Adjusting Earth's thermostat, with caution

November 17, 2014, Harvard University
A composite image of the Western hemisphere of the Earth. Credit: NASA

A vast majority of scientists believe that the Earth is warming at an unprecedented rate and that human activity is almost certainly the dominant cause. But on the topics of response and mitigation, there is far less consensus.

One of the most controversial propositions for slowing the increase in temperatures here on Earth is to manipulate the atmosphere above. Specifically, some scientists believe it should be possible to offset the warming effect of greenhouses gases by reflecting more of the sun's energy back into space.

The potential risks—and benefits—of solar radiation management (SRM) are substantial. So far, however, all of the serious testing has been confined to laboratory chambers and theoretical models. While those approaches are valuable, they do not capture the full range of interactions among chemicals, the impact of sunlight on these reactions, or multiscale variations in the atmosphere.

Now, a team of researchers from the Harvard School of Engineering and Applied Sciences (SEAS) has outlined how a small-scale "stratospheric perturbation experiment" could work. By proposing, in detail, a way to take the science of to the skies, they hope to stimulate serious discussion of the practice by policymakers and scientists.

Ultimately, they say, informed decisions on climate policy will need to rely on the best information available from controlled and cautious field experiments.

The paper is among several published today in a special issue of the Philosophical Transactions of the Royal Society A that examine the nuances, the possible consequences, and the current state of scientific understanding of . David Keith, whose work features prominently in the issue, is Gordon McKay Professor of Applied Physics at Harvard SEAS and a professor of public policy at Harvard Kennedy School. His coauthors on the topic of field experiments include James Anderson, Philip S. Weld Professor of Applied Chemistry at Harvard SEAS and in Harvard's Department of Chemistry and Chemical Biology; and other colleagues at Harvard SEAS.

"The idea of conducting experiments to alter atmospheric processes is justifiably controversial, and our experiment, SCoPEx, is just a proposal," Keith emphasizes. "It will continue to evolve until it is funded, and we will only move ahead if the funding is substantially public, with a formal approval process and independent risk assessment."

With so much at stake, Keith believes transparency is essential. But the science of climate engineering is also widely misunderstood.

"People often claim that you cannot test geoengineering except by doing it at full scale," says Keith. "This is nonsense. It is possible to do a small-scale test, with quite low risks, that measures key aspects of the risk of geoengineering—in this case the risk of ozone loss."

Such controlled experiments, targeting key questions in atmospheric chemistry, Keith says, would reduce the number of "unknown unknowns" and help to inform science-based policy.

The experiment Keith and Anderson's team is proposing would involve only a tiny amount of material—a few hundred grams of sulfuric acid, an amount Keith says is roughly equivalent to what a typical commercial aircraft releases in a few minutes while flying in the stratosphere. It would provide important insight into how much SRM would reduce radiative heating, the concentration of water vapor in the stratosphere, and the processes that determine water vapor transport—which affects the concentration of ozone.

In addition to the experiment proposed in that publication, another paper coauthored by Keith and collaborators at the California Institute of Technology (CalTech) collects and reviews a number of other experimental methods, to demonstrate the diversity of possible approaches.

"There is a wide range of experiments that could be done that would significantly reduce our uncertainty about the risks and effectiveness of solar geoengineering," Keith says. "Many could be done with very small local risks."

A third paper explores how solar geoengineering might actually be implemented, if an international consensus were reached, and suggests that a gradual implementation that aims to limit the rate of climate change would be a plausible strategy.

"Many people assume that solar geoengineering would be used to suddenly restore the Earth's climate to preindustrial temperatures," says Keith, "but it's very unlikely that it would make any policy sense to try to do so."

Keith also points to another paper in the Royal Society's special issue—one by Andy Parker at the Belfer Center for Science and International Affairs at Harvard Kennedy School. Parker's paper furthers the discussion of governance and good practices in geoengineering research in the absence of both national legislation and international agreement, a topic raised last year in Science by Keith and Edward Parson of UCLA.

