Researchers find unintended consequences of geoengineering to slow climate change

September 9, 2015 by Mark Dwortzan
A large phytoplankton bloom off the coast of Portugal. Credit: Jacques Descloitres/NASA Goddard Space Flight Center

Like the leaves of New England maples, phytoplankton, the microalgae at the base of most oceanic food webs, photosynthesize when exposed to sunlight. In the process, they absorb carbon dioxide from the atmosphere, converting it to carbohydrates and oxygen. Many phytoplankton species also release dimethyl sulfide (DMS) into the atmosphere, where it forms sulfate aerosols, which can directly reflect sunlight or increase cloud cover and reflectivity, resulting in a cooling effect. The ability of phytoplankton to draw planet-warming carbon dioxide (CO2) from the atmosphere and produce aerosols that promote further cooling has made ocean fertilization—through massive dispersal of iron sulfite and other nutrients that stimulate phytoplankton growth—an attractive geoengineering method to reduce global warming.

But undesirable climate impacts could result from such a large-scale operation, which would significantly increase emissions of DMS, the primary source of sulfate aerosol over much of the Earth's surface, and a key player in the global climate system. Now, in a study published in Nature's Scientific Reports, MIT researchers found that enhanced DMS emissions, while offsetting greenhouse gas-induced warming across most of the world, would induce changes in rainfall patterns that could adversely impact water resources and livelihoods in some regions.

"Discussions of geoengineering are gaining ground recently, so it's important to understand any unintended consequences," says Chien Wang, a co-author of the study and a senior research scientist at MIT's Center for Global Change Science and the Department of Earth, Atmospheric, and Planetary Sciences. "Our work is the first in-depth analysis of that has highlighted the potential danger of impacting rainfall adversely."

To investigate the impact of enhanced DMS emissions on and precipitation, the researchers used one of the used by the Intergovernmental Panel on Climate Change (IPCC), which simulates the evolution of and interactions among the ocean, atmosphere, and land masses. Running simulations that compared two scenarios, they found mixed results. In one simulation they implemented a scenario known as RCP4.5 that is used by the IPCC to project , aerosol emissions, and land-use change based on policies that lead to moderate mitigation of over the course of the 21st century. They also used RCP4.5 in a second simulation, with one exception: DMS emissions from the ocean were increased to the maximum feasible levels, or about 2.5 times higher.

The simulations showed that enhanced DMS emissions would reduce the increase in average global surface temperature to half that of the RCP4.5 scenario, resulting in a net increase of 1.2 degrees Celsius by 2100. But the cost would be a substantial reduction in precipitation for some regions.

"Generally, our results suggest that the cooling effect associated with enhanced DMS would offset warming across the globe, especially in the Arctic," says the study's first author, Benjamin Grandey, a senior postdoc in Wang's group who configured the model simulations and analyzed the data. "Precipitation would also decline worldwide, and some parts of the world would be worse off. Europe, the Horn of Africa, and Pakistan may receive less rainfall than they have historically."

Grandey and Wang warn that the lower rainfall could reduce water resources considerably, threatening the hydrological cycle, the environment, and livelihoods in the affected regions.

The researchers hope their investigation will inspire further studies of more realistic ocean fertilization scenarios, and of the potential impacts on marine ecosystems as well as human livelihoods. Further research will be needed, they say, to fully evaluate the viability of ocean fertilization as a geoengineering method to offset greenhouse gas-induced warming.

Explore further: Ocean acidification amplifies global warming (Update)

More information: "Enhanced marine sulphur emissions offset global warming and impact rainfall." Scientific Reports 5, DOI: 10.1038/srep13055

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34 comments

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dogbert
3 / 5 (16) Sep 09, 2015
Hubris. We don't understand climate, cannot predict it and yet we talk about geoengineering as if we knew all about it.

We are letting apes play in the missile control room. Insane.
antigoracle
2.5 / 5 (11) Sep 09, 2015
We are letting apes play in the missile control room.

OK. Firstly, that's an insult to apes. Secondly, these morons are so committed to their dogma, that they are prepared to alter reality to make their doom and gloom happen. And why shouldn't they? When they totally screw us, they already have the perfect excuse. It wasn't them, they were just too late.
Eddy Courant
2.6 / 5 (10) Sep 09, 2015
What antigoracle said.
axemaster
4.6 / 5 (14) Sep 09, 2015
Hubris. We don't understand climate, cannot predict it and yet we talk about geoengineering as if we knew all about it.

