Can geoengineering put the freeze on global warming?

March 21, 2011 By Dan Vergano

Scientists call it "geoengineering," but in plain speak, it means things like this: blasting tons of sulfate particles into the sky to reflect sunlight away from Earth; filling the ocean with iron filings to grow plankton that will suck up carbon; even dimming sunlight with space shades.

Each brings its own set of risks, but in a world fretting about the consequences of global warming, are these ideas whose time has come?

With 2010 tying as the world's warmest year on record and efforts to slow looking stymied, calls are rising for research into engineering our way out of global warming - everything from launching solar shade spacecraft to genetically engineering green deserts. An international consortium of 12 universities and research institutes recently, for example, announced plans to pioneer large-scale "ocean fertilization" experiments aimed at using the sea to pull more greenhouse gases out of the sky.

Once the domain of scientists' off-hours schemes scrawled on cocktail napkins, such is getting a serious look in the political realm.

"We're moving into a different kind of world," says environmental economist Scott Barrett of Columbia University. "Better we turn to asking if 'geoengineering' could work, than waiting until it becomes a necessity."

A National Academy of Sciences' best estimate has global warming bumping up average temperatures by 3 to 7 degrees Fahrenheit by the end of the century. Meanwhile, greenhouse gas emissions that are largely responsible, most from burning the modern economy's main fuels, coal and oil, look set to continue to rise for the next quarter-century, according to Energy Information Agency estimates.

"That's where geoengineering comes in," says international relations expert David Victor of the University of California, San Diego. "Research into geoengineering creates another option for the public."

Geoengineering takes its cue from the natural experiment that actually had made the only dent in global warming's rise in the last two decades - the 1991 eruption of Mount Pinatubo in the Philippines, which blasted more than 15 million tons of sulfur dioxide 21 miles high, straight into the stratosphere. The stratosphere suspended those sulfur particles in the air worldwide, where the haze they created scattered and reflected sunlight away from the Earth and cooled global atmospheric temperatures nearly 0.7 to 0.9 degrees Fahrenheit in 1992 and 1993, before finally washing out, according to NASA Goddard Institute for Space Studies estimates. Firing about half that much sulfur into the stratosphere every year for 30 years would help stabilize global warming's rise, National Center for Atmospheric Research climate scientist Tom Wigley estimated in a much-debated 2006 Science journal report.

Humanity would effectively become addicted to sky-borne sulfates to keep the cooling on track. The tradeoff is that rain and snow patterns would likely shift, a 2008 Proceedings of the National Academy of Sciences study found, consigning hundreds of millions of the poorest people on the planet in Africa and Asia to recurring drought.

"Geoengineering is no longer a taboo topic at scientific meetings. They are looking at it as one more policy prescription," says Science magazine reporter Eli Kintisch, author of Hack the Planet: Science's Best Hope - Or Worst Nightmare - For Averting Climate Catastrophe. "But it is yet to become a household word."

That may be changing, as the terms of debate about geoengineering become clear. On the pro-research side, this October the U.S. House Committee on Science and Technology called for more research into geoengineering, "to better understand which technologies or methods, if any, represent viable stopgap strategies for managing our changing climate and which pose unacceptable risks." On the more cautious side, a United Nations Environment Programme species conservation meeting in Nagoya, Japan, ended that same month with a call for, "no climate-related geoengineering activities," without environmental and scientific review.

What are the actual geoengineering proposals? Broadly, they come in two flavors: those that deal with greenhouse gases directly by soaking up carbon dioxide (the greenhouse gas with the biggest warming impact); and those that seek to limit the sunlight that warms those greenhouse gases. Here's a sampling, from the deep ocean to deep space:

-Ocean fertilization: Dumping iron filings into the ocean to spur phytoplankton blooms is the saltwater version of forestation. The increased mass of the plankton's cells would swell with carbon pulled from the air. On the downside, it may kill fish, belch out other such as methane, and hasn't worked very well in small trials.

-Forestation: Intense planting of trees and reclaiming deserts with hardier plants is one of the ideas endorsed at the recent Cancun, Mexico, climate meeting, where representatives of 192 nations made some progress on an international climate agreement. More fantastic versions, endorsed by Princeton physicist Freeman Dyson, would rely on genetic engineering to produce trees that act as natural carbon scrubbers, their trunks swollen with carbon pulled from the air.

