Geoengineering climate Change: Treating the symptom over the cause?
The present article by Crutzen (2006) on the use of albedo enhancement to address the problem of greenhouse warming is bound to evoke diverse reactions among the community. It is important to note that Crutzen argues that this idea be studied in depth and openly before any large scale action is taken. A basic assumption to this approach is that we, humans, understand the Earth system sufficiently to modify it and ‘know’ how the system will respond. Cicerone in his article argues that open discussion of these ideas is an appropriate means to explore engineering solutions to climate change, and further proposes a protocol to prevent inadvertent abuse of geoengineering experiments. These papers evoke both scientific and ethical issues that should stimulate discussions on the engineering of Earth’s climate system. We have already ‘chosen’ to geoengineer our climate system through our use of fossil fuels, where the engineering of the climate system is an inadvertent by product of our values around forms of consumption. Proposals to consciously alter the climate system to treat the symptom of our behaviors imply we understand all of the complexities of Earth as a system. At times Earth performs a stratospheric albedo enhancement experiment through the eruption of volcanoes. As pointed out by Crutzen, the Earth does cool due to this experiment, but this experiment also provides ample evidence of the non-local and non-linear response of Earth’s climate system, e.g. winter NH warming. This example exhibits how Earth’s climate system is far more complex than a simple energy balance picture. For this reason, I support Crutzen’s argument that more detailed and comprehensive modelling studies be carried out with regards to experiments. But my concern is that all models have their limitations (e.g. note the inability of models to predict the appearance of the Antarctic ozone hole before it was observed). When will we know a model is ‘good enough’ to go out and perform a real experiment?