Engineering the climate is clearly a risky business. Some geoengineering methods such as, putting reflective particles in the stratosphere or ‘mirrors’ outside the atmosphere, aim to reduce the incoming solar radiation to cool the planet. These methods will reduce the warming but temperature changes are not the only aspect which drives climate change (Hegerl and Solomon, 2009). For example, the 1991 eruption of Mount Pinatubo led to increases in the incidences of drought (Hegerl and Solomon, 2009). Volcanic eruptions can cause a decrease in rainfall because with less incoming shortwave radiation, the surface is cooler, and therefore there is less energy for evaporation (Hegerl and Solomon, 2009). Therefore methods which use temperature as the sole proxy for its effects are inappropriate and produce too many risks (Hegerl and Solomon, 2009).
The previous blog posts have shown some promising ideas, however all of them have risks attached. I think afforestation and a combination of CCS and enhanced carbonation of rocks should be seriously considered as methods to start mitigating climate change. Some of the issues with these are economic. For example, the cost of installing CCS will be expensive and realistically may not be implemented in developing countries. There are also the political implications of geoengineering methods. For example, the storage of the carbon would occur in particular countries which could cause an over reliance on other countries. For the geoengineering solutions to be implemented in the first place there would need to be a solid international community agreement which is unlikely to happen. Another issue is the spatial capacity to implement geoengineering solutions. For example, afforestation requires space in fertile areas which are mostly required for agriculture.
None of these options are likely to work in the long term. The only solution to mitigate global warming is to reduce our CO2 emissions. For this to succeed local governments need to work with national governments on small scale plans which will produce small changes but right across a country over time. Otherwise geoengineering may be focusing on how to keep humanity alive rather than how to mitigate climate change. Vincent Callebaut has been generating plans for future living. The example shown below shows the Lilypad. It is a self-sufficient floating island and would be able to house 50,000 residents. The increased flooding caused by global warming would make these structures ideal but they would also be exclusively for the very rich.
Hegerl, G. C., S. Solomon (2009) 'Risks of Climate Engineering' Science, 325, pp.955-956
DOI: 10.1126/science.1178530