-Cloud engineering: Painting rooftops white, genetically engineering crops to have shinier surfaces, and floating blocks of white Styrofoam in the oceans are all proposals to mimic the effects of clouds, whose white surfaces reflect sunlight. Pumping sea salt into the sky from thousands of "spray ships" could increase clouds themselves. Cost-effectiveness aside, such cloud-seeding might end up dumping rain on the ocean or already soggy regions, instead of where it's needed.

-Pinatubo a-go-go: As mentioned above, sulfur aerosols could be fired into the sky by cannons, released by balloons or dropped from planes.

-Space mirrors. Hundreds of thousands of thin reflective yard-long disks fired into a gravitational balance point between the sun and Earth could dim sunlight. Cost aside, rocket failures or collisions might lead to a tremendous orbital debris cloud circling the Earth. And a recent Geophysical Research Letters space tourism report suggests the rocket fuel burned to launch the needed number of shades would dump enough black soot - which absorbs sunlight and heats the atmosphere - to increase average global temperatures about 1.4 degrees.

"Most of the technologies are not yet proven and are at the theoretical or research phase," an August Congressional Research Service report noted.

On the environmental side, cutting temperature increases through these techniques may still shift rain and snow patterns, leaving the planet cooler, but it could also trigger droughts across vast swaths of farmland in Africa and India. Further, ocean fertilization could contribute to mass killing of sea life and releases of methane greenhouse gas, while using sulfur aerosols could bring not only drought but also enlarged ozone holes.

Leaving aside the environmental risks each one carries, the estimated costs tend to increase with how quickly each method removes carbon or deflects sunlight. The space reflectors would top the bill at a cost of several trillion dollars over 25 years.

"Geoengineering technologies, once developed, may enable short-sighted and unwise deployment, with potentially serious unforeseen consequences," said a 2009 American Meteorological Society statement. Turning over weather management to human beings raises, "legal, ethical, diplomatic, and even national security concerns," the statement added. Deflected storm tracks could result in floods such as the ones hitting Australia last month or Pakistan last year. And simply cutting temperatures won't stop the rise in ocean acidification arising from increased carbon dioxide levels in the air, which may affect marine life underlying the ocean food web.

Simply putting a worldwide price on carbon emissions from smokestacks and letting the marketplace lead to lower carbon emissions would likely be cheaper and more sensible than geoengineering, says Barrett, the economist. "But let's face it. We're talking about (geoengineering) because we don't have a price on carbon."

That's why geoengineering could happen before a global climate treaty ever passes the U.S. Senate, suggests Victor. International climate talks rest on getting 192 self-interested and short-sighted nations to cooperate in ways that will benefit some and cost others, particularly coal-powered ones such as the United States and China. But with geoengineering, you only need one nation to start "hacking," or geoengineering, the planet.

"It would be not at all surprising to wake up one morning and discover that Chinese testing (of geoengineering) has begun on a large scale," Victor says. "That would freak everyone out and create huge international tensions."

No international treaty governs geoengineering, other than a 2008 amendment to ocean pollution agreements limiting ocean fertilization to research studies.

A Yale University survey of 1,001 people nationwide last year found that 1 percent could correctly describe geoengineering. The field needs to be researched, suggests climate scientist Michael MacCracken of the Climate Institute in Washington, D.C., before opinions harden without accurate information. Geoengineering at this point looks like one of many options in addressing climate change, MacCracken adds. "You can only geoengineer so much before the side effects become so much worse than the cure that it doesn't make sense to bother."

He and others argue geoengineering research should begin in earnest, before some abrupt climate change, such as Greenland's ice sheet melting precipitously, stampedes the world into an overreaction and rush to costly technology as a quick, untested fix.

"No research is really going on in a lot of these areas," he says, raising the prospect of a lot of fruitless or counterproductive climate engineering efforts suddenly sprouting in a global panic about collapsing ice sheets decades from now.

Global warming by itself is a kind of geoengineering, noted as far back as 1896 by the Swedish scientist Svante Arrhenius, who calculated that doubling the amount of carbon dioxide (the most noted greenhouse gas) in the atmosphere by burning fossil fuels would likely warm the atmosphere by 9 degrees. Arrhenius supposed that would take thousands of years to happen, based on fossil fuel use rates at the turn of the century. Instead, the global average temperature has warmed about 1.4 degrees since he made his estimate, as carbon dioxide levels have increased tremendously, and his 9-degree increase is now within the range of forecasts for 2100.