"The scientific aspects of geoengineering research must, by necessity, advance in tandem with a thorough discussion of the social science and policy," Keith warns. "Of course, these risks must also be weighed against the risk of doing nothing."

Explore further: Experts propose new structure for regulation of geoengineering research

More information: "Stratospheric controlled perturbation experiment (SCoPEx): A small-scale experiment to improve understanding of the risks of solar geoengineering" rsta.royalsocietypublishing.or … .1098/rsta.2014.0059

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teslaberry
2 / 5 (8) Nov 17, 2014
when the government begins mass subsidies for poisoning the atmosphere in order to 'save us all'. you know that 'climate science' gas become an excuse for total wacko behavior and something is seriously wrong.

any scientist worth their salt will come out against such lunacy in a very strong and vocal manner.

these wackjobs who want to poison the atmosphere are a menace and at the very least poisoning the well of respectable science with lunacy equivalent to perpetual motion machines and cold fusion. at worst, they may succeed in getting millions of dollars to poison the air we breathe in order to 'save us'.
craig james
1.8 / 5 (10) Nov 17, 2014
We have had almost two decades of flat lined global temperatures in spite of huge increases in greenhouse gasses. The present AGW hypothesis is on very shaky legs and needs a serious review. To spend billions upon billions of dollars on a small temperature variation (0.8C) over a century is reckless and wasteful. To use this small temperature variation to tax workers and redistribute wealth is in almost no ones best interest
runrig
4.3 / 5 (11) Nov 17, 2014
We have had almost two decades of flat lined global temperatures in spite of huge increases in greenhouse gasses. The present AGW hypothesis is on very shaky legs and needs a serious review. To spend billions upon billions of dollars on a small temperature variation (0.8C) over a century is reckless and wasteful. To use this small temperature variation to tax workers and redistribute wealth is in almost no ones best interest

http://www.skepti...2011.jpg
fortranfixer
3.7 / 5 (7) Nov 17, 2014
In my opinion, there isn't enough political will to make meaningful cuts in carbon dioxide emissions in the available time period. That means, in the short-term, atmospheric cooling is the only kludge available to control CO2 caused warming. Direct carbon dioxide removal is a possible long term kludge to avert warming.
gkam
3 / 5 (14) Nov 17, 2014
craig, look up the ten hottest years in history and report back to us.

And you are apparently unaware of the link between ocean heat and the severity of storms.

gkam
2.8 / 5 (13) Nov 17, 2014
teslaberry needs a good course in Environmental Economics, to see how wrong he is, from an economic perspective.
Captain Stumpy
4.6 / 5 (9) Nov 17, 2014
to tax workers and redistribute wealth
@craig_james
fear and stupidity will not save you from reality, nor will ignoring the overwhelming amount of science that says you are wrong
tell you what... there is plenty of evidence of AGW (not a hypothesis) so, given your post, you must have some way of refuting the science, so i will post some basic science, and you can give equivalent evidence for refute, ok?
http://www.scienc...5682/362
http://www.nature...65a.html
http://rspb.royal...20141856
here are some good articles that you cannot even refute: http://www.epa.go...dity.pdf
http://www.azimut...fication
http://www.epa.go...ity.html
or refute any of these papers: http://scholar.go...as_sdtp=
KDK
1.9 / 5 (9) Nov 17, 2014
By vast majority you mean the 97 percent of the 35 percent that participated in the survey that is typically sighted? One in which many of the 97 percent did agree with the human causation part! Are you a science publication or a Leftist shill organization!
Captain Stumpy
4.5 / 5 (8) Nov 17, 2014
The present AGW hypothesis
@craig_james
quit trying to reason from fear and ignorance
research science and open your eyes before commenting
you are on a science site, so i suggest trying to learn some REAL science: http://ocw.mit.edu/index.htm
there are a LOT of people pouring lots of $$ into trying to undermine the science, so don't believe anything you read unless it comes from a reputable peer reveiwed source: http://www.drexel...nge.ashx
don't fold to peer pressure: http://arstechnic...nformed/
or religion: http://sgo.sagepu...13518932
http://phys.org/n...firstCmt
lastly... spouting fringe political BS is not going to help anyone
quit being a pert of the problem and be a part of the solution
ubavontuba
1 / 5 (6) Nov 17, 2014
http://www.skepticalscience.com/graphics/Total_Heat_Content_2011.jpg
And yet you still have yet to explain how a little extra CO2 in the atmosphere is supposedly warming the oceans, without warming the atmosphere or land surfaces. Is it magic?

