Engineering the atmosphere to forestall the worst results of global warming was once considered too hubristic to seriously contemplate. The grim prospects for passing an international climate-change treaty have changed that. Last year the National Academies of Science in the U.S. and the Royal Society in the U.K. both convened meetings on geoengineering. The schemes generally fall into two categories—CO2 capture (pulling carbon dioxide from the air) or solar-radiation management (reflecting sunlight)—but it’s a form of the latter, which involves using airplanes or long hoses to pour sulfate aerosols into the lower stratosphere, that’s the most audacious.
Once in the stratosphere, the theory goes, the aerosols would reflect some solar radiation and prevent a devastating rise in the average global temperature. The theory is not crazy. In 1991, after the eruption of Mt. Pinatubo in the Philippines spewed 20 million tons of sulfur dioxide into the stratosphere, the average global temperature dropped by about 1° F from 1991 to 1993. But administering such a program well would require an unprecedented degree of international coordination and funding, and the odds of miscalculation are high.
And the potential negative consequences are, in the worst case, extreme.
Consider a hypothetical scenario in the year 2030. Severe storms and floods, prolonged droughts and wildfires have become commonplace. China has become the world’s largest economy, and two decades of coal-fired hyper-growth have overwhelmed the country’s advances in clean energy and efficiency. It is losing nearly 2,000 square miles a year to desertification, at a cost of $10 billion annually. Its eastern agricultural regions, which once fed a substantial fraction of the world’s population, have seen water tables decline precipitously from drought and overuse. Food shortages have become widespread.
Under pressure to address climate change yet unable to slow growth without risking domestic unrest, the Chinese government pressures the U.S. and the European Union to cooperate on a program of geoengineering. It proposes launching military aircraft into the lower stratosphere to release several million tons a year of sulfur-based gases, with the intent of reflecting sunlight and blunting the rise in global temperature. The U.S. and E.U. balk, and China goes ahead alone. Lacking the power to stop it, Western countries look on in dismay as Chinese jets take to the sky.
The U.S. soon has no choice but to step in as a partner, if only to stabilize the delivery and geographic dispersal of the particles. With the world’s two most powerful nations now perceived as “in charge” of the climate, other countries suspect that they are manipulating the weather to their own benefit. Every flood or fire is seen as a Sino-American responsibility.
After about five years, scientists begin to realize that blocking sunlight causes far worse side effects than anticipated. Less heat has meant less evaporation and less water entering the hydrological cycle. The Asian and African monsoons bring less and less rain, leading to droughts that disrupt food supplies for billions of people. Meanwhile ocean acidification, which sun-blocking does not mitigate, has begun to shut down major fisheries.
After 10 years, pressure from battered countries is overwhelming. To avert war, China and the West abandon their geoengineering programs, despite the frantic protests of their scientists. And what happens next is even worse.
Within two years, atmospheric sulfur levels plunge to pre-geoengineering levels, and the global average temperature, artificially suppressed for a decade, comes roaring back. Once again, patterns of precipitation and temperature shift abruptly, wiping out the efforts of the world’s farmers to adapt to the changes of the decade prior. The high temperatures free billions of tons of methane—a greenhouse gas 30 times as potent as CO2—from the melting Arctic permafrost, which in turn accelerates warming. The process becomes self-reinforcing and unstoppable. By 2050, starvation, disease and near-constant armed conflict have devastated the developing world. India and Pakistan, starving, desperate and paranoid, are on a nuclear hair trigger. Then a bomb goes off in India, and things really start going badly.
Avoid having to even contemplate geoengineering by keeping atmospheric CO2 levels low—ideally, to 350 ppm.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.


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What about something way more expensive and ambitious, yet more controllable or even abortable? I'm talking about space based solar shades. You don't need the earth's electromagnetic protection for something of that nature so you could place it in the first Lagrangian Point. You could even use the shade to cool the water ahead of tropical storms in order to drain their power. You reverse desertification is other places.
i like the idea featured here a while ago something like fans that blow air through h2so4 to reduce co2
some artificial gases which are heat reflectors and not conductors ejected into space.
this is sure to help reduce global warming.
@dhruv2202
because you would need to release the gas accross the entire or bit of the sun, that would be an amazing amount, probably more matter than the entire mass of the earth itself...... maybe......
Sigh...
First off, this sort of geo-engineering would not be expensive... the option was discussed in the second Freakonomics book, where the cost was estimated to be in the seven-figure range (when you need to put gas in the atmosphere, you don't load it into jets and fly them around like crop-dusters... you stick a balloon on the end of a hose and pump it up there).
@recsnfx--kindly explain how something can be both 'way more expensive' and 'way more affordable'?
What would certainly require an "unprecedent amount of international coordination and funding" would be the alternative you seemingly suggest, i.e. requiring every nation on earth to act directly against its own immediate self-interest and the the good of its people by adhereing to an economic suicide pact, like the Kyoto Treaty.
This entire article is nothing more than an exercise in neophobic hand-wringing. Of course the worst case scenario is terrifying.. you imagined it for that express purpose. The reality of the matter is that geo-engineering appears to offer the best cost to benefit ratio--even when (realistically) considering the risks involved.
