Plant Talk: Seeding the Future – by Octavia

“Give me half a tank of iron, and I’ll give you an ice age.” So said John Martin, the former director of the Moss Landing Marine Laboratory, in a famous off-the-cuff remark.

Whether or not this is an exaggeration, we live in a science fiction age. Our species – just by going about our daily lives, with no intent to do anything else – is capable of drastically altering our world in a sort of unintended terraforming programme. Some people find the thought of this upsetting, especially when we begin to talk about doing it deliberately. It is one thing to knock an entire ecosystem off-balance accidentally, but quite another to risk it in cold blood. It is one thing for the Industrial Revolution to trigger climate change, but quite another to try and deliberately reverse-engineer it in a global marine bio-geo-engineering scheme. It really is like something out of science fiction, and we all know what happens there when humanity gets too big for its boots.

But we shouldn’t let squeamishness blind us to the truth. Bloating the atmosphere with CO2 may have started off as an accidental result of industrialisation, but today we no longer have the excuse of ignorance. We damn well know what we’re doing when we drive the car to work instead of taking the bus, when we don’t bother to use our green supermarket bags. As a deeply interconnected society, we are already engaged upon a deliberate bio-geo-engineering programme. We were just dumb enough to pick the wrong one.

It’s hard for people to actually care that we’ve done so, to realise the effect our species is having on the climate – difficult because it doesn’t seem as if we are individually responsible. It’s the “Why should I if you won’t?” effect. Given human nature, it’s unrealistic to expect that people are going to deny themselves the right to take part in this global tragedy of the commons – except here we’re not destroying the village green by all grazing our individuals cows on it. We’re altering the climate so that we can live our individual lives to the extent that we see fit as individuals, rather than as a community holding our environment in trust for future use.

This attitude is going to lead – is already leading – to trouble in the Pacific region: migration due to ocean level rise in the islands and along the coast of South-East Asia, higher transport costs, water shortages in Australia, and food shortages as agricultural patterns change due to changes in climate. All these things will lead to conflict between communities that will further exacerbate the environmental problems. Many of the Pacific communities will be hardest hit by any climate change. Thus the responsibility and the incentive to lead the research on the application and – crucially – dissemination of technology that mitigates the causes and effects of climate change falls on us. An example of this is seeding iron through the world’s oceans – especially the Pacific – to sequester atmospheric CO2. Looking to strategies such as this is not a “quick fix”, nor is it indulging in science fiction fantasies. It is acknowledging that the will-power necessary to retrench standards of living in response to global climate change may be insufficient, and adjusting our responses accordingly.

There has been a 6% annual decline in Pacific plankton over the past 20 years (Gregg et al. 2003). Warmer oceans stratify more easily, and the reduced mixing that comes from increased surface temperature reduces the available nutrients needed for planktonic productivity to increase. There has also been a 25% fall in oceanic iron levels, resulting from a decrease in the amount of atmospheric iron deposited in the ocean by dust clouds – itself a result of anthropogenic changes in land use (Bettwy 2007). The inherent difficulty in effectively seeding social change ensures that we may not do enough to significantly cool the warming oceanic surface temperatures by limiting our output of CO2… but increasing the availability of iron in prime planktonic breeding grounds like the central Pacific Ocean may be something we can help.

We know that past changes in dust deposition have affected atmospheric carbon. Levels in atmospheric CO2 fluctuate strongly between glacial (CO2 decreases) and interglacial (CO2 increases) periods. Admittedly, the roughly 100ppm change in atmospheric CO2 found in Antarctic ice core samples from the last 420,000 years is not all explained by changes in dust deposition. In fact, decreased deposition accounted for a maximum increase of only 20ppm during the last glacial-interglacial transition period (Röthlisberger et al. 2004). Even if we assume that this remains constant in today’s environment, it is still a 20% increase – not the majority, but not to be sneezed at either. So should we be concentrating more strongly on mitigating this portion of the CO2 budget now, or do we wait until the effects of climate change become more apparent?