ubavontuba
1 / 5 (5) Nov 17, 2014
look up the ten hottest years in history and report back to us.
Hmm... this looks kinda' warm:

http://en.wikiped..._Maximum

...Brrr-r-rr-r. That made me want to put on some warm jammies and snuggle by the fire, as by comparison, we're deep within an iceage!

you are apparently unaware of the link between ocean heat and the severity of storms.
What "severity of storms," where?

GSK2000
1.5 / 5 (8) Nov 17, 2014
@Captain Stumpy,

Your first link and second links: this from the Sripps Institute:
"…natural variability has prompted the suggestion that "an appropriate null hypothesis may be, until evidence is obtained to the contrary, that major biogeochemical processes in the oceans other than calcification will not be fundamentally different under future higher CO2/lower pH conditions"
http://www.ploson....0028983

Your third link is more of the same 'acidification' of an alkaline mass. The study subjected specimens to ever decreasing alkalinity until the organism died. Who'da thunk? The problem is that the Scripps study was actual data from the real world; "
None of your links says anything about AGW.
GSK2000
1.4 / 5 (9) Nov 17, 2014
@Captain Stumpy your link asserts $64 million per year for this alleged counter movement. Doesn't even get close to the AGW cabal:

The Global Landscape of Climate Finance 2013: global climate finance flows have plateaued at USD 359 billion, or around USD 1 billion per day...
http://climatepol...ce-2013/

Thats over 5000 years at $64 million per year, doesn't really stack up, does it Stumpmiester?
gkam
2.8 / 5 (11) Nov 17, 2014
Why is the lunatic fringe on this topic limited to the United States? The Deniers I know were the first to scream "WMD!", . . . . then, to take the Bush stickers off their cars. They are not Bush Voters any more, they are Tea Folk, who don't know nothin' about no Bush Wars.
Captain Stumpy
4.4 / 5 (7) Nov 18, 2014
Your first link and second links:
@GSK2000
your study in no way refutes the first two links
what is the point you are trying to make here?
next-
The problem is that the Scripps study was actual data from the real world
all my links have empirical data
None of your links says anything about AGW
are you stupid or blind?
REALLY? so... what part of
Most carbon dioxide released into the atmosphere as a result of the burning of fossil fuels will eventually be absorbed by the ocean
or
Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans...Current atmospheric concentrations are now approaching 380 ppm as a result of the industrial and land use activities of humankind. In the past few decades, only half of the CO2 released by human activity has remained in the atmosphere; of the remainder, about 30% has been taken up by the ocean and 20% by the terrestrial biosphere
did you miss, misunderstand or simply ignore
Captain Stumpy
5 / 5 (6) Nov 18, 2014
None of your links says anything about AGW.
@GSK2000
here is another one for you to read: http://www.scienc...abstract
i hope that one opens your eyes up a lot more... because you seem to be intentionally ignoring a lot of data here
specifically, like how CO2, ocean acidification and more is caused by AGW and CO2, which IS stated in the articles i linked
Thats over 5000 years at $64 million per year, doesn't really stack up, does it Stumpmiester?
you are going to argue the $$ vs the science?
really?
personally, your fear of the future is strange to me, and your ignoring the evidence stranger still... it is not like you will have to personally sign over 64million yourself
also... your political argument is not relevant to me anyway as i don't care

argue politics with Ryg

PS- hey ZEPHIR
still lurking and ignoring the science?
still no EVIDENCE?
LMFAO
a one star from you means i am doing something right!
Mike_Massen
4.2 / 5 (5) Nov 18, 2014
ubavontuba STILL refusing to get an education in Science ie Heat & specific heat
http://www.skepti...2011.jpg
And yet you still have yet to explain how a little extra CO2 in the atmosphere is supposedly warming the oceans, without warming the atmosphere or land surfaces. Is it magic?
For U yes because you ubavontuba are a mere simpleton. Besides land has warmed but as its heat capacity is lower it loses some of it to - guess what - the material that has higher heat capacity & within issues of equilibria & mixing & complicated by long wave radiation ie Not simple etc etc