As for the nuclear war bit... really? REALLY??
"Global warming", or "climate change", whatever, if the earth is warming up, that means more water will evaporate, creating more clouds and precipitation. but more clouds also means more heat will be reflected back into space. not only will the earth warming help expand lush tropical climates because of precipitation and temperatures, but it will also cool itself in time.
The Dune series by Frank Herbert is a great read if geo-engineering interest you. The underlying plot being the transformation of the desolate desert planet.
@marcopoplo1613
Exactly. Earth has it's own heating and cooling cycles. It would be ironically hilarious and tragic if the tree huggers ended up being the cause of the extinction and destruction of our ecosystem as we know it. Honestly though, it wouldn't be all that surprising.
The idea of puny man trying to control nature is laughable. Nature always wins don't you know?
You cannot effectively control temperatures using chemicals whose reactions with other gases is not totally known--there are just way to many parameters to consider.
A better way is to block the sunlight with panels in space designed to capture the sunlight and send it down to earth via microwaves. Then you kill two birds with one stone--you have extra 'free' energy and you cool the earth AND you can control the cooling by adjusting the number of panels blocking the sun (just rotate them 90 degrees to allow the sun through).
That's the same way that we should be terra forming the planet Venus for future colonization by blocking almost ALL of the sun for a few million years until it's surface temperatures are reduced to earth-like levels or below so that volcanic activity will decline over a few more million years and then they begin trying to adjust the atmosphere to add oxygen, etc. It would take hundreds of millions of years to accomplish a stable Venus with an air breathing atmosphere but it can be done with some imagination!
So let me get this straight...
Those people claiming that we humans are causing climate change want to implement a method to...cause climate change?
A bit hippocrital, no?
I agree with Army....there is a very good chance they screw it up worse than they think it is now.
Case in point...
"You are all killing the trees by using them for shopping bags! We must force people to use PLASTIC"
Yeah, hows that working out for ya, jerk-wads?
It amazes me how the human race survived this long.
Ha ha ha HA HAAA! Thanks for the funny musings. Yes, geoengineering is fraught with unintended consequences. Just as funny was the "how we can do better" suggestion at the end. Is 350 ppm a magically selected number? Did you use Harry Potter's School Sorting Hat to divine 350 as the Golden Number? Perhaps Chinese mythology? Arab numerology anyone? Ha ha ha HAAAA! I crack myself up.
For more humor visit the 350.org website. Funny stuff, especially when you consider:
1. there's nothing wrong with higher atmospheric CO2 saturation, looking back millions of years.
2. CO2 has a negligible warming effect compared to other factors (like water vapor) and its effect is logarithmic meaning it takes a LOT of CO2 saturation to produce very little (theoretical) warming.
3. CO2 saturation increased and decreased naturally in the past (geologically speaking) before humans were around. No one knows why, although it appears to be CAUSED by warming and cooling of the planet, perhaps because of increasing and decreasing plant production.
4. reducing CO2 output to bring us back to 350 ppm (that magical number) would be stupendously costly...unless the entire planet collectively agreed to revert to pre-industrial living standards for many decades. Think inefficient agricultural methods (which would starve the majority of humanity) and all the other glories of pre-industrial life.
It's likely that the explosive growth in human population and industry over the last century is a significant contributor, but, well, so what? We don't know that CO2 is a problem. In fact CO2 is essential to photosynthesis.
I have an even better "how can we do better." Do nothing. World population is projected to peak in the next 50 years or so and human CO2 output will naturally decline after that, long before it ever becomes a problem. Even if we enacted global carbon-emission-limiting legislation before then, the world population will peak before it has any effect.
Plus, since flourishing free-market economies always produce increasingly efficient means of doing things, CO2 output per unit of energy used will naturally decline. So I take it back. Let's do something. Let's promote democracy and free markets around the world.
Why do you have to blame China for causing starvation, death, and disease. Any country could make the choice to try to control global warming like this, even the United States.
@futurewiz14526
I didn't interpret the article as being a criticism of China as much as just speculating a disaster scenario where China played a bit part, given it's population and economic development. You do often hear commentators, politicians and the media seeking to put alot of the responsibility on China, India, Brazil, and other large developing nations for the increase in per capita emissions as a result of their development, without taking account of the disproportionate per capita emissions of citizens in the US and other "developed" countries. Given that the per capita emissions of an American, for example, are so many multiples of the emissions of a Chinese or Indian person. My own personal view is that we need to put more emphasis on the per capita metrics than country by country metrics, though both are important - but obviously that's the last thing politicians will do, specially in the US.
@Americano
I think your use of "per capita metris"is flawes if anything it proves the points of the article, once the country becomes as you put it "developed" they will reach the levels we use but instead of it being 310 mil. it will be 4-5 times as many, if our "per capita" emissions is less than 2 even 3 times less than chineses citizens as whole contry they are still creating more emissions. this goes for India as well both with populations of 1 Bil. plus. In the next 10-15 years i see out emmissions as whole country dropping like a rock. Electric cars, easier and cheaper access to solar panels. Maybe even (fingers crossed)bringing back nuclear technology. In essences i feel that you can make bigger gains by focusing on a group rather than the person. try changing a person, the try changing a person in a group that is changing.