The earliest laboratory experiments indicate that seeding the entire Southern Ocean might counter-act up to 25% of the global carbon emissions each year, and that every ton of iron could remove anywhere from 30,000 to 110,000 tons of CO2 from the air (FOI). Recent experiments are much more conservative – a 2004 research expedition in the Southern Ocean found that seeding 1.26 tonnes of iron sequestered about 900 tons of CO2 (Buesseler et al. 2004). A 2007 study on the naturally-occurring blooms about the Kerguelen plateau proved to be ten times more efficient at sequestration than induced blooms (Blain et al. 2007). This suggests that iron availability may not be the only limiting factor, and that other contributing nutrients – such as silicon – may be needed to increase the efficiency of seeded blooms.

There are downsides even past the sequestration efficiencies. The possibility of seeding toxic algal blooms is distinctly unattractive, especially when they may gut the fishing industry that so many Pacific Islands depend upon. There may be ecological outcomes that we just can’t see right now, and ethical considerations in continuing our habit of bio-geo-engineering without enough thought for the consequences. The perception of over-reliance on technology at the expense of common sense solutions such as consuming less and consuming smarter also seems counter-intuitive – especially when we forget about the tragedy of the commons.

But it’s foolish to rely on any one solution, and to ignore alternative options because there might be reasons against them. Combating climate change – both globally and in the Pacific – is going to need a hybrid effort: changes in consumption habits linked with cleaner and more restorative technologies. We live in a world where the science fiction, think-big solution is a way of life. John Martin could see this. It’s time for us to do the same.

The Pacific marine and geological research communities have an extraordinary opportunity to continue to work, right on their doorstep, on the flaws in the seeded sequestration process. Longer observations, larger scales, deeper measurements, and different types of iron additions (multiple versus singular, and with other added nutrients) are desperately needed. Conflicting results – some giving much more efficient sequestrations than others – are a fact, so further research from the Pacific community on the climatic and ecological effects of seeding the Pacific Ocean with iron is absolutely crucial.
Bettwy, M., 2007. Ocean Plant Life Slows Down. 1 May 2008. vision/earth/environment/ocean_plants_21.html

Blain, S., Quéguiner, B., Armand, L., Belviso, S., Bombled, B., Bopp, L., Bowie, A., Brunet, C., Brussaard, C., Carlotti, F., Christaki, U., Corbière, A., Durand, I., Ebersbach, F., Fuda, J-L., Garcia, N., Gerringa, L., Griffiths, B., Guigue, C., Guillerm, C., Jacquet, S., Jeandel, C., Laan, P., Lefèvre, D., Lo Monaco, C., Malits, A., Mosseri1, J., Obernosterer, I., Park, Y-H., Picheral, M., Pondaven, P., Remenyi, T., Sandroni, V., Sarthou, G., Savoye, N., Scouarnec, L., Souhaut, M., Thuiller, D., Timmermans, K., Trull, T., Uitz, J., van Beek, P., Veldhuis, M., Vincent, D., Viollier, E., Vong, L., and Wagener, T., 2007. Effect of natural iron fertilization on carbon sequestration in the Southern Ocean. Nature. 446: 1070-1074. doi:10.1038/nature05700

Buesseler, K.O., Andrews, J.E., Pike, S.M., and Charette, M.A., 2004. The effects of iron fertilization on carbon sequestration in the southern ocean. Science. 304.5669: 414-417.

Fertilising the Ocean with Iron. Oceanus. Woods Hole Oceanographic Institution. 1 May 2008.

Gregg, W.W., Conkwright, M.E., Ginoux, P., O’Reilley, J.E., and Casey, N.W., 2003. Ocean primary productivity and climate: global decadal changes. Geophysical Research Letters. 30.15: 1809, doi:10.1029/2003GL016889.

Ocean Iron Fertilization – Why Dump Iron into the Ocean. Café Thorium. Woods Hole Oceanographic Institution. 1 May 2008. MCG/cafethorium/website/projects/iron.html

Röthlisberger, R., Bigler, M., Wolff, E.W., Joos, F., Monnin, E. and Hutterli, M.A., 2004. Ice core evidence for the extent of past atmospheric CO2 change due to iron fertilisation. Geophysical Research Letters. 31: L16207, doi:10.1029/ 2004GL020338.


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