For those mature interested in an education its a wee bit more complex as U should know oceans have 4000x heat capacity of atmosphere AND from what we KNOW of heat, it moves from hotter to cooler.

Or are you claiming ubavontuba the oceans are at a higher temperature than the atmosphere ?

Science does seem too complicated for you ubavontuba !
Selena
Nov 18, 2014
This comment has been removed by a moderator.
antigoracle
1 / 5 (4) Nov 18, 2014
a way to take the science of geoengineering to the skies

Do you really want these morons messing with the environment?. Just look at their track record:
Bio-diesel from food crops, which not only sent prices skyrocketing, but as it turns out is more toxic to the environment and us.
Multi-billion dollar solar and wind farms, that not only fail to meet expectations, but are killing birds by the millions.

These morons foresight only goes as far as their bank accounts.
howhot2
5 / 5 (3) Nov 22, 2014
AL GORW once said, "Today we're dumping 70 million tons of global-warming pollution into the environment, and tomorrow we will dump more, and there is no effective worldwide response. Until we start sharply reducing global-warming pollution, I will feel that I have failed.

@antigoracle says "Do you really want these morons messing with the environment?" And then complains "Bio-diesel from food crops, which not only sent prices skyrocketing, but as it turns out is more toxic to the environment and us.
Multi-billion dollar solar and wind farms, that not only fail to meet expectations, but are killing birds by the millions."

"Get a brain moran!" Quote from a teaparty protester sign.

You deniers are total idiots that we science people ignore. We know what we are doing, and you don't and your ignorance proves the point that you can not rule fairly. Liberals will just have to shove this down your throat like it or not!
ryggesogn2
1 / 5 (2) Nov 22, 2014
"Such controlled experiments, targeting key questions in atmospheric chemistry, Keith says, would reduce the number of "unknown unknowns" and help to inform science-based policy."

What 'unknown unknowns'?
AGWites claim they know all.
howhot2
5 / 5 (3) Nov 22, 2014
Typo; that was AL GORE, not GORW. It is a very serious question being asked in the article. Should we engineer the atmosphere to undo man-made global warming? Given the severity of the destruction done by man on the global temperature balancing systems from excessive fossil fuel burning, should we engineer systems to remove and sequester CO2 (The primary cause of global warming) from the atmosphere and ocean?

Given the ignorant response of the denier's I say full speed ahead on engineering a change. Let science rule!
antigoracle
1 / 5 (3) Nov 22, 2014
AL GORW once said, "Today we're dumping 70 million tons of global-warming pollution into the environment, and tomorrow we will dump more, and there is no effective worldwide response. Until we start sharply reducing global-warming pollution, I will feel that I have failed.

Wow!! HowTurd surfaces from the bottom of it's cesspool of ignorance with the gem above.
https://www.googl...ypocrite
howhot2
5 / 5 (3) Nov 22, 2014
AL GORE also said "There is the natural tendency that all of us are vulnerable to, to deny unpleasant realities and to look for any excuse to push them away and resolve to think about them another day long in the future."

Which is exactly what you are doing @antigoracle. Push your recognition of global warming fact to another time. Deny... reality. Deny... fact. Deny... Science.


antigoracle
1 / 5 (1) Nov 22, 2014
And what are you denying?
How your False "Profit" Al could take advantage of your ignorance, preaching to you about the "sins" of others while living a life of hypocrisy. Seriously howhot, if that won't open your eyes then nothing will.
http://www.popula...ing.html

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