Solar geoengineering to cool the earth? Human intervention on climate can cause life-threatening consequences

Solar geoengineering, i.e. the use of techniques for partially shading sun rays, is one of the suggested options to offset the effects of human-induced climate change. But what could happen if country leaders decided to employ geoengineering? A research group set out to study for the first time the conceivable repercussions of climate engineering through an experiment that considered the behaviours of the stakeholders and the key-factors at play.

The results of this study - published on the journal PNAS - reveal scenarios that, at times, defeat some of the most hopeful expectations. In using this technology, the human factor could indeed bring to a reduction of social well-being and an increase of imbalances at the international level. "The use of solar geoengineering and its consequences are uncharted territory" explains Marco Casari, one of the authors of the study and professor at the University of Bologna. "Our experiment sheds some light on some of the possible repercussions linked to such choices". 

By putting an end to the greenhouse effect and even lowering the average temperatures on the planet, solar geoengineering could control some of the effects of climate change. The issue, however, is about the right temperature. Some countries in various parts of the world might be interested in keeping different average temperatures, and this could have dangerous consequences.

The experiment shows how making climate engineering available to single nations could lead to significant imbalances. Nations that are severely hit by climate change could decide to use solar geoengineering to lower the temperatures beyond ideal values. This would lead to an excessive cooling down of the planet, which, in turn, would damage countries somewhere else in the world. According to researchers, all this would then encourage opposite reactions, eventually triggering a "geoengineering war" between nations with conflicting interests.

Therefore, instead of suggesting a common solution to a global issue, the unilateral application of climate engineering could reduce social well-being and worsen inequalities on a global scale. "What we do with this experiments is very similar to what happens in aeronautical engineering when prototypes are tested in the wind tunnel to reveal possible design flaws and shortcomings. The experimental method in social sciences allows to highlight the weaknesses of new policies, rules or institutions", says professor Casari. "The results we obtained provide us with crucial guidelines to manage international negotiations on these topics". More generally, these results show how the human factor with its rational and irrational sides represents a critical element that must be considered while managing political decisions in the field of climate change.

The title of the study is “Solar geoengineering may lead to excessive cooling and high strategic uncertainty” and was published on the journal PNAS. Professor Marco Cesari from the Department of Economics participated in this research on behalf of the University of Bologna. Among the participants we can also find researchers at the RFF-CMCC European Institute of Economics and the Environment, the Foundation "Centro Euro-Mediterraneo sui Cambiamenti Climatici", Bocconi University, Milan-Bicocca University and the Polytechnic University of Milan.