"I think it is settled that some climate engineering research will go forward," Kintisch says. "We haven't seen it enter the national debate yet. Hard to know what will happen when it does. That may be the biggest question."

Explore further: Climate change: Can geoengineering satisfy everyone?


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3 / 5 (8) Mar 21, 2011
Liliputian ass-hattery.

Any group attempting to do any of the things this article mentioned should be arrested by whatever responsible and rational authority exists in the world.

What climate is most desireable for earth? How do you set this standard?

aren't high carbon dioxide levels and warmer temperatures more like the cambrian era, where there was the greatest abundance of life?

Isn't the climate we live in now nothing but warm periods between ice ages and our world is abnormally low in CO2 and colder than is ideal for life?

Climate changes, but how do you define good climate? Good for who? Good for what?
3.3 / 5 (8) Mar 21, 2011
And if some or all of these harebrained schemes are implemented and the globe is plunged into a deep ice age that exterminates most of humanity, who is going to take the fall for that huge miscalculation? I tell you, it will be the "rank and file" of humanity, not the "experts" or "leaders". So, IMHO, NO GOVERNMENT or "SCIENCE" consortium should be allowed to tamper with the planet while the people who are going to be most affected by it have no voice or choice in the matter.
3 / 5 (6) Mar 21, 2011
A few days ago i found this website: (copy n paste)

They are already doing it.. bastards.
2.4 / 5 (5) Mar 21, 2011
In answer to Arkaleus, the scientists will focus on a climate we evolved in. We humans and other creatures would not do well in the heat of the Cambrian era - unless you like living in a terrarium which is set in the sun.

It would be best to reduce CO2 levels now while we still have a fighting chance. We can then at least save a lot of our assets, especially along the coasts, our most populated area.

NASA's most recent report indicated a sea level rise of 1 foot by 2050. We are coming out of a low Milankovtich solar cycle, so the heat is really going to be felt in the next few years. Human caused climate change is occuring very rapidly now, and although it hurts me to say, it is best that we do the research now in the event of a climate emergency.
2.1 / 5 (7) Mar 21, 2011
First, CO2 levels do not dictate the climate. When Mother Nature reduces the energy coming in EVERY NIGHT, EVERY WINTER every 60 Year cooling cycle etc, the temperature goes DOWN, regardless of how much CO2 there is. It is the amount of incoming energy that dictates warming or cooling. eg it warms in the morning when the sun comes up.
Second, there is a Law of Physics called the Stefan- Boltzmann Law. It says that energy radiates out proportionate to the temperature raised to the 4th power. In other words if it gets too hot, more heat radiates out to return to the old equilibrium, if it gets too cold less heat radiates out & it warms up. THe equlibrium temperature is set by the amount of heat coming in, not by CO2. Most of the heat comes from the forces of gravity (causes tides, liquid core tides etc) and by planetary eccentricity potential energy.
Which means that any geoengineering done by man is doomed to failure. LEarn some physics before wasting my money.
2.8 / 5 (5) Mar 21, 2011
..We can then at least save a lot of our assets, especially along the coasts, our most populated area...

Sorry, I don't have a beachhouse, nor own a hotel or resort there..! Seriously, ANYTHING you do these days that remotely deemed (there'd alsway be someone) to have any effect on the enviroment- be it endangered sandfleas or seaweeds-that will it cost 1000% in lawsuits and delays to get it started, if ever. Then the detractors can sit back and say it's not economical, feasible nor advisible to do so. How many billions has been wasted on nuclear, coal, hydro, solar power stations delay costs, and thus the costs passed onto the consumers? And do you know these idiotic hypocrites are continously prducing and posting their protests on their PCs that run by the power produced by means that they so detested? Hypocrites! the worst kind of scum.

