Chapter 10: Impact of Geo-engineering on Stratospheric Ozone and Climate

The distribution of stratospheric ozone in the early 21^st century is strongly influenced by large-scale anthropogenic emissions of chlorofluorocarbons that occurred in the last half of the 20^th century. Further, continuously increasing greenhouse gases have a significant impact on the composition of the atmosphere and the ozone layer, as discussed in earlier chapters. For the future, there might be another important factor influencing ozone and climate, the potential deployment of “geo-engineering” or “climate engineering” schemes, understood as “the deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change”. This chapter introduces some basic concepts of geo-engineering, and further focuses on the impact of one of the most discussed geo-engineering schemes, the injection of particles into the stratosphere to counteract global warming by increasing the Earth's albedo. This approach is analogous to large-scale volcanic eruptions, which have been shown to produce transient cooling of the Earth's surface. To date, only limited studies, based on more or less simplified models, have been performed to quantify the effectiveness and also the side-effects and uncertainties of this type of geo-engineering, including its significant impact on the ozone layer.