Thursday, 18 February 2010

Front Page Pipes

Courtesy of hard work on the part of my old boss, another paper on ocean pipes has now been published, and its made our institute's front page. My contribution this time extended largely to comments and some discussion, rather than simulation and number-crunching.

I've alluded to this paper before, largely because its results are much more interesting than those that I found. In part, this stems from the use of a more detailed physical model that includes a simplified atmosphere which allows feedbacks that my ocean-only simulation just had to gloss over. The model (UVic for those who care) is also lower resolution than OCCAM, so longer simulations were possible.

Anyway, what happened? In the ocean, the pipes were still largely inefficient at sequestering carbon, although here they were allowed to cleverly alter their lengths here to maximise their use of so-called preformed nutrients (i.e. those that come with no associated carbon). Interestingly, the pipes did slightly counter the slowdown of the THC caused by global warming in the simulation (although in doing so they also brought up more CO2-rich seawater).

However, the real action was on the land. Here, cooler temperatures, driven by the cooling effect of the ocean pipes, led to a drop in the respiration of the land biota (TRIFFID for those who care). In fact, the changes on land were responsible for about 80% of the total sequestration of carbon in the simulation. Not what the proposers of ocean pipes had in mind, and not something that'd be easily verified in the real world to gain carbon credits.

Another interesting result was that switching off the ocean pipes leads to a (slightly) warmer Earth than would happen in the no-pipes control Earth. So, if the pipes are running but start to have some unforeseen negative effect, turning them off comes with an additional climate change penalty. Essentially, you'd have been better off not using them at all. Again, not what the proposers of ocean pipes had in mind.

While there are still some questions that the ocean pipes throw up, this seems another knock to them. Still, the geoengineers are rarely put off by such hurdles ...

P.S. The press release associated with this paper has been cut-and-pasted into (at least) three external blogs (here, here and here). This seems a pretty armchair approach to adding content to your web presence. Perhaps Strange News could bump up its posting-rate this way ...

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