Solar flares/CME dangers to life? I know a repeat of the 1859 Carrington Event (coronal mass ejection) would pose a severe risk to power grids and telecommunication networks but wouldn't pose an immediate threat to life.
If a large solar flare can release 10e32 ergs of energy, is there an energy level where a solar flare or CME would pose an immediate threat to any life on the Earth that doesn't live below sea level.
Abrevaya et al. (2020) in &quot;The UV surface habitability of Proxima b: first experiments revealing probable life survival to stellar flares&quot; (abstract, PDF) say:
&quot;Our results show the impact that a typical flare and a superflare would have on life: when microorganisms receive very high fluences of UVC, such as those expected to reach the surface of Proxima b after a typical flare or a superflare, a fraction of the population is able to survive. Our study suggests that life could cope with highly UV irradiated environments in exoplanets under conditions that cannot be found on Earth. &quot;
That suggests that total-extinction conditions aren't found on Earth, either.  The paper has a lot more detail of their assumptions and modeling, but that's my quick takeaway from the abstract.