We are letting apes play in the missile control room. Insane.


That's because we're letting scientifically illiterate politicians run things. If scientists had the authority to set policy we would never have gotten into this mess in the first place.

And it's entirely predictable that politicians are going to end up advocating for geoengineering. Their oil buddies will demand it, and they'll implement it. Despite the fact that it's a waste of time and money (your tax dollars, remember?).

The real problem with geoengineering isn't the side effects, which would probably be severe. The issue is that it does nothing to solve the underlying problems - CO2 levels will continue to increase, and ocean acidification will get worse and worse. And if you ever turn off the geoengineering, the full brunt of the warming comes back.
nevermark
4.5 / 5 (8) Sep 09, 2015
We don't understand climate, cannot predict it and yet we talk about geoengineering as if we knew all about it.

Secondly, these morons are so committed to their dogma, that they are prepared to alter reality to make their doom and gloom happen.

How does someone read an article where scientists look, find and report on major risks of geoengineering then conclude they are advocating for doing something risky? These nonsensical unscientific comments appear so reliably, it has to be intentional.

The only way to know anything and make wise decisions is to research options. But don't expect a thank you from the anti-science crowd.
FritzVonDago
1.7 / 5 (11) Sep 09, 2015
Why cant we do real science anymore? This so-called global warmest neo-research is spending funds we could use in other areas that is more important......Climate Change neo-research is simply political HOGWASH!
Bongstar420
2.1 / 5 (7) Sep 09, 2015
They need to show recent paloehistory (when the continents were arranged like today) where CO2 levels correlated with world wide reduced rain fall...

If you look at temperatures, Cold is dryer than Warm
greenonions
4.1 / 5 (9) Sep 09, 2015
Fritz
This so-called global warmest neo-research is spending funds we could use in other areas that is more important


I feel the same way about military spending. I would much prefer us to put our resources into science. I guess we both have to live with the reality that we don't get to make these choices.
howhot2
3.7 / 5 (3) Sep 09, 2015
We have the knowledge. We have the engineering and technology. We have the cojones. We can do this! All in favor say Aye!

tommo
3 / 5 (4) Sep 09, 2015
A private person dumped tons of iron sulfite near shore in the Pacific NW and it was a disaster irrc, and biologists are still angry about it, I suggest that this team wasn't aware of this incident perhaps?

In any case ocean acidification will soon make it a no-go, we're killing carbonate shelled plankton and doing that takes the entire ocean food-chain down.

The shellfish industry has already been impacted by this with a 6-year period when oyster spat growers got zero new oysters until with biologists & systems from UW & NOAA found it was upwelling events tipping the scale of pH such that larvae couldn't produce their first shell to then sink to the bottom.

We need to end the Steam Age, and run biodiesel made from sewage for transportation & heating fuel, get clever at reducing soot from doing that & stop being stupid by doing nothing in the rich countries, they are who needs to do this not developing countries.

Only 3-5% of society produces 60-80% of emissions.
classicplastic
3 / 5 (4) Sep 10, 2015
Well, you can't make an omelette without breaking eggs. It would be a lot cheaper to mitigate Europe, the Horn of Africa and Pakistan than the entire planet.

You need to do deep-ocean upwelling, which is far less acidic than surface waters. If you can bring down CO2 levels, the acidification will take care of itself. Even if it's a temporary deal from proactive efforts, it will at least buy us more time to get our acts together. Though, I don't think that sewage sludge is a big enough resource to make much of a dent in the need for biofuels.

As for Dogbert's assertion that "We don't understand climate" that only applies to you and your hubris. There are people far smarter than you who do understand it. So, get out of the way!

If we can safely capture and sequester atmospheric enough carbon, it's fairly safe to presume that the planet will restabilize itself, at least if we haven't already hit the tipping point and it's already too late.
antialias_physorg
4.6 / 5 (10) Sep 10, 2015
There's only one approach to geoengineering: Don't.
We're really not at the stage where we can foresee all problems inherent in even minimally complex mechanical systems. No way we can foresee all ramifications about something as complex as climate.

If we really need to interfere with climate for survival then we should do it in a way that can be turned off instantly without any side effects. And the only way I could envision for this would be via space-based shades.
nevermark
5 / 5 (7) Sep 10, 2015
And the only way I could envision for this would be via space-based shades.


