Thursday, 8 October 2009

Climate change Thursday #10

There was a frankly disturbing article in The Observer by Robin McKie last weekend on the increasing evidence of rapid ocean acidification.

This ocean ecosystem devastating process is another consequence of anthropogenic carbon dioxide intensification alongside climate change. In fact, climate change and ocean acidification interact with one another creating the type of feedback loop that is so unpredictable and unhelpful in terms of its environmental consequences. Cold water absorbs carbon dioxide at a faster rate than warm water.

This means that cold waters- such as the Arctic Ocean- acidify quicker (Co2 dissolves in water to produce Carbonic Acid) but as waters warm up they will leave more Co2 in the atmosphere hastening global warming. The oceans have absorbed half the Co2 we have produced since the industrial revolution. According to the research quoted in The Observer piece, they are now only absorbing 25 per cent of it- 6 million tonnes per day.

According to a report by the Royal Society published in 2005, the issue is not just the increasing acidification of the world's oceans- 100 per cent of the Arctic Ocean is forecast to be corrosively acidic by 2100. But it is the rapid nature of change also. To quote Ocean acidification due to increasing atmospheric carbon dioxide:
As CO2 continues to enter the atmosphere from human activity, a proportion will be taken up by the oceans. If CO2 emissions are not regulated, this could result in the pH decreasing by 0.5 units by the year 2100. This is beyond the range of current natural variability and probably to a level not experienced for at least hundreds of thousands of years and possibly much longer. Critically, the rate of change is also probably at least 100 times higher than the maximum rate during this time period. These changes are so rapid that they will significantly reduce the buffering capacity of the natural processes that have moderated changes in ocean chemistry over most of geological time.
Like global warming, the issue is not just volumes but the rapidity of change and the inability of ecosystems to adapt to rapid change.

What is the impact of this acidification? Well, whole ecosystems could collapse- organisms who rely on calcified shells, mussels etc, could be threatened as could fish that feed on them. Coral reefs could simply dissolve. For humans the economic cost could be considerable, the natural cost immense (e.g. coral reefs protect coastlines from erosion), and the whole thing is mightily unpredictable.

What's more, the ocean that has been shielding us from from much of the negative impact of increasing CO2 levels in the atmosphere will not be able to cope with the continued intensification. The Royal Society report details that photosynthesising plankton only increase their CO2 absorption by 10 per cent with each doubling of atmospheric CO2. Again, over to the Royal Society:
In almost all of the phytoplankton species examined to date, it has been found that doubling the present atmospheric CO2 concentration has only a small direct effect, 10% or less, on the rate of photosynthesis.
Finally, almost no mitigation technique (bunging limescale in the oceans for example) will work other than on a local scale. Only one thing will work: reducing the amount of anthropogenic CO2 in the atmosphere. There are no easy routes out of this one.

Which brings us nicely onto the EON's decision to postpone the construction of a new coal-fired power station at Kingsnorth. I am extremely agnostic about carbon capture and sequestration (CCS). Pragmatically, it may well be essential but it almost seems too good to be true and so probably is. Even if the UK does not adopt the technology, other nations will build coal-fired power stations and so globally technological progress may be necessary. The UK, with government leadership, has the opportunity to be at the forefront of that.

EON's decision is an economic one. The government's insistence that any new coal-fired power stations should be carbon capture and sequestration ready has altered the economics and certainty of any new investment. The company clearly wishes to pause for breath while it considers these issues more thoroughly.

From the UK's perspective, it would be possible to rapidly increase the deployment of renewable energy generation. Indeed, it is necessary to do so. However, the pragmatist in me suggests that globally CCS may be a necessary technology. So why not make the innovation here for export? It would be a major aspect of a UK comparative advantage in the provision of low and zero carbon energy generation.

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