抄録
With actions to reduce greenhouse gas emissions slow, an increasing number of scientists are calling for research into climate geoengineering, in light of heightened recognition of the risks of dangerous climate change. Previous studies have shown that the probability of the atmospheric temperature rise exceeding 2 degrees Celsius is fairly large even for scenarios with enormous mitigation efforts. Using a well-known integrated assessment model, the Dynamic Integrated model of Climate Economy, we show that solar radiation management (SRM) such as stratospheric aerosol injection has a potential to drastically reduce such probability of exceeding 2 degrees Celsius in an ideal case. We also consider the case in which SRM itself might introduce negative side effects. The result shows that the optimal amount of stratospheric aerosol injection is non-zero and can improve overall output even if the side effects of geoengineering are assumed to be much larger than CO2-driven damage. Our analysis demonstrates large economic benefits of geoengineering, although its research and deployment require serious considerations of ethical, social, and environmental aspects of this technology.