That would seem the most environmentally friendly solution, but perhaps a century away from being economically possible. Also, the sheer number of launches to create what would be the largest construction ever (by orders of magnitudes) might have a noticeable impact itself.

And as others point out, this does nothing to solve ocean acidification.

The simplest/cheapest solution (and its neither cheap nor simple) is to cut emissions, since that treats the problem instead of trying to solve individual symptoms one at a time.
antialias_physorg
4.1 / 5 (9) Sep 10, 2015
The simplest/cheapest solution (and its neither cheap nor simple) is to cut emissions

I totally agree - but it ain't gonna happen, because humans (and especially governments) are terrible at making long term decisions. We like to pass stuff on to others to handle (preferrably opposing political parties, so that they can be slagged for 'wasting money')

We're going to run ourselves into the ground until we're so far up a certain creek that unless we make a massive impact within a very short timespan it's game over. CO2 is a problem that sticks around for a century or more once released. So by do-or-die-time it'll be way past the point when CO2 reductions will do any good.
antigoracle
1.8 / 5 (5) Sep 10, 2015
We like to pass stuff on to others to handle

Isn't that exactly what you Chicken Littles are doing. You believe that we are all going to die, so that's probably why you continue to burn fossil fuel like there is no tomorrow. If you don't, then please share with us your sources of "clean" fuel and power, so that we can join you in saving the planet.
qitana
5 / 5 (1) Sep 10, 2015
Another solution is to stop deforestation.
antigoracle
1.4 / 5 (5) Sep 10, 2015
Another solution is to stop deforestation.

Why not start something instead. Replace every tree removed to build your home.
Whydening Gyre
5 / 5 (3) Sep 10, 2015
Another solution is to stop deforestation.

Why not start something instead. Replace every tree removed to build your home.

Mine is brick......
And I've added almost 100 trees in the front half over the last 20 years (that more than cover for the roof and ceiling joists and siding...)
antigoracle
3 / 5 (2) Sep 10, 2015
Excellent work WG, and I am serious. But, I should have been clearer in stating that I meant the plot of land.
MR166
3 / 5 (2) Sep 10, 2015
Yet biofules and the deforestation and soil depletion that it causes is still considered a green solution to energy problems. Green energy and the subsidies that it requires is nothing more than a system developed to enrich political favorites.
MR166
3 / 5 (2) Sep 10, 2015
"Mine is brick......
And I've added almost 100 trees in the front half over the last 20 years (that more than cover for the roof and ceiling joists and siding...)"

Yup, plant a few trees to counteract the small amount of wood housing uses each year. Meanwhile 1000s of acres are cut each year in the US and sent to England for biomass power.

http://www.dailym...ain.html

There is no group more out of touch with reality than the green advocacy.
Whydening Gyre
5 / 5 (5) Sep 10, 2015
Excellent work WG, and I am serious. But, I should have been clearer in stating that I meant the plot of land.

Suburban Chicago was a plain, anyway. With 160 trees of various sorts on my little 3 acres, I'd like to think I've done my share...:-)
(Gawd, I hope that didn't make me sound like Benni...:-)
antialias_physorg
5 / 5 (6) Sep 11, 2015
Isn't that exactly what you Chicken Littles are doing. You believe that we are all going to die, so that's probably why you continue to burn fossil fuel like there is no tomorrow.

You're contradicting yourself within the span of two sentences. Care to go for one?

No, we don't believe we're all going to die (if we did we wouldn't bother arguing). But all evidence points to the fact that if we don't get our act together and make some changes that we'll all be paying for it dearly in the future (some less fortunate ones with their lives, the rest of us with a massively reduced standard of living).

If you don't, then please share with us your sources of "clean" fuel and power, so that we can join you in saving the planet.

Hello? Wind? Solar? Biogas (to a degree)? Hydro? ... Have you been raeding ANY news in the last 30 years at all?
antialias_physorg
5 / 5 (5) Sep 11, 2015
That would seem the most environmentally friendly solution, but perhaps a century away from being economically possible. Also, the sheer number of launches to create what would be the largest construction ever (by orders of magnitudes) might have a noticeable impact itself.

