We Know Not What We Do

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Responses to the concern that there is too much carbon dioxide in the atmosphere tend to fall into one of two categories.  

There are those, like Al Gore, who advocate we consume less and then there are those, like Tim Flannery, who suggest geoengineering solutions. 

Geoengineering is the deliberate deployment of large scale changes to the earth system in the hope of counteracting the worst effects of anthropogenic greenhouse gas emission.   

Along these lines Dr Flannery has suggested that sulfur be dispersed by jet fuel to create an artificial sulfate aerosol layer in the lower stratosphere that would reflect solar radiation.

While this proposal has not yet been tried, Victor Smetacek of Germany’s Alfred Wegener Institute had the opportunity to dump six tonnes of dissolved iron into the Southern Ocean earlier this year.

There were concerns that the plan would have all sorts of perverse outcomes.  

A spokesperson for environmental group WWF claimed the proposal violated international agreements on marine protection because the algae growth from the iron pollution would result in eutrophication, sapping the oxygen out of the ocean and eliminating other sea life.  

Some no doubt had images of Blue whales turning belly-up from such a misguided intervention.

Anyway, despite protests, the German government gave the green light and as expected, the iron stimulated growth of algae, in particular phytoplankton.

The short-lived phytoplankton was expected to drop to the bottom of the ocean and become a form of sequestered carbon.

But instead the phytoplankton was eaten by krill which in turn was probably eaten by Blue whales.   So instead of ending up dead, the Blue whales have likely benefits from the iron ‘pollution’.

There is so much we don’t understand about ocean ecosystems and also climate.

Recent findings published in the journal ‘Global Biogeochemical Cycles’ suggest a 50 percent decrease in the amount of carbon dioxide absorbed by the North Atlantic Ocean over the last ten years.  

It’s not krill or global warming that is considered at fault here, but rather changes in the North Atlantic Oscillation; which also controls the strength and direction of storms in this region.

Given all the unknowns it is hard to understand why the federal government is pressing ahead with its emissions trading scheme – another intervention likely to have unforeseen consequences. 

But they are unlikely to be as benign as the dumping of six tonnes of iron in the Southern Ocean.

Published in The Land

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