  We consider global catastrophic risks due to cosmic explosions (supernovae,
magnetars and gamma-ray bursts) and possible mitigation strategies by humans
and other hypothetical intelligent beings. While by their very nature these
events are so huge to daunt conventional thinking on mitigation and response,
we wish to argue that advanced technological civilizations would be able to
develop efficient responses in the domain of astroengineering within their home
planetary systems. In particular, we suggest that construction of shielding
swarms of small objects/particles confined by electromagnetic fields could be
one way of mitigating the risk of cosmic explosions and corresponding ionizing
radiation surges. Such feats of astroengineering could, in principle, be
detectable from afar by advanced Dysonian SETI searches.
