Plan to Slow Global Warming By Dumping Iron Sulphate into Oceans

ananyo writes "In the search for methods of geoengineering to limit global warming, it seems that stimulating the growth of algae in the oceans might be an efficient way of removing excess carbon dioxide from the atmosphere after all. Despite attracting controversy and a UN moratorium, as well as previous studies suggesting that this approach was ineffective, a recent analysis of an ocean-fertilization experiment eight years ago in the Southern Ocean indicates that encouraging algal blooms to grow can soak up carbon that is then deposited in the deep ocean as the algae die. Each atom of added iron pulled at least 13,000 atoms of carbon out of the atmosphere by encouraging algal growth which, through photosynthesis, captures carbon. The team reports that much of the captured carbon was transported to the deep ocean, where it will remain sequestered for centuries — a 'carbon sink' (abstract)."

Comments

Ending badly?

[eisonlyme]

I always worry about these ideas, they seem good in theory, but in reality you can just end up with a cane toad problem..i.e. when the algae has covered all the oceans we have no pollution...but also no fish....
anywho...maybe we can just set fire to the algae if it gets out of control...

Re:Ending badly?

[aXis100]

It's not a new thing - iron dust has been blowing into the oceans for millenia.

Recent urban development around our coastlines have significantly reduced this natural nutrient source, so projects like this are really just restoring balance.

Re:Ending badly?

[Black Parrot]

I always worry about these ideas, they seem good in theory, but in reality you can just end up with a cane toad problem..i.e. when the algae has covered all the oceans we have no pollution...but also no fish....

anywho...maybe we can just set fire to the algae if it gets out of control...

The underlying problem is, people are willing to consider anything - except addressing the cause of the problem.

Re:Ending badly?

[Anonymous Coward]

The basic problem I can see is that the ocean is a complex set of currents that moves nutrients around. Dumping a compound into the ocean at one point to encourage algae blooms may sequester carbon in that location but it also locks up other nutrients as well that would have normally travelled to another part of the ocean. Now maybe such an action will disturb the proliferation of jellyfish somewhere but it's more likely that the missing nutrients will simply impede the growth of algae in another location where, instead of simply dying and sequestering carbon at the bottom of the ocean (from which it will eventually bubble up as methane at some future time) the algae would have provided the base of some local food chain. SO, in short, we lock up both carbon and nutrients in some normally unused part of the ocean while starving another part of the ocean for nutrients.

Yeah, terraforming is an interesting science but it's a risky one when you only have one test case and every bit of life you know of in the universe lives in that single test case.

But, I did see reports of the earlier test case and the motivation behind it. It wasn't really all about saving the planet as much as it was about creating a measurable amount of carbon credits that had a solid monetary value. That was the real motive, creating a way to manufacture carbon credits for sale. The test was done to see if they could find the ratio of carbon sequestered per ton of iron compound dumped into the ocean. That way they could dump a known amount of iron in the ocean and then sell a calculated amount of carbon credits on the carbon credit exchange.

Re:Ending badly?

[saxoholic]

These ideas always sicken me, we will be paying corporations out of our tax dollars for the air we breathe, hmm, that's going to work out well, 'NOT'.

Quick! Someone trademark the brand name Perri-Air

Re:Ending badly?

[Anonymous Coward]

And the side effects are not all bad: it should increase the amount of fish that can be sustainably harvested.

The 2 side effects mentioned in the article both kill fish. Toxic algal blooms poison fish, either causing them to grow abnormally or death. Depleted oxygen levels does the same thing to the fish as it does to you, suffocation.

Far-fetched

[LordLucless]

Seems no more far-fetched than the current plan, which is assuming world leaders of developed and developing nations can all agree to limit the economic function and development of their respective countries, and not fall into a prisoner's dilemma.

The Risks of Iron Fertilization

[catchblue22]

I took a course on oceanography a few years ago, and we actually studied this. I'll summarize my professor's powerpoint notes as best I can.

Iron is a limiting nutrient in phytoplankton growth. This is not in dispute. However if we are to add iron to the ocean in order to increase phytoplankton counts, and thus to increase CO2 uptake then we must consider several things. Firstly, how much CO2 will be semi-permanently transported to the ocean floor. In terms of percentages, if increased phytoplankton counts caused a CO2 flux in the surface layer of 50 Gt Carbon / year, the corresponding CO2 flux to the ocean floor would be about 0.7 Gt Carbon / year. This is due to the fact that the mechanisms of carbon transport from the surface to the sea floor (the "biological pump") is quite inefficient. Thus the increase in phytoplankton at the surface would have to be HUGE to transport meaningful amounts of CO2 to the sea floor.

Secondly, there may be dire unintended or undesired consequences of increasing the surface phytoplankton counts. Imagine we put significant amounts of iron in the ocean and imagine that surface phytoplankton counts increased significantly. At the surface we could get increased CO2 uptake and O2 production. But what happens when those phytoplankton die? They sink. And when they sink to deeper layers, other organisms would decompose them. Those decomposers would be oxygen breathers and would consume oxygen at the deeper layer. If their numbers increased due to increased dead phytoplankton, the decomposers could deplete the O2 levels in that level, creating anoxic zones at deeper levels in the ocean. In addition, some of these decomposers might be methane producing bacteria, especially in the absence of oxygen. That methane might make its way into the ocean. The worry is that the imbalanced increase in phytoplankton might result in an anoxic jellyfish ocean that would be rather unfriendly to fish like salmon, tuna, and the other common species that currently exist.

Unless the above arguments have been refuted, I don't know why iron fertilization is still being pushed as a realistic option. It seems to me that many decision makers are nearly completely illiterate in science.

We're all in denial

[hessian]

Climate change is but one of the problems we face. Pollution, loss of species, erosion and depletion of natural resources are all big problems as well.

The sad fact is that all of these have a single cause: humans, or rather, too many humans.

As of right now, the average Chinese person emits as much carbon as the average European -- and there are many more Chinese people.

The rest of the developing world is going to follow this pattern. Soon we'll all be emitting high amounts of carbon, but even more, each of us will require a lot of land for our lifestyles. Not just our homes, but roads, hospitals, shopping, parking, schools, storage, government buildings, etc.

For every person we put on this earth, there's less space for the natural world and its forests and oceans which renew our air and water. Earth is finite; humans are acting like its capacity to have new humans is infinite.

We're all in denial of how simple this is. There are too many people. We're making even more. At some point, we will have used up enough land so that pollution, species loss and loss of renewable resources makes us get a Darwin award as a species.

Re:Just as sure

[Kell Bengal]

This always confuses me. Why do people seem to think that climate scientists advocate deindustrialisation? I have never heard a serious case arguing for it. And yet, many arguments against global warming measures seem to claim that that is what is being proposed. Wherefore this misconception?