The problem with the 'conservation only' approach which so many hippies* promote is that it clearly not working, as there are too many indivduals who would need to change and too many people with a vested interest not to change.
But the hippies will continue to bang their heads against the wall rather than looking for alternative approaches...as these alternative approaches are put into practice by either 'Governments' or 'The Corportations (Man!)', and the hippies don't get that warm fuzzy feeling of saving the world...
It is this warm fuzzy feeling that hippies* get from either making the changes themselves, or chastising others for not changing that motivates too many of them, and blinds them to other approaches like this!
*note I don't use the term 'environmentalists intentionally
So, a huge eruption, likely equal to what a world based economy could produce as its sole goal dropped the temperature 1 degree.
True, a large enough increase would be bad (another "Year without a Summer" type event). That would require MASSIVE overshoots, however, and would be swiftly rectified by reducing the amount of sulfer pumped into the air.
Since global climate, however, is incrimental in its change and constantly variable, where would your baseline be?
No government would ever spend that much money for so little change with such unreliable outcomes.
The entire industrial history of MANKIND has barely been shown to have an impact on climate. The idea that we could not only take over the wheel of that big rig, but make it turn a 180, is ridiculous.
I'm going to wonder a few things out loud...
Wouldn't a warmer world mean that the hydrological processes of the earth (evaporation to clouds, rain to earth, groundwater buildup, rivers to ocean) would increase, providing a faster pump for our water use?
Hasn't the earth been completely ice free for the vast majority of its existence as a planet (except for the 5 ice ages in history, including the one we are in now)? And hasn't the current intelligent life of mankind only developed in one of the relatively short and warm interglacial periods that started about 15,000 years ago?
Which would be worse: A warmer and wetter world where the areas that receive moisture gradually shift over time, or a colder world where much less of the planet is habitable and where much less food can be grown?
Seeing as how we are in a short interglacial period in an ice age, would it be better to err on the side of letting the planet warm, or cooling it off unexpectedly?
Is it plausible that basic intelligent life developed in some previous warm interglacial periods, only to be killed off and destroyed by the return of the freeze?
Just feels like to me that we can live and adapt to a warmer world easier than a colder one. And in a several thousand years (should we survive that long), we might be frantically trying to figure out how to keep our warm interglacial period from ending and killing us all.
JAGUAR6CY
The introduction of sulfate aerosols, commonly known as Budyco's Blanket, is a simple, cheap, controllable and reversible solution. But deploying it is unlikely. It has no inherent support or advantages. It offers no hope of increased government taxation and does nothing to halt the growth of the United States economy. Those two factors alone will eliminate any chance of even testing the Blanket.
It's already going on and nobody admits it. chemtrails are real. they are using this for both weather control, cooling, and to aid the HAARP program.
@marcoreid
Good post. I would like to add that a cooler world would require more resources to keep its occupants warm. And in an age of declining resources that would not be a good thing.
Check Newsweek April 28, 1975. Global Cooling was going to kill us unless we put carbon black on the polar ice caps.
It's hard to take these scientist seriously
when they try to change the environment to
suit their needs. This is why Global Warming
scientist can never be taken seriously.
Heres a suggestion for the author, David Roberts and, all others that believe geoengineering is not happening, yet. Take your lunch outdoors and look up.
I kept reading about chemtrails and geoengineering and all I thought was, these folks are losing it. Then one day, I looked up. I saw these planes spraying the sky in a grid pattern. By the time they were finished my sky looked like a checker board. However, about 30 minutes later as the trails grew fatter and fatter the sky looked like a bowl of milk and the sunshine couldn't get through.
I've started taking pictures and keeping a diary. These guys mean business. However I believe there is more to it than geoengineering because in January we had 9" of snow on the ground here in Georgia that closed businesses and schools for a solid week. We very much needed the sun to do its job and thaw this mess. They didn't seem to agree because everyday they came in and filled the sky with artificial clouds.
I've read the lame excuses, "Its just contrails caused by more planes being in the sky." That's pure BS, planes follow a set path in the sky, what I'm seeing is chaos in the sky. Some days they spray grids, some days my sky looks like stripped fabric, Sunday they were cutting the spray on and off making it look like the divided white lines that strip lanes on a highway. Other days its a mess with no design at all.
They start out small then grow to the point where they no longer look like they came from a plane at all. To fully understand you have to watch them spray and then watch to see how the "contrail" changes. Contrails have never lasted for hours. They spray at night too, to the point they render my telescope useless.
So, Mr. Roberts, for the sake of your readers and for the sake of honesty and our planet, please look into this. Look up, do some research and then let us know what you see and think. They are destroying our planet and our health.
BTW...last week the CBS station in Atlanta did a story on this and their system was overwhelmed with people sending in their photos. The people that look up know.
Thank you.