4 / 5 (4) Mar 21, 2011

CO2 and other greenhouse gases affect the rate at which Earth loses heat imparted by the Sun. The atmosphere acts as a blanket. Consider a human body, maintaining constant body temperature -- thereby outputting a constant heat flux (this is the equivalent of Earth surface radiating back absorbed solar heat.) Now wrap that body in thermal insulation; what's going to be the effect on body temperature?
THe equlibrium temperature is set by the amount of heat coming in, not by CO2.
No, it's set by the rate of heat coming in, AND the rate of heat going out. Stefan-Boltzmann is formulated in vacuum. It does not take any thermal insulation into account. The Earth as a whole (together with its atmosphere) would track Stefan-Boltzmann; however Earth's surface (beneath the atmosphere) will not.
Most of the heat comes from the forces of gravity (causes tides, liquid core tides etc) and by planetary eccentricity potential energy
No, most heat comes from the Sun.
3 / 5 (4) Mar 21, 2011
It is a wonder that these geoengineering scientists can fit through the front door because their heads are so gigantic.
not rated yet Mar 21, 2011
Some of the heat comes from the friction between Stefen and Svante. :) Tell them to come back from wherever they are, or at least make a comment here on Physorg. :)
3 / 5 (2) Mar 22, 2011
We're screwed if anyone buys into geoengineering. It'd be much cheaper to develop better 'green' technologies than to dump trillions of dollars into something that's guaranteed to have unwanted side effects of an unknown scale on our planet.
3 / 5 (4) Mar 22, 2011
I have to put my stupidity alarm on vibrate because if it was on audible this so-called technology would make it go off so loud it would give me permanent hearing loss.
1.3 / 5 (3) Mar 22, 2011
PinkElephant thank you for trying to talk sense into these people. but also you people need to tweak your view. here it is Don't just go for 1 solution. do a lot of solutions otherwise if that one fails than your screwed but if you did a lot of different solutions than if one or two fail you still have more. geoengineering, alternitive energy, forestation, endangered species act, de-acidifiying (spelling) the ocean should all be put into practice at the same time to combat this. because like it or not we are warming because of our co2 and we need to stop it.
2.6 / 5 (5) Mar 22, 2011
There has been 1 degree F of warming, up from from one of a handful of cool periods of the last 10k years. Everyone can relax. We're still far below the average of the last 10k years.

However, we will need geo-engineering - to manufacture warmth when the next ice age starts.
5 / 5 (1) Mar 22, 2011
Politicians.. they are going to do it anyway. scientists in this area should take notice of what happens when science takes the place of nature. We do not know enough about our planet to take over its bodily functions.
3.7 / 5 (3) Mar 22, 2011
There has been 1 degree F of warming, up from from one of a handful of cool periods of the last 10k years.
It's not what has happened so far, but what we're front-loading for the next couple of centuries. Earth's climate has a large time constant (oceans take a long time to heat up -- because water has a high heat capacity, and it circulates); even with current greenhouse gas concentrations (without pumping any more carbon into the atmosphere), we're locked into another degree or two of warming. With continued emissions of fossil carbon, we're setting ourselves up for a climate that hasn't existed on our planet for millions of years.
we will need geo-engineering - to manufacture warmth when the next ice age starts.
That won't be for another couple of millennia.
not rated yet Mar 26, 2011
Out of the options listed, the only one that could be expected to have the least "unintended consequences" is reforestation- which would be a good thing, any way you slice it.

In the mean time, only alternative power generation(solar, wind, wave, et al) has a prayer of providing us with enregy without exacerbating the problem.

Rather than resort to these geoengineering projects(which, IMO) are mainly only being bruited for the simple reason that they will generate huge profits for the groups that deploy them -why not go direct, space-based solsr power capture, with laser or microwave transmission to earth? There are plenty of places where this could be accomplished with minimal to zero risk, especially with adequate safeguards, and the cost would likely be less than deploying all these other geoengineering projects- while the benefits would be orders of magnitude greater.

not rated yet Mar 27, 2011
And if some or all of these harebrained schemes are implemented and the globe is plunged into a deep ice age

That's why we should only do stuff that can be undone. Seeding the oceans is one scheme that cannot be undone if it goes wrong - so we should not do it.

Using space based solar shades might be worth a try, though. If things work out too well we can always move them.

Reforestation isn't really a solution because trees are, over their life cycle, carbon neutral. The only thing that would actively pull carbon out of the air would be plankton which settles to the ground after death and turns into a sediment which does NOT decay aerobically (trapping the carbon). But for the above mentioned reason any kind of 'seeding the oceans with nutrients' should be a big no-no.

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