We could also add a-risks: that human civilisation will destroy alien life and alien civilizations. For example, LHC-false vacuum-catastrophe or UFAI could dangerously affect all visible universe and kill an unknown number of the alien civilisations or prevent their existence.
Preventing risks to alien life is one of the main efforts in the sterilisation of Mars rovers and sinking of Galileo and Cassini in Jupiter and Saturn after the end of their missions.
The flip side of this idea is "cosmic rescue missions" (term coined by David Pearce), which refers to the hypothetical scenario in which human civilization help to reduce the suffering of sentient extraterrestrials (in the original context, it referred to the use of technology to abolish suffering). Of course, this is more relevant for simple animal-like aliens and less so for advanced civilizations, which would presumably have already either implemented a similar technology or decided to reject such technology. Brian Tomasik argues that cosmic r... (read more)