29 December 2009: Geoengineering – plan A+

In the words of Nobel-prize winning chemist Paul Crutzen, we live in a new geological era – the anthropocene. He chose this name because, since the industrial revolution, the human influence on climate has been so great that we are already engineering the climate, albeit not deliberately.

Geoengineering is the term given to proposals to try to control the climate through technologies. Some of these proposals are new and bizarre, and unlikely to happen, or to work if they did – giant mirrors in space fall into this category. Some are new ways of applying old approaches – such as producing and then burying charcoal. And some are new but likely to work – such as biomass with CCS.

Some environmentalists say that all ‘technological fixes’ should be rejected – that what is needed is behavioural, political and economic transformation. Whatever your view of this argument, it must now be accepted that the need to control climate change is so great and so urgent that all methods must be used, including technological solutions to ‘engineer the climate’. This does not mean that there is no need, or less need, to reduce emissions fast. It means accepting that, even if we were to reduce emissions massively tomorrow (which we will not), there is still a need to reduce the amount of CO2 already in the atmosphere from historic emissions.

The UK’s Royal Society, the leading scientific body, published a comprehensive report on this in September 2009 (see The Royal Society: Geoengineering the climate: science, governance and uncertainty). This excellent report is summarised in the accompanying article in the technology section of Climate Answers (see Geoengineering). The Royal Society divides geoengineering into two categories: CO2 removal techniques and solar radiation management techniques. The former:

… address the root cause of climate change, rising CO2 concentrations, [so] they have relatively low uncertainties and risks. However, these techniques work slowly to reduce global temperatures.

The latter:

… act quickly, and so may represent the only way to lower global temperatures quickly in the event of a climate crisis. However, they only reduce some, but not all, effects of climate change, while possibly creating other problems. They also do not affect CO2 levels and therefore fail to address the wider effects of rising CO2, including ocean acidification.

Therefore, the Royal Society favours CO2 removal techniques. However:

… should temperatures rise to such a level where more rapid action needs to be taken, solar radiation management techniques should also be used.

Not surprisingly, the scientists argue for more (publicly-funded) research into several aspects of geoengineering. However, in this instance, the demand for more research is not just self-interest. They make a compelling case.

Proposals to reduce the CO2 in the atmosphere by burning biomass (for electricity generation) and then capturing and storing the carbon dioxide should certainly be supported. So should proposals to convert biomass into charcoal (though the Royal Society is more sceptical about the role of this ‘biochar’). However, not all proposals given the label ‘geoengineering’ should be supported or publicly funded. Space mirrors are not a good use of money. Ocean fertilisation to create more algal blooms has too great a risk of unexpected and undesirable side effects.

Anyone interested in geoengineering, but without time to read the Royal Society report, could instead read the excellent article on this in Prospect Magazine (see Prospect: Fixing the climate), written by the Energy and Environment Editor of the Economist, Oliver Morton. As Morton says:

Geoengineering is not an alternative, but it can be an addition.

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