel and burying the CO2 emissions. Even replanting trees. All have been mooted as potential methods of “geoengineering“—”deliberate large-scale manipulation of the planetary environment,” as the U.K.’s Royal Society puts it.

The goal, of course, is to cool the planet by remove heat-trapping gases in the atmosphere  or reflecting sunlight away. But rising temperature is just one impact of our seemingly limitless emission of greenhouse gases, largely carbon dioxide, into the atmosphere. Arguably a more devastating consequence would be the rise of the seas as warmer waters expand and melting icecaps fill ocean basins higher, potentially swamping nations and the estimated 150 million people living within one meter of high tide. Can geoengineering hold back that tide?

That’s what scientists attempted to assess with computer models in a paper published online August 23 in Proceedings of the National Academy of Sciences. In their words, “sea level rise by 2100 will likely be 30 centimeters higher than 2000 levels despite all but the most aggressive geoengineeering.” In large part, that’s because the ocean has a lot of thermal inertia: it  only slowly warms as a result of increasing greenhouse gas levels—and it will only slowly cool down again.

To appreciably change that lag time, the researchers estimate that humanity would require the equivalent of the eruption of Mount Pinatubo—which put 20 million metric tons of particles into the air—at least every other year. That’s not as impossible as it sounds, given that commercial aircraft each year bring that much mass to the tropopause (the layer between the troposphere and the stratosphere) but it only buys time, delaying sea level rise by roughly 60 years, and if only if done continuously without pause—a daunting prospect.

Nor would drawing down the carbon dioxide in the atmosphere yield better results. Replanting trees on all the lands that have been cleared of forests during the past 200 years only ends up lowering atmospheric concentrations of greenhouse gases by 45 parts per million (current levels are roughly 390 ppm, 110 ppm above pre-industrial levels). Biochar nets even less: 35 ppm, though it has other benefits.

Perhaps the only way to reduce warming enough to minimize the rise of the oceans is an all-out effort that also includes burning biomass as fuel (either to replace coal or gasoline or both) and pairing it with CO2 capture and storage. Together, they could suck down greenhouse gas levels by 180 ppm—more than enough to bring us below pre-industrial levels. As a result, sea level rise is held to just 10 centimers by 2100, according to the author’s modeling.

Such extensive geoengineering seems impractical given its economic (and environmental) cost. But interfering with the planet’s carbon cycle—something we’re already doing by adding so much CO2 to the atmosphere—appears to be the better bet, even if only by curbing current CO2 emissions. Otherwise, we’re leaving our descendants one heck of a mess or, as the authors put it, “substituting geoengineering for greenhouse gas emission abatement or removal constitutes a conscious risk transfer to future generations.”

Image: © / Gregory Albertini

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  1. 1. candide 5:50 pm 08/23/2010

    The one aspect of any geo-engineering project I fear the most would be any unforseen consequences.

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  2. 2. cornsyrupsolids 6:05 pm 08/23/2010

    Geoengineering wont work because PEOPLE can’t control the climate, or have significant impact on it!!!!
    Stop the charade.

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  3. 3. eddiequest 7:12 pm 08/23/2010

    That’s what they said about cyanobacteria. But without those little guys, WE would not be breathing oxygen.
    Try to stay on top of the science, rather than under the thumbs of your masters.

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  4. 4. eddiequest 7:17 pm 08/23/2010

    I understand your fear. But the situation we are in now forces our hands. Which shall it be – an "unforseen consequence"; or a known result of our past actions. One will almost certainly lead to our demise (something my kids prefer not to experience). The other has the potential to save our silly little species.

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  5. 5. RonStrong 7:50 pm 08/23/2010

    There’s a very simple solution for rising sea levels – slowly abandon low lying ground .

    Don’t provide government support, loans, or insurance for new building in locations that are likely to be at risk in 50-75 years. Let the existing ones use up their economic value.

    Areas of human habitation have been changing due to climate and other factors throughout the existence of the human species. We now have the advantage that we can roughly predict when a particular area will no longer be habitable. Sensible policies that take this into account will greatly reduce the costs incurred by changes in sea level.

    Coupled with the huge advantages of a warmer world – longer growing seasons and millions square miles of currently worthless northern lands becoming habitable, global warming is to be embraced, not feared.

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  6. 6. John_Toradze 8:11 pm 08/23/2010

    May as well embrace it.

    But RonStrong is, I think a bit overoptimistic about consequences. Warming will cause desertification and more extreme weather. It won’t be pretty. We have no idea how many people will die, but probably billions. We also don’t really know how fast sea level will rise. We are seeing faster melting in Greenland than we thought.