While it would be large I think it would be doable. Note that we only need to shade a tiny percentage. It needn't be a solid installation at all. It could be something based on this:
http://phys.org/n...ror.html
(which needs next to no construction and potentially allows for the dust to be brought into orbit via simpler means (like railguns))

It's not a solution, but it would give us more time.
MR166
2 / 5 (4) Sep 11, 2015
Ah the science continues, global warming will cause cooling.

http://www.msnbc....scenario

Good God!!!, the useful idiots will be up in arms when they find out about this. The only real solution is to stop all human activity on the planet. Perhaps the POTUS plans to create WWIII will solve the problem once and for all.
antigoracle
1 / 5 (4) Sep 11, 2015
Isn't that exactly what you Chicken Littles are doing. You believe that we are all going to die, so that's probably why you continue to burn fossil fuel like there is no tomorrow.

You're contradicting yourself within the span of two sentences. Care to go for one?

Yeah, really didn't expect you to get that one nor the next one.


Hello? Wind? Solar? Biogas (to a degree)? Hydro? ... Have you been raeding ANY news in the last 30 years at all?

So, which of those run your car/transport?
And, of course, none of your power comes from fossil fuels?
antialias_physorg
5 / 5 (6) Sep 11, 2015
And, of course, none of your power comes from fossil fuels?

Well, I buy my money through a plan where the company has to buy as much power from renewables as I use (of course this doesn't mean all my power is renewables all the time, thatis only going to happen when there's quite a bit more wind/solar powerplants and a bit more storage/biogas backups going)

So, which of those run your car/transport?

I try to use my car as little as possible...but yeah: it still runs on gas. When Tesla starts selling that Model 3 that may well change. The specs on that one look mighty nice.
ryggesogn2
2 / 5 (4) Sep 11, 2015
Do the mining and refining companies that make the materials for the Tesla use diesel fuel and/or other fossil fuels?
antialias_physorg
4.5 / 5 (8) Sep 11, 2015
Do the mining and refining companies that make the materials for the Tesla use diesel fuel and/or other fossil fuels?

Are you mental? What are you trying to argue here? That if a 100% conversion to renewables immediately at this moment is not possible then we shouldn't do it at all?

How stupid do you have to be to consider that is even some kind of argument?
Zzzzzzzz
3.5 / 5 (8) Sep 11, 2015
The more correct term is psychotic, rather than mental. Deniers desperately need to defend their fragile delusions. Stupidity is rarely a factor - the capacity for self delusion comes from a psychosis, which is usually a state independent of the intellectual capacity of the subject. Suprisingly, the clinically recognized psychosis are more common as intellect increases.
There have been studies that have revealed that the capacity for self delusion has held, or perhaps sill holds a survival benefit in humans. So, the most common human psychosis are not clinically recognized.
dogbert
2.3 / 5 (6) Sep 12, 2015
Zzzzzzzz,
The more correct term is psychotic, rather than mental. Deniers desperately need to defend their fragile delusions.


A tactic used by the left ad nauseam is attacking personalities rather than discussing the issues.

Barf.
denglish
2.3 / 5 (6) Sep 12, 2015
But all evidence points to the fact that if we don't get our act together and make some changes that we'll all be paying for it dearly in the future

Evidence points closer to the earth experiencing normal change.

Wind? Solar? Biogas (to a degree)? Hydro?

We all want a cleaner Earth. Unfortunately, the cleaner energy alternatives cannot support the Status Quo. Thus, we must do what we're doing until the day clean energy can carry us.

antigoracle
2.1 / 5 (7) Sep 12, 2015
Deniers desperately need to defend their fragile delusions. Stupidity is rarely a factor..

Uh huh, we all know the delusions of you Chicken Littles are quite robust. After all, how could you berate others on the evils of fossil fuels and continue to burn it yourself....oh..wait..that only requires hypocrisy.
With you Chicken Littles, stupidity is not only a factor, but an absolute necessity. How else could you be duped by High Priest of the Cult, Al. Who burns 24 times the power of the average home, hobnobs the globe in private jets, rides gas guzzling SUVs and limos and, buys a beachfront mansion with his ill gotten millions when cult dogma claims the sea will gobble it up.
Fastfish
3 / 5 (2) Sep 13, 2015
Wow. I can find one possible negative 'unanticipated' side-effect and thus his conclusion is that "we do not recommend it". There is a large percentage of climate scientists that absolutely and categorically discount any human engineered solution to rising CO2 levels. They will find any opportunity to discredit any effort employing CO2 removal technology as a solution and stick only to elimination of CO2 emissions as the only-only solution - dogma. And discredit at all opportunity those that try:haidasalmonrestoration

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