    But, since it will happen, I agree that we should be pragmatic and plan for it.

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  7. 7. RonStrong 8:39 pm 08/23/2010

    Greater desertification? I thought that a warmer world was going to result in greater rainfall due to greater oceanic evaporation. And remember that since the beginning of the Pleistocene, the Sahara desert has had its periodic wet periods during periods of highest global temperatures.

    There will be climatic winners and loosers as climate changes, whether the changes are those which would have occurred naturally had there been no anthropogenic CO2 emissions or under current conditions of heavy use of fossil fuels.

    Claims that we know what those changes would be in a "natural" environment or in the current environment are nothing more than scientific chutzpah – we cannot yet predict the general shape of next year’s hurricane season, let alone what will happen 100 or more years from now.

    In a wealthy world, few will die – certainly not billions. People in a wealthy world can buy food from half way around the planet if need be. But in a world made poor by controls on CO2 emissions sufficient to make a difference, many will die when inevitable climate changes do take place.

    For the last several million years the earth has been suffering through the coldest climate in the last 250 million years. Permanent ice at both poles has existed for only a tiny part of the history of earth since life migrated onto land.

    I will be a great legacy if our generation pushes out enough CO2 that it breaks the grip that ice has had on our planet over the last couple of million years and returns us to a climate closer to the norm of the last several hundred million years.

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  8. 8. Oliver Wingenter 10:07 pm 08/23/2010

    Dear Mr. Biello,

    In light of our recently published article, your news article title is misleading, "All-out geoengineering still would not stop sea level rise".

    Our geoengineering proposal introduces a new way of thinking about GE. By applying GE to specific areas, possible benefits may be leveraged. Our plan is intended to help reduce and possibly reverse Antarctic ice loss. We welcome your review of our recent paper, "Restoring the westerly winds in the Southern Hemisphere: Climates lever" which was published in Atmospheric Environment online in July and will be out in print in October 2010.

    Oliver Wingenter
    Assoc. Prof. Chemistry
    Research Scientist
    Geophysical Research Center
    New Mexico Tech
    801 Leroy Place
    Socorro, NM 87801

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  9. 9. jtdwyer 10:23 pm 08/23/2010

    So if we burn all the crops and forests and our houses and furniture to reduce atmospheric GHGs to preindustrial levels, how long will it take for the temperature to moderate?

    Will a new Little Ice Age be required to return the global ice sheets to previous levels, preventing continued sea level increases? That would restore thermal equilibrium, right?

    Great! What’s for lunch?

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  10. 10. tichead 1:29 am 08/24/2010

    If I may indulge a metaphor: "Global Vacation"

    Dad (government) and Mom (corporation) are driving the car taking Kid#1 (most people) and Kid#2, (scientist), who are in the back seat, down the road on a summer vaction. Dad and Mom are playing coocheefatchee in the front seat having a good time, refeeling their youthful oats, and not really paying attention to the road. Kid#1 is lost in the ipod, head banging the window and everything else available, while Kid#2 is screaming at full lung capacity that the road ends in 300, no, 200, too late, 100, AAAAggggghhhh, crash through the dead end barricade, feet.

    So, Kid#2 has been screaming about the road being a dead end for the last 10 miles but nobody wanted to listen. Now they are all in the middle of the desert with the wheels buried to the axle in sand. Then the rain starts, hard rain, desert monsoon rain. They are all swept away down the wash.

    The moral of the story: We don’t need to turn around. We just need to stop.

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  11. 11. jtdwyer 4:41 am 08/24/2010

    tichead – But we have no brakes to absorb our thermal momentum.

    Even accepting that human contribution to GHGs is the sole cause of global warming, if humanity disappeared overnight global warming would continue for some indeterminable but significant period of time.

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  12. 12. sandcanyongal 4:49 am 08/24/2010

    RonStrong. Have your findings been peer reviewed or can to point to where what you have written is fact and fits into the accelerated warming. In the past, it happened over hundreds or millions of years. In this case it has happended over the course of 150 years, coincidentally paralleling man’s industrialization. Just try harnessing strong earthquakes or tsunamis. How about tornados, volcanos and hurricanes. It won’t happen on man’s best dilusional day. If man doesn’t quit procrastinating and back-peddle to zero emissions now, we are extinct.

    Why aren’t those monster wind turbines made of 100% recycled materials or provided the equivalent care given before a shuttle is launched. It’s incomprehsible to ignore our vital lifelines, wild lands, fauna and ecosystems to ensure they’re not disturbed and threatened or trashed permanently.

    The Mojave Desert, Tehachapi and Sierra Mts. are about to be changed forever if all of the 49 planned energy facilities are a go. There is nothing green about destroying a huge land mass full of wild life to we have green energy. It’s actually being completed as energy infrastructure for Los Angeles urban sprawl. There are no plans to cut back growth and the sovereign people are paying 30% of the full cost of them. The Kern County General Plan was changed and rezoned for industrial, commercial and residential. The protected Mojave desert tortoises, burros and horses were removed a few years ago, approved by BLM. Even Ft. Irwin removed them 3 times to keep expanding their training facilities. I urge everyone to help stop our government and companies from charging through more land and ecosystems. It’s wrong and is going to hurt us all. Start with getting all those diesel guzzling pleasure boats out the the water permanently and other follies. Instead of turning rural Kern County into cities with concrete, asphalt and stucco, it needs to be kept farming and ranching to feed the large cities. It’s time to man-up.

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  13. 13. sandcanyongal 5:36 am 08/24/2010

    A final thought about climate, is that climate scientists are speaking out about what needs to take place that is deserving of checking out.

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  14. 14. cornsyrupsolids 8:38 am 08/24/2010

    Eddie; Who said that? There were no humans on earth when oxygenation began. 1-2
    Since there is no validity to the premise, you choose belittlement to make yourself out to be superior; I’m impressed!
    The only thing I fear is "scientists" trying to control something they can’t even predict or understand.
    It is right not to pollute, but it is wrong to pollute the discussion.

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  15. 15. rament 9:32 am 08/24/2010

    Why don’t you tell the residents of Pakistan, Moscow and China to embrace global warming

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  16. 16. Sisko 12:29 pm 08/24/2010

    This article is really pointless. When you track ocean levels on planet earth over the long term (500 M years) we are currently at near to the historically all time low ocean levels. Given that as an undisputed fact, isn’t it silly to believe that humans can maintain the oceans at their levels??? I am not saying we did not accelerate the rise, but ocean levels rising WILL HAPPEN.

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  17. 17. outsidethebox 1:15 pm 08/24/2010

    I’m always perturbed by those who speak out against geo-engineering and insist cutting back/eliminating carbon based energy production as the only answer. Right or wrong your method is not going to be put into practice. Did you fail to learn anything from the last two worldwide conferences on the subject? That’s demonstrably not how human beings behave. They talk about insanity as keep doing the same thing while expecting different results. Better to move along to geo-engineering if that’s all that can be implemented instead of complaining its not a perfect solution.

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  18. 18. silvrhairdevil 1:33 pm 08/24/2010

    The oceans are not level anyway – that’s why there are locks on the Panama Canal.

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  19. 19. Sisko 2:25 pm 08/24/2010

    @rament–why not tell them to be realistic. Ocean levels will rise over time. They will probably rise faster due to humans, but they will rise.

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  20. 20. methusela238 4:49 pm 08/24/2010

    Geo-engineering on Earth is good practice for future space geo-engineering and vice-versa. We (modern civilized society) need lots of things, and we don’t have any direct routes to anything we need. Adapting to the current situation is like asking every person who works on Earth to only work within a mile or two of where they are. We assume this cannot be done, because almost all of the civilized world has evolved around motor vehicular transportation as a means to survival, or at least the means to acquiring more debt certificates/"bio-survival" tickets(money). No one wants to adapt because it means less comfort or more work.

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  21. 21. jtdwyer 6:31 pm 08/24/2010

    outsidethebox – IMO, inadvertent geoengineering produced the immediate problem of global warming. I also think that we are still not capable of accurately predicting the effects of changes to this exceedingly complex system, making effective management of the environment impossible.

    Moreover, controlling the environment is far beyond our capabilities, now or in any foreseeable future, as it would require that we predict and control the behavior of all humanity. Any misguided efforts to do so would likely aggravate conditions.

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  22. 22. erichj 11:13 pm 08/24/2010

    Dear Mr. Biello,
    You Have misinterpreted what the study said;

    "We suggested that the most effective approach would be a combination of three different techniques for managing the carbon cycle," said Dr Jevrejeva.

    She explained that these scenarios relied on biological mechanisms to remove CO2 from the air and store it in biomass, soils or geological storage sites.

    For instance, afforestation, or adding forests to places where they have been cut down or never existed, would lower the amount of atmospheric CO2, but only by 45ppm (parts-per-million) – a lot less than the amount humans have already emitted.

    Biochar would reduce the CO2 levels by even less – 35ppm.

    Biofuel production would be more effective, and the combination of the three methods could eliminate up to 250ppm of CO2 and limit sea level rise to between 20 and 40cm.

    The Carbon Capture they are talking about is SOIL CARBON SEQUESTRATION via BIOCHAR.

    Reverse-Geo-Engineering & Prayer

    It’s a real shame that biochar is grouped with infra-structurally impossible "Geo-Engineering" schemes. I would much rather see it framed as it is in this PNAS report (by a Nobel lariat) which underlines Biochar systems sequestration potential;
    Proceedings of the National Academy of Sciences
    Reducing abrupt climate change risk using
    the Montreal Protocol and other regulatory
    actions to complement cuts in CO2 emissions … l.pdf+html

    Biochar is more reverse-Geo-Engineering. This is why Dr. W.Ruddiman’s work at UVA, boldly showing the atmospheric hall marks of Combustion & Ag technology engineering over 10 millenniums need mitigation, with IMHO, biochar and land-management the perfect logical choice.
    We just plan to but the carbon back where it came from.

    For those looking for an overview of biochar and its benefits, These authors have done a very nice job of distilling a great deal of information about biochar and applying it to the US context:
    US -Focused Biochar report: Assessment of of Biochar’s Benefits for the USA;

    Every 1 ton of Biomass yields 1/3 ton Charcoal for soil Sequestration (= to 1 Ton CO2e) + Bio-Gas & Bio-oil fuels = to 1MWh exported electricity, so is a totally virtuous, carbon negative energy cycle.

    The Biochar Fund,
    Exceptional results from biochar experiment in Cameroon

    We have filled the air, filling the seas to full, Soil is the Only Beneficial place left
    Carbon to the Soil, the only ubiquitous and economic place to put it.

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  23. 23. Cyborgbill 4:35 pm 08/25/2010

    Unless my calculator is seriously wrong, 30cm is just slightly less than 1 foot. One foot sea level rise does not a "Waterworld" scenario make. I seriously doubt it hurt anyone.

    And since we puny humans cannot make much difference in the planetary climate ANY WAY . . .

    For my money humans claiming to be able to significantly alter the global climate is analogous to a pigmy shrew (and the runt of the litter at that) climbing up an elephant’s leg with rape on his mind. Even assuming he did ihs worst would the elephant even KNOW??

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  24. 24. dusty14 6:10 pm 08/25/2010

    Sea levels and temperatures have both changed dramatically over the Earth’s history, and will continue to do so. It would be far more productive to learn to adapt to this change, or even to find ways to profit from it, than to make feeble but expensive attempts to change the inevitable. People are mobile and will adapt, and many will surely welcome the warmer climates to come.

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  25. 25. jtdwyer 6:54 am 08/26/2010

    dusty14 – Sounds reasonable, but in what lands will hundreds of millions live and what infrastructure will support them? The survivors will turn the world into a poor man’s Mexico City. Then things will get worse. When’s lunch?

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  26. 26. Neptunerover 7:27 pm 08/26/2010

    It’s too late for this planet. Let’s terraform Mars.

    "Geoengineering" Gimme a break! Let me guess: It will be incredibly expensive. And who can tell if it worked or not? A perfect scam.

    Why not bioengineer a microorganism that floats in the air, gobbles up CO2 and farts out fresh air? Make them be good for our lungs too. And if the fresh air could smell like roses, even better.

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  27. 27. nismail 5:04 am 08/28/2010

    Sea level will NOT rise in a million years. That is just elementary science imagination – ice melts into water.

    As a life organisim, planet Earth operates its own regulated system like our body. It was called Gaia Theory before.

    Daily it inhales sunlight as heat, and nightly exhales it out as kinetic energy in falling condensation to give us morning dew or fog as such. CO2 (GHG) blocking heat escape is nonsense.
    Heat turns into kinetic energy all the time in fast exit. Every explosion does that. Heat radiation is miniscule below 200 C.
    and the CO2 theory for AGW is all wet and baseless.

    When glaciers disappear, they sublime into vapour to mop up man made heat to keep Earth cool. Then it returns in torrents like over in Pakistan to do the work again if not absorbed first in the process for irrigation. Much of it stays up in the air as long as we keep pumping more heat into it.

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  28. 28. 2:10 pm 11/9/2010

    Are you aware that geoengineering is already taking place, globally, and is making people and animals seriously ill, impeding plant growth and causing untold damage to our environment? Watch "What In The World Are They Spraying?", a documentary which presents evidence that covert geoengineering operations are literally poisoning us and destroying our planet.

